'use strict';

const _ = require('lodash');
const winston = require('winston');
const nconf = require('nconf');
const fs = require('fs');
const path = require('path');
const { mkdirp } = require('mkdirp');

const plugins = require('../plugins');
const db = require('../database');
const file = require('../file');
const minifier = require('./minifier');
const utils = require('../utils');

const CSS = module.exports;

CSS.supportedSkins = [
	'cerulean', 'cosmo', 'cyborg', 'darkly', 'flatly', 'journal', 'litera',
	'lumen', 'lux', 'materia', 'minty', 'morph', 'pulse', 'quartz', 'sandstone',
	'simplex', 'sketchy', 'slate', 'solar', 'spacelab', 'superhero', 'united',
	'vapor', 'yeti', 'zephyr',
];

const buildImports = {
	client: function (source, themeData) {
		return [
			boostrapImport(themeData),
			'@import "@adactive/bootstrap-tagsinput/src/bootstrap-tagsinput";',
			source,
			'@import "jquery-ui";',
			'@import "cropperjs/dist/cropper";',
		].join('\n');
	},
	admin: function (source) {
		return [
			'@import "admin/overrides";',
			'@import "bootstrap/scss/bootstrap";',
			'@import "mixins";',
			'@import "fontawesome/loader";',
			getFontawesomeStyle(),
			'@import "@adactive/bootstrap-tagsinput/src/bootstrap-tagsinput";',
			'@import "generics";',
			'@import "responsive-utilities";',
			'@import "admin/admin";',
			source,
			'@import "jquery-ui";',
		].join('\n');
	},
};

function boostrapImport(themeData) {
	// see https://getbootstrap.com/docs/5.0/customize/sass/#variable-defaults
	// for an explanation of this order and https://bootswatch.com/help/
	const { bootswatchSkin, bsVariables, isCustomSkin } = themeData;
	function bsvariables() {
		if (bootswatchSkin) {
			if (isCustomSkin) {
				return themeData._variables || '';
			}
			return `@import "bootswatch/dist/${bootswatchSkin}/variables";`;
		}
		return bsVariables;
	}

	return [
		bsvariables(),
		'@import "bootstrap/scss/mixins/banner";',
		'@include bsBanner("");',
		// functions must be included first
		'@import "bootstrap/scss/functions";',

		// overrides for bs5 variables
		'@import "./scss/overrides";', // this file is in the themes scss folder
		'@import "overrides.scss";', // core scss overrides

		// bs files
		'@import "bootstrap/scss/variables";',
		'@import "bootstrap/scss/variables-dark";',
		'@import "bootstrap/scss/maps";',
		'@import "bootstrap/scss/mixins";',
		'@import "bootstrap/scss/utilities";',

		// Layout & components
		'@import "bootstrap/scss/root";',
		'@import "bootstrap/scss/reboot";',
		'@import "bootstrap/scss/type";',
		'@import "bootstrap/scss/images";',
		'@import "bootstrap/scss/containers";',
		'@import "bootstrap/scss/grid";',
		'@import "bootstrap/scss/tables";',
		'@import "bootstrap/scss/forms";',
		'@import "bootstrap/scss/buttons";',
		'@import "bootstrap/scss/transitions";',
		'@import "bootstrap/scss/dropdown";',
		'@import "bootstrap/scss/button-group";',
		'@import "bootstrap/scss/nav";',
		'@import "bootstrap/scss/navbar";',
		'@import "bootstrap/scss/card";',
		'@import "bootstrap/scss/accordion";',
		'@import "bootstrap/scss/breadcrumb";',
		'@import "bootstrap/scss/pagination";',
		'@import "bootstrap/scss/badge";',
		'@import "bootstrap/scss/alert";',
		'@import "bootstrap/scss/progress";',
		'@import "bootstrap/scss/list-group";',
		'@import "bootstrap/scss/close";',
		'@import "bootstrap/scss/toasts";',
		'@import "bootstrap/scss/modal";',
		'@import "bootstrap/scss/tooltip";',
		'@import "bootstrap/scss/popover";',
		'@import "bootstrap/scss/carousel";',
		'@import "bootstrap/scss/spinners";',
		'@import "bootstrap/scss/offcanvas";',
		'@import "bootstrap/scss/placeholders";',

		// Helpers
		'@import "bootstrap/scss/helpers";',

		'@import "responsive-utilities";',

		// Utilities
		'@import "bootstrap/scss/utilities/api";',
		// scss-docs-end import-stack

