import { z } from "zod";
import type { FormAnswerValue } from "@/lib/form/form-answer-values";
import { decodeCheckboxAnswer } from "@/lib/form/form-answer-values";

export type Question = {
  id: string;
  formId: string;
  type: "text" | "textarea" | "radio" | "checkbox";
  label: string;
  imageUrl: string | null;
  displayOrder: number;
  required: boolean;
  options: string[] | null;
  allowOther: boolean;
  imageAnswerMode: "none" | "optional" | "required";
};

export type AnswerDraft = {
  value: FormAnswerValue;
  imageCdnId: string | null;
};

export type FormFillerClientProps = {
  form: {
    id: string;
    title: string;
    description: string | null;
    isOpen: boolean;
    closesAt: string | null;
    allowMultipleSubmissions: boolean;
  };
  questions: Question[];
  initialAnswers?: Record<string, AnswerDraft>;
  hasSubmission?: boolean;
  selectedSubmissionId?: string | null;
  ownSubmissions?: {
    id: string;
    submittedAt: string;
    answers: Record<string, AnswerDraft>;
  }[];
  totalAnswers: number;
  queueNumber: number | null;
  preview?: boolean;
};

export type FormValues = Record<string, string | string[] | undefined>;

export function formatQueuePosition(queueNumber: number) {
  return `#${queueNumber}`;
}

export type StoredDraft = {
  version: 1;
  answers: FormValues;
  otherValues: Record<string, string>;
  imageAnswers?: Record<string, string | null>;
};

export function buildFormSchema(questions: Question[]) {
  const shape: Record<string, z.ZodTypeAny> = {};
  questions.forEach((question) => {
    if (question.type === "checkbox") {
      shape[question.id] = question.required
        ? z.array(z.string()).min(1, "จำเป็นต้องตอบข้อนี้")
        : z.array(z.string()).optional();
    } else {
      shape[question.id] = question.required
        ? z.string().trim().min(1, "จำเป็นต้องตอบข้อนี้")
        : z.string().optional();
    }
  });
  return z.object(shape);
}

export function prepareInitialState(
  questions: Question[],
  answers: Record<string, AnswerDraft | undefined>,
  savedOtherValues: Record<string, string> = {}
) {
  const values: FormValues = {};
  const imageAnswers: Record<string, string | null> = {};
  const otherValues = { ...savedOtherValues };

  questions.forEach((question) => {
    const answer = answers[question.id]?.value;
    imageAnswers[question.id] = answers[question.id]?.imageCdnId ?? null;

    if (question.type === "checkbox") {
      let selected = decodeCheckboxAnswer(answer);
      if (question.allowOther && question.options) {
        const customAnswers = selected.filter(
          (value) => !question.options?.includes(value) && value !== "__OTHER__"
        );
        if (customAnswers.length > 0) {
          otherValues[question.id] = customAnswers.join(", ");
        }
        if (selected.includes("__OTHER__") || customAnswers.length > 0) {
          selected = selected.filter((value) => question.options?.includes(value));
          selected.push("__OTHER__");
        }
      }
      values[question.id] = selected;
      return;
    }

    if (question.type === "radio") {
      let selected = typeof answer === "string" ? answer : "";
      if (
        question.allowOther &&
        question.options &&
        selected &&
        !question.options.includes(selected)
      ) {
        if (selected !== "__OTHER__") {
          otherValues[question.id] = selected;
        }
        selected = "__OTHER__";
      }
      values[question.id] = selected;
      return;
    }

    values[question.id] = typeof answer === "string" ? answer : "";
  });

  return { values, otherValues, imageAnswers };
}

export function parseStoredDraft(raw: string) {
  const parsed: unknown = JSON.parse(raw);
  if (
    parsed &&
    typeof parsed === "object" &&
    "version" in parsed &&
    parsed.version === 1 &&
    "answers" in parsed
  ) {
    const draft = parsed as StoredDraft;
    return {
      answers: draft.answers ?? {},
      otherValues: draft.otherValues ?? {},
      imageAnswers: draft.imageAnswers ?? {},
    };
  }

  return {
    answers: (parsed as FormValues) ?? {},
    otherValues: {},
    imageAnswers: {},
  };
}