diff --git a/SKILL.md b/SKILL.md
index d08410e..cc1e65e 100644
--- a/SKILL.md
+++ b/SKILL.md
@@ -31,9 +31,9 @@ This successfully provides a fully responsive, easily configurable, and containe
 
 ## 5. Form Module Structure
 - **Public Form Viewer:** Located at `app/form/page.tsx` and `app/form/client.tsx`. This is where users see and submit the form. It renders questions and handles user input with validation.
-- **Admin Form Builder:** Located at `app/form/admin/page.tsx` and `app/form/admin/client.tsx`. This interface allows administrators to create and edit questions, change form settings, and specify input types (Text, Textarea, Radio, Checkboxes).
+- **Admin Form Builder:** Located under `app/admin/form/`. This interface allows administrators to create and edit questions, change form settings, and specify input types (Text, Textarea, Radio, Checkboxes).
 - **Database Schema:** Defined in `db/schema/form.ts`, which contains definitions for `forms`, `questions`, `submissions`, and `answers`.
-- **Server Actions:** Backend logic for managing the form (such as creating/updating questions and handling submissions) are located in `app/actions/form.ts`, `app/actions/questions.ts`, and `app/actions/submissions.ts`.
+- **Server Actions:** Backend logic for managing forms and submissions is located in `app/admin/form/actions.ts`, `app/actions/questions.ts`, and `app/actions/submissions.ts`. Shared authorization lives in `lib/auth.ts`.
 
 Behavioral guidelines to reduce common LLM coding mistakes. Merge with project-specific instructions as needed.
 
@@ -97,4 +97,4 @@ Strong success criteria let you loop independently. Weak criteria ("make it work
 
 ---
 
-**These guidelines are working if:** fewer unnecessary changes in diffs, fewer rewrites due to overcomplication, and clarifying questions come before implementation rather than after mistakes.
\ No newline at end of file
+**These guidelines are working if:** fewer unnecessary changes in diffs, fewer rewrites due to overcomplication, and clarifying questions come before implementation rather than after mistakes.
diff --git a/app/actions/discord.ts b/app/actions/discord.ts
index 46d503d..05d41fa 100644
--- a/app/actions/discord.ts
+++ b/app/actions/discord.ts
@@ -1,149 +1,9 @@
 "use server";
 
-import { getServerSession } from "next-auth";
-import { authOptions } from "@/app/api/auth/[...nextauth]/route";
+import { requireAdmin } from "@/lib/auth";
+import { getGuildRolesInternal, type DiscordRole } from "@/lib/discord";
 
-export interface DiscordRole {
-  id: string;
-  name: string;
-  color: number;
-  position: number;
-}
-
-// --- In-memory caches with TTL ---
-interface CacheEntry<T> { data: T; expiresAt: number }
-const rolesCache: { entry: CacheEntry<DiscordRole[]> | null } = { entry: null };
-const profileCache = new Map<string, CacheEntry<any>>();
-const CACHE_TTL = 60_000; // 60 seconds
-
-function getCached<T>(entry: CacheEntry<T> | null | undefined): T | null {
-  if (entry && Date.now() < entry.expiresAt) return entry.data;
-  return null;
-}
-
-/** Internal: fetch guild roles without auth check (for use by other server functions). */
-async function getGuildRolesInternal(): Promise<DiscordRole[]> {
-  const cached = getCached(rolesCache.entry);
-  if (cached) return cached;
-
-  const token = process.env.DISCORD_BOT_TOKEN;
-  const guildId = process.env.DISCORD_GUILD_ID;
-  if (!token || !guildId) return [];
-
-  try {
-    const res = await fetch(`https://discord.com/api/v10/guilds/${guildId}/roles`, {
-      headers: { Authorization: `Bot ${token}` },
-      signal: AbortSignal.timeout(5000),
-    });
-    
-    if (!res.ok) return [];
-    
-    const roles: any[] = await res.json();
-    const result = roles.map(r => ({
-      id: r.id,
-      name: r.name,
-      color: r.color,
-      position: r.position,
-    })).sort((a, b) => b.position - a.position);
-
-    rolesCache.entry = { data: result, expiresAt: Date.now() + CACHE_TTL };
-    return result;
-  } catch {
-    return [];
-  }
-}
-
-/** Public: fetch guild roles with admin auth check. */
 export async function getGuildRoles(): Promise<DiscordRole[]> {
-  const session = await getServerSession(authOptions);
-  const discordId = (session?.user as any)?.discordId;
-  const admins = (process.env.ADMIN_DISCORD_IDS || "").split(",");
-  if (!discordId || !admins.includes(discordId)) {
-    throw new Error("Unauthorized");
-  }
-
+  await requireAdmin();
   return getGuildRolesInternal();
 }
-
-export async function getGuildMemberRoles(discordId: string): Promise<string[]> {
-  const token = process.env.DISCORD_BOT_TOKEN;
-  const guildId = process.env.DISCORD_GUILD_ID;
-  if (!token || !guildId || !discordId) return [];
-
-  try {
-    const res = await fetch(`https://discord.com/api/v10/guilds/${guildId}/members/${discordId}`, {
-      headers: { Authorization: `Bot ${token}` },
-      cache: "no-store", // Always fresh for access control
-      signal: AbortSignal.timeout(5000),
-    });
-    
-    if (!res.ok) return [];
-
-    const member = await res.json();
-    return member.roles || [];
-  } catch {
-    return [];
-  }
-}
-
-export async function getDiscordMemberProfile(discordId: string) {
-  const cached = getCached(profileCache.get(discordId));
-  if (cached) return cached;
-
-  const token = process.env.DISCORD_BOT_TOKEN;
-  const guildId = process.env.DISCORD_GUILD_ID;
-  if (!token || !guildId || !discordId) return null;
-
-  try {
-    const [memberRes, allRoles] = await Promise.all([
-      fetch(`https://discord.com/api/v10/guilds/${guildId}/members/${discordId}`, {
-        headers: { Authorization: `Bot ${token}` },
-        cache: "no-store",
-        signal: AbortSignal.timeout(5000),
-      }),
-      getGuildRolesInternal(),
-    ]);
-    
-    if (!memberRes.ok) return null;
-    const member = await memberRes.json();
-    
-    // Map member role IDs to actual role objects
-    const memberRoleIds = member.roles || [];
-    const roles = memberRoleIds
-      .map((id: string) => allRoles.find(r => r.id === id))
-      .filter(Boolean);
-
-    // Sort roles by position (descending)
-    roles.sort((a: any, b: any) => (b?.position || 0) - (a?.position || 0));
-
-    const user = member.user;
-    
-    let avatarUrl = null;
-    if (user.avatar) {
-      const ext = user.avatar.startsWith("a_") ? "gif" : "png";
-      avatarUrl = `https://cdn.discordapp.com/avatars/${user.id}/${user.avatar}.${ext}?size=128`;
-    }
-
-    let bannerUrl = null;
-    if (user.banner) {
-      const ext = user.banner.startsWith("a_") ? "gif" : "png";
-      bannerUrl = `https://cdn.discordapp.com/banners/${user.id}/${user.banner}.${ext}?size=512`;
-    }
-
-    const result = {
-      id: user.id,
-      username: user.username,
-      globalName: user.global_name || null,
-      avatarUrl,
-      bannerUrl,
-      accentColor: user.accent_color || null,
-      roles,
-    };
-
-    profileCache.set(discordId, { data: result, expiresAt: Date.now() + CACHE_TTL });
-    return result;
-  } catch (e) {
-    console.error("Failed to fetch member profile", e);
-    return null;
-  }
-}
diff --git a/app/actions/questions.ts b/app/actions/questions.ts
index 39e7f3f..b78e042 100644
--- a/app/actions/questions.ts
+++ b/app/actions/questions.ts
@@ -7,17 +7,8 @@ import { questions } from "@/db/schema";
 import type { QuestionType } from "@/db/schema";
 import { eq } from "drizzle-orm";
 import { revalidatePath } from "next/cache";
-import { getServerSession } from "next-auth";
-import { authOptions } from "@/app/api/auth/[...nextauth]/route";
-
-async function assertAdmin() {
-  const session = await getServerSession(authOptions);
-  const adminIds = (process.env.ADMIN_DISCORD_IDS ?? "").split(",").map((s) => s.trim()).filter(Boolean);
-  const discordId = (session?.user as { discordId?: string } | undefined)?.discordId;
-  if (!discordId || !adminIds.includes(discordId)) {
-    throw new Error("Unauthorized");
-  }
-}
+import { requireAdmin } from "@/lib/auth";
+import { sanitizeHtml } from "@/lib/sanitize-html";
 
 export async function createQuestion(
   formId: string,
@@ -29,18 +20,18 @@ export async function createQuestion(
     options?: string[];
   }
 ) {
-  await assertAdmin();
+  await requireAdmin();
   await db.insert(questions).values({
     formId,
     type: data.type,
-    label: data.label,
+    label: sanitizeHtml(data.label),
     required: data.required,
     displayOrder: data.displayOrder,
     options: data.options ?? [],
     allowOther: false,
   });
   revalidatePath("/form");
-  revalidatePath("/form/admin");
+  revalidatePath("/admin/form");
 }
 
 export async function updateQuestion(
@@ -56,7 +47,7 @@ export async function updateQuestion(
     allowOther: boolean;
   }>
 ) {
-  await assertAdmin();
+  await requireAdmin();
   if (data.imageUrl !== undefined) {
     const q = await db.query.questions.findFirst({
       where: (q, { eq }) => eq(q.id, id),
@@ -65,9 +56,14 @@ export async function updateQuestion(
       await deleteImageFile(q.imageUrl);
     }
   }
-  await db.update(questions).set(data).where(eq(questions.id, id));
+  const nextData = {
+    ...data,
+    label: data.label === undefined ? undefined : sanitizeHtml(data.label),
+  };
+
+  await db.update(questions).set(nextData).where(eq(questions.id, id));
   revalidatePath("/form");
-  revalidatePath("/form/admin");
+  revalidatePath("/admin/form");
 }
 
 export async function bulkUpdateQuestions(
@@ -82,7 +78,7 @@ export async function bulkUpdateQuestions(
     allowOther: boolean;
   }[]
 ) {
-  await assertAdmin();
+  await requireAdmin();
   
   // Use Promise.all to update all questions concurrently
   await Promise.all(
@@ -90,7 +86,7 @@ export async function bulkUpdateQuestions(
       db
         .update(questions)
         .set({
-          label: u.label,
+          label: sanitizeHtml(u.label),
           type: u.type,
           required: u.required,
           displayOrder: u.displayOrder,
@@ -102,7 +98,7 @@ export async function bulkUpdateQuestions(
   );
   
   revalidatePath("/form");
-  revalidatePath("/form/admin");
+  revalidatePath("/admin/form");
 }
 
 async function deleteImageFile(imageUrl: string | null) {
@@ -119,7 +115,7 @@ async function deleteImageFile(imageUrl: string | null) {
 }
 
 export async function deleteQuestion(id: string, formId: string) {
-  await assertAdmin();
+  await requireAdmin();
   const q = await db.query.questions.findFirst({
     where: (q, { eq }) => eq(q.id, id),
   });
@@ -128,14 +124,14 @@ export async function deleteQuestion(id: string, formId: string) {
   }
   await db.delete(questions).where(eq(questions.id, id));
   revalidatePath("/form");
-  revalidatePath("/form/admin");
+  revalidatePath(`/admin/form/${formId}`);
 }
 
 export async function reorderQuestions(
   formId: string,
   orderedIds: string[]
 ) {
-  await assertAdmin();
+  await requireAdmin();
   await Promise.all(
     orderedIds.map((id, index) =>
       db
@@ -145,5 +141,5 @@ export async function reorderQuestions(
     )
   );
   revalidatePath("/form");
-  revalidatePath("/form/admin");
+  revalidatePath(`/admin/form/${formId}`);
 }
diff --git a/app/actions/submissions.ts b/app/actions/submissions.ts
index 38846ee..44c883d 100644
--- a/app/actions/submissions.ts
+++ b/app/actions/submissions.ts
@@ -6,6 +6,7 @@ import { eq } from "drizzle-orm";
 import { revalidatePath } from "next/cache";
 import { getServerSession } from "next-auth";
 import { authOptions } from "@/app/api/auth/[...nextauth]/route";
+import { requireAdmin, requireDiscordId, requireFormAccess } from "@/lib/auth";
 
 export async function submitForm(
   formId: string,
@@ -14,85 +15,76 @@ export async function submitForm(
   const session = await getServerSession(authOptions);
   if (!session?.user) throw new Error("Not authenticated");
 
