/**
 * Data access layer for Two Essays (TE).
 *
 * Reads from MongoDB via Prisma.
 * TE is a collection of 2 standalone essays using the `essays` collection
 * (not `prose_chapters`). Essays are grouped by `group: "two-essays"`.
 *
 * Collections used:
 *   - book_meta (via Prisma BookMeta model)
 *   - essays (via Prisma Essay model)
 */

import { prisma } from "@/lib/db";
import type { JsonValue } from "@prisma/client/runtime/library";

// ---------------------------------------------------------------------------
// Constants
// ---------------------------------------------------------------------------

const GROUP = "two-essays";
const BOOK = "te";

// ---------------------------------------------------------------------------
// Types
// ---------------------------------------------------------------------------

export type TeMeta = {
  group: string;
  title: string;
  author: string;
  year: number;
  description: string;
  essays: TeEssayEntry[];
};

export type TeEssayEntry = {
  slug: string;
  title: string;
  order: number;
};

export type TeEssay = {
  slug: string;
  title: string;
  author: string;
  year: number | null;
  group: string | null;
  order: number;
  paragraphs: string[];
};

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

// ---------------------------------------------------------------------------
// HTML sanitisation (mirrors lib/ej.ts)
// ---------------------------------------------------------------------------

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;
}

/** Normalize paragraphs — handles both native arrays and stringified JSON. */
function normalizeParagraphs(paragraphs: string[] | JsonValue): 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);
}

// ---------------------------------------------------------------------------
// Book meta
// ---------------------------------------------------------------------------

/**
 * Book-level metadata (title, author, essay list, etc.)
 */
export async function getTeMeta(): Promise<TeMeta | null> {
  const meta = await prisma.bookMeta.findUnique({ where: { book: BOOK } });
  if (!meta) return null;
  return meta.data as unknown as TeMeta;
}

// ---------------------------------------------------------------------------
// Essays
// ---------------------------------------------------------------------------

/**
 * All essays in the "two-essays" group, ordered by `order`.
 */
export async function getTeEssays(): Promise<TeEssay[]> {
  const results = await prisma.essay.findMany({
    where: { group: GROUP },
    orderBy: { order: "asc" },
  });

  return results.map((doc) => ({
    slug: doc.slug,
    title: doc.title,
    author: doc.author,
    year: doc.year,
    group: doc.group,
    order: doc.order,
    paragraphs: normalizeParagraphs(doc.paragraphs),
  }));
}

/**
 * A single essay by slug.
 */
export async function getTeEssay(slug: string): Promise<TeEssay | null> {
  const doc = await prisma.essay.findUnique({ where: { slug } });
  if (!doc) return null;

  return {
    slug: doc.slug,
    title: doc.title,
    author: doc.author,
    year: doc.year,
    group: doc.group,
    order: doc.order,
    paragraphs: normalizeParagraphs(doc.paragraphs),
  };
}

// ---------------------------------------------------------------------------
// Sidebar navigation
// ---------------------------------------------------------------------------

/**
 * Build the sidebar navigation list from meta.
 */
export async function getTeSidebarItems(): Promise<TeSidebarItem[]> {
  const meta = await getTeMeta();
  if (!meta) return [];
  return meta.essays.map((e) => ({
    slug: e.slug,
    label: e.title,
  }));
}