'use strict';

// ============================================================================
// Localization
// This is based on Polyglot, but with some changes to avoid dependencies on
// additional libraries and with support for Vue.
// ============================================================================

import {SERVER} from 'utilities/constants';
import {has} from 'utilities/object';
import Module from 'utilities/module';


// ============================================================================
// TranslationManager
// ============================================================================

export class TranslationManager extends Module {
	constructor(...args) {
		super(...args);
		this.inject('settings');

		this.availableLocales = ['en']; //, 'de', 'ja'];

		this.localeData = {
			en: { name: 'English' },
			//de: { name: 'Deutsch' },
			//ja: { name: '日本語' }
		}

		this.settings.add('i18n.locale', {
			default: -1,
			process: (ctx, val) => {
				if ( val === -1 )
					val = ctx.get('context.session.languageCode');

				return this.availableLocales.includes(val) ? val : 'en'
			},

			_ui: {
				path: 'Appearance > Localization >> General',
				title: 'Language',
				// description: '',

				component: 'setting-select-box',
				data: (profile, val) => [{
					selected: val === -1,
					value: -1,
					i18n_key: 'setting.appearance.localization.general.language.twitch',
					title: "Use Twitch's Language"
				}].concat(this.availableLocales.map(l => ({
					selected: val === l,
					value: l,
					title: this.localeData[l].name
				})))
			},

			changed: val => this.locale = val
		});

	}

	onEnable() {
		this._ = new TranslationCore; /*({
			awarn: (...args) => this.log.info(...args)
		});*/

		this.locale = this.settings.get('i18n.locale');
	}

	get locale() {
		return this._.locale;
	}

	set locale(new_locale) {
		this.setLocale(new_locale);
	}


	toLocaleString(thing) {
		if ( thing && thing.toLocaleString )
			return thing.toLocaleString(this._.locale);
		return thing;
	}


	async loadLocale(locale) {
		/*if ( locale === 'en' )
			return {};

		if ( locale === 'de' )
			return {
				site: {
					menu_button: 'FrankerFaceZ Leitstelle'
				},

				player: {
					reset_button: 'Doppelklicken, um den Player zurückzusetzen'
				},

				setting: {
					reset: 'Zurücksetzen',

					appearance: {
						_: 'Aussehen',
						description: 'Personalisieren Sie das Aussehen von Twitch. Ändern Sie das Farbschema und die Schriften und stimmen Sie das Layout so ab, dass Sie ein optimales Erlebnis erleben.<br><br>(Yes, this is Google Translate still.)',
						localization: {
							_: 'Lokalisierung',

							general: {
								language: {
									_: 'Sprache',
									twitch: "Verwenden Sie Twitch's Sprache"
								}
							},


							dates_and_times: {
								_: 'Termine und Zeiten',
								allow_relative_times: {
									_: 'Relative Zeiten zulassen',
									description: 'Wenn dies aktiviert ist, zeigt FrankerFaceZ einige Male in einem relativen Format an. <br>Beispiel: vor 3 Stunden'
								}
							}


						},
						layout: 'Layout',
						theme: 'Thema'
					},

					profiles: {
						_: 'Profile',

						active: 'Dieses Profil ist aktiv.',
						inactive: {
							_: 'Dieses Profil ist nicht aktiv.',
							description: 'Dieses Profil stimmt nicht mit dem aktuellen Kontext überein und ist momentan nicht aktiv, so dass Sie keine Änderungen sehen, die Sie hier bei Twitch vorgenommen haben.'
						},

						configure: 'Konfigurieren',

						default: {
							_: 'Standard Profil',
							description: 'Einstellungen, die überall auf Twitch angewendet werden.'
						},

						moderation: {
							_: 'Mäßigung',
							description: 'Einstellungen, die gelten, wenn Sie ein Moderator des aktuellen Kanals sind.'
						}
					},

					add_ons: {
						_: 'Erweiterung'
					},

					'inherited-from': 'Vererbt von: %{title}',
					'overridden-by': 'Überschrieben von: %{title}'
				},

				'main-menu': {
					search: 'Sucheinstellungen',

					about: {
						_: 'Über',
						news: 'Nachrichten',
						support: 'Unterstützung'
					}
				}
			}

		if ( locale === 'ja' )
			return {
				greeting: 'こんにちは',

				site: {
					menu_button: 'FrankerFaceZコントロールセンター'
				},

				setting: {
					appearance: {
						_: '外観',
						localization: '局地化',
						layout: '設計',
						theme: '題材'
					}
				},