-  const discordId = (session.user as { discordId?: string }).discordId;
-  if (!discordId) throw new Error("No Discord ID found");
-
-  const form = await db.query.forms.findFirst({
-    where: (f, { eq }) => eq(f.id, formId),
-  });
-  if (!form) throw new Error("Form not found");
+  const discordId = await requireDiscordId();
+  const userName = session.user.name ?? null;
+  const form = await requireFormAccess(formId, discordId);
   if (!form.isOpen) throw new Error("This form is disabled for now");
 
-  const existingSubmission = await db.query.submissions.findFirst({
-    where: (s, { eq, and }) =>
-      and(eq(s.formId, formId), eq(s.userDiscordId, discordId)),
-  });
-
-  let submissionId = "";
-  const isUpdate = !!existingSubmission;
-  let oldAnswersDict: Record<string, string> = {};
-
-  if (existingSubmission) {
-    submissionId = existingSubmission.id;
-
-    // Fetch old answers
-    const oldAnswersList = await db.query.answers.findMany({
-      where: (a, { eq }) => eq(a.submissionId, submissionId),
+  const result = await db.transaction(async (tx) => {
+    const existingSubmission = await tx.query.submissions.findFirst({
+      where: (submission, { eq, and }) =>
+        and(eq(submission.formId, formId), eq(submission.userDiscordId, discordId)),
     });
 
-    oldAnswersDict = oldAnswersList.reduce((acc, curr) => {
-      acc[curr.questionId] = curr.value;
-      return acc;
-    }, {} as Record<string, string>);
+    let submissionId = "";
+    const isUpdate = Boolean(existingSubmission);
+    let oldAnswersDict: Record<string, string> = {};
 
-    // Ensure editHistory is an array
-    let history = existingSubmission.editHistory;
-    if (!Array.isArray(history)) {
-      history = [];
+    if (existingSubmission) {
+      submissionId = existingSubmission.id;
+
+      const oldAnswersList = await tx.query.answers.findMany({
+        where: (answer, { eq }) => eq(answer.submissionId, submissionId),
+      });
+
+      oldAnswersDict = oldAnswersList.reduce<Record<string, string>>((acc, curr) => {
+        acc[curr.questionId] = curr.value;
+        return acc;
+      }, {});
+
+      const history = Array.isArray(existingSubmission.editHistory)
+        ? [...existingSubmission.editHistory]
+        : [];
+      history.push({
+        editedAt: new Date().toISOString(),
+        oldAnswers: oldAnswersDict,
+      });
+
+      await tx
+        .update(submissions)
+        .set({ editHistory: history })
+        .where(eq(submissions.id, submissionId));
+
+      await tx.delete(answers).where(eq(answers.submissionId, submissionId));
+    } else {
+      const [inserted] = await tx
+        .insert(submissions)
+        .values({
+          formId,
+          userDiscordId: discordId,
+          userName,
+        })
+        .returning();
+      submissionId = inserted.id;
     }
 
-    // Push the old answers to history
-    history.push({
-      editedAt: new Date().toISOString(),
-      oldAnswers: oldAnswersDict,
-    });
+    if (answersList.length > 0) {
+      await tx.insert(answers).values(
+        answersList.map((answer) => ({
+          submissionId,
+          questionId: answer.questionId,
+          value: answer.value,
+        }))
+      );
+    }
 
-    // Update submission record
-    await db
-      .update(submissions)
-      .set({
-        editHistory: history,
-      })
-      .where(eq(submissions.id, submissionId));
-
-    // Delete old answers
-    await db.delete(answers).where(eq(answers.submissionId, submissionId));
-  } else {
-    // Insert new submission
-    const [inserted] = await db
-      .insert(submissions)
-      .values({
-        formId,
-        userDiscordId: discordId,
-        userName: session.user.name ?? null,
-      })
-      .returning();
-    submissionId = inserted.id;
-  }
-
-  // Insert new/updated answers
-  if (answersList.length > 0) {
-    await db.insert(answers).values(
-      answersList.map((a) => ({
-        submissionId,
-        questionId: a.questionId,
-        value: a.value,
-      }))
-    );
-  }
+    return { submissionId, isUpdate, oldAnswersDict };
+  });
 
   // Send Discord Webhook
-  const templateToUse = isUpdate ? (form as any).discordWebhookUpdateTemplate : form.discordWebhookTemplate;
+  const templateToUse = result.isUpdate
+    ? form.discordWebhookUpdateTemplate
+    : form.discordWebhookTemplate;
 
   if (form.discordWebhookUrl && templateToUse) {
     try {
@@ -114,10 +106,10 @@ export async function submitForm(
       }, {} as Record<string, string>);
 
       let updatesText = "";
-      if (isUpdate) {
+      if (result.isUpdate) {
         const changed: string[] = [];
         for (const ans of answersList) {
-          const oldVal = oldAnswersDict[ans.questionId];
+          const oldVal = result.oldAnswersDict[ans.questionId];
           if (oldVal !== ans.value) {
             const qTitle = questionsList.find(q => q.id === ans.questionId)?.label || `Question`;
             changed.push(`**${qTitle}**: \`${oldVal || "Empty"}\` ➡️ \`${ans.value || "Empty"}\``);
@@ -156,22 +148,20 @@ export async function submitForm(
     }
   }
 
-  revalidatePath("/form/admin/result");
+  revalidatePath(`/admin/form/${formId}/result`);
   return { ok: true };
 }
 
 export async function deleteSubmission(id: string) {
-  const session = await getServerSession(authOptions);
-  if (!session?.user) throw new Error("Not authenticated");
+  await requireAdmin();
 
   await db.delete(submissions).where(eq(submissions.id, id));
-  revalidatePath("/form/admin/result");
+  revalidatePath("/admin/form");
   return { ok: true };
 }
 
 export async function deleteAllSubmissions(formId: string) {
-  const session = await getServerSession(authOptions);
-  if (!session?.user) throw new Error("Not authenticated");
+  await requireAdmin();
 
   await db.delete(submissions).where(eq(submissions.formId, formId));
   revalidatePath(`/admin/form/${formId}/result`);
@@ -179,11 +169,7 @@ export async function deleteAllSubmissions(formId: string) {
 }
 
 export async function deleteOwnSubmission(formId: string) {
-  const session = await getServerSession(authOptions);
-  if (!session?.user) throw new Error("Not authenticated");
-
-  const discordId = (session.user as { discordId?: string }).discordId;
-  if (!discordId) throw new Error("No Discord ID found");
+  const discordId = await requireDiscordId();
 
   const { and } = await import("drizzle-orm");
 
@@ -194,6 +180,6 @@ export async function deleteOwnSubmission(formId: string) {
     )
   );
   revalidatePath(`/form`);
-  revalidatePath("/form/admin/result");
+  revalidatePath(`/admin/form/${formId}/result`);
   return { ok: true };
 }
diff --git a/app/admin/backend/actions.ts b/app/admin/backend/actions.ts
index d8b7284..a299127 100644
--- a/app/admin/backend/actions.ts
+++ b/app/admin/backend/actions.ts
@@ -3,6 +3,8 @@
 import { revalidateTag } from "next/cache";
 const validPlatforms = ["youtube", "roblox", "discord", "tiktok"];
 
+type FollowerFetcher = () => Promise<unknown>;
+
 export async function refetchPlatform(
   platform: string
 ): Promise<{ count: number | null }> {
@@ -15,10 +17,10 @@ export async function refetchPlatform(
   let tiktokProfile = null;
 
   try {
-    const mod = await import(`@/lib/followers/${platform}`);
+    const mod = (await import(`@/lib/followers/${platform}`)) as Record<string, unknown>;
     const fns = Object.entries(mod).filter(
-      ([, v]) => typeof v === "function"
-    ) as [string, Function][];
+      (entry): entry is [string, FollowerFetcher] => typeof entry[1] === "function"
+    );
 
     // Prefer function with "Count" or "Member" in name
     const countFn = fns.find(([name]) => /count|member/i.test(name));
@@ -33,7 +35,8 @@ export async function refetchPlatform(
       } else if (
         result &&
         typeof result === "object" &&
-        "followerCount" in result
+        "followerCount" in result &&
+        (typeof result.followerCount === "number" || result.followerCount === null)
       ) {
         count = result.followerCount;
         tiktokProfile = result;
diff --git a/app/admin/form/[id]/client.tsx b/app/admin/form/[id]/client.tsx
index cd6dbec..9e90c6a 100644
--- a/app/admin/form/[id]/client.tsx
+++ b/app/admin/form/[id]/client.tsx
@@ -39,6 +39,7 @@ import { RichTextEditor } from "@/components/rich-text-editor";
 import { FormattedText } from "@/components/formatted-text";
 import { ThemeToggle } from "@/components/theme-toggle";
 import { DropdownMenuAvatar, DiscordMemberProfile } from "@/components/dropdown-menu-avatar";
+import { getErrorMessage } from "@/lib/errors";
 
 interface Question {
   id: string;
@@ -84,10 +85,12 @@ export default function FormEditorClient({ form, initialQuestions }: FormEditorC
   const formIsOpenRef = useRef(formIsOpen);
   const questionsRef = useRef(questions);
 
-  formTitleRef.current = formTitle;
-  formDescriptionRef.current = formDescription;
-  formIsOpenRef.current = formIsOpen;
-  questionsRef.current = questions;
+  useEffect(() => {
+    formTitleRef.current = formTitle;
+    formDescriptionRef.current = formDescription;
+    formIsOpenRef.current = formIsOpen;
+    questionsRef.current = questions;
+  }, [formDescription, formIsOpen, formTitle, questions]);
 
   const autoSaveForm = useCallback(() => {
     if (formTimerRef.current) clearTimeout(formTimerRef.current);
@@ -170,7 +173,7 @@ export default function FormEditorClient({ form, initialQuestions }: FormEditorC
         options: [],
       });
       router.refresh();
-    } catch (err: any) {
+    } catch (err: unknown) {
       console.error("Failed to add question:", err);
     }
   };
@@ -186,7 +189,7 @@ export default function FormEditorClient({ form, initialQuestions }: FormEditorC
     try {
       await deleteQuestion(id, form.id);
       router.refresh();
-    } catch (err: any) {
+    } catch (err: unknown) {
       console.error("Failed to delete question:", err);
     }
   };
@@ -243,7 +246,7 @@ export default function FormEditorClient({ form, initialQuestions }: FormEditorC
       {
         loading: "Uploading image...",
         success: "Image uploaded!",
-        error: (err: any) => err.message || "Failed to upload image.",
+        error: (err: unknown) => getErrorMessage(err, "Failed to upload image."),
       }
     );
   };
@@ -259,7 +262,7 @@ export default function FormEditorClient({ form, initialQuestions }: FormEditorC
       {
         loading: "Removing image...",
         success: "Image removed.",
-        error: (err: any) => err.message || "Failed to remove image.",
+        error: (err: unknown) => getErrorMessage(err, "Failed to remove image."),
       }
     );
   };
@@ -283,8 +286,9 @@ export default function FormEditorClient({ form, initialQuestions }: FormEditorC
     handleUpdateQuestion(question.id, { options });
   };
 