		'@import "fontawesome/loader";',
		getFontawesomeStyle(),

		'@import "mixins";', // core mixins
		'@import "generics";',
		'@import "client";', // core page styles
		'@import "./theme";', // rest of the theme scss
		bootswatchSkin && !isCustomSkin ? `@import "bootswatch/dist/${bootswatchSkin}/bootswatch";` : '',
	].join('\n');
}


function getFontawesomeStyle() {
	const styles = utils.getFontawesomeStyles();
	return styles.map(style => `@import "fontawesome/style-${style}";`).join('\n');
}

async function copyFontAwesomeFiles() {
	await mkdirp(path.join(__dirname, '../../build/public/fontawesome/webfonts'));
	const fonts = await fs.promises.opendir(path.join(utils.getFontawesomePath(), '/webfonts'));
	const copyOperations = [];
	for await (const file of fonts) {
		if (file.isFile() && file.name.match(/\.(woff2|ttf|eot)?$/)) { // there shouldn't be any legacy eot files, but just in case we'll allow it
			copyOperations.push(
				fs.promises.copyFile(path.join(fonts.path, file.name), path.join(__dirname, '../../build/public/fontawesome/webfonts/', file.name))
			);
		}
	}
	await Promise.all(copyOperations);
}

async function filterMissingFiles(filepaths) {
	const exists = await Promise.all(
		filepaths.map(async (filepath) => {
			const exists = await file.exists(path.join(__dirname, '../../node_modules', filepath));
			if (!exists) {
				winston.warn(`[meta/css] File not found! ${filepath}`);
			}
			return exists;
		})
	);
	return filepaths.filter((filePath, i) => exists[i]);
}

async function getImports(files, extension) {
	const pluginDirectories = [];
	let source = '';

	function pathToImport(file) {
		if (!file) {
			return '';
		}
		// trim css extension so it inlines the css like less (inline)
		const parsed = path.parse(file);
		const newFile = path.join(parsed.dir, parsed.name);
		return `\n@import "${newFile.replace(/\\/g, '/')}";`;
	}

	files.forEach((styleFile) => {
		if (styleFile.endsWith(extension)) {
			source += pathToImport(styleFile);
		} else {
			pluginDirectories.push(styleFile);
		}
	});
	await Promise.all(pluginDirectories.map(async (directory) => {
		const styleFiles = await file.walk(directory);
		styleFiles.forEach((styleFile) => {
			source += pathToImport(styleFile);
		});
	}));
	return source;
}

async function getBundleMetadata(target) {
	const paths = [
		path.join(__dirname, '../../node_modules'),
		path.join(__dirname, '../../public/scss'),
		path.join(__dirname, '../../public/fontawesome/scss'),
		path.join(utils.getFontawesomePath(), 'scss'),
	];

	// Skin support
	let skin;
	let isCustomSkin = false;
	if (target.startsWith('client-')) {
		skin = target.split('-').slice(1).join('-');
		const isBootswatchSkin = CSS.supportedSkins.includes(skin);
		isCustomSkin = !isBootswatchSkin && await CSS.isCustomSkin(skin);
		target = 'client';
		if (!isBootswatchSkin && !isCustomSkin) {
			skin = ''; // invalid skin or deleted use default
		}
	}

	let themeData = null;
	if (target === 'client') {
		themeData = await db.getObjectFields('config', ['theme:type', 'theme:id', 'useBSVariables', 'bsVariables']);
		const themeId = (themeData['theme:id'] || 'nodebb-theme-harmony');
		const baseThemePath = path.join(
			nconf.get('themes_path'),
			(themeData['theme:type'] && themeData['theme:type'] === 'local' ? themeId : 'nodebb-theme-harmony')
		);
		paths.unshift(baseThemePath);
		paths.unshift(`${baseThemePath}/node_modules`);
		themeData.bsVariables = parseInt(themeData.useBSVariables, 10) === 1 ? (themeData.bsVariables || '') : '';
		themeData.bootswatchSkin = skin;
		themeData.isCustomSkin = isCustomSkin;
		const customSkin = isCustomSkin ? await CSS.getCustomSkin(skin) : null;
		themeData._variables = customSkin && customSkin._variables;
	}

