gerard2p/koaton

import * as render from 'consolidate';
import { extname, resolve, basename } from 'upath';
import * as fs from 'fs';
import * as SetUpEngines from './setup';
import debug from '../support/debug';

/** @ignore */
let avaliableEngines = Object.keys(render);
avaliableEngines.splice(avaliableEngines.indexOf('requires'), 1);
/** @ignore */
const testedEngines = [ 'handlebars', 'nunjucks' ],
    npmpackage = require(ProyPath('package.json')),
    exists = function (target) {
        try {
            fs.accessSync(target, fs.constants.R_OK);
            return true;
        } catch (err) {
            return false;
        }
    };
    /* istanbul ignore next */
if (Object.keys(npmpackage.dependencies).indexOf('mongoose') > -1) {
    require(ProyPath('node_modules', 'mongoose')).Promise = Promise;
}
/** @ignore */
let extMapper = {
        '': 'html',
        'njk': 'nunjucks'
    },
    cacher = {};
/**
* This function return the correct enginge for the path provided
* path  engine is stored in a cache
* @param {String} fullpath - filename to render
* @return {engine}
*/
function ex2engine (fullpath) {
    let extension = extname(fullpath).slice(1);
    let file = fullpath.replace(extname(fullpath), '');
    let engine;
    if (!extension && !cacher[fullpath] && !exists(fullpath)) {
        for (const engineExt of testedEngines) {
            /* istanbul ignore else */
            if (exists(`${file}.${engineExt}`)) {
                extension = engineExt;
                break;
            }
        }
    }
    if (!cacher[fullpath]) {
        engine = extMapper[extension] || extension;
        let path = `${file}.${extension}`;
        if (testedEngines.indexOf(engine) === -1 && avaliableEngines.indexOf(engine) > -1 && engine !== 'html') {
            console.warn(`${engine} engine is avaliable but not tested`);
        } else if (avaliableEngines.indexOf(engine) === -1 && engine !== 'html') {
            throw Error(`${engine} engine is not supported`);
        }
        cacher[fullpath] = [engine, path];
    }
    return cacher[fullpath];
}
for (const engine of avaliableEngines) {
    if (npmpackage.dependencies[engine] !== undefined && SetUpEngines[engine] !== undefined) {
        render.requires[engine] = SetUpEngines[engine]();
        if (configuration.views[engine] !== undefined) {
            configuration.views[engine](render.requires[engine]);
        }
    }
}
/**
* This function return the correct enginge for the path provided
* path  engine is stored in a cache
* @param {String} file - relative to views/
* @return {Object}
*/
function template (file, locals) {
    let fullpath = resolve('views', file);
    const [engine, target] = ex2engine(fullpath);
    if (engine !== 'html') {
        return render[engine](target, Object.assign({}, locals, {
            liveReloadHost: process.env.liveReloadHost,
            isDevelopment: configuration.env !== 'production'
        }));
    } else {
        return new Promise(function (resolve, reject) {
            try {
                fs.accessSync(target, fs.constants.R_OK);
                resolve(fs.readFileSync(target, 'utf-8'));
            } catch (err) {
                /* istanbul ignore next */
                reject(err);
            }
        });
    }
}
/**
 * Sets up some of the initial values
 * @param {Object} options={} - you can pass custom mapping for extname <--> engine relation
 */
export function initialize (/* istanbul ignore next */ options = {}) {
    extMapper = Object.assign({}, extMapper, options.extensions);
}
/**
 * This middleware allows you to render or return send files
 * and appends ctx.send ad ctx.render
 * @param {KoaContext} ctx
 * @param {KoaNext} next
 * @param {JSURL} ctx.send - function(file: String) reference attached.
 * @param {JSURL} ctx.render - function(file: String, locals: Object)reference attached.
 */
export async function viewsMiddleware (ctx, next) {
    ctx.send = async (file) => {
        ctx.type = extname(basename(file));
        ctx.body = fs.createReadStream(file);
        ctx.state.nocache = false;
    };
    ctx.render = async function (file, locals) {
        try {
            ctx.body = await template(file, Object.assign({}, locals, {
                path: ctx.request.path,
                route: ctx.state.route,
                subdomain: ctx.state.subdomain
            }));
            ctx.state.nocache = false;
        } catch (err) {
            debug(err);
            ctx.status = 500;
        }
    };
    await next();
}