import { Client } from 'discord.js';
import { readdir } from 'fs/promises';
import { removeExtension } from './misc';

/**
 * Load the localizations files into memory.
 *
 * Show percentage of translations.
 * @param default_lang default lang
 * @returns Map of map with all the localizations
 */
export const loadLocales = async (default_lang: string) => {
	// Get files from locales/ directory
	const old_path = __dirname.split('/');
	old_path.pop();
	const files = await readdir(`${old_path.join('/')}/locales`);

	// Read JSON files content and load it into the memory
	const locales = new Map<string, Map<string, string>>();
	await Promise.all(
		files.map(async lang => {
			// Import file
			const content: {
				[key: string]: string
			} = await import(
				`../locales/${lang}`
			);

			// Add it to the memory
			locales.set(
				removeExtension(lang),
				new Map(Object.keys(content)
					// Ignore the default key
					.filter(str => str !== 'default')
					.map(str => {
						return [str, content[str]];
					}),
				)
			);
		})
	);

	// Check locales sanity
	checkLocales(locales, default_lang);

	return locales;
};

/**
 * Builds a dictionary, if a translation is not available,
 * we fallback to default lang.
 * @param client Client
 * @param text Name of string to fetch
 * @returns the dictionary
 */
export const getLocalizations = (client: Client, text: string) => {
	const data: Record<string, string> = {};

	// Load all the localizations
	client.locales.forEach((locale, lang) => {
		// Fetch the text and fallback to default lang if needed
		// See getLocale for more info on why we *can* fallback
		const str = locale.get(text)
			?? client.locales.get(client.config.default_lang)?.get(text);

		// Store it if defined
		if (str !== undefined) {
			data[lang] = str;
		}
	});

	return data;
};

/**
 * Return the locale data for a lang,
 * fallback to default language when a string isn't available.
 * @param client Client
 * @param lang Lang to fetch
 * @returns the map with the desired languaged clogged with the default one
 */
export const getLocale = (client: Client, lang: string) => {
	// Load default lang
	const default_locales = client.locales.get(client.config.default_lang);
	// Load desired lang
	const desired_locales = client.locales.get(lang);

	// Get text and fallback to default lang if needed
	//
	// We can fallback to the default one without any problem
	// because we make sure that the default language always contains
	// the desired text, and that the other languages are only translations
	const locales = new Map();
	default_locales?.forEach((_, key) => {
		locales.set(key, desired_locales?.get(key) ?? default_locales.get(key));
	});

	return locales;
};

/**
 * Show percentage of translation progression.
 *
 * Raise an error if the default lang isn't
 * the lang with most text.
 * @param locales Locales loaded
 * @param default_lang default lang
 * @returns void
 */
const checkLocales =
async (locales: Map<string, Map<string, string>>, default_lang: string) => {
	// Associate each lang with the number of locale it has
	let locales_size = new Map<string, number>();
	locales.forEach((locales_data, lang) => {
		locales_size.set(lang, locales_data.size);
	});

	// Sort the map
	locales_size = new Map([...locales_size.entries()]
		.sort((a, b) => b[1] - a[1]));

	// Check if default lang is 100%
	const [max_size_name] = locales_size.keys();
	const [max_size] = locales_size.values();
	const default_lang_size = locales_size.get(default_lang) ?? 0;
	if (max_size > default_lang_size) {
		// Throw error because in this case we are sure than the security
		// explained in getLocale isn't true.
		// However, it is possible that this condition is true
		// and the security is poor, but it's better than nothing.
		throw new Error(
			`The default locale (${default_lang} = ${default_lang_size}) isn't complete `
			+ `(${max_size_name} = ${max_size}).`
		);
	}

	// Remove the default language as it is used as a reference
	locales_size.delete(default_lang);

	// Displays the percentages according to the default language
	// lower is bigger
	const bar_size = 4;
	locales_size.forEach((size, lang) => {
		const percentage = (size / max_size) * 100;
		// Colored bar part
		const blocks = ' '.repeat(percentage / bar_size);
		// Blank bar part
		const blank = ' '.repeat((100 - percentage) / bar_size);
		const color = () => {
			switch (true) {
				case percentage <= 25:
					// Red
					return '\x1b[41m';
				case percentage <= 50:
					// Mangeta
					return '\x1b[45m';
				case percentage <= 75:
					// Cyan
					return '\x1b[46m';
				case percentage <= 100:
					// Green
					return '\x1b[42m';
				default:
					return '';
			}
		};

		console.log(`${lang} | ${color()}${blocks}\x1b[0m${blank} | ${percentage}%`);
	});
};