-  React.useEffect(() => {
-    setQuestions(initialQuestions);
+  useEffect(() => {
+    const timeout = setTimeout(() => setQuestions(initialQuestions), 0);
+    return () => clearTimeout(timeout);
   }, [initialQuestions]);
 
   return (
@@ -360,7 +364,7 @@ export default function FormEditorClient({ form, initialQuestions }: FormEditorC
                 <div className="flex items-center gap-2 self-end sm:self-auto">
                   <Select
                     value={q.type}
-                    onValueChange={(val: any) => handleUpdateQuestion(q.id, { type: val })}
+                    onValueChange={(val) => handleUpdateQuestion(q.id, { type: val as Question["type"] })}
                   >
                     <SelectTrigger className="w-36">
                       <SelectValue />
@@ -499,7 +503,7 @@ export default function FormEditorClient({ form, initialQuestions }: FormEditorC
                         onCheckedChange={(checked) => handleUpdateQuestion(q.id, { allowOther: checked })}
                       />
                       <Label htmlFor={`allowOther-${q.id}`} className="text-sm font-normal text-muted-foreground">
-                        Add 'Other' option
+                      Add &apos;Other&apos; option
                       </Label>
                     </div>
                   )}
diff --git a/app/admin/form/[id]/extra/client.tsx b/app/admin/form/[id]/extra/client.tsx
index 0cfcfbe..dd657f9 100644
--- a/app/admin/form/[id]/extra/client.tsx
+++ b/app/admin/form/[id]/extra/client.tsx
@@ -1,6 +1,6 @@
 "use client";
 
-import { useState, useTransition, useEffect, useRef } from "react";
+import { useCallback, useState, useTransition, useEffect, useRef } from "react";
 import { useRouter } from "next/navigation";
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
 import { Button } from "@/components/ui/button";
@@ -10,7 +10,8 @@ import { Label } from "@/components/ui/label";
 import { toast } from "sonner";
 import { updateForm } from "@/app/admin/form/actions";
 import { Loader2, ChevronDown, Check } from "lucide-react";
-import { getGuildRoles, DiscordRole } from "@/app/actions/discord";
+import { getGuildRoles } from "@/app/actions/discord";
+import type { DiscordRole } from "@/lib/discord";
 import {
   DropdownMenu,
   DropdownMenuCheckboxItem,
@@ -18,6 +19,7 @@ import {
   DropdownMenuTrigger,
 } from "@/components/ui/dropdown-menu";
 import { ScrollArea } from "@/components/ui/scroll-area"
+import { getErrorMessage } from "@/lib/errors";
 
 interface FormExtraClientProps {
   form: {
@@ -43,7 +45,7 @@ export default function FormExtraClient({ form }: FormExtraClientProps) {
   const [roles, setRoles] = useState<DiscordRole[]>([]);
   const [loadingRoles, setLoadingRoles] = useState(true);
 
-  const [isSaving, startSaveTransition] = useTransition();
+  const [, startSaveTransition] = useTransition();
   const [saveStatus, setSaveStatus] = useState<AutoSaveStatus>("idle");
   const [lastEdited, setLastEdited] = useState<"access" | "webhook" | null>(null);
 
@@ -57,7 +59,7 @@ export default function FormExtraClient({ form }: FormExtraClientProps) {
       .finally(() => setLoadingRoles(false));
   }, []);
 
-  const handleSave = (silent = false) => {
+  const handleSave = useCallback(() => {
     setSaveStatus("saving");
     startSaveTransition(async () => {
       try {
@@ -71,12 +73,21 @@ export default function FormExtraClient({ form }: FormExtraClientProps) {
         setSaveStatus("saved");
         setTimeout(() => setSaveStatus("idle"), 2000);
         router.refresh();
-      } catch (err: any) {
+      } catch (err: unknown) {
         setSaveStatus("idle");
-        toast.error(err.message || "Failed to update settings.");
+        toast.error(getErrorMessage(err, "Failed to update settings."));
       }
     });
-  };
+  }, [
+    allowedRoles,
+    deniedRoles,
+    form.id,
+    router,
+    startSaveTransition,
+    webhookTemplate,
+    webhookUpdateTemplate,
+    webhookUrl,
+  ]);
 
   useEffect(() => {
     if (isFirstRender.current) {
@@ -87,13 +98,13 @@ export default function FormExtraClient({ form }: FormExtraClientProps) {
     if (saveTimeout.current) clearTimeout(saveTimeout.current);
     
     saveTimeout.current = setTimeout(() => {
-      handleSave(true);
+      handleSave();
     }, 1000);
 
     return () => {
       if (saveTimeout.current) clearTimeout(saveTimeout.current);
     };
-  }, [webhookUrl, webhookTemplate, webhookUpdateTemplate, allowedRoles, deniedRoles]);
+  }, [handleSave]);
 
   const toggleRole = (list: string[], setList: (v: string[]) => void, roleId: string) => {
     setLastEdited("access");
diff --git a/app/admin/form/[id]/layout.tsx b/app/admin/form/[id]/layout.tsx
index c6f75b3..6654053 100644
--- a/app/admin/form/[id]/layout.tsx
+++ b/app/admin/form/[id]/layout.tsx
@@ -3,7 +3,8 @@ import { AdminSidebar } from "./client";
 import { Metadata } from "next";
 import { getServerSession } from "next-auth";
 import { authOptions } from "@/app/api/auth/[...nextauth]/route";
-import { getDiscordMemberProfile } from "@/app/actions/discord";
+import { getSessionDiscordId } from "@/lib/auth";
+import { getDiscordMemberProfile } from "@/lib/discord";
 
 export const metadata: Metadata = {
   title: {
@@ -22,7 +23,7 @@ export default async function AdminFormLayout(
   const session = await getServerSession(authOptions);
   
   let profile = null;
-  const discordId = (session?.user as any)?.discordId;
+  const discordId = getSessionDiscordId(session);
   if (discordId) {
     profile = await getDiscordMemberProfile(discordId);
   }
@@ -45,4 +46,4 @@ export default async function AdminFormLayout(
       </div>
     </SidebarProvider>
   );
-}
\ No newline at end of file
+}
diff --git a/app/admin/form/[id]/result/[submissionId]/client.tsx b/app/admin/form/[id]/result/[submissionId]/client.tsx
index 89e859a..32c5b70 100644
--- a/app/admin/form/[id]/result/[submissionId]/client.tsx
+++ b/app/admin/form/[id]/result/[submissionId]/client.tsx
@@ -1,9 +1,8 @@
 "use client";
 
-import React, { useState, useEffect, useRef } from "react";
+import React, { useState } from "react";
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
 import { Button } from "@/components/ui/button";
-import { Label } from "@/components/ui/label";
 import { 
   ContextMenu, 
   ContextMenuTrigger, 
@@ -14,7 +13,7 @@ import {
   ContextMenuGroup 
 } from "@/components/ui/context-menu";
 import { Copy, Check, Users, Calendar, Clock } from "lucide-react";
-import { ScrollArea, ScrollBar } from "@/components/ui/scroll-area";
+import { ScrollArea } from "@/components/ui/scroll-area";
 import Image from 'next/image';
 import { stripHtml } from "@/lib/utils";
 import { HtmlDisplay } from "@/components/html-display";
diff --git a/app/admin/form/actions.ts b/app/admin/form/actions.ts
index 39a3310..cd94f0b 100644
--- a/app/admin/form/actions.ts
+++ b/app/admin/form/actions.ts
@@ -5,49 +5,55 @@ import { forms } from "@/db/schema";
 import { eq } from "drizzle-orm";
 import { revalidatePath } from "next/cache";
 import { redirect } from "next/navigation";
-import { getServerSession } from "next-auth";
-import { authOptions } from "@/app/api/auth/[...nextauth]/route";
+import { requireAdmin } from "@/lib/auth";
+import { sanitizeHtml } from "@/lib/sanitize-html";
 
 export async function createForm(formData: FormData) {
-  const session = await getServerSession(authOptions);
-  const adminIds = (process.env.ADMIN_DISCORD_IDS ?? "").split(",").map((s) => s.trim()).filter(Boolean);
-  const discordId = (session?.user as { discordId?: string } | undefined)?.discordId;
-  if (!discordId || !adminIds.includes(discordId)) {
-    throw new Error("Unauthorized");
-  }
+  await requireAdmin();
 
   const title = formData.get("title") as string;
   const description = formData.get("description") as string | null;
 
   const [form] = await db
     .insert(forms)
-    .values({ title, description: description ?? null })
+    .values({ title, description: description ? sanitizeHtml(description) : null })
     .returning();
 
-  revalidatePath("/form/admin");
-  redirect(`/form/admin/${form.id}/edit`);
+  revalidatePath("/admin/form");
+  redirect(`/admin/form/${form.id}`);
+}
+
+export async function createDefaultForm() {
+  await requireAdmin();
+
+  const [form] = await db
+    .insert(forms)
+    .values({ title: "New Form", description: "" })
+    .returning();
+
+  revalidatePath("/admin/form");
+  redirect(`/admin/form/${form.id}`);
 }
 
 export async function updateForm(id: string, data: { title?: string; description?: string | null; isOpen?: boolean; discordWebhookUrl?: string | null; discordWebhookTemplate?: string | null; discordWebhookUpdateTemplate?: string | null; allowedRoles?: string[]; deniedRoles?: string[] }) {
-  const session = await getServerSession(authOptions);
-  const adminIds = (process.env.ADMIN_DISCORD_IDS ?? "").split(",").map((s) => s.trim()).filter(Boolean);
-  const discordId = (session?.user as { discordId?: string } | undefined)?.discordId;
-  if (!discordId || !adminIds.includes(discordId)) {
-    throw new Error("Unauthorized");
-  }
+  await requireAdmin();
 
-  await db.update(forms).set(data).where(eq(forms.id, id));
+  const nextData = {
+    ...data,
+    description: data.description === undefined
+      ? undefined
+      : data.description
+        ? sanitizeHtml(data.description)
+        : data.description,
+  };
+
+  await db.update(forms).set(nextData).where(eq(forms.id, id));
   revalidatePath("/form");
-  revalidatePath("/form/admin");
+  revalidatePath("/admin/form");
 }
 
 export async function deleteForm(id: string) {
-  const session = await getServerSession(authOptions);
-  const adminIds = (process.env.ADMIN_DISCORD_IDS ?? "").split(",").map((s) => s.trim()).filter(Boolean);
-  const discordId = (session?.user as { discordId?: string } | undefined)?.discordId;
-  if (!discordId || !adminIds.includes(discordId)) {
-    throw new Error("Unauthorized");
-  }
+  await requireAdmin();
 
   await db.delete(forms).where(eq(forms.id, id));
   revalidatePath("/admin/form");
diff --git a/app/admin/form/page.tsx b/app/admin/form/page.tsx
index bb0b246..764422b 100644
--- a/app/admin/form/page.tsx
+++ b/app/admin/form/page.tsx
@@ -11,9 +11,9 @@ import {
 } from "@/components/ui/table";
 import { Badge } from "@/components/ui/badge";
 import { Plus } from "lucide-react";
-import { redirect } from "next/navigation";
 import { DeleteFormButton } from "@/components/delete-buttons";
 import { AdminShellServer } from "@/components/admin-shell-server";
+import { createDefaultForm } from "./actions";
 
 export const dynamic = "force-dynamic";
 