				'main-menu': {
					search: '検索設定',
					version: 'バージョン%{version}',

					about: {
						_: '約',
						news: '便り',
						support: '対応'
					}
				}
			}*/

		const resp = await fetch(`${SERVER}/script/i18n/${locale}.json`);
		if ( ! resp.ok ) {
			if ( resp.status === 404 ) {
				this.log.info(`Cannot Load Locale: ${locale}`);
				return {};
			}

			this.log.warn(`Cannot Load Locale: ${locale} -- Status: ${resp.status}`);
			throw new Error(`http error ${resp.status} loading phrases`);
		}

		return resp.json();
	}

	async setLocale(new_locale) {
		const old_locale = this._.locale;
		if ( new_locale === old_locale )
			return [];

		this._.locale = new_locale;
		this._.clear();
		this.log.info(`Changed Locale: ${new_locale} -- Old: ${old_locale}`);
		this.emit(':changed', new_locale, old_locale);
		this.emit(':update');

		if ( new_locale === 'en' ) {
			// All the built-in messages are English. We don't need special
			// logic to load the translations.
			this.emit(':loaded', []);
			return [];
		}

		const phrases = await this.loadLocale(new_locale);

		if ( this._.locale !== new_locale )
			throw new Error('locale has changed since we started loading');

		const added = this._.extend(phrases);
		if ( added.length ) {
			this.log.info(`Loaded Locale: ${new_locale} -- Phrases: ${added.length}`);
			this.emit(':loaded', added);
			this.emit(':update');
		}

		return added;
	}

	has(key) {
		return this._.has(key);
	}

	formatNumber(...args) {
		return this._.formatNumber(...args);
	}

	t(...args) {
		return this._.t(...args);
	}
}



// ============================================================================
// TranslationCore
// ============================================================================

const REPLACE = String.prototype.replace,
	SPLIT = String.prototype.split;

const DEFAULT_FORMATTERS = {
	en_plural: n => n !== 1 ? 's' : '',
	number: (n, locale) => n.toLocaleString(locale)
}


export default class TranslationCore {
	constructor(options) {
		options = options || {};
		this.warn = options.warn;
		this.phrases = new Map;
		this.extend(options.phrases);
		this.locale = options.locale || 'en';
		this.defaultLocale = options.defaultLocale || this.locale;

		const allowMissing = options.allowMissing ? transformPhrase : null;
		this.onMissingKey = typeof options.onMissingKey === 'function' ? options.onMissingKey : allowMissing;
		this.transformPhrase = typeof options.transformPhrase === 'function' ? options.transformPhrase : transformPhrase;
		this.delimiter = options.delimiter || /\s*\|\|\|\|\s*/;
		this.tokenRegex = options.tokenRegex || /%\{(.*?)(?:\|(.*?))?\}/g;
		this.formatters = Object.assign({}, DEFAULT_FORMATTERS, options.formatters || {});
	}


	formatNumber(value) {
		return value.toLocaleString(this.locale);
	}


	extend(phrases, prefix) {
		const added = [];
		for(const key in phrases)
			if ( has(phrases, key) ) {
				let phrase = phrases[key];
				const pref_key = prefix ? key === '_' ? prefix : `${prefix}.${key}` : key;

				if ( typeof phrase === 'object' )
					added.push(...this.extend(phrase, pref_key));
				else {
					if ( typeof phrase === 'string' && phrase.indexOf(this.delimiter) !== -1 )
						phrase = SPLIT.call(phrase, this.delimiter);
					this.phrases.set(pref_key, phrase);
					added.push(pref_key);
				}
			}

		return added;
	}

	unset(phrases, prefix) {
		if ( typeof phrases === 'string' )
			phrases = [phrases];

		const keys = Array.isArray(phrases) ? phrases : Object.keys(phrases);
		for(const key of keys) {
			const pref_key = prefix ? `${prefix}.${key}` : key;
			const phrase = phrases[key];
			if ( typeof phrase === 'object' )
				this.unset(phrase, pref_key);
			else
				this.phrases.delete(pref_key);
		}
	}

	has(key) {
		return this.phrases.has(key);
	}

	set(key, phrase) {
		if ( typeof phrase === 'string' && phrase.indexOf(this.delimiter) !== -1 )
			phrase = SPLIT.call(phrase, this.delimiter);

		this.phrases.set(key, phrase);
	}

	clear() {
		this.phrases.clear();
	}

	replace(phrases) {
		this.clear();
		this.extend(phrases);
	}

	t(key, phrase, options, use_default) {
		const opts = options == null ? {} : options;
		let p, locale;

		if ( use_default ) {
			p = phrase;
			locale = this.defaultLocale;

