import fs from 'node:fs';
import path from 'node:path';
import type Database from 'better-sqlite3';
import { detectPlatform } from '$lib/platform';
import { toSlug, isImageFile } from '$lib/utils';
import { env } from '$env/dynamic/private';

function isSeriesFolder(entries: fs.Dirent[]): boolean {
	return entries.some(
		(e) =>
			e.isDirectory() &&
			!e.name.toLowerCase().endsWith('.app') &&
			e.name.toLowerCase() !== 'screenshots'
	);
}

function scanGameFolder(
	db: Database.Database,
	folderPath: string,
	title: string,
	library: 'public' | 'private',
	seriesId: number | null
): void {
	const slug = toSlug(title);

	let entries: fs.Dirent[];
	try {
		entries = fs.readdirSync(folderPath, { withFileTypes: true });
	} catch {
		return;
	}

	const hasCover = entries.some(
		(e) => e.isFile() && /^cover\.(png|jpg|jpeg|webp)$/i.test(e.name)
	);
	const hasWide = entries.some(
		(e) => e.isFile() && /^widecover\.(png|jpg|jpeg|webp)$/i.test(e.name)
	);

	db.prepare(
		`INSERT INTO games (slug, title, library, folder_path, has_cover, has_wide, series_id)
         VALUES (?, ?, ?, ?, ?, ?, ?)
         ON CONFLICT(slug) DO UPDATE SET
           title           = excluded.title,
           library         = excluded.library,
           folder_path     = excluded.folder_path,
           has_cover       = excluded.has_cover,
           has_wide        = excluded.has_wide,
           series_id       = excluded.series_id,
           last_scanned_at = datetime('now')`
	).run(slug, title, library, folderPath, hasCover ? 1 : 0, hasWide ? 1 : 0, seriesId);

	const game = db.prepare('SELECT id FROM games WHERE slug = ?').get(slug) as { id: number };

	db.prepare('DELETE FROM game_files WHERE game_id = ?').run(game.id);
	for (const entry of entries) {
		const platform = detectPlatform(entry.name, entry.isDirectory());
		if (platform === null) continue;

		const isDir = entry.isDirectory() ? 1 : 0;
		let fileSize = 0;
		if (!isDir) {
			try {
				fileSize = fs.statSync(path.join(folderPath, entry.name)).size;
			} catch {
				/* ignore */
			}
		}

		db.prepare(
			`INSERT INTO game_files (game_id, filename, rel_path, platform, is_dir, file_size)
           VALUES (?, ?, ?, ?, ?, ?)`
		).run(game.id, entry.name, entry.name, platform, isDir, fileSize);
	}

	db.prepare('DELETE FROM screenshots WHERE game_id = ?').run(game.id);
	const ssDir = path.join(folderPath, 'screenshots');
	if (fs.existsSync(ssDir)) {
		const ssFiles = fs.readdirSync(ssDir).filter(isImageFile).sort();
		ssFiles.forEach((filename, i) => {
			db.prepare(
				`INSERT INTO screenshots (game_id, filename, rel_path, sort_order)
             VALUES (?, ?, ?, ?)`
			).run(game.id, filename, `screenshots/${filename}`, i);
		});
	}
}

export function scanLibraries(db: Database.Database): void {
	const GAMES_PATH = env.GAMES_PATH ?? path.join(process.cwd(), 'games');
	for (const library of ['public', 'private'] as const) {
		const libPath = path.join(GAMES_PATH, library);
		if (!fs.existsSync(libPath)) continue;

		let topFolders: fs.Dirent[];
		try {
			topFolders = fs
				.readdirSync(libPath, { withFileTypes: true })
				.filter((d) => d.isDirectory());
		} catch {
			continue;
		}

		for (const folder of topFolders) {
			const title = folder.name;
			const folderPath = path.join(libPath, folder.name);

			let entries: fs.Dirent[];
			try {
				entries = fs.readdirSync(folderPath, { withFileTypes: true });
			} catch {
				continue;
			}

			if (isSeriesFolder(entries)) {
				const seriesSlug = toSlug(title);
				const hasCover = entries.some(
					(e) => e.isFile() && /^cover\.(png|jpg|jpeg|webp)$/i.test(e.name)
				);

				db.prepare(
					`INSERT INTO series (slug, title, library, folder_path, has_cover)
             VALUES (?, ?, ?, ?, ?)
             ON CONFLICT(slug) DO UPDATE SET
               title           = excluded.title,
               library         = excluded.library,
               folder_path     = excluded.folder_path,
               has_cover       = excluded.has_cover,
               last_scanned_at = datetime('now')`
				).run(seriesSlug, title, library, folderPath, hasCover ? 1 : 0);

				const seriesRow = db
					.prepare('SELECT id FROM series WHERE slug = ?')
					.get(seriesSlug) as { id: number };

				for (const entry of entries) {
					if (
						!entry.isDirectory() ||
						entry.name.toLowerCase().endsWith('.app') ||
						entry.name.toLowerCase() === 'screenshots'
					)
						continue;

					const gameFolderPath = path.join(folderPath, entry.name);
					scanGameFolder(db, gameFolderPath, entry.name, library, seriesRow.id);
				}
			} else {
				scanGameFolder(db, folderPath, title, library, null);
			}
		}

		// Remove DB rows for game folders that no longer exist on disk
		const existingGames = db
			.prepare('SELECT id, folder_path FROM games WHERE library = ?')
			.all(library) as Array<{ id: number; folder_path: string }>;
		for (const row of existingGames) {
			if (!fs.existsSync(row.folder_path)) {
				db.prepare('DELETE FROM games WHERE id = ?').run(row.id);
			}
		}

		// Remove DB rows for series folders that no longer exist on disk
		const existingSeries = db
			.prepare('SELECT id, folder_path FROM series WHERE library = ?')
			.all(library) as Array<{ id: number; folder_path: string }>;
		for (const row of existingSeries) {
			if (!fs.existsSync(row.folder_path)) {
				db.prepare('DELETE FROM series WHERE id = ?').run(row.id);
			}
		}
	}
}