@@ -32,15 +32,7 @@ export default async function AdminFormsPage() {
               Manage your custom forms and view submissions.
             </p>
           </div>
-          <form action={async () => {
-            "use server";
-            const { forms } = await import("@/db/schema");
-            const [newForm] = await db.insert(forms).values({
-              title: "New Form",
-              description: "",
-            }).returning();
-            redirect(`/admin/form/${newForm.id}`);
-          }}>
+          <form action={createDefaultForm}>
             <Button type="submit">
               <Plus className="mr-2 h-4 w-4" />
               Create Form
diff --git a/app/admin/layout.tsx b/app/admin/layout.tsx
index b3bb9dd..e4e8e6e 100644
--- a/app/admin/layout.tsx
+++ b/app/admin/layout.tsx
@@ -1,6 +1,7 @@
 import { getServerSession } from "next-auth";
 import { authOptions } from "@/app/api/auth/[...nextauth]/route";
 import { redirect } from "next/navigation";
+import { getAdminDiscordIds, getSessionDiscordId } from "@/lib/auth";
 
 export default async function AdminLayout({
   children,
@@ -8,13 +9,9 @@ export default async function AdminLayout({
   children: React.ReactNode;
 }) {
   const session = await getServerSession(authOptions);
-  const adminIds = (process.env.ADMIN_DISCORD_IDS ?? "")
-    .split(",")
-    .map((s) => s.trim())
-    .filter(Boolean);
-  const discordId = (session?.user as any)?.discordId;
+  const discordId = getSessionDiscordId(session);
 
-  if (!discordId || !adminIds.includes(discordId)) {
+  if (!discordId || !getAdminDiscordIds().includes(discordId)) {
     redirect("/");
   }
 
diff --git a/app/api/auth/[...nextauth]/route.ts b/app/api/auth/[...nextauth]/route.ts
index 1d59899..c004cd4 100644
--- a/app/api/auth/[...nextauth]/route.ts
+++ b/app/api/auth/[...nextauth]/route.ts
@@ -3,6 +3,7 @@ import DiscordProvider from "next-auth/providers/discord";
 import { DrizzleAdapter } from "@auth/drizzle-adapter";
 import { db } from "@/db";
 import { accounts, sessions, users, verificationTokens } from "@/db/schema";
+import type { SessionWithDiscord } from "@/lib/auth";
 
 const discordIdCache = new Map<string, string>();
 
@@ -22,7 +23,7 @@ export const authOptions: NextAuthOptions = {
   callbacks: {
     async session({ session, user }) {
       if (session.user) {
-        (session.user as any).id = user.id;
+        (session as SessionWithDiscord).user!.id = user.id;
 
         let discordId = discordIdCache.get(user.id);
         if (!discordId) {
@@ -37,7 +38,7 @@ export const authOptions: NextAuthOptions = {
           }
         }
         if (discordId) {
-          (session.user as typeof session.user & { discordId: string }).discordId = discordId;
+          (session as SessionWithDiscord).user!.discordId = discordId;
         }
       }
       return session;
diff --git a/app/api/upload/route.ts b/app/api/upload/route.ts
index d520447..5e30325 100644
--- a/app/api/upload/route.ts
+++ b/app/api/upload/route.ts
@@ -1,18 +1,13 @@
 import { NextResponse } from "next/server";
-import { getServerSession } from "next-auth";
-import { authOptions } from "@/app/api/auth/[...nextauth]/route";
+import { requireAdmin } from "@/lib/auth";
+
+const MAX_UPLOAD_BYTES = 1024 * 1024;
 
 export async function POST(req: Request) {
   try {
-    const session = await getServerSession(authOptions);
-    const adminIds = (process.env.ADMIN_DISCORD_IDS ?? "")
-      .split(",")
-      .map((s) => s.trim())
-      .filter(Boolean);
-    const discordId = (session?.user as { discordId?: string } | undefined)
-      ?.discordId;
-    
-    if (!discordId || !adminIds.includes(discordId)) {
+    try {
+      await requireAdmin();
+    } catch {
       return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
     }
 
@@ -27,6 +22,10 @@ export async function POST(req: Request) {
       return NextResponse.json({ error: "Only image files are allowed" }, { status: 400 });
     }
 
+    if (file.size > MAX_UPLOAD_BYTES) {
+      return NextResponse.json({ error: "Image must be 1MB or smaller" }, { status: 400 });
+    }
+
     const allowedExtensions = ["png", "jpg", "jpeg", "webp", "gif"];
     const originalExt = (file.name.split(".").pop() || "").toLowerCase();
 
@@ -40,8 +39,9 @@ export async function POST(req: Request) {
     const dataUri = `data:${mimeType};base64,${base64}`;
 
     return NextResponse.json({ url: dataUri });
-  } catch (error: any) {
+  } catch (error) {
     console.error("Upload error:", error);
-    return NextResponse.json({ error: error.message || "Internal server error" }, { status: 500 });
+    const message = error instanceof Error ? error.message : "Internal server error";
+    return NextResponse.json({ error: message }, { status: 500 });
   }
 }
diff --git a/app/form/[id]/not-found.tsx b/app/form/[id]/not-found.tsx
index ff68b1b..760ac5f 100644
--- a/app/form/[id]/not-found.tsx
+++ b/app/form/[id]/not-found.tsx
@@ -3,28 +3,23 @@
 import Link from "next/link";
 import Image from "next/image";
 import { Button } from "@/components/ui/button";
-import { useEffect, useState } from "react";
+import { useState } from "react";
 import { Spinner } from "@/components/ui/spinner";
 import Background from "@/public/404.png";
 import Profile from "@/public/404-image.jpg";
 import { Activity, Home } from "lucide-react";
-import { Skeleton } from "@/components/ui/skeleton";
+
+const MESSAGES = [
+  "ฟอร์มนี้อาจจะถูก Erika กินไปแล้ว...",
+  "หรือว่าฟอร์มนี้โดน Sukuna เล่นไปแล้ว...",
+  "ฟอร์มนี้อาจจะหมดอายุหรือโดนลบไปแล้ว...",
+  "บางทีคนสร้างอาจจะลืมเปิดฟอร์มนะ...",
+  "ฟอร์มหายไปไหนน้า... ลองเช็คลิงก์ดูอีกทีสิ",
+];
 
 export default function NotFound() {
   const [goingHome, goHome] = useState(false);
-  const [message, setMessage] = useState("");
-
-  useEffect(() => {
-    const messages = [
-      "ฟอร์มนี้อาจจะถูก Erika กินไปแล้ว...",
-      "หรือว่าฟอร์มนี้โดน Sukuna เล่นไปแล้ว...",
-      "ฟอร์มนี้อาจจะหมดอายุหรือโดนลบไปแล้ว...",
-      "บางทีคนสร้างอาจจะลืมเปิดฟอร์มนะ...",
-      "ฟอร์มหายไปไหนน้า... ลองเช็คลิงก์ดูอีกทีสิ",
-    ];
-
-    setMessage(messages[Math.floor(Math.random() * messages.length)]);
-  }, []);
+  const [message] = useState(() => MESSAGES[Math.floor(Math.random() * MESSAGES.length)]);
   
   return (
     <div className="relative flex min-h-screen w-full flex-col items-center justify-center gap-2">
@@ -45,7 +40,7 @@ export default function NotFound() {
         />
       </div>
       <h2 className="text-2xl font-semibold">404 ไม่พบหน้านี้</h2>
-        <span>{message || <Skeleton className="h-6 w-40" />}</span>
+        <span>{message}</span>
         <div className="flex gap-2">
           <Link href="/">
             <Button
diff --git a/app/form/[id]/page.tsx b/app/form/[id]/page.tsx
index e4ad9b9..b322027 100644
--- a/app/form/[id]/page.tsx
+++ b/app/form/[id]/page.tsx
@@ -3,8 +3,8 @@ import { FormFillerClient } from "../client";
 import { getServerSession } from "next-auth";
 import { authOptions } from "@/app/api/auth/[...nextauth]/route";
 import { notFound } from "next/navigation";
-import { getGuildMemberRoles } from "@/app/actions/discord";
 import LoginDialog from "@/components/login-dialog";
+import { canAccessForm, getSessionDiscordId } from "@/lib/auth";
 
 export const dynamic = "force-dynamic";
 
@@ -15,7 +15,7 @@ export default async function FormsSubmitPage(
 ) {
   const params = await props.params;
   const session = await getServerSession(authOptions);
-  const discordId = (session?.user as { discordId?: string })?.discordId;
+  const discordId = getSessionDiscordId(session);
 
   const form = await db.query.forms.findFirst({
     where: (f, { eq }) => eq(f.id, params.id),
@@ -25,30 +25,8 @@ export default async function FormsSubmitPage(
     return notFound();
   }
 
-  const allowedRoles = form.allowedRoles || [];
-  const deniedRoles = form.deniedRoles || [];
-  const hasRoleRestrictions = allowedRoles.length > 0 || deniedRoles.length > 0;
-
-  if (hasRoleRestrictions) {
-    if (!discordId) {
-      return notFound();
-    }
-
-    const userRoles = await getGuildMemberRoles(discordId);
-    
-    let isAllowed = allowedRoles.length === 0;
-    if (allowedRoles.length > 0) {
-      isAllowed = userRoles.some(r => allowedRoles.includes(r));
-    }
-
-    let isDenied = false;
-    if (deniedRoles.length > 0) {
-      isDenied = userRoles.some(r => deniedRoles.includes(r));
-    }
-
-    if (!isAllowed || isDenied) {
-      return notFound();
-    }
+  if (!(await canAccessForm(form, discordId))) {
+    return notFound();
   }
 
   const questionsList = await db.query.questions.findMany({
@@ -56,7 +34,7 @@ export default async function FormsSubmitPage(
     orderBy: (q, { asc }) => [asc(q.displayOrder)],
   });
 