	const [scssImports, cssImports, acpScssImports] = await Promise.all([
		filterGetImports(plugins.scssFiles, '.scss'),
		filterGetImports(plugins.cssFiles, '.css'),
		target === 'client' ? '' : filterGetImports(plugins.acpScssFiles, '.scss'),
	]);

	async function filterGetImports(files, extension) {
		const filteredFiles = await filterMissingFiles(files);
		return await getImports(filteredFiles, extension);
	}

	let imports = `${cssImports}\n${scssImports}\n${acpScssImports}`;
	imports = buildImports[target](imports, themeData);

	return { paths: paths, imports: imports };
}

CSS.getSkinSwitcherOptions = async function (uid) {
	const user = require('../user');
	const meta = require('./index');
	const [userSettings, customSkins] = await Promise.all([
		user.getSettings(uid),
		CSS.getCustomSkins(),
	]);

	const foundCustom = customSkins.find(skin => skin.value === meta.config.bootswatchSkin);
	const defaultSkin = foundCustom ?
		foundCustom.name :
		_.capitalize(meta.config.bootswatchSkin) || '[[user:no-skin]]';

	const defaultSkins = [
		{ name: `[[user:default, ${defaultSkin}]]`, value: '', selected: userSettings.bootswatchSkin === '' },
		{ name: '[[user:no-skin]]', value: 'noskin', selected: userSettings.bootswatchSkin === 'noskin' },
	];
	const lightSkins = [
		'cerulean', 'cosmo', 'flatly', 'journal', 'litera',
		'lumen', 'lux', 'materia', 'minty', 'morph', 'pulse', 'sandstone',
		'simplex', 'sketchy', 'spacelab', 'united', 'yeti', 'zephyr',
	];
	const darkSkins = [
		'cyborg', 'darkly', 'quartz', 'slate', 'solar', 'superhero', 'vapor',
	];
	function parseSkins(skins) {
		skins = skins.map(skin => ({
			name: _.capitalize(skin),
			value: skin,
		}));
		skins.forEach((skin) => {
			skin.selected = skin.value === userSettings.bootswatchSkin;
		});
		return skins;
	}
	return await plugins.hooks.fire('filter:meta.css.getSkinSwitcherOptions', {
		default: defaultSkins,
		custom: customSkins.map(s => ({ ...s, selected: s.value === userSettings.bootswatchSkin })),
		light: parseSkins(lightSkins),
		dark: parseSkins(darkSkins),
	});
};

CSS.getCustomSkins = async function (opts = {}) {
	const meta = require('./index');
	const slugify = require('../slugify');
	const { loadVariables } = opts;
	const customSkins = await meta.settings.get('custom-skins');
	const returnSkins = [];
	if (customSkins && Array.isArray(customSkins['custom-skin-list'])) {
		customSkins['custom-skin-list'].forEach((customSkin) => {
			if (customSkin) {
				returnSkins.push({
					name: customSkin['custom-skin-name'],
					value: slugify(customSkin['custom-skin-name']),
					_variables: loadVariables ? customSkin._variables : undefined,
				});
			}
		});
	}
	return returnSkins;
};

CSS.isSkinValid = async function (skin) {
	return CSS.supportedSkins.includes(skin) || await CSS.isCustomSkin(skin);
};

CSS.isCustomSkin = async function (skin) {
	const skins = await CSS.getCustomSkins();
	return !!skins.find(s => s.value === skin);
};

CSS.getCustomSkin = async function (skin) {
	const skins = await CSS.getCustomSkins({ loadVariables: true });
	return skins.find(s => s.value === skin);
};

CSS.buildBundle = async function (target, fork) {
	if (target === 'client') {
		let files = await fs.promises.readdir(path.join(__dirname, '../../build/public'));
		files = files.filter(f => f.match(/^client.*\.css$/));
		await Promise.all(files.map(f => fs.promises.unlink(path.join(__dirname, '../../build/public', f))));
	}

	const data = await getBundleMetadata(target);
	const minify = process.env.NODE_ENV !== 'development';
	const { ltr, rtl } = await minifier.css.bundle(data.imports, data.paths, minify, fork);

	await Promise.all([
		fs.promises.writeFile(path.join(__dirname, '../../build/public', `${target}.css`), ltr.code),
		fs.promises.writeFile(path.join(__dirname, '../../build/public', `${target}-rtl.css`), rtl.code),
		copyFontAwesomeFiles(),
	]);
	return [ltr.code, rtl.code];
};