"use client";

import Link from "next/link";
import { useState, type FormEvent } from "react";
import { Alert, AlertDescription } from "@/components/ui/alert";
import { Button } from "@/components/ui/button";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { Field, FieldGroup, FieldLabel } from "@/components/ui/field";
import { Input } from "@/components/ui/input";
import { authClient } from "@/lib/auth/client";

type Mode = "forgot" | "reset";

export function EmailActionForm({ mode, token = "", invalidToken = false, nextPath = "/" }: {
  mode: Mode; token?: string; invalidToken?: boolean; nextPath?: string;
}) {
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState("");
  const [sent, setSent] = useState(false);

  async function submit(event: FormEvent<HTMLFormElement>) {
    event.preventDefault();
    if (busy) return;
    const form = new FormData(event.currentTarget);
    const address = String(form.get("email") ?? "").trim();
    setBusy(true);
    setError("");
    try {
      if (mode === "forgot") {
        const returnQuery = nextPath === "/" ? "" : `?next=${encodeURIComponent(nextPath)}`;
        const result = await authClient.requestPasswordReset({ email: address, redirectTo: `/auth/password-reset${returnQuery}` });
        if (result.error) throw new Error("ส่งลิงก์รีเซ็ตไม่สำเร็จ กรุณาลองอีกครั้ง");
      } else {
        const password = String(form.get("password") ?? "");
        if (password !== String(form.get("confirmPassword") ?? "")) {
          setError("รหัสผ่านใหม่ไม่ตรงกัน");
          return;
        }
        const result = await authClient.resetPassword({ newPassword: password, token });
        if (result.error) throw new Error("รีเซ็ตรหัสผ่านไม่สำเร็จ ลิงก์อาจหมดอายุแล้ว");
      }
      setSent(true);
    } catch (cause) {
      setError(cause instanceof Error ? cause.message : "ลองอีกครั้ง");
    } finally {
      setBusy(false);
    }
  }

  const title = mode === "forgot" ? "ลืมรหัสผ่าน" : "ตั้งรหัสผ่านใหม่";
  const loginHref = `/auth/login${nextPath === "/" ? "" : `?next=${encodeURIComponent(nextPath)}`}`;
  const canReset = Boolean(token) && !invalidToken;
  return <Card className="w-full max-w-sm">
    <CardHeader><CardTitle>{title}</CardTitle></CardHeader>
    <CardContent className="flex flex-col gap-4">
      {sent && <Alert><AlertDescription>{mode === "reset"
        ? "ตั้งรหัสผ่านใหม่แล้ว กรุณาเข้าสู่ระบบ"
        : "หากอีเมลนี้มีบัญชีอยู่ โปรดตรวจสอบกล่องจดหมายและโฟลเดอร์สแปม"}</AlertDescription></Alert>}
      {invalidToken && <Alert variant="destructive"><AlertDescription>
        ลิงก์รีเซ็ตไม่ถูกต้องหรือหมดอายุ กรุณาขอลิงก์ใหม่
      </AlertDescription></Alert>}
      {error && <Alert variant="destructive"><AlertDescription>{error}</AlertDescription></Alert>}
      {(mode !== "reset" || (!sent && canReset)) && <form onSubmit={submit}>
        <FieldGroup>
          {mode !== "reset" ? <Field>
            <FieldLabel htmlFor="auth-email">อีเมล</FieldLabel>
            <Input id="auth-email" name="email" type="email" autoComplete="email" required disabled={busy} />
          </Field> : <>
            <Field><FieldLabel htmlFor="new-password">รหัสผ่านใหม่</FieldLabel>
              <Input id="new-password" name="password" type="password" minLength={6} maxLength={128}
                autoComplete="new-password" required disabled={busy} /></Field>
            <Field><FieldLabel htmlFor="confirm-password">ยืนยันรหัสผ่านใหม่</FieldLabel>
              <Input id="confirm-password" name="confirmPassword" type="password" minLength={6} maxLength={128}
                autoComplete="new-password" required disabled={busy} /></Field>
          </>}
          <Button type="submit" disabled={busy}>{busy ? "กำลังดำเนินการ..." :
            mode === "forgot" ? "ส่งลิงก์รีเซ็ต" : "ตั้งรหัสผ่าน"}</Button>
        </FieldGroup>
      </form>}
      {mode === "reset" && !canReset && !sent && <Button variant="link" nativeButton={false} render={<Link href={`/auth/forgot-password${nextPath === "/" ? "" : `?next=${encodeURIComponent(nextPath)}`}`} />}>
        ขอลิงก์รีเซ็ตใหม่
      </Button>}
      <Button variant="link" nativeButton={false} render={<Link href={loginHref} />}>กลับไปเข้าสู่ระบบ</Button>
    </CardContent>
  </Card>;
}