-  let initialAnswers: Record<string, string> = {};
+  const initialAnswers: Record<string, string> = {};
   if (discordId) {
     const existingSubmission = await db.query.submissions.findFirst({
       where: (s, { eq, and }) =>
diff --git a/app/form/client.tsx b/app/form/client.tsx
index e6a2187..3b60f65 100644
--- a/app/form/client.tsx
+++ b/app/form/client.tsx
@@ -2,7 +2,7 @@
 
 import React, { useState, useEffect, useMemo } from "react";
 import { useRouter } from "next/navigation";
-import { Card, CardContent, CardDescription, CardHeader, CardTitle, CardFooter } from "@/components/ui/card";
+import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Textarea } from "@/components/ui/textarea";
@@ -16,11 +16,11 @@ import { Dialog, DialogContent, DialogTrigger, DialogTitle } from "@/components/
 import { AlertDialog, AlertDialogAction, AlertDialogCancel, AlertDialogContent, AlertDialogDescription, AlertDialogFooter, AlertDialogHeader, AlertDialogTitle, AlertDialogTrigger } from "@/components/ui/alert-dialog";
 import { toast } from "sonner";
 import { submitForm, deleteOwnSubmission } from "@/app/actions/submissions";
-import { Loader2, LogOut } from "lucide-react";
-import { signIn, signOut } from "next-auth/react";
+import { Loader2 } from "lucide-react";
+import { signIn } from "next-auth/react";
 import Image from "next/image";
 import { z } from "zod";
-import { useForm, Controller } from "react-hook-form";
+import { useForm, useWatch } from "react-hook-form";
 import { zodResolver } from "@hookform/resolvers/zod";
 import {
   Form,
@@ -30,6 +30,7 @@ import {
   FormMessage,
 } from "@/components/ui/form";
 import { DropdownMenuAvatar, DiscordMemberProfile } from "@/components/dropdown-menu-avatar";
+import { getErrorMessage } from "@/lib/errors";
 
 export function FormLayoutClient({
   userName,
@@ -81,11 +82,11 @@ interface FormFillerClientProps {
 }
 
 const LS_KEY = (formId: string) => `form-draft-${formId}`;
+type FormValues = Record<string, string | string[] | undefined>;
 
 const buildSchema = (questions: Question[]) => {
   const shape: Record<string, z.ZodTypeAny> = {};
   questions.forEach(q => {
-    const plainLabel = stripHtml(q.label);
     if (q.type === "checkbox") {
       shape[q.id] = q.required 
         ? z.array(z.string()).min(1, `จำเป็นต้องตอบข้อนี้`) 
@@ -107,15 +108,15 @@ export function FormFillerClient({ form, questions, initialAnswers = {} }: FormF
 
   const { defaultValues, initialOtherValues } = useMemo(() => {
     const serverAnswers = { ...initialAnswers };
-    let draft: Record<string, any> = {};
+    let draft: FormValues = {};
     try {
       const raw = localStorage.getItem(LS_KEY(form.id));
-      if (raw) draft = JSON.parse(raw);
+      if (raw) draft = JSON.parse(raw) as FormValues;
     } catch {}
     
     const merged = { ...draft, ...serverAnswers };
     
-    const vals: Record<string, any> = {};
+    const vals: FormValues = {};
     const others: Record<string, string> = {};
 
     questions.forEach(q => {
@@ -136,7 +137,7 @@ export function FormFillerClient({ form, questions, initialAnswers = {} }: FormF
         }
         vals[q.id] = arr;
       } else if (q.type === "radio") {
-        let val = ans || "";
+        let val = typeof ans === "string" ? ans : "";
         if (q.allowOther && q.options && val !== "" && !q.options.includes(val)) {
           if (val !== "__OTHER__") {
             others[q.id] = val;
@@ -145,7 +146,7 @@ export function FormFillerClient({ form, questions, initialAnswers = {} }: FormF
         }
         vals[q.id] = val;
       } else {
-        vals[q.id] = ans || "";
+        vals[q.id] = typeof ans === "string" ? ans : "";
       }
     });
     return { defaultValues: vals, initialOtherValues: others };
@@ -160,16 +161,14 @@ export function FormFillerClient({ form, questions, initialAnswers = {} }: FormF
     mode: "onTouched",
   });
 
-  const { handleSubmit, control, watch, formState: { isSubmitting }, trigger, reset } = methods;
+  const { handleSubmit, control, formState: { isSubmitting }, reset } = methods;
+  const watchedValues = useWatch({ control });
 
   useEffect(() => {
-    const subscription = watch((value) => {
-      try {
-        localStorage.setItem(LS_KEY(form.id), JSON.stringify(value));
-      } catch {}
-    });
-    return () => subscription.unsubscribe();
-  }, [watch, form.id]);
+    try {
+      localStorage.setItem(LS_KEY(form.id), JSON.stringify(watchedValues));
+    } catch {}
+  }, [form.id, watchedValues]);
 
 
 
@@ -206,9 +205,9 @@ export function FormFillerClient({ form, questions, initialAnswers = {} }: FormF
           router.refresh();
         }
       }
-    } catch (err: any) {
+    } catch (err: unknown) {
       console.error(err);
-      toast.error(err.message || "ไม่สามารถส่งฟอร์มได้");
+      toast.error(getErrorMessage(err, "ไม่สามารถส่งฟอร์มได้"));
     }
   };
 
@@ -221,9 +220,9 @@ export function FormFillerClient({ form, questions, initialAnswers = {} }: FormF
         reset({});
         router.refresh();
       }
-    } catch (err: any) {
+    } catch (err: unknown) {
       console.error(err);
-      toast.error(err.message || "ไม่สามารถลบข้อมูลได้");
+      toast.error(getErrorMessage(err, "ไม่สามารถลบข้อมูลได้"));
     }
   };
 
@@ -502,5 +501,3 @@ export function FormFillerClient({ form, questions, initialAnswers = {} }: FormF
     </div>
   );
 }
-
-
diff --git a/app/form/layout.tsx b/app/form/layout.tsx
index f3e12c9..b412a93 100644
--- a/app/form/layout.tsx
+++ b/app/form/layout.tsx
@@ -3,7 +3,8 @@ import { authOptions } from "@/app/api/auth/[...nextauth]/route";
 import { FormLayoutClient, LoginButton } from "./client";
 import { Metadata } from "next";
 import { ThemeToggle } from "@/components/theme-toggle";
-import { getDiscordMemberProfile } from "@/app/actions/discord";
+import { getSessionDiscordId } from "@/lib/auth";
+import { getDiscordMemberProfile } from "@/lib/discord";
 import Link from 'next/link';
 
 const siteUrl = process.env.BASE_URL;
@@ -35,7 +36,7 @@ export default async function FormLayout({
   children: React.ReactNode;
 }) {
   const session = await getServerSession(authOptions);
-  const discordId = (session?.user as any)?.discordId;
+  const discordId = getSessionDiscordId(session);
   let profile = null;
 
   if (discordId) {
diff --git a/app/form/page.tsx b/app/form/page.tsx
index 1f4758f..b47d2c8 100644
--- a/app/form/page.tsx
+++ b/app/form/page.tsx
@@ -4,12 +4,11 @@ import {
   Card,
   CardHeader,
   CardTitle,
-  CardDescription,
 } from "@/components/ui/card";
 import { HtmlDisplay } from "@/components/html-display";
 import { getServerSession } from "next-auth";
 import { authOptions } from "@/app/api/auth/[...nextauth]/route";
-import { getGuildMemberRoles } from "@/app/actions/discord";
+import { canAccessForm, getSessionDiscordId } from "@/lib/auth";
 
 export const dynamic = "force-dynamic";
 
@@ -20,44 +19,14 @@ export default async function FormsListingPage() {
   });
 
   const session = await getServerSession(authOptions);
-  const discordId = (session?.user as { discordId?: string })?.discordId;
-
-  // Only fetch roles if at least one form has role restrictions
-  const hasRoleRestrictions = formsList.some(
-    (f) => (f.allowedRoles?.length ?? 0) > 0 || (f.deniedRoles?.length ?? 0) > 0
-  );
-
-  let userRoles: string[] = [];
-  if (discordId && hasRoleRestrictions) {
-    try {
-      userRoles = await getGuildMemberRoles(discordId);
-    } catch (e) {
-      console.error(e);
+  const discordId = getSessionDiscordId(session);
+  const visibleForms = [];
+  for (const form of formsList) {
+    if (await canAccessForm(form, discordId)) {
+      visibleForms.push(form);
     }
   }
 
-  const visibleForms = formsList.filter((form) => {
-    const allowedRoles = form.allowedRoles || [];
-    const deniedRoles = form.deniedRoles || [];
-
-    if (allowedRoles.length === 0 && deniedRoles.length === 0) return true;
-
-    // If user is not logged in but there are role restrictions, hide it.
-    if (!discordId) return false;
-
-    let isAllowed = allowedRoles.length === 0;
-    if (allowedRoles.length > 0) {
-      isAllowed = userRoles.some(r => allowedRoles.includes(r));
-    }
-
-    let isDenied = false;
-    if (deniedRoles.length > 0) {
-      isDenied = userRoles.some(r => deniedRoles.includes(r));
-    }
-
-    return isAllowed && !isDenied;
-  });
-
   return (
     <div className="max-w-4xl mx-auto p-4 md:p-6 space-y-6">
       <h1 className="text-3xl font-bold tracking-tight">Form ทั้งหมด</h1>
diff --git a/app/not-found.tsx b/app/not-found.tsx
index 24b1093..408f4f2 100644
--- a/app/not-found.tsx
+++ b/app/not-found.tsx
@@ -3,28 +3,23 @@
 import Link from "next/link";
 import Image from "next/image";
 import { Button } from "@/components/ui/button";
-import { useEffect, useState } from "react";
+import { useState } from "react";
 import { Spinner } from "@/components/ui/spinner";
 import Background from "@/public/404.png";
 import Profile from "@/public/404-image.jpg";
 import { Activity, Home } from "lucide-react";
-import { Skeleton } from "@/components/ui/skeleton";
+
+const MESSAGES = [
+  "Erika กินหน้านี้ไปแล้ว...",
+  "หรือจริงๆแล้วหน้านี้จะโดน Sukuna เล่น...",
+  "อาจจะโดนต่อยจากคนด้านบนแล้วก็ได้...",
+  "หรือ Erika ตัวปลอมขะมีอยู่จริง...",
+  "หน้านี้อาจโดนErikaตัวปลอมทำลายไปแล้วนะ...",
+];
 
 export default function NotFound() {
   const [goingHome, goHome] = useState(false);
-  const [message, setMessage] = useState("");
-
-  useEffect(() => {
-    const messages = [
-      "Erika กินหน้านี้ไปแล้ว...",
-      "หรือจริงๆแล้วหน้านี้จะโดน Sukuna เล่น...",
-      "อาจจะโดนต่อยจากคนด้านบนแล้วก็ได้...",
-      "หรือ Erika ตัวปลอมขะมีอยู่จริง...",
-      "หน้านี้อาจโดนErikaตัวปลอมทำลายไปแล้วนะ...",
-    ];
-
-    setMessage(messages[Math.floor(Math.random() * messages.length)]);
-  }, []);
+  const [message] = useState(() => MESSAGES[Math.floor(Math.random() * MESSAGES.length)]);
   
   return (
     <div className="flex min-h-screen w-full flex-col items-center justify-center gap-2 bg-[#2225] backdrop-blur-md backdrop-grayscale">
@@ -45,7 +40,7 @@ export default function NotFound() {
         />
       </div>
       <h2 className="text-2xl font-semibold">404 ไม่พบหน้านี้</h2>
-        <span>{message || <Skeleton className="h-6 w-40" />}</span>
+        <span>{message}</span>
         <div className="flex gap-2">
           <Link href="/">
             <Button
diff --git a/components/admin-shell-server.tsx b/components/admin-shell-server.tsx
index dcdd8a5..0beff54 100644
--- a/components/admin-shell-server.tsx
+++ b/components/admin-shell-server.tsx
@@ -1,11 +1,12 @@
 import { getServerSession } from "next-auth";
 import { authOptions } from "@/app/api/auth/[...nextauth]/route";
-import { getDiscordMemberProfile } from "@/app/actions/discord";
+import { getSessionDiscordId } from "@/lib/auth";
+import { getDiscordMemberProfile } from "@/lib/discord";
 import { AdminShell } from "@/components/admin-shell";
 
 export async function AdminShellServer({ children }: { children: React.ReactNode }) {
   const session = await getServerSession(authOptions);
-  const discordId = (session?.user as any)?.discordId;
+  const discordId = getSessionDiscordId(session);
   let profile = null;
 
