const fs = require('fs');
const swc = require('@swc/core');
const path = require('path');
const util = require('util');
const exec = util.promisify(require('child_process').exec);
const postcss = require('postcss');
const htmlminify = require('html-minifier-terser').minify;
const utils = require('./assets/utils.js');
const assproc = require('./assets/assproc.js');

const rootDir = __dirname;

const assetsDir = path.join(rootDir, 'assets');
const assetsInfo = path.join(assetsDir, 'current.json');

const pubDir = path.join(rootDir, 'public');
const pubAssets = '/assets';
const pubAssetsFull = path.join(pubDir, pubAssets);
const pubAssetCSSFormat = '%s-%s.css';
const pubAssetJSFormat = '%s-%s.js';

const isDebugBuild = fs.existsSync(path.join(rootDir, '.debug'));

const renderTemplates = [
    { in: 'errors/401', out: '/error-401.html' },
    { in: 'errors/403', out: '/error-403.html' },
    { in: 'errors/404', out: '/error-404.html' },
    { in: 'errors/500', out: '/error-500.html' },
    { in: 'errors/503', out: '/error-503.html' },
];

const swcJscOptions = {
    target: 'es2016',
    loose: false,
    externalHelpers: false,
    keepClassNames: true,
    preserveAllComments: false,
    transform: {},
    parser: {
        syntax: 'ecmascript',
        jsx: true,
        dynamicImport: false,
        privateMethod: false,
        functionBind: false,
        exportDefaultFrom: false,
        exportNamespaceFrom: false,
        decorators: false,
        decoratorsBeforeExport: false,
        topLevelAwait: true,
        importMeta: false,
    },
    transform: {
        react: {
            runtime: 'classic',
            pragma: '$er',
        },
    },
};

const htmlMinifyOptions = {
    collapseBooleanAttributes: true,
    collapseWhitespace: true,
    conservativeCollapse: false,
    decodeEntities: false,
    quoteCharacter: '"',
    removeAttributeQuotes: true,
    removeComments: true,
    removeEmptyAttributes: true,
    removeOptionalTags: true,
    removeScriptTypeAttributes: true,
    removeStyleLinkTypeAttributes: true,
    sortAttributes: true,
    sortClassName: true,
};

const postcssPlugins = [];
if(!isDebugBuild) postcssPlugins.push(require('cssnano'));
postcssPlugins.push(require('autoprefixer')({
    remove: false,
}));

fs.mkdirSync(pubAssetsFull, { recursive: true });

(async () => {
    console.log('Building assets...');

    const dirs = fs.readdirSync(assetsDir);
    const assets = {};

    const _postcss = postcss(postcssPlugins);

    for(const dir of dirs) {
        const dirPath = path.join(assetsDir, dir);
        if(!fs.statSync(dirPath).isDirectory())
            continue;

        const parts = dir.split('.', 2);
        if(parts.length < 2)
            continue;

        console.log();
        console.log(dir);

        let filePath = '';
        let fileBody = '';

        if(parts[1] === 'js') {
            fileBody = await assproc.process(dirPath, { 'prefix': '#', 'entry': 'main.js' });
            fileBody = (await swc.transform(fileBody, {
                filename: dir,
                sourceMaps: false,
                isModule: false,
                minify: !isDebugBuild,
                jsc: swcJscOptions,
            })).code;
            filePath = path.join(pubAssets, util.format(pubAssetJSFormat, parts[0], utils.shortHash(fileBody)));
        } else if(parts[1] === 'css') {
            fileBody = await assproc.process(dirPath, { 'prefix': '@', 'entry': 'main.css' });
            fileBody = (await _postcss.process(fileBody, { from: dir })).css;
            filePath = path.join(pubAssets, util.format(pubAssetCSSFormat, parts[0], utils.shortHash(fileBody)));
        }

        if(filePath !== '') {
            assets[dir] = filePath;
            fs.writeFileSync(path.join(pubDir, filePath), fileBody);
        } else console.error(`Unknown type: ${parts[1]}`);
    }

    console.log('Writing assets info...');
    fs.writeFileSync(assetsInfo, JSON.stringify(assets));

    console.log('Housekeeping...');
    assproc.housekeep(pubAssetsFull);

    console.log('Prerendering templates...');

    const renderCommand = path.join(rootDir, 'tools/render-tpl');
    console.log(renderCommand);

    for(const info of renderTemplates) {
        console.log();
        console.log(info.in);

        const { stdout, stderr } = await exec(`${renderCommand} ${info.in}`);

        if(stdout.trim() === '') {
            console.error(stderr);
            continue;
        }

        let body = await htmlminify(stdout, htmlMinifyOptions);

        fs.writeFileSync(path.join(pubDir, info.out), body);
    }
})();