/**
 * Data access layer for Magazines (Back to Godhead, etc.).
 *
 * Uses the BFF API instead of direct Prisma queries.
 * Falls back to local JSON files when BFF is unavailable.
 */

import { bff, bffList } from "@/lib/bff";
import fs from "fs";
import path from "path";

const LOCAL_JSON_DIR = path.join(process.cwd(), "lib", "jsons", "magazines");

export type MagazineSubChapter = { slug: string; title: string };
export type MagazineVolumeGroup = {
  title: string;
  subChapters: MagazineSubChapter[];
};
export type MagazineChapterEntry = MagazineSubChapter | MagazineVolumeGroup;

export type MagazineMetaData = {
  book: string;
  title: string;
  author: string;
  year: number | null;
  description: string | null;
  totalIssues: number;
  totalArticles: number;
  flag: string | null;
  chapters: MagazineChapterEntry[];
};

export type MagazineIssueData = {
  book: string;
  volume: number | null;
  part: number;
  title: string;
  slug: string;
  paragraphs: string[];
};

export type MagazineSummary = {
  book: string;
  title: string;
  author: string;
  year: number | null;
  description: string | null;
  totalIssues: number;
  flag: string | null;
};

export type MagazineSidebarItem = {
  slug: string;
  label: string;
  type: string;
};

// --- BFF response types ---

type BffMagazineMeta = {
  id: string;
  book: string;
  data: {
    title: string;
    author: string;
    year: number | null;
    description: string | null;
    totalIssues: number;
    totalArticles: number;
    flag: string | null;
    chapters: MagazineChapterEntry[];
  };
};

type BffMagazineIssue = {
  book: string;
  volume: number | null;
  part: number;
  title: string;
  slug: string;
  paragraphs: string[];
  paragraphs_json?: string;
};

// --- HTML sanitisation ---

function sanitizeHtml(html: string): string {
  let clean = html.replace(/<script[\s>][\s\S]*?<\/script>/gi, "");
  clean = clean.replace(/<style[\s>][\s\S]*?<\/style>/gi, "");
  clean = clean.replace(/<iframe[\s>][\s\S]*?<\/iframe>/gi, "");
  clean = clean.replace(
    /<\/?(?:script|style|iframe|object|embed|form|input|textarea|select|button)[^>]*>/gi,
    "",
  );
  clean = clean.replace(/\s+on\w+\s*=\s*(?:"[^"]*"|'[^']*'|[^\s>]+)/gi, "");
  clean = clean.replace(/href\s*=\s*"javascript:[^"]*"/gi, 'href=""');
  clean = clean.replace(/href\s*=\s*'javascript:[^']*'/gi, "href=''");
  return clean;
}

function normalizeParagraphs(paragraphs: string[] | unknown): string[] {
  let result: string[];
  if (typeof paragraphs === "string") {
    try {
      const parsed = JSON.parse(paragraphs);
      result = Array.isArray(parsed) ? parsed : [paragraphs];
    } catch {
      result = [paragraphs];
    }
  } else if (Array.isArray(paragraphs)) {
    result = paragraphs as string[];
  } else {
    result = [];
  }
  return result.map(sanitizeHtml);
}

// --- BFF → domain mappers ---

function mapBffMetaToMagazineMetaData(raw: BffMagazineMeta): MagazineMetaData {
  return {
    book: raw.book,
    title: raw.data.title,
    author: raw.data.author,
    year: raw.data.year ?? null,
    description: raw.data.description ?? null,
    totalIssues: raw.data.totalIssues,
    totalArticles: raw.data.totalArticles,
    flag: raw.data.flag ?? null,
    chapters: raw.data.chapters,
  };
}

function mapBffMetaToSummary(raw: BffMagazineMeta): MagazineSummary {
  return {
    book: raw.book,
    title: raw.data.title,
    author: raw.data.author,
    year: raw.data.year ?? null,
    description: raw.data.description ?? null,
    totalIssues: raw.data.totalIssues,
    flag: raw.data.flag ?? null,
  };
}

function mapBffIssue(raw: BffMagazineIssue): MagazineIssueData {
  // Handle paragraphs_json fallback
  let paragraphs = raw.paragraphs;
  if ((!paragraphs || !paragraphs.length) && raw.paragraphs_json) {
    try {
      paragraphs = JSON.parse(raw.paragraphs_json);
    } catch {
      paragraphs = [];
    }
  }

  return {
    book: raw.book,
    volume: raw.volume,
    part: raw.part,
    title: raw.title,
    slug: raw.slug,
    paragraphs: normalizeParagraphs(paragraphs),
  };
}