		} else if ( key === undefined && phrase ) {
			p = phrase;
			locale = this.defaultLocale;
			if ( this.warn )
				this.warn(`Translation key not generated with phrase "${phrase}"`);

		} else if ( this.phrases.has(key) ) {
			p = this.phrases.get(key);
			locale = this.locale;
		} else if ( phrase ) {
			if ( this.warn && this.locale !== this.defaultLocale )
				this.warn(`Missing translation for key "${key}" in locale "${this.locale}"`);

			p = phrase;
			locale = this.defaultLocale;
		} else if ( this.onMissingKey )
			return this.onMissingKey(key, opts, this.locale, this.tokenRegex, this.formatters);
		else {
			if ( this.warn )
				this.warn(`Missing translation for key "${key}" in locale "${this.locale}"`);

			return key;
		}

		return this.transformPhrase(p, opts, locale, this.tokenRegex, this.formatters);
	}
}


// ============================================================================
// Transformations
// ============================================================================

const DOLLAR_REGEX = /\$/g;

export function transformPhrase(phrase, substitutions, locale, token_regex, formatters) {
	const is_array = Array.isArray(phrase);
	if ( substitutions == null )
		return is_array ? phrase[0] : phrase;

	let result = phrase;
	const options = typeof substitutions === 'number' ? {count: substitutions} : substitutions;

	if ( is_array )
		result = result[pluralTypeIndex(
			locale || 'en',
			has(options, 'count') ? options.count : 1
		)] || result[0];

	if ( typeof result === 'string' )
		result = REPLACE.call(result, token_regex, (expr, arg, fmt) => {
			if ( ! has(options, arg) )
				return '';

			let val = options[arg];
			const formatter = formatters[fmt];
			if ( typeof formatter === 'function' )
				val = formatter(val, locale, options);
			else if ( typeof val === 'string' )
				val = REPLACE.call(val, DOLLAR_REGEX, '$$');

			return val;
		});

	return result;
}


// ============================================================================
// Plural Nonsense
// ============================================================================

const PLURAL_TYPE_TO_LANG = {
	arabic: ['ar'],
	chinese: ['fa', 'id', 'ja', 'ko', 'lo', 'ms', 'th', 'tr', 'zh'],
	german: ['da', 'de', 'en', 'es', 'es', 'fi', 'el', 'he', 'hu', 'it', 'nl', 'no', 'pt', 'sv'],
	french: ['fr', 'tl', 'pt-br'],
	russian: ['hr', 'ru', 'lt'],
	czech: ['cs', 'sk'],
	polish: ['pl'],
	icelandic: ['is']
};

const PLURAL_LANG_TO_TYPE = {};

for(const type in PLURAL_TYPE_TO_LANG) // eslint-disable-line guard-for-in
	for(const lang of PLURAL_TYPE_TO_LANG[type])
		PLURAL_LANG_TO_TYPE[lang] = type;

const PLURAL_TYPES = {
	arabic: n => {
		if ( n < 3 ) return n;
		const n1 = n % 100;
		if ( n1 >= 3 && n1 <= 10 ) return 3;
		return n1 >= 11 ? 4 : 5;
	},
	chinese: () => 0,
	german: n => n !== 1 ? 1 : 0,
	french: n => n > 1 ? 1 : 0,
	russian: n => {
		const n1 = n % 10, n2 = n % 100;
		if ( n1 === 1 && n2 !== 11 ) return 0;
		return n1 >= 2 && n1 <= 4 && (n2 < 10 || n2 >= 20) ? 1 : 2;
	},
	czech: n => {
		if ( n === 1 ) return 0;
		return n >= 2 && n <= 4 ? 1 : 2;
	},
	polish: n => {
		if ( n === 1 ) return 0;
		const n1 = n % 10, n2 = n % 100;
		return n1 >= 2 && n1 <= 4 && (n2 < 10 || n2 >= 20) ? 1 : 2;
	},
	icelandic: n => n % 10 !== 1 || n % 100 === 11 ? 1 : 0
};


export function pluralTypeIndex(locale, n) {
	let type = PLURAL_LANG_TO_TYPE[locale];
	if ( ! type ) {
		const idx = locale.indexOf('-');
		if ( idx !== -1 )
			type = PLURAL_LANG_TO_TYPE[locale.slice(0, idx)]
	}

	return PLURAL_TYPES[type || 'german'](n);
}