   if (discordId) {
diff --git a/components/admin-shell.tsx b/components/admin-shell.tsx
index 2c6436a..5448fbb 100644
--- a/components/admin-shell.tsx
+++ b/components/admin-shell.tsx
@@ -7,7 +7,6 @@ import {
   Sidebar,
   SidebarContent,
   SidebarGroup,
-  SidebarGroupLabel,
   SidebarGroupContent,
   SidebarMenu,
   SidebarMenuItem,
@@ -113,4 +112,4 @@ export function AdminShell({
       </div>
     </SidebarProvider>
   );
-}
\ No newline at end of file
+}
diff --git a/components/copybutton.tsx b/components/copybutton.tsx
index c808fab..da28c5d 100644
--- a/components/copybutton.tsx
+++ b/components/copybutton.tsx
@@ -2,15 +2,16 @@
 
 import React, { useState } from "react";
 import { Check, Copy } from "lucide-react";
-import { Button } from "@/components/ui/button";
+import { Button, buttonVariants } from "@/components/ui/button";
 import { copyToClipboard } from "@/lib/utils";
 import { cn } from "@/lib/utils";
+import type { VariantProps } from "class-variance-authority";
 
 export interface CopyButtonProps extends React.ButtonHTMLAttributes<HTMLButtonElement> {
   text?: string | (() => string);
   onCopy?: () => void;
   iconOnly?: boolean;
-  variant?: any;
+  variant?: VariantProps<typeof buttonVariants>["variant"];
 }
 
 export const CopyButton = React.forwardRef<HTMLButtonElement, CopyButtonProps>(
@@ -51,4 +52,4 @@ export const CopyButton = React.forwardRef<HTMLButtonElement, CopyButtonProps>(
     );
   }
 );
-CopyButton.displayName = "CopyButton";
\ No newline at end of file
+CopyButton.displayName = "CopyButton";
diff --git a/components/delete-buttons.tsx b/components/delete-buttons.tsx
index dc5ff48..d1a920c 100644
--- a/components/delete-buttons.tsx
+++ b/components/delete-buttons.tsx
@@ -28,6 +28,7 @@ import {
   AlertDialogTrigger,
 } from "@/components/ui/alert-dialog";
 import { Spinner } from "@/components/ui/spinner";
+import { getErrorMessage } from "@/lib/errors";
 
 interface DeleteFormButtonProps {
   formId: string;
@@ -46,9 +47,9 @@ export function DeleteFormButton({ formId }: DeleteFormButtonProps) {
         setDeleting(false);
         return "Form deleted successfully!";
       },
-      error: (err: any) => {
+      error: (err: unknown) => {
         setDeleting(false);
-        return err.message || "Failed to delete form.";
+        return getErrorMessage(err, "Failed to delete form.");
       },
     });
   };
@@ -102,9 +103,9 @@ export function DeleteSubmissionButton({ id, redirectUrl }: { id: string, redire
         setLoading(false);
         return "Submission deleted";
       },
-      error: (err: any) => {
+      error: (err: unknown) => {
         setLoading(false);
-        return err.message || "Failed to delete submission";
+        return getErrorMessage(err, "Failed to delete submission");
       },
     });
   };
@@ -146,9 +147,9 @@ export function DeleteAllSubmissionsButton({ formId }: { formId: string }) {
         setLoading(false);
         return "All submissions deleted";
       },
-      error: (err: any) => {
+      error: (err: unknown) => {
         setLoading(false);
-        return err.message || "Failed to delete submissions";
+        return getErrorMessage(err, "Failed to delete submissions");
       },
     });
   };
diff --git a/components/dropdown-menu-avatar.tsx b/components/dropdown-menu-avatar.tsx
index c97847c..b576b1c 100644
--- a/components/dropdown-menu-avatar.tsx
+++ b/components/dropdown-menu-avatar.tsx
@@ -1,6 +1,6 @@
 "use client";
 
-import { useState, useMemo } from "react";
+import { useState } from "react";
 import { usePathname } from "next/navigation";
 import Image from "next/image";
 import { LogOut } from "lucide-react";
@@ -12,7 +12,7 @@ import {
   DropdownMenuTrigger,
 } from "@/components/ui/dropdown-menu";
 import { Button } from "@/components/ui/button";
-import { DiscordRole } from "@/app/actions/discord";
+import type { DiscordRole } from "@/lib/discord";
 
 export interface DiscordMemberProfile {
   id: string;
@@ -60,20 +60,15 @@ export function DropdownMenuAvatar({
   const displayName = profile?.globalName || userName;
   const username = profile?.username || userName;
 
-  const bannerStyle = useMemo(
-    () => ({
-      height: 100,
-      backgroundColor: profile?.accentColor
-        ? toHex(profile.accentColor)
-        : "hsl(var(--muted))",
-      backgroundImage: profile?.bannerUrl
-        ? `url(${profile.bannerUrl})`
-        : "none",
-      backgroundSize: "cover" as const,
-      backgroundPosition: "center" as const,
-    }),
-    [profile?.accentColor, profile?.bannerUrl]
-  );
+  const bannerStyle = {
+    height: 100,
+    backgroundColor: profile?.accentColor
+      ? toHex(profile.accentColor)
+      : "hsl(var(--muted))",
+    backgroundImage: profile?.bannerUrl ? `url(${profile.bannerUrl})` : "none",
+    backgroundSize: "cover" as const,
+    backgroundPosition: "center" as const,
+  };
 
   return (
     <DropdownMenu>
@@ -163,4 +158,4 @@ export function DropdownMenuAvatar({
       </DropdownMenuContent>
     </DropdownMenu>
   );
-}
\ No newline at end of file
+}
diff --git a/components/html-display.tsx b/components/html-display.tsx
index e9ab2e5..3be25d0 100644
--- a/components/html-display.tsx
+++ b/components/html-display.tsx
@@ -1,5 +1,6 @@
 import * as React from "react"
 import { cn } from "@/lib/utils"
+import { sanitizeHtml } from "@/lib/sanitize-html"
 
 export interface HtmlDisplayProps extends React.HTMLAttributes<HTMLDivElement> {
   html?: string | null;
@@ -11,7 +12,7 @@ export function HtmlDisplay({ html, className, ...props }: HtmlDisplayProps) {
   return (
     <div
       className={cn("prose prose-sm dark:prose-invert max-w-none [&>p]:m-0 leading-snug", className)}
-      dangerouslySetInnerHTML={{ __html: html }}
+      dangerouslySetInnerHTML={{ __html: sanitizeHtml(html) }}
       {...props}
     />
   )
diff --git a/components/page-progress.tsx b/components/page-progress.tsx
index 78f6374..aea5dc3 100644
--- a/components/page-progress.tsx
+++ b/components/page-progress.tsx
@@ -1,6 +1,6 @@
 "use client"
 
-import { Suspense, useEffect, useState } from "react"
+import { Suspense, useEffect, useRef, useState } from "react"
 import { usePathname, useSearchParams } from "next/navigation"
 import { Progress } from "@/components/ui/progress"
 
@@ -9,6 +9,7 @@ function PageProgressContent() {
   const searchParams = useSearchParams()
   const [progress, setProgress] = useState(0)
   const [isVisible, setIsVisible] = useState(false)
+  const intervalRef = useRef<ReturnType<typeof setInterval> | null>(null)
 
   // Start progress on click
   useEffect(() => {
@@ -39,9 +40,7 @@ function PageProgressContent() {
             return prev + (95 - prev) * 0.1
           })
         }, 100)
-        
-        // Store interval so we can clear it on route change
-        ;(window as any).__page_progress_interval = interval
+        intervalRef.current = interval
       }
     }
 
@@ -51,17 +50,21 @@ function PageProgressContent() {
 
   // Finish progress on route change
   useEffect(() => {
-    if (typeof window !== "undefined" && (window as any).__page_progress_interval) {
-      clearInterval((window as any).__page_progress_interval)
+    if (intervalRef.current) {
+      clearInterval(intervalRef.current)
+      intervalRef.current = null
     }
     
     if (isVisible) {
-      setProgress(100)
+      const finishTimeout = setTimeout(() => setProgress(100), 0)
       const timeout = setTimeout(() => {
         setIsVisible(false)
         setTimeout(() => setProgress(0), 300) // Reset after hiding
       }, 400)
-      return () => clearTimeout(timeout)
+      return () => {
+        clearTimeout(finishTimeout)
+        clearTimeout(timeout)
+      }
     }
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [pathname, searchParams])
diff --git a/components/rich-text-editor.tsx b/components/rich-text-editor.tsx
index 5a07799..7b7e7fe 100644
--- a/components/rich-text-editor.tsx
+++ b/components/rich-text-editor.tsx
@@ -10,6 +10,7 @@ import { Bold, Italic, Underline as UnderlineIcon, Strikethrough, Link as LinkIc
 import { Button } from "@/components/ui/button";
 import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogFooter } from "@/components/ui/dialog";
 import { Input } from "@/components/ui/input";
+import { sanitizeHtml, sanitizeUrl } from "@/lib/sanitize-html";
 
 interface RichTextEditorProps {
   value: string;
@@ -18,7 +19,7 @@ interface RichTextEditorProps {
   className?: string;
 }
 
-export function RichTextEditor({ value, onChange, placeholder, className }: RichTextEditorProps) {
+export function RichTextEditor({ value, onChange, className }: RichTextEditorProps) {
   const [isLinkDialogOpen, setIsLinkDialogOpen] = useState(false);
   const [linkUrl, setLinkUrl] = useState("");
   const [linkText, setLinkText] = useState("");
@@ -40,7 +41,7 @@ export function RichTextEditor({ value, onChange, placeholder, className }: Rich
       // Get HTML output. If empty, maybe output empty string to avoid empty p tags.
       let html = editor.getHTML();
       if (html === "<p></p>") html = "";
-      onChange(html);
+      onChange(sanitizeHtml(html));
     },
     editorProps: {
       attributes: {
@@ -71,10 +72,18 @@ export function RichTextEditor({ value, onChange, placeholder, className }: Rich
     if (linkUrl === "") {
       editor.chain().focus().extendMarkRange("link").unsetLink().run();
     } else {
+      const safeUrl = sanitizeUrl(linkUrl);
+      if (!safeUrl) {
+        return;
+      }
       if (linkText) {
-        editor.chain().focus().insertContent(`<a href="${linkUrl}">${linkText}</a>`).run();
+        editor.chain().focus().insertContent({
+          type: "text",
+          text: linkText,
+          marks: [{ type: "link", attrs: { href: safeUrl } }],
+        }).run();
       } else {
-        editor.chain().focus().extendMarkRange("link").setLink({ href: linkUrl }).run();
+        editor.chain().focus().extendMarkRange("link").setLink({ href: safeUrl }).run();
       }
     }
     setIsLinkDialogOpen(false);
diff --git a/components/theme-provider.tsx b/components/theme-provider.tsx
index 34a9890..672159e 100644
--- a/components/theme-provider.tsx
+++ b/components/theme-provider.tsx
@@ -1,7 +1,12 @@
 "use client"
 
 import { ThemeProvider as NextThemesProvider, type ThemeProviderProps } from "next-themes"
+import type { ReactNode } from "react"
 
-export function ThemeProvider({ children, ...props }: ThemeProviderProps) {
+type Props = ThemeProviderProps & {
+  children: ReactNode;
+}
+
+export function ThemeProvider({ children, ...props }: Props) {
   return <NextThemesProvider {...props}>{children}</NextThemesProvider>
 }
diff --git a/components/theme-toggle.tsx b/components/theme-toggle.tsx
index 718033e..87b6001 100644
--- a/components/theme-toggle.tsx
+++ b/components/theme-toggle.tsx
@@ -31,7 +31,8 @@ export function ThemeToggle() {
   const [mounted, setMounted] = React.useState(false)
 
