import { env } from '$env/dynamic/public';
import { Audit } from '$lib/server/audit/audit.js';
import { AuditAction } from '$lib/server/audit/types.js';
import { Challenge } from '$lib/server/challenge.js';
import { Changesets } from '$lib/server/changesets.js';
import { OAuth2Clients } from '$lib/server/oauth2/index.js';
import { Users } from '$lib/server/users/index.js';
import { TimeOTP } from '$lib/server/users/totp.js';
import type { OAuth2ClientInfo } from '$lib/types';
import { error, fail, redirect, type Actions } from '@sveltejs/kit';
import { RateLimiter } from 'sveltekit-rate-limiter/server';

interface LoginChallenge {
	email: string;
}

const rainbowTableLimiter = new RateLimiter({
	IP: [3, '10s']
});

const limiter = new RateLimiter({
	IP: [6, 'm']
});

export const actions = {
	default: async (event) => {
		const { request, locals, url } = event;
		if (await limiter.isLimited(event)) {
			await Audit.insertRequest(AuditAction.THROTTLE, event, undefined, 'login');
			throw error(429);
		}

		// Redirect
		const redirectUrl = url.searchParams.has('redirectTo')
			? (url.searchParams.get('redirectTo') as string)
			: '/';

		// Already logged in
		if (locals.session.data?.user) {
			return redirect(303, redirectUrl);
		}

		const body = await request.formData();
		const { email, password, challenge, otpCode } = Changesets.only(
			['email', 'password', 'challenge', 'otpCode'],
			body
		);

		if (!email) {
			return fail(400, { incorrect: true });
		}

		if (!password && (!challenge || !otpCode)) {
			return fail(400, { incorrect: true });
		}

		// Find existing active user
		const loginUser = await Users.getByLogin(email);
		if (!loginUser) {
			if (await rainbowTableLimiter.isLimited(event)) {
				await Audit.insertRequest(
					AuditAction.THROTTLE,
					event,
					undefined,
					`rainbow table\nemail=${email}`
				);
				throw error(429);
			}

			return fail(400, { email, incorrect: true });
		}

		// Check OTP challenge
		if (challenge && otpCode) {
			const userOtp = await TimeOTP.getUserOtp(loginUser);
			if (!userOtp) {
				return fail(400, { email, incorrect: true });
			}

			try {
				const valid = await Challenge.verifyChallenge<LoginChallenge>(
					challenge,
					loginUser.uuid,
					otpCode,
					userOtp.token
				);

				if (email !== valid.email) {
					return fail(400, { email, incorrect: true });
				}
			} catch {
				return fail(400, { email, incorrect: true });
			}
		} else {
			// Compare user password
			if (!password || !(await Users.validatePassword(loginUser, password))) {
				if (await rainbowTableLimiter.isLimited(event)) {
					await Audit.insertRequest(
						AuditAction.THROTTLE,
						event,
						loginUser,
						`password attempts\nemail=${email}`
					);
					throw error(429);
				}

				return fail(400, { email, incorrect: true });
			}
		}

		// Issue two-factor challenge
		if (!challenge) {
			const isOtp = await TimeOTP.isUserOtp(loginUser);
			if (isOtp) {
				const issued = await Challenge.issueChallenge<LoginChallenge>({ email }, loginUser.uuid);
				return { otpRequired: issued, email };
			}
		}

		// Create session data for user
		const sessionUser = await Users.toSession(loginUser);
		await locals.session.set({ user: sessionUser });

		await Audit.insertRequest(AuditAction.LOGIN, event, loginUser, sessionUser.sid);

		return redirect(303, redirectUrl);
	}
} as Actions;

export const load = async ({ locals, url, ...event }) => {
	let clientInfo: OAuth2ClientInfo | undefined;

	if (url.searchParams.has('redirectTo')) {
		// Check that the redirect URL is a local path
		if (!url.searchParams.get('redirectTo')?.startsWith('/')) {
			return redirect(301, '/login');
		}

		// Redirect if already logged in
		if (locals.session.data?.user) {
			return redirect(301, url.searchParams.get('redirectTo') || '/');
		}

		// Take client ID from the redirect if applicable
		const parsedParams = new URL(url.searchParams.get('redirectTo') as string, env.PUBLIC_URL);
		const clientId = parsedParams.searchParams.get('client_id') as string;
		if (clientId) {
			const client = await OAuth2Clients.fetchById(clientId);
			if (!client) {
				return redirect(301, '/login');
			}

			// Displays client info on the login page to make the redirect less confusing
			clientInfo = await OAuth2Clients.authorizeClientInfo(client, []);
		}
	}

	// Activation routine
	if (url.searchParams.has('activate')) {
		const activationInfo = await Users.getActivationToken(
			url.searchParams.get('activate') as string
		);

		if (!activationInfo?.user) {
			return {
				activated: false
			};
		}

		await Users.activateUserBy(activationInfo.token, activationInfo.user);
		await Audit.insertRequest(AuditAction.USER_UPDATE, event, activationInfo?.user, 'activate');

		return {
			activated: true
		};
	}

	return {
		activated: null,
		clientInfo
	};
};