// --- Local JSON fallback helpers ---

function findLocalDirForBook(bookCode: string): string | null {
  if (!fs.existsSync(LOCAL_JSON_DIR)) return null;
  const entries = fs.readdirSync(LOCAL_JSON_DIR);
  for (const entry of entries) {
    const introPath = path.join(LOCAL_JSON_DIR, entry, "intro.json");
    if (fs.existsSync(introPath)) {
      try {
        const intro = JSON.parse(fs.readFileSync(introPath, "utf-8"));
        if (intro.book === bookCode) return entry;
      } catch {
        /* skip */
      }
    }
  }
  return null;
}

function readLocalJson<T>(filePath: string): T | null {
  try {
    if (!fs.existsSync(filePath)) return null;
    return JSON.parse(fs.readFileSync(filePath, "utf-8")) as T;
  } catch {
    return null;
  }
}

function getAllLocalMetas(): MagazineMetaData[] {
  if (!fs.existsSync(LOCAL_JSON_DIR)) return [];
  const entries = fs.readdirSync(LOCAL_JSON_DIR).sort();
  const metas: MagazineMetaData[] = [];
  for (const entry of entries) {
    const intro = readLocalJson<MagazineMetaData>(
      path.join(LOCAL_JSON_DIR, entry, "intro.json"),
    );
    if (intro) metas.push(intro);
  }
  return metas;
}

function getLocalMeta(bookCode: string): MagazineMetaData | null {
  const dir = findLocalDirForBook(bookCode);
  if (!dir) return null;
  return readLocalJson<MagazineMetaData>(
    path.join(LOCAL_JSON_DIR, dir, "intro.json"),
  );
}

function getLocalIssue(
  bookCode: string,
  slug: string,
): MagazineIssueData | null {
  const dir = findLocalDirForBook(bookCode);
  if (!dir) return null;
  const data = readLocalJson<MagazineIssueData>(
    path.join(LOCAL_JSON_DIR, dir, "issues", `${slug}.json`),
  );
  if (!data) return null;
  return { ...data, paragraphs: data.paragraphs.map(sanitizeHtml) };
}

// Public API

export async function getAllMagazines(): Promise<MagazineSummary[]> {
  try {
    const results = await bffList<BffMagazineMeta>("/magazines");
    if (results.length > 0) {
      return results.map(mapBffMetaToSummary);
    }
  } catch {
    /* fall through */
  }
  const localMetas = getAllLocalMetas();
  return localMetas.map((meta) => ({
    book: meta.book,
    title: meta.title,
    author: meta.author,
    year: meta.year ?? null,
    description: meta.description ?? null,
    totalIssues: meta.totalIssues,
    flag: meta.flag ?? null,
  }));
}

export async function getMagazineMeta(
  bookCode: string,
): Promise<MagazineMetaData | null> {
  try {
    const raw = await bff<BffMagazineMeta>(`/magazines/${bookCode}`);
    if (raw) return mapBffMetaToMagazineMetaData(raw);
  } catch {
    /* fall through */
  }
  return getLocalMeta(bookCode);
}

export async function getMagazineIssue(
  bookCode: string,
  slug: string,
): Promise<MagazineIssueData | null> {
  if (!slug) return null;
  try {
    const raw = await bff<BffMagazineIssue>(
      `/magazines/${bookCode}/issues/${slug}`,
    );
    if (raw) return mapBffIssue(raw);
  } catch {
    /* fall through */
  }
  return getLocalIssue(bookCode, slug);
}

export async function getMagazineContent(
  bookCode: string,
  slug: string,
): Promise<MagazineIssueData | null> {
  return getMagazineIssue(bookCode, slug);
}

function isSubChapter(ch: MagazineChapterEntry): ch is MagazineSubChapter {
  return "slug" in ch && !("subChapters" in ch);
}

function hasSubChapters(ch: MagazineChapterEntry): ch is MagazineVolumeGroup {
  return "subChapters" in ch && Array.isArray(ch.subChapters);
}

export async function getMagazineSidebarItems(
  bookCode: string,
): Promise<MagazineSidebarItem[]> {
  const meta = await getMagazineMeta(bookCode);
  if (!meta) return [];

  const items: MagazineSidebarItem[] = [];
  function addEntry(entry: MagazineChapterEntry) {
    if (isSubChapter(entry)) {
      items.push({ slug: entry.slug, label: entry.title, type: "chapter" });
    } else if (hasSubChapters(entry)) {
      items.push({ slug: "", label: entry.title, type: "heading" });
      for (const sc of entry.subChapters) {
        addEntry(sc);
      }
    }
  }
  for (const ch of meta.chapters) {
    addEntry(ch);
  }
  return items;
}

export function bookCodeToSlug(bookCode: string): string {
  return bookCode;
}
export function slugToBookCode(slug: string): string {
  return slug;
}