   React.useEffect(() => {
-    setMounted(true)
+    const timeout = setTimeout(() => setMounted(true), 0)
+    return () => clearTimeout(timeout)
   }, [])
 
   // Once mounted, resolve "system" to its actual rendered theme for the icon
@@ -62,4 +63,4 @@ export function ThemeToggle() {
       </DropdownMenuContent>
     </DropdownMenu>
   )
-}
\ No newline at end of file
+}
diff --git a/db/schema/form.ts b/db/schema/form.ts
index 22d389d..e7036d5 100644
--- a/db/schema/form.ts
+++ b/db/schema/form.ts
@@ -5,6 +5,7 @@ import {
   boolean,
   integer,
   jsonb,
+  uniqueIndex,
 } from "drizzle-orm/pg-core";
 import { uuidv7 } from "uuidv7";
 
@@ -43,20 +44,29 @@ export const questions = formSchema.table("question", {
   allowOther: boolean("allow_other").notNull().default(false),
 });
 
-export const submissions = formSchema.table("submission", {
-  id: text("id")
-    .primaryKey()
-    .$defaultFn(() => uuidv7()),
-  formId: text("form_id")
-    .notNull()
-    .references(() => forms.id, { onDelete: "cascade" }),
-  userDiscordId: text("user_discord_id"),
-  userName: text("user_name"),
-  submittedAt: timestamp("submitted_at", { mode: "date" }).defaultNow().notNull(),
-  editHistory: jsonb("edit_history")
-    .$type<{ editedAt: string; oldAnswers: Record<string, string> }[]>()
-    .default([]),
-});
+export const submissions = formSchema.table(
+  "submission",
+  {
+    id: text("id")
+      .primaryKey()
+      .$defaultFn(() => uuidv7()),
+    formId: text("form_id")
+      .notNull()
+      .references(() => forms.id, { onDelete: "cascade" }),
+    userDiscordId: text("user_discord_id"),
+    userName: text("user_name"),
+    submittedAt: timestamp("submitted_at", { mode: "date" }).defaultNow().notNull(),
+    editHistory: jsonb("edit_history")
+      .$type<{ editedAt: string; oldAnswers: Record<string, string> }[]>()
+      .default([]),
+  },
+  (submission) => [
+    uniqueIndex("submission_form_user_discord_id_unique").on(
+      submission.formId,
+      submission.userDiscordId
+    ),
+  ]
+);
 
 export const answers = formSchema.table("answer", {
   id: text("id")
diff --git a/drizzle/0011_unique_submission_user.sql b/drizzle/0011_unique_submission_user.sql
new file mode 100644
index 0000000..b7a08da
--- /dev/null
+++ b/drizzle/0011_unique_submission_user.sql
@@ -0,0 +1 @@
+CREATE UNIQUE INDEX "submission_form_user_discord_id_unique" ON "form"."submission" USING btree ("form_id","user_discord_id");
diff --git a/drizzle/meta/_journal.json b/drizzle/meta/_journal.json
index be5acee..52cd48d 100644
--- a/drizzle/meta/_journal.json
+++ b/drizzle/meta/_journal.json
@@ -78,6 +78,13 @@
       "when": 1783089081925,
       "tag": "0010_rainy_speedball",
       "breakpoints": true
+    },
+    {
+      "idx": 11,
+      "version": "7",
+      "when": 1783613113217,
+      "tag": "0011_unique_submission_user",
+      "breakpoints": true
     }
   ]
-}
\ No newline at end of file
+}
diff --git a/hooks/use-mobile.ts b/hooks/use-mobile.ts
index 2b0fe1d..1ebbc73 100644
--- a/hooks/use-mobile.ts
+++ b/hooks/use-mobile.ts
@@ -11,8 +11,11 @@ export function useIsMobile() {
       setIsMobile(window.innerWidth < MOBILE_BREAKPOINT)
     }
     mql.addEventListener("change", onChange)
-    setIsMobile(window.innerWidth < MOBILE_BREAKPOINT)
-    return () => mql.removeEventListener("change", onChange)
+    const timeout = setTimeout(onChange, 0)
+    return () => {
+      clearTimeout(timeout)
+      mql.removeEventListener("change", onChange)
+    }
   }, [])
 
   return !!isMobile
diff --git a/lib/auth.ts b/lib/auth.ts
new file mode 100644
index 0000000..b2fbeb9
--- /dev/null
+++ b/lib/auth.ts
@@ -0,0 +1,86 @@
+import { getServerSession } from "next-auth";
+import type { Session } from "next-auth";
+import { db } from "@/db";
+import { authOptions } from "@/app/api/auth/[...nextauth]/route";
+import { getGuildMemberRoles } from "@/lib/discord";
+
+export type SessionWithDiscord = Session & {
+  user?: Session["user"] & {
+    id?: string;
+    discordId?: string;
+  };
+};
+
+export type FormAccessConfig = {
+  id: string;
+  allowedRoles?: string[] | null;
+  deniedRoles?: string[] | null;
+};
+
+export function getAdminDiscordIds() {
+  return (process.env.ADMIN_DISCORD_IDS ?? "")
+    .split(",")
+    .map((id) => id.trim())
+    .filter(Boolean);
+}
+
+export function getSessionDiscordId(session: Session | null) {
+  return (session as SessionWithDiscord | null)?.user?.discordId ?? null;
+}
+
+export async function getCurrentDiscordId() {
+  const session = await getServerSession(authOptions);
+  return getSessionDiscordId(session);
+}
+
+export async function requireDiscordId() {
+  const discordId = await getCurrentDiscordId();
+  if (!discordId) {
+    throw new Error("Not authenticated");
+  }
+  return discordId;
+}
+
+export async function requireAdmin() {
+  const discordId = await requireDiscordId();
+  if (!getAdminDiscordIds().includes(discordId)) {
+    throw new Error("Unauthorized");
+  }
+  return discordId;
+}
+
+export async function canAccessForm(form: FormAccessConfig, discordId: string | null) {
+  const allowedRoles = form.allowedRoles ?? [];
+  const deniedRoles = form.deniedRoles ?? [];
+
+  if (allowedRoles.length === 0 && deniedRoles.length === 0) {
+    return true;
+  }
+
+  if (!discordId) {
+    return false;
+  }
+
+  const userRoles = await getGuildMemberRoles(discordId);
+  const isAllowed =
+    allowedRoles.length === 0 || userRoles.some((role) => allowedRoles.includes(role));
+  const isDenied = deniedRoles.some((role) => userRoles.includes(role));
+
+  return isAllowed && !isDenied;
+}
+
+export async function requireFormAccess(formId: string, discordId: string) {
+  const form = await db.query.forms.findFirst({
+    where: (forms, { eq }) => eq(forms.id, formId),
+  });
+
+  if (!form) {
+    throw new Error("Form not found");
+  }
+
+  if (!(await canAccessForm(form, discordId))) {
+    throw new Error("Unauthorized");
+  }
+
+  return form;
+}
diff --git a/lib/discord.ts b/lib/discord.ts
new file mode 100644
index 0000000..b77c5a0
--- /dev/null
+++ b/lib/discord.ts
@@ -0,0 +1,151 @@
+export interface DiscordRole {
+  id: string;
+  name: string;
+  color: number;
+  position: number;
+}
+
+export interface DiscordMemberProfile {
+  id: string;
+  username: string;
+  globalName: string | null;
+  avatarUrl: string | null;
+  bannerUrl: string | null;
+  accentColor: number | null;
+  roles: DiscordRole[];
+}
+
+interface CacheEntry<T> {
+  data: T;
+  expiresAt: number;
+}
+
+const rolesCache: { entry: CacheEntry<DiscordRole[]> | null } = { entry: null };
+const profileCache = new Map<string, CacheEntry<DiscordMemberProfile>>();
+const CACHE_TTL = 60_000;
+
+function getCached<T>(entry: CacheEntry<T> | null | undefined): T | null {
+  if (entry && Date.now() < entry.expiresAt) return entry.data;
+  return null;
+}
+
+export async function getGuildRolesInternal(): Promise<DiscordRole[]> {
+  const cached = getCached(rolesCache.entry);
+  if (cached) return cached;
+
+  const token = process.env.DISCORD_BOT_TOKEN;
+  const guildId = process.env.DISCORD_GUILD_ID;
+  if (!token || !guildId) return [];
+
+  try {
+    const res = await fetch(`https://discord.com/api/v10/guilds/${guildId}/roles`, {
+      headers: { Authorization: `Bot ${token}` },
+      signal: AbortSignal.timeout(5000),
+    });
+
+    if (!res.ok) return [];
+
+    const roles = (await res.json()) as Array<{
+      id: string;
+      name: string;
+      color: number;
+      position: number;
+    }>;
+    const result = roles
+      .map((role) => ({
+        id: role.id,
+        name: role.name,
+        color: role.color,
+        position: role.position,
+      }))
+      .sort((a, b) => b.position - a.position);
+
+    rolesCache.entry = { data: result, expiresAt: Date.now() + CACHE_TTL };
+    return result;
+  } catch {
+    return [];
+  }
+}
+
+export async function getGuildMemberRoles(discordId: string): Promise<string[]> {
+  const token = process.env.DISCORD_BOT_TOKEN;
+  const guildId = process.env.DISCORD_GUILD_ID;
+  if (!token || !guildId || !discordId) return [];
+
+  try {
+    const res = await fetch(`https://discord.com/api/v10/guilds/${guildId}/members/${discordId}`, {
+      headers: { Authorization: `Bot ${token}` },
+      cache: "no-store",
+      signal: AbortSignal.timeout(5000),
+    });
+
+    if (!res.ok) return [];
+
+    const member = (await res.json()) as { roles?: string[] };
+    return member.roles ?? [];
+  } catch {
+    return [];
+  }
+}
+
+export async function getDiscordMemberProfile(discordId: string): Promise<DiscordMemberProfile | null> {
+  const cached = getCached(profileCache.get(discordId));
+  if (cached) return cached;
+
+  const token = process.env.DISCORD_BOT_TOKEN;
+  const guildId = process.env.DISCORD_GUILD_ID;
+  if (!token || !guildId || !discordId) return null;
+
+  try {
+    const [memberRes, allRoles] = await Promise.all([
+      fetch(`https://discord.com/api/v10/guilds/${guildId}/members/${discordId}`, {
+        headers: { Authorization: `Bot ${token}` },
+        cache: "no-store",
+        signal: AbortSignal.timeout(5000),
+      }),
+      getGuildRolesInternal(),
+    ]);
+
+    if (!memberRes.ok) return null;
+    const member = (await memberRes.json()) as {
+      roles?: string[];
+      user: {
+        id: string;
+        username: string;
+        global_name?: string | null;
+        avatar?: string | null;
+        banner?: string | null;
+        accent_color?: number | null;
+      };
+    };
+
+    const roles = (member.roles ?? [])
+      .map((id) => allRoles.find((role) => role.id === id))
+      .filter((role): role is DiscordRole => Boolean(role))
+      .sort((a, b) => b.position - a.position);
+
+    const { user } = member;
+    const avatarUrl = user.avatar
+      ? `https://cdn.discordapp.com/avatars/${user.id}/${user.avatar}.${user.avatar.startsWith("a_") ? "gif" : "png"}?size=128`
+      : null;
+    const bannerUrl = user.banner
+      ? `https://cdn.discordapp.com/banners/${user.id}/${user.banner}.${user.banner.startsWith("a_") ? "gif" : "png"}?size=512`
+      : null;
+
+    const result = {
+      id: user.id,
+      username: user.username,
+      globalName: user.global_name ?? null,
+      avatarUrl,
+      bannerUrl,
+      accentColor: user.accent_color ?? null,
+      roles,
+    };
+
+    profileCache.set(discordId, { data: result, expiresAt: Date.now() + CACHE_TTL });
+    return result;
+  } catch (error) {
+    console.error("Failed to fetch member profile", error);
+    return null;
+  }
+}
diff --git a/lib/errors.ts b/lib/errors.ts
new file mode 100644
index 0000000..48b0b96
--- /dev/null
+++ b/lib/errors.ts
@@ -0,0 +1,3 @@
+export function getErrorMessage(error: unknown, fallback: string) {
+  return error instanceof Error ? error.message : fallback;
+}
diff --git a/lib/redis.ts b/lib/redis.ts
index 4bea579..b6fa7b9 100644
--- a/lib/redis.ts
+++ b/lib/redis.ts
@@ -1,4 +1,4 @@
-// @ts-ignore
+// @ts-expect-error Bun exposes RedisClient at runtime.
 import { RedisClient } from "bun";
 
