import { json } from '@sveltejs/kit';
import type { RequestHandler } from './$types';
import { listBooks, recentlyAddedBooks, allProgress, getHomeStats } from '$lib/server/pocketbase';
import { log } from '$lib/server/logger';
import type { Book, Progress } from '$lib/server/pocketbase';

/**
 * GET /api/home
 * Returns home screen data: continue-reading list, recently updated books, and stats.
 * Requires authentication (enforced by layout guard).
 */
export const GET: RequestHandler = async ({ locals }) => {
	let allBooks: Book[] = [];
	let recentBooks: Book[] = [];
	let progressList: Progress[] = [];
	let stats = { totalBooks: 0, totalChapters: 0 };

	try {
		[allBooks, recentBooks, progressList, stats] = await Promise.all([
			listBooks(),
			recentlyAddedBooks(8),
			allProgress(locals.sessionId, locals.user?.id),
			getHomeStats()
		]);
	} catch (e) {
		log.error('api/home', 'failed to load home data', { err: String(e) });
	}

	const bookMap = new Map<string, Book>(allBooks.map((b) => [b.slug, b]));

	const continueReading = progressList
		.filter((p) => bookMap.has(p.slug))
		.slice(0, 6)
		.map((p) => ({ book: bookMap.get(p.slug)!, chapter: p.chapter }));

	const inProgressSlugs = new Set(continueReading.map((c) => c.book.slug));
	const recentlyUpdated = recentBooks.filter((b) => !inProgressSlugs.has(b.slug)).slice(0, 6);

	return json({
		continue_reading: continueReading,
		recently_updated: recentlyUpdated,
		stats: {
			totalBooks: stats.totalBooks,
			totalChapters: stats.totalChapters,
			booksInProgress: continueReading.length
		}
	});
};