tweb/src/lib/langPack.ts

import { MOUNT_CLASS_TO } from "../config/debug";
import { safeAssign } from "../helpers/object";
import { LangPackDifference, LangPackString } from "../layer";
import apiManager from "./mtproto/mtprotoworker";
import sessionStorage from "./sessionStorage";

export const langPack: {[actionType: string]: string} = {
  "messageActionChatCreate": "created the group",
	"messageActionChatEditTitle": "changed group name",
	"messageActionChatEditPhoto": "changed group photo",
	"messageActionChatDeletePhoto": "removed group photo",
	"messageActionChatReturn": "returned to group",
	"messageActionChatJoined": "joined the group",
  "messageActionChatAddUser": "invited {}",
  "messageActionChatAddUsers": "invited {} users",
	"messageActionChatLeave": "left the group",
	"messageActionChatDeleteUser": "removed user {}",
	"messageActionChatJoinedByLink": "joined the group via invite link",
  "messageActionPinMessage": "pinned message",
  "messageActionContactSignUp": "joined Telegram",
	"messageActionChannelCreate": "Channel created",
	"messageActionChannelEditTitle": "Channel renamed",
	"messageActionChannelEditPhoto": "Channel photo updated",
  "messageActionChannelDeletePhoto": "Channel photo removed",
  "messageActionHistoryClear": "History was cleared",

  "messageActionChannelMigrateFrom": "",

  "messageActionPhoneCall.in_ok": "Incoming Call",
	"messageActionPhoneCall.out_ok": "Outgoing Call",
	"messageActionPhoneCall.in_missed": "Missed Call",
	"messageActionPhoneCall.out_missed": "Cancelled Call",

	"messageActionBotAllowed": "You allowed this bot to message you when logged in {}"
};

namespace Strings {
	export type Bio = 'Bio.Description';

	export type LoginRegister = 'Login.Register.FirstName.Placeholder' | 'Login.Register.LastName.Placeholder';

	export type EditAccount = 'EditAccount.Logout' | 'EditAccount.Title' | 'EditAccount.Title' | 'EditAccount.Username';

	export type AccountSettings = 'AccountSettings.Filters' | 'AccountSettings.Notifications' | 'AccountSettings.PrivacyAndSecurity' | 'AccountSettings.Language' | 'AccountSettings.Bio';

	export type Telegram = 'Telegram.GeneralSettingsViewController' | 'Telegram.NotificationSettingsViewController' | 'Telegram.LanguageViewController';

	export type ChatList = ChatListFilter;
	export type ChatListAdd = 'ChatList.Add.TopSeparator' | 'ChatList.Add.BottomSeparator';
	export type ChatListFilterIncluded = 'ChatList.Filter.Include.Header' | 'ChatList.Filter.Include.AddChat';
	export type ChatListFilterExcluded = 'ChatList.Filter.Exclude.Header' | 'ChatList.Filter.Exclude.AddChat';
	export type ChatListFilterList = 'ChatList.Filter.List.Header' | 'ChatList.Filter.List.Title';
	export type ChatListFilterRecommended = 'ChatList.Filter.Recommended.Header' | 'ChatList.Filter.Recommended.Add';
	export type ChatListFilter = ChatListAdd | ChatListFilterIncluded | ChatListFilterExcluded | ChatListFilterList | ChatListFilterRecommended | 'ChatList.Filter.Header' | 'ChatList.Filter.NewTitle' | 'ChatList.Filter.NonContacts' | 'ChatList.Filter.Contacts' | 'ChatList.Filter.Groups' | 'ChatList.Filter.Channels' | 'ChatList.Filter.Bots';

	export type AutoDownloadSettings = 'AutoDownloadSettings.TypePrivateChats' | 'AutoDownloadSettings.TypeChannels';

	export type DataAndStorage = 'DataAndStorage.CategorySettings.GroupChats';

	export type Suggest = 'Suggest.Localization.Other';

	export type UsernameSettings = 'UsernameSettings.ChangeDescription';

	export type LangPackKey = string | AccountSettings | EditAccount | Telegram | ChatList | LoginRegister | Bio | AutoDownloadSettings | DataAndStorage | Suggest | UsernameSettings;
}

export type LangPackKey = Strings.LangPackKey;

namespace I18n {
	export const strings: Map<LangPackKey, LangPackString> = new Map();
	let pluralRules: Intl.PluralRules;

	let lastRequestedLangCode: string;
	export function getCacheLangPack(): Promise<LangPackDifference> {
		return Promise.all([
			sessionStorage.get('langPack'),
			polyfillPromise
		]).then(([langPack]) => {
			if(!langPack) {
				return getLangPack('en');
			}
			
			if(!lastRequestedLangCode) {
				lastRequestedLangCode = langPack.lang_code;
			}
			
			applyLangPack(langPack);
			return langPack;
		});
	}

	export function getLangPack(langCode: string) {
		lastRequestedLangCode = langCode;
		return Promise.all([
			apiManager.invokeApi('langpack.getLangPack', {
				lang_code: langCode,
				lang_pack: 'macos'
			}),
			polyfillPromise
		]).then(([langPack, _]) => {
			return sessionStorage.set({langPack}).then(() => {
				applyLangPack(langPack);
				return langPack;
			});
		});
	}

	export const polyfillPromise = (function checkIfPolyfillNeeded() {
		if(typeof(Intl) !== 'undefined' && typeof(Intl.PluralRules) !== 'undefined'/*  && false */) {
			return Promise.resolve();
		} else {
			return import('./pluralPolyfill').then(_Intl => {
				(window as any).Intl = _Intl.default;
			});
		}
	})();
	
	export function applyLangPack(langPack: LangPackDifference) {
		if(langPack.lang_code !== lastRequestedLangCode) {
			return;
		}

		pluralRules = new Intl.PluralRules(langPack.lang_code);

		strings.clear();

		for(const string of langPack.strings) {
			strings.set(string.key as LangPackKey, string);
		}

		const elements = Array.from(document.querySelectorAll(`.i18n`)) as HTMLElement[];
		elements.forEach(element => {
			const instance = weakMap.get(element);

			if(instance) {
				instance.update();
			}
		});
	}
	
	export function getString(key: LangPackKey, args?: any[]) {
		const str = strings.get(key);
		let out = '';

		if(str) {
			if(str._ === 'langPackStringPluralized') {
				const v = args[0] as number;
				const s = pluralRules.select(v);
				// @ts-ignore
				out = str[s + '_value'];
			} else if(str._ === 'langPackString') {
				out = str.value;
			} else {
				out = '[' + key + ']';
			}
		} else {
			out = '[' + key + ']';
		}

		if(args?.length) {
			out = out.replace(/%./g, (match, offset, string) => {
				return '' + args.shift();
			});
		}

		return out;
	}

	const weakMap: WeakMap<HTMLElement, IntlElement> = new WeakMap();

	export type IntlElementOptions = {
		element?: HTMLElement,
		property?: 'innerText' | 'innerHTML' | 'placeholder'
		key: LangPackKey,
		args?: any[]
	};
	export class IntlElement {
		public element: IntlElementOptions['element'];
		public key: IntlElementOptions['key'];
		public args: IntlElementOptions['args'];
		public property: IntlElementOptions['property'] = 'innerText';
	
		constructor(options: IntlElementOptions) {
			this.element = options.element || document.createElement('span');
			this.element.classList.add('i18n');
			
			this.update(options);
			weakMap.set(this.element, this);
		}
	
		public update(options?: IntlElementOptions) {
			safeAssign(this, options);
	
			(this.element as any)[this.property] = getString(this.key, this.args);
		}
	}

	export function i18n(key: LangPackKey, args?: any[]) {
		return new IntlElement({key, args}).element;
	}
	
	export function i18n_(options: IntlElementOptions) {
		return new IntlElement(options).element;
	}

	export function _i18n(element: HTMLElement, key: LangPackKey, args?: any[], property?: IntlElementOptions['property']) {
		return new IntlElement({element, key, args, property}).element;
	}
}

export {I18n};
export default I18n;

const i18n = I18n.i18n;
export {i18n};

const i18n_ = I18n.i18n_;
export {i18n_};

const _i18n = I18n._i18n;
export {_i18n};

MOUNT_CLASS_TO && (MOUNT_CLASS_TO.I18n = I18n);