 const globalForRedis = global as unknown as { redis: RedisClient };
diff --git a/lib/sanitize-html.ts b/lib/sanitize-html.ts
new file mode 100644
index 0000000..553575f
--- /dev/null
+++ b/lib/sanitize-html.ts
@@ -0,0 +1,79 @@
+const ALLOWED_TAGS = new Set([
+  "a",
+  "b",
+  "blockquote",
+  "br",
+  "code",
+  "em",
+  "h1",
+  "h2",
+  "h3",
+  "h4",
+  "h5",
+  "h6",
+  "i",
+  "li",
+  "ol",
+  "p",
+  "pre",
+  "s",
+  "strong",
+  "strike",
+  "u",
+  "ul",
+]);
+
+const BLOCKED_TAGS = /<(script|style|iframe|object|embed|svg|math|template)[\s\S]*?<\/\1>/gi;
+const TAG_RE = /<\/?([a-zA-Z][a-zA-Z0-9-]*)([^>]*)>/g;
+const ATTR_RE = /([a-zA-Z_:][a-zA-Z0-9_:.-]*)\s*=\s*("[^"]*"|'[^']*'|[^\s"'=<>`]+)/g;
+
+export function sanitizeUrl(url: string) {
+  const trimmed = url.trim();
+  if (!trimmed) return "";
+
+  try {
+    const parsed = new URL(trimmed, "https://erika.sudloh.com");
+    if (parsed.protocol === "http:" || parsed.protocol === "https:" || parsed.protocol === "mailto:") {
+      return trimmed;
+    }
+  } catch {
+    return "";
+  }
+
+  return "";
+}
+
+function escapeAttribute(value: string) {
+  return value
+    .replace(/&/g, "&amp;")
+    .replace(/"/g, "&quot;")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;");
+}
+
+export function sanitizeHtml(html: string) {
+  return html.replace(BLOCKED_TAGS, "").replace(TAG_RE, (tag, rawName: string, rawAttrs: string) => {
+    const name = rawName.toLowerCase();
+    if (!ALLOWED_TAGS.has(name)) return "";
+
+    if (tag.startsWith("</")) {
+      return `</${name}>`;
+    }
+
+    if (name !== "a") {
+      return `<${name}>`;
+    }
+
+    let href = "";
+    for (const match of rawAttrs.matchAll(ATTR_RE)) {
+      if (match[1].toLowerCase() === "href") {
+        href = sanitizeUrl(match[2].replace(/^["']|["']$/g, ""));
+        break;
+      }
+    }
+
+    return href
+      ? `<a href="${escapeAttribute(href)}" target="_blank" rel="noopener noreferrer">`
+      : "<a>";
+  });
+}
diff --git a/next.config.ts b/next.config.ts
index 3656f5a..a16b0b5 100644
--- a/next.config.ts
+++ b/next.config.ts
@@ -2,7 +2,6 @@ import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
   serverExternalPackages: ["bun"],
-  // @ts-ignore
   turbopack: {
     root: process.cwd(),
   },
diff --git a/proxy.ts b/proxy.ts
index 8856eb5..065ecfa 100644
--- a/proxy.ts
+++ b/proxy.ts
@@ -1,7 +1,6 @@
 import { NextResponse } from "next/server";
-import type { NextRequest } from "next/server";
 
-export function proxy(request: NextRequest) {
+export function proxy() {
   // All /form routes are allowed through — auth is handled via dialog in the layout
   return NextResponse.next();
 }
diff --git a/scripts/apply-0011-migration.ts b/scripts/apply-0011-migration.ts
new file mode 100644
index 0000000..0e63355
--- /dev/null
+++ b/scripts/apply-0011-migration.ts
@@ -0,0 +1,65 @@
+import { readFile } from "fs/promises";
+import postgres from "postgres";
+
+const migrationTag = "0011_unique_submission_user";
+const migrationPath = "drizzle/0011_unique_submission_user.sql";
+
+const databaseUrl = process.env.DATABASE_URL;
+if (!databaseUrl) {
+  throw new Error("DATABASE_URL is not set");
+}
+
+const sql = postgres(databaseUrl, { max: 1 });
+
+try {
+  const duplicates = await sql<{ form_id: string; user_discord_id: string; count: string }[]>`
+    select form_id, user_discord_id, count(*)::text as count
+    from form.submission
+    where user_discord_id is not null
+    group by form_id, user_discord_id
+    having count(*) > 1
+    limit 20
+  `;
+
+  if (duplicates.length > 0) {
+    console.error("Duplicate submissions would violate the unique index:");
+    for (const duplicate of duplicates) {
+      console.error(
+        `form_id=${duplicate.form_id} user_discord_id=${duplicate.user_discord_id} count=${duplicate.count}`
+      );
+    }
+    process.exit(1);
+  }
+
+  await sql`
+    create unique index if not exists "submission_form_user_discord_id_unique"
+    on "form"."submission" using btree ("form_id", "user_discord_id")
+  `;
+
+  const migrationTable = await sql<{ exists: boolean }[]>`
+    select to_regclass('drizzle.__drizzle_migrations') is not null as exists
+  `;
+
+  if (migrationTable[0]?.exists) {
+    const existing = await sql<{ count: string }[]>`
+      select count(*)::text as count
+      from drizzle.__drizzle_migrations
+      where hash = ${migrationTag}
+    `;
+
+    if (existing[0]?.count === "0") {
+      const migrationSql = await readFile(migrationPath, "utf8");
+      await sql`
+        insert into drizzle.__drizzle_migrations (hash, created_at)
+        values (${migrationTag}, ${Date.now()})
+      `;
+      console.log(`Applied ${migrationTag}: ${migrationSql.trim()}`);
+    } else {
+      console.log(`${migrationTag} was already recorded.`);
+    }
+  } else {
+    console.log("Applied index. Drizzle migration table was not found, so no migration row was recorded.");
+  }
+} finally {
+  await sql.end();
+}
diff --git a/skill/erika/SKILL.md b/skill/erika/SKILL.md
index 44d42e1..27984d6 100644
--- a/skill/erika/SKILL.md
+++ b/skill/erika/SKILL.md
@@ -164,7 +164,9 @@ Erika is a Next.js website for the content creator "Erika!". It has two main fea
 | `lib/config.ts` | **Linktree configuration for the root page (`/`).** Defines the profile (name, description, avatar) and the list of social links (Roblox, Discord, TikTok, YouTube) displayed on the landing page. Also defines `config_p2` which adds the Form link. This does NOT configure the form system. |
 | `lib/icons.tsx` | SVG icon components for social platforms (Roblox, Discord, TikTok, YouTube, Form) |
 | `lib/redis.ts` | Redis client singleton using Bun's built-in `RedisClient`. Used for caching follower counts (1hr TTL) and tracking unique visitors. |
-| `lib/discord.ts` | Shared Discord webhook notification utilities |
+| `lib/auth.ts` | Shared session, admin, and form role-access authorization helpers |
+| `lib/discord.ts` | Shared Discord API utilities for guild roles/member profiles with in-memory TTL caching |
+| `lib/sanitize-html.ts` | Sanitizes admin-authored rich text before storage/rendering |
 | `lib/utils.ts` | Utility functions (e.g. `cn()` for className merging) |
 
 ### `lib/followers/` — Follower Count Fetchers
@@ -190,7 +192,7 @@ Erika is a Next.js website for the content creator "Erika!". It has two main fea
 
 | File | Purpose |
 |---|---|
-| `app/actions/discord.ts` | Fetches Discord server roles natively via API for admin configuration and user access control |
+| `app/actions/discord.ts` | Admin-protected server action for loading Discord server roles in the form settings UI |
 
 ### `app/` — Routes
 
@@ -296,8 +298,10 @@ Erika is a Next.js website for the content creator "Erika!". It has two main fea
 2. **Admin check**: Server-side only. Compares the logged-in user's `discordId` (from session) against the comma-separated `ADMIN_DISCORD_IDS` env var. The primary guard is **centralized** in `app/admin/layout.tsx` which protects all `/admin/*` routes. Additional per-action checks exist in:
    - `app/admin/form/actions.ts` (form CRUD actions)
    - `app/actions/questions.ts` (question CRUD actions)
+   - `app/actions/submissions.ts` (admin submission deletion actions)
    - `app/api/upload/route.ts` (file uploads)
-3. **No middleware.ts**: Modern Next.js replaces `middleware.ts` with `proxy.ts`. The project has a `proxy.ts` that matches `/form/:path*` but currently just passes through. Auth checks are done per-page/per-action in server components and server actions.
+3. **Form role access check**: `lib/auth.ts` contains the shared role-access check. Public form pages use it before rendering restricted forms, and `submitForm()` repeats the same check before mutating data.
+4. **No middleware.ts**: Modern Next.js replaces `middleware.ts` with `proxy.ts`. The project has a `proxy.ts` that matches `/form/:path*` but currently just passes through. Auth checks are done per-page/per-action in server components and server actions.
 
 ---
 
@@ -307,8 +311,7 @@ The following optimizations have been implemented to keep CPU and RAM usage extr
 
 1. **DB Connection Pooling**: `db/index.ts` uses a `globalThis` singleton to prevent connection leaks during dev hot-reloads, with a strict max pool size (`max: 5`) to reduce idle RAM.
 2. **Session Caching**: The NextAuth session callback uses an in-memory `Map` with a TTL to cache the `discordId` lookup. This prevents a DB hit on *every single request* that checks the session.
-3. **Discord API Caching**: `app/actions/discord.ts` aggressively caches Discord API responses (roles, profiles) in memory with a 60s TTL. This avoids massive delays (30s-50s) on admin pages caused by redundant external API requests.
+3. **Discord API Caching**: `lib/discord.ts` aggressively caches Discord API responses (roles, profiles) in memory with a 60s TTL. This avoids massive delays (30s-50s) on admin pages caused by redundant external API requests.
 4. **Redis Batching**: The unique visitor tracking (`app/page.tsx`) only runs the `scard` (count) command if `sadd` (add IP) actually added a new IP.
 5. **Single Docker Replica**: The project runs on a **single replica** (`replicas: 1` in docker-compose.yml). Given Bun's performance, 1 replica is sufficient and drastically reduces the total RAM footprint compared to running 3 replicas.
 6. **Nginx Streaming**: Nginx must have `proxy_buffering off;` (or specifically disabled for the Next.js upstream) so that Next.js App Router streaming (React Server Components and Server Actions) works without hanging or causing 504 timeouts.
-