import {Express} from "express";

import AssetPreCompiler from "./AssetPreCompiler.js";

export default abstract class ViewEngine extends AssetPreCompiler {
    protected constructor(
        targetDir: string,
        assetType: string,
        extension: string,
        outputToPublicDir: boolean,
        ...additionalViewPaths: string[]
    ) {
        super(targetDir, assetType, extension, outputToPublicDir, ...additionalViewPaths);
    }

    public abstract render(
        file: string,
        locals: Record<string, unknown>,
    ): Promise<string>;

    public setup(app: Express, main: boolean): void {
        app.engine(this.extension, (path, options, callback) => {
            // Props (locals)
            const locals = Object.assign(this.getGlobals().get(), options);

            this.render(path, locals)
                .then(value => callback(null, value))
                .catch(err => callback(err));
        });

        const existingViewPaths = app.get('views');
        app.set('views', Array.isArray(existingViewPaths) ?
            [...new Set([
                ...existingViewPaths,
                ...this.getViewPaths(),
            ])] :
            this.getViewPaths());

        if (main) {
            app.set('view engine', this.extension);
        }
    }
}