import { fail, redirect } from '@sveltejs/kit';
import type { Actions, PageServerLoad } from './$types';
import { loginUser, createUser, mergeSessionProgress, createUserSession } from '$lib/server/pocketbase';
import { createAuthToken } from '../../hooks.server';
import { log } from '$lib/server/logger';
import { randomBytes } from 'node:crypto';

const AUTH_COOKIE = 'libnovel_auth';
const ONE_YEAR = 60 * 60 * 24 * 365;

export const load: PageServerLoad = async ({ locals }) => {
	// Already logged in — send to home
	if (locals.user) {
		redirect(302, '/');
	}
	return {};
};

export const actions: Actions = {
	login: async ({ request, cookies, locals }) => {
		const data = await request.formData();
		const username = (data.get('username') as string | null)?.trim() ?? '';
		const password = (data.get('password') as string | null) ?? '';

		if (!username || !password) {
			return fail(400, { action: 'login', error: 'Username and password are required.' });
		}

		let user;
		try {
			user = await loginUser(username, password);
		} catch (err) {
			log.error('auth', 'login unexpected error', { username, err: String(err) });
			return fail(500, { action: 'login', error: 'An error occurred. Please try again.' });
		}

		if (!user) {
			return fail(401, { action: 'login', error: 'Invalid username or password.' });
		}

		// Merge any anonymous session progress into the user's account so that
		// chapters read before logging in are preserved and portable across devices.
		mergeSessionProgress(locals.sessionId, user.id).catch((err) =>
			log.warn('auth', 'login: mergeSessionProgress failed (non-fatal)', { err: String(err) })
		);

		// Create a unique auth session ID for this login
		const authSessionId = randomBytes(16).toString('hex');

		// Record the session in PocketBase (best-effort, non-fatal)
		const userAgent = request.headers.get('user-agent') ?? '';
		const ip =
			request.headers.get('x-forwarded-for')?.split(',')[0]?.trim() ??
			request.headers.get('x-real-ip') ??
			'';
		createUserSession(user.id, authSessionId, userAgent, ip).catch((err) =>
			log.warn('auth', 'login: createUserSession failed (non-fatal)', { err: String(err) })
		);

		const token = createAuthToken(user.id, user.username, user.role ?? 'user', authSessionId);
		cookies.set(AUTH_COOKIE, token, {
			path: '/',
			httpOnly: true,
			sameSite: 'lax',
			maxAge: ONE_YEAR
		});

		redirect(302, '/');
	},

	register: async ({ request, cookies, locals }) => {
		const data = await request.formData();
		const username = (data.get('username') as string | null)?.trim() ?? '';
		const password = (data.get('password') as string | null) ?? '';
		const confirm = (data.get('confirm') as string | null) ?? '';

		if (!username || !password) {
			return fail(400, { action: 'register', error: 'Username and password are required.' });
		}
		if (username.length < 3 || username.length > 32) {
			return fail(400, {
				action: 'register',
				error: 'Username must be between 3 and 32 characters.'
			});
		}
		if (!/^[a-zA-Z0-9_-]+$/.test(username)) {
			return fail(400, {
				action: 'register',
				error: 'Username may only contain letters, numbers, underscores and hyphens.'
			});
		}
		if (password.length < 8) {
			return fail(400, {
				action: 'register',
				error: 'Password must be at least 8 characters.'
			});
		}
		if (password !== confirm) {
			return fail(400, { action: 'register', error: 'Passwords do not match.' });
		}

		let user;
		try {
			user = await createUser(username, password);
		} catch (err: unknown) {
			const msg = err instanceof Error ? err.message : 'Registration failed.';
			if (msg.includes('Username already taken')) {
				return fail(409, { action: 'register', error: 'That username is already taken.' });
			}
			log.error('auth', 'register unexpected error', { username, err: String(err) });
			return fail(500, { action: 'register', error: 'An error occurred. Please try again.' });
		}

		// Merge any anonymous session progress into the newly created account.
		mergeSessionProgress(locals.sessionId, user.id).catch((err) =>
			log.warn('auth', 'register: mergeSessionProgress failed (non-fatal)', { err: String(err) })
		);

		// Create a unique auth session ID for this registration
		const authSessionId = randomBytes(16).toString('hex');

		// Record the session in PocketBase (best-effort, non-fatal)
		const userAgent = request.headers.get('user-agent') ?? '';
		const ip =
			request.headers.get('x-forwarded-for')?.split(',')[0]?.trim() ??
			request.headers.get('x-real-ip') ??
			'';
		createUserSession(user.id, authSessionId, userAgent, ip).catch((err) =>
			log.warn('auth', 'register: createUserSession failed (non-fatal)', { err: String(err) })
		);

		const token = createAuthToken(user.id, user.username, user.role ?? 'user', authSessionId);
		cookies.set(AUTH_COOKIE, token, {
			path: '/',
			httpOnly: true,
			sameSite: 'lax',
			maxAge: ONE_YEAR
		});

		redirect(302, '/');
	}
};