import { createSession, setSessionTokenCookie } from '$lib/server/auth';
import { authentik } from '$lib/server/oauth';
import { decodeIdToken } from 'arctic';

import type { RequestEvent } from '@sveltejs/kit';
import type { OAuth2Tokens } from 'arctic';
import { db } from '$lib/server/db';
import { eq } from 'drizzle-orm';

import * as table from '$lib/server/db/schema';

export async function GET(event: RequestEvent): Promise<Response> {
	const code = event.url.searchParams.get('code');
	const state = event.url.searchParams.get('state');
	const storedState = event.cookies.get('authentik_oauth_state') ?? null;
	const codeVerifier = event.cookies.get('authentik_code_verifier') ?? null;

	if (code === null || state === null || storedState === null || codeVerifier === null) {
		return new Response(null, {
			status: 400,
		});
	}
	if (state !== storedState) {
		return new Response(null, {
			status: 400,
		});
	}

	let tokens: OAuth2Tokens;
	try {
		tokens = await authentik.validateAuthorizationCode(code, codeVerifier);
	} catch (e) {
		// Invalid code or client credentials
		return new Response(null, {
			status: 400,
		});
	}
	const claims = decodeIdToken(tokens.idToken()) as {
		sub: string;
		preferred_username: string;
		name: string;
	};
	console.log('claims', claims);
	const userId: string = claims.sub;
	const username: string = claims.preferred_username;

	const existingUser = await db.query.users.findFirst({ where: eq(table.users.id, userId) });

	if (existingUser) {
		const session = await createSession(existingUser.id);
		setSessionTokenCookie(event, session.id, session.expiresAt);
		return new Response(null, {
			status: 302,
			headers: {
				Location: '/',
			},
		});
	}

	const user: table.User = {
		id: userId,
		authSource: 'authentik',
		username,
		name: claims.name as string,
	};

	try {
		await db.insert(table.users).values(user);
		const session = await createSession(user.id);
		setSessionTokenCookie(event, session.id, session.expiresAt);
	} catch (e) {
		console.error('failed to create user', e);
		return new Response(null, {
			status: 500,
		});
	}

	return new Response(null, {
		status: 302,
		headers: {
			Location: '/',
		},
	});
}