import { promises as fs } from "fs";
import path from "path";
import { demoBooks } from "@/data/demo-books";
import { Book } from "@/types/book";
export { getBookEntries, getBookContentCount, getBookStructureStats } from "@/lib/book-helpers";

const storageCatalogPath = path.join(process.cwd(), "storage", "books", "catalog.json");

function normalizeBooks(books: Book[]) {
  return books
    .map((book) => ({
      ...book,
      sections: [...book.sections]
        .sort((a, b) => a.order - b.order)
        .map((section) => ({
          ...section,
          entries: [...section.entries].sort((a, b) => a.order - b.order)
        }))
    }))
    .sort((a, b) => a.title.localeCompare(b.title, "zh-CN"));
}

export async function getBooks() {
  try {
    const raw = await fs.readFile(storageCatalogPath, "utf8");
    const parsed = JSON.parse(raw) as Book[];

    if (Array.isArray(parsed) && parsed.length > 0) {
      return normalizeBooks(parsed);
    }
  } catch {
    // Fall back to bundled demo books when no formal catalog exists yet.
  }

  return normalizeBooks(demoBooks);
}

export async function getBookById(bookId: string) {
  const books = await getBooks();
  return books.find((book) => book.id === bookId);
}