internationalisation.service.ts

import { Injectable } from "@angular/core";

import { Message, MessageCode, Observable, Observer } from "jalhyd";

import { StringMap } from "../../stringmap";
import { ApplicationSetupService } from "../app-setup/app-setup.service";
import { HttpService } from "../http/http.service";

/*
  language tag : fr-FR
  primary subcode : fr
  optional subcode : FR
 */
export enum LanguageCode {
    FRENCH,

    ENGLISH,
}


export class Language {
    private _code: LanguageCode;
    private _tag: string;
    private _label: string;

    constructor(c: LanguageCode, t: string, l: string) {
        this._code = c;
        this._tag = t;
        this._label = l;
    }

    get code(): LanguageCode {
        return this._code;
    }

    get tag(): string {
        return this._tag;
    }

    get label(): string {
        return this._label;
    }
}

@Injectable()
export class I18nService extends Observable implements Observer {

    private _currLang: Language;
    private _Messages: StringMap;
    private _languages: Language[];

    constructor(
        private applicationSetupService: ApplicationSetupService,
        private httpService: HttpService) {

        super();
        this._languages = [];
        this._languages.push(new Language(LanguageCode.FRENCH, "fr", "Français"));
        this._languages.push(new Language(LanguageCode.ENGLISH, "en", "English"));
        // add language preferences observer
        this.applicationSetupService.addObserver(this);
    }

    public get languages() {
        return this._languages;
    }

    public get currentLanguage() {
        return this._currLang;
    }

    public get currentMap() {
        return this._Messages;
    }

    private getLanguageFromCode(lc: LanguageCode) {
        for (const l of this._languages) {
            if (l.code === lc) {
                return l;
            }
        }
        throw new Message(MessageCode.ERROR_LANG_UNSUPPORTED);
    }

    private getLanguageFromTag(tag: string) {
        for (const l of this._languages) {
            if (l.tag === tag) {
                return l;
            }
        }
        const e = new Message(MessageCode.ERROR_LANG_UNSUPPORTED);
        e.extraVar["locale"] = tag;
        throw e;
    }

    public setLocale(lng: string | LanguageCode) {
        let oldLang;
        if (this._currLang !== undefined) {
            oldLang = this._currLang.code;
        }

        if (typeof lng === "string") {
            const t: string = lng.substr(0, 2).toLowerCase();
            this._currLang = this.getLanguageFromTag(t);
        } else {
            this._currLang = this.getLanguageFromCode(lng);
        }

        if (this._currLang.code !== oldLang) {
            this._Messages = undefined;
            const prom = this.httpGetMessages();

            const is: I18nService = this;
            prom.then((res) => {
                // propagate language change to all application
                is.notifyObservers(undefined);
            });
        }
    }

    private httpGetMessages(): Promise<void> {
        const is: I18nService = this;
        const processData = function (s: string) {
            // fermeture nécessaire pour capturer la valeur de this (undefined sinon)
            is._Messages = JSON.parse(s);
        };

        let l: string;
        switch (this._currLang.code) {
            case LanguageCode.FRENCH:
                l = "fr";
                break;

            default:
                l = "en";
        }

        const f: string = "messages." + l + ".json";
        return this.httpService.httpGetRequestPromise("locale/" + f).then(
            (res: any) => { is._Messages = res; }
        );
    }

    private getMessageFromCode(c: MessageCode): string {
        if (! this._Messages) {
            return `*** Messages not loaded yet ***`;
        }
        if (this._Messages[MessageCode[c]] === undefined) {
            return `*** Message ${MessageCode[c]} non traduit ***`;
        }
        return this._Messages[MessageCode[c]];
    }

    private replaceAll(str: string, find: string, replace: string) {
        return str.replace(new RegExp(find, "g"), replace);
    }

    /**
     * traduit un message
     * @param r message
     * @param nDigits nombre de chiffres à utiliser pour l'arrondi dans le cas de données numériques
     */
    public localizeMessage(r: Message, nDigits: number = 3): string {
        const sCode: string = MessageCode[r.code];
        let m: string = this.getMessageFromCode(r.code);

        for (const k in r.extraVar) {
            if (r.extraVar.hasOwnProperty(k)) {
                const v: any = r.extraVar[k];
                let s: string;
                if (typeof v === "number") {
                    s = v.toFixed(nDigits);
                } else {
                    s = v;
                }
                m = this.replaceAll(m, "%" + k + "%", s);
            }
        }

        return m;
    }

    /**
     * Traduit un texte défini dans un fichier de langue (locale/error_message.xx.json par défaut)
     * Les ids dans ces fichiers sont soit un enum de JalHyd, soit une chaine libre correspondant au code passé àlocalizeText()
     * @param code id du texte
     * @param messages Contenu du fichier de langua à utiliser (locale/error_message.xx.json par défaut)
     */
    public localizeText(code: string, messages = this._Messages) {
        if (messages === undefined) {
            return `*** messages not loaded: ${code} ***`;
        }
        if (messages[code] === undefined) {
            return `*** message not exists: ${code} ***`;
        }
        return messages[code];
    }

    /**
     * analyse un libellé du type ouvrage[n].XX
     */
    private parseLabel(lbl: string) {
        const re = /([A-Z,a-z]+)\[(\d+)\]\.(.+)/;
        return re.exec(lbl);
    }

    /**
     * Traduit un libellé qui peut être un code
     */
    public getExtraResLabel(s: string) {
        const key = "INFO_EXTRARES_LIB_";
        const match = this.parseLabel(s);
        if (match) {
            // Code du type "Ouvrage[n].XXX"
            // Les libellés correspondants sont INFO OUVRAGE et INFO_EXTRARES_LIB_OUVRAGE_XXX
            return this.localizeText(`INFO_${match[1].toUpperCase()}`) + " n°" + (+match[2] + 1) + ": " +
                this.localizeText(`${key}${match[1].toUpperCase()}_${match[3].toUpperCase()}`);
        } else {
            // Autres codes INFO_EXTRARES_LIB_XXX
            return this.localizeText(`${key}${s.toUpperCase()}`);
        }
    }

    /**
     * Met en forme un extraResult en fonction du libellé qui l'accompagne
     * Les extraResult avec le terme "ENUM_" sont traduit avec le message INFO_EXTRARES_ENUM_[Nom de la variable après ENUM_]
     */
    public formatResult(label: string, value: number): string {
        const match = label.indexOf("ENUM_");
        if (match > -1) {
                return this.localizeText(`INFO_EXTRARES_${label.substring(match).toUpperCase()}_${value}`);
        }
        const nDigits = this.applicationSetupService.displayDigits;
        return value.toFixed(nDigits);
    }

    // interface Observer

    /**
     * Should only be triggered once at app startup, when setup service tries loading language
     * @param sender should always be ApplicationSetupService
     * @param data object {
     *                  action: should always be "languagePreferenceChanged"
     *                  languages: languages codes to try until one works
     *              }
     */
    public update(sender: any, data: any): void {
        if (sender instanceof ApplicationSetupService) {
            if (data.action === "languagePreferenceChanged