import nunjucks, {Environment} from "nunjucks";
import config from "config";
import {Express, Router} from "express";
import ApplicationComponent from "../ApplicationComponent";
import Controller from "../Controller";
import {ServerError} from "../HttpError";

export default class NunjucksComponent extends ApplicationComponent<void> {
    private readonly viewsPath: string;
    private env?: Environment;

    constructor(viewsPath: string = 'views') {
        super();
        this.viewsPath = viewsPath;
    }

    public async start(app: Express): Promise<void> {
        let coreVersion = 'unknown';
        try {
            coreVersion = require('../../package.json').version;
        } catch (e) {
            try {
                coreVersion = require('../package.json').version;
            } catch (e) {
            }
        }

        this.env = nunjucks.configure(this.viewsPath, {
            autoescape: true,
            express: app,
            noCache: !config.get('view.cache'),
            throwOnUndefined: true,
        })
            .addGlobal('route', (route: string, params: { [p: string]: string } | [] = [], absolute: boolean = false) => {
                const path = Controller.route(route, params, absolute);
                if (path === null) throw new ServerError(`Route ${route} not found.`);
                return path;
            })
            .addGlobal('app_version', this.app!.getVersion())
            .addGlobal('core_version', coreVersion)
            .addFilter('hex', (v: number) => {
                return v.toString(16);
            });
        app.set('view engine', 'njk');
    }

    public async init(router: Router): Promise<void> {
        router.use((req, res, next) => {
            req.env = this.env!;
            res.locals.url = req.url;
            res.locals.params = () => req.params;

            res.locals.app = config.get('app');

            next();
        });
    }
}