require('require-yaml');
const gulp = require('gulp');
const PluginError = require('plugin-error');
const argv = require('minimist')(process.argv.slice(2));
const log = require('fancy-log');
const Myt = require('@verdnatura/myt/myt');
const Run = require('@verdnatura/myt/myt-run');
const Start = require('@verdnatura/myt/myt-start');

// Configuration

let isWindows = /^win/.test(process.platform);

if (argv.NODE_ENV)
    process.env.NODE_ENV = argv.NODE_ENV;

let langs = ['es', 'en'];
let srcDir = './front';
let modulesDir = './modules';
let buildDir = 'dist';

let backSources = [
    '!node_modules',
    '!loopback/locale/*.json',
    'loopback',
    'modules/*/back/**',
    'modules/*/back/*',
    'back',
    'print'
];

// Development

const localesRoutes = gulp.parallel(locales, routes);
localesRoutes.description = `Builds locales and routes`;

const front = gulp.series(clean, gulp.parallel(localesRoutes, watch, webpackDevServer));
front.description = `Starts frontend service`;

function backOnly(done) {
    let app = require(`./loopback/server/server`);
    app.start();
    app.on('started', done);
}
backOnly.description = `Starts backend service`;

function backWatch(done) {
    const nodemon = require('gulp-nodemon');

    // XXX: Workaround to avoid nodemon bug
    // https://github.com/remy/nodemon/issues/1346
    let commands = ['node --tls-min-v1.0 --inspect ./node_modules/gulp/bin/gulp.js'];
    if (!isWindows) commands.unshift('sleep 1');

    nodemon({
        exec: commands.join(' && '),
        ext: 'js html css json',
        args: ['backOnly'],
        watch: backSources,
        done: done
    });
}
backWatch.description = `Starts backend in watcher mode`;

const back = gulp.series(dockerStart, backWatch);
back.description = `Starts backend and database service`;

const defaultTask = gulp.parallel(front, back);
defaultTask.description = `Starts all application services`;
function install() {
    const install = require('gulp-install');
    const print = require('gulp-print');

    let npmArgs = [];
    if (argv.ci) npmArgs = ['--no-audit', '--prefer-offline'];

    let packageFiles = ['front/package.json', 'print/package.json'];
    return gulp.src(packageFiles)
        .pipe(print(filepath => {
            return `Installing packages in ${filepath}`;
        }))
        .pipe(install({npm: npmArgs}));
}
install.description = `Installs node dependencies in all directories`;

const i = gulp.series(install);
i.description = `Alias for the 'install' task`;

// Deployment

const build = gulp.series(clean, gulp.parallel(localesRoutes, webpack));
build.description = `Generates binaries and configuration files`;

function clean() {
    const del = require('del');
    const files = [
        `${buildDir}/*`
    ];
    return del(files, {force: true});
}
clean.description = `Cleans all files generated by the 'build' task`;

// Webpack

function webpack(done) {
    const webpackCompile = require('webpack');
    const merge = require('webpack-merge');

    let wpConfig = require('./webpack.config.js');
    wpConfig = merge(wpConfig, {});

    let compiler = webpackCompile(wpConfig);

    compiler.run(function(err, stats) {
        if (err) throw new PluginError('webpack', err);
        log('[webpack]', stats.toString(wpConfig.stats));
        done();
    });
}
webpack.description = `Transpiles application into files`;

function webpackDevServer(done) {
    const webpack = require('webpack');
    const merge = require('webpack-merge');
    const WebpackDevServer = require('webpack-dev-server');

    let wpConfig = require('./webpack.config.js');
    wpConfig = merge(wpConfig, {});

    let devServer = wpConfig.devServer;

    for (let entryName in wpConfig.entry) {
        let entry = wpConfig.entry[entryName];
        if (!Array.isArray(entry))
            entry = [entry];

        let wdsAssets = [
            `webpack-dev-server/client?http://localhost:${devServer.port}/`,
            `webpack/hot/dev-server`
        ];
        wpConfig.entry[entryName] = wdsAssets.concat(entry);
    }

    let compiler = webpack(wpConfig);
    new WebpackDevServer(compiler, wpConfig.devServer)
        .listen(devServer.port, devServer.host, function(err) {
            if (err) throw new PluginError('webpack-dev-server', err);
            // XXX: Keep the server alive or continue?
            done();
        });
}
webpackDevServer.description = `Transpiles application into memory`;

// Locale

let localeFiles = [
    `${srcDir}/**/locale/*.yml`,
    `${modulesDir}/*/front/**/locale/*.yml`
];

/**
 * Mixes all locale files into one JSON file per module and language. It looks
 * recursively in all project directories for locale folders with per language
 * yaml translation files.
 *
 * @return {Stream} The merged gulp streams
 */
function locales() {
    const mergeJson = require('gulp-merge-json');
    const gulpFile = require('gulp-file');
    const yaml = require('gulp-yaml');
    const merge = require('merge-stream');
    const fs = require('fs-extra');

    let streams = [];
    let localePaths = [];

    let modules = fs.readdirSync(modulesDir);
    for (let mod of modules)
        localePaths[mod] = `${modulesDir}/${mod}`;

    let baseMods = ['core', 'salix'];
    for (let mod of baseMods)
        localePaths[mod] = `${srcDir}/${mod}`;

    for (let mod in localePaths) {
        let path = localePaths[mod];
        for (let lang of langs) {
            let localeFiles = `${path}/**/locale/${lang}.yml`;
            streams.push(gulp.src(localeFiles)
                .pipe(yaml())
                .pipe(mergeJson({fileName: `${lang}.json`}))
                .pipe(gulp.dest(`${buildDir}/locale/${mod}`)));
        }
    }

    for (let mod in localePaths) {
        for (let lang of langs) {
            let file = `${buildDir}/locale/${mod}/${lang}.json`;
            if (fs.existsSync(file)) continue;
            streams.push(gulpFile('en.json', '{}', {src: true})
                .pipe(gulp.dest(`${buildDir}/locale/${mod}`)));
        }
    }

    return merge(streams);
}
locales.description = `Generates client locale files`;

// Routes

let routeFiles = `${modulesDir}/*/front/routes.json`;

function routes() {
    const concat = require('gulp-concat');
    const wrap = require('gulp-wrap');

    return gulp.src(routeFiles)
        .pipe(concat('routes.js', {newLine: ','}))
        .pipe(wrap('var routes = [<%=contents%>\n];'))
        .pipe(gulp.dest(buildDir));
}
routes.description = 'Merges all module routes file into one file';

// Watch

function watch(done) {
    gulp.watch(routeFiles, gulp.series(routes));
    gulp.watch(localeFiles, gulp.series(locales));
    done();
}
watch.description = `Watches for changes in routes and locale files`;

// Docker
async function dockerStart() {
    const myt = new Myt();
    await myt.init({workspace: __dirname});
    await myt.run(Start);
    await myt.deinit();
}
dockerStart.description = `Starts the DB container`;

async function docker() {
    const myt = new Myt();
    await myt.init({workspace: __dirname});
    await myt.run(Run);
    await myt.deinit();
}
docker.description = `Builds and starts the DB container`;

module.exports = {
    default: defaultTask,
    front,
    back,
    backOnly,
    backWatch,
    i,
    install,
    build,
    clean,
    webpack,
    webpackDevServer,
    routes,
    locales,
    localesRoutes,
    watch,
    dockerStart,
    docker
};