import {NextFunction, Request, Response} from "express";

import Controller from "../Controller.js";
import ModelFactory from "../db/ModelFactory.js";
import {UnknownRelationValidationError} from "../db/Validator.js";
import {BadRequestError} from "../HttpError.js";
import AuthComponent, {AuthMiddleware, RequireAuthMiddleware, RequireGuestMiddleware} from "./AuthComponent.js";
import AuthMethod from "./AuthMethod.js";
import AuthProof from "./AuthProof.js";
import User from "./models/User.js";
import UserNameComponent from "./models/UserNameComponent.js";
import UserPasswordComponent from "./password/UserPasswordComponent.js";

export default class AuthController extends Controller {
    public static flashSuccessfulAuthenticationWelcomeMessage(
        user: User,
        req: Request,
        messagePrefix: string,
    ): void {
        const name = user.asOptional(UserNameComponent)?.getName();
        req.flash('success', `${messagePrefix} Welcome${name ? `, ${name}` : ''}.`);
    }

    public getRoutesPrefix(): string {
        return '/auth';
    }

    public routes(): void {
        this.post('/logout', this.postLogout, 'logout', RequireAuthMiddleware);

        this.use(async (req, res, next) => {
            const authGuard = this.getApp().as(AuthComponent).getAuthGuard();
            if (await authGuard.interruptAuth(req, res)) return;
            next();
        });

        this.get('/', this.getAuth, 'auth', RequireGuestMiddleware);
        this.post('/login', this.postLogin, 'login', RequireGuestMiddleware);
        this.post('/register', this.postRegister, 'register', RequireGuestMiddleware);
    }

    protected async getAuth(req: Request, res: Response, _next: NextFunction): Promise<void> {
        const authGuard = this.getApp().as(AuthComponent).getAuthGuard();

        const userModelFactory = ModelFactory.get(User);
        const hasUsername = userModelFactory.hasComponent(UserNameComponent);
        const hasPassword = userModelFactory.hasComponent(UserPasswordComponent);
        res.formatViewData('auth/auth', {
            auth_methods: authGuard.getAuthMethodNames(),
            hasUsername: hasUsername,
            hasPassword: hasPassword,
            canRegisterWithPassword: hasUsername && hasPassword,
        });
    }

    protected async postLogin(req: Request, res: Response): Promise<void> {
        return await this.handleAuth(req, res, false);
    }

    protected async postRegister(req: Request, res: Response): Promise<void> {
        return await this.handleAuth(req, res, true);
    }

    protected async handleAuth(req: Request, res: Response, isRegistration: boolean): Promise<void> {
        if (isRegistration && !req.body.auth_method) {
            throw new BadRequestError('Cannot register without specifying desired auth_method.',
                'Please specify auth_method.', req.url);
        }

        const authGuard = this.getApp().as(AuthComponent).getAuthGuard();

        const identifier = req.body.identifier;
        if (!identifier) throw new BadRequestError('Identifier not specified.', 'Please try again.', req.originalUrl);

        // Get requested auth method
        if (req.body.auth_method) {
            const method = await authGuard.getAuthMethodByName(req.body.auth_method);
            if (!method) {
                throw new BadRequestError('Invalid auth method: ' + req.body.auth_method,
                    'Available methods are: ' + authGuard.getAuthMethodNames(), req.url);
            }

            // Register
            if (isRegistration) return await method.attemptRegister(req, res, identifier);

            const user = await method.findUserByIdentifier(identifier);

            // Redirect to registration if user not found
            if (!user) return await this.redirectToRegistration(req, res, identifier);

            // Login
            return await method.attemptLogin(req, res, user);
        }

        const methods = await authGuard.getAuthMethodsByIdentifier(identifier);

        // Redirect to registration if user not found
        if (methods.length === 0) return await this.redirectToRegistration(req, res, identifier);

        // Choose best matching method
        let user: User | null = null;
        let method: AuthMethod<AuthProof<User>> | null = null;
        let weight = -1;

        for (const entry of methods) {
            const methodWeight = entry.method.getWeightForRequest(req);
            if (methodWeight > weight) {
                user = entry.user;
                method = entry.method;
                weight = methodWeight;
            }
        }

        if (!method || !user) ({method, user} = methods[0]); // Default to first method

        // Login
        return await method.attemptLogin(req, res, user);
    }

    protected async postLogout(req: Request, res: Response, _next: NextFunction): Promise<void> {
        const userId = typeof req.body.user_id === 'string' ? parseInt(req.body.user_id) : null;

        const proofs = await req.as(AuthMiddleware).getAuthGuard().getProofs(req);

        for (const proof of proofs) {
            if (userId === null || (await proof.getResource())?.id === userId) {
                await proof.revoke();
            }
        }

        req.flash('success', 'Successfully logged out.');
        res.redirect(req.getIntendedUrl() || '/');
    }

    protected async redirectToRegistration(req: Request, res: Response, identifier: string): Promise<void> {
        const error = new UnknownRelationValidationError(User.table, 'identifier');
        error.thingName = 'identifier';
        error.value = identifier;
        throw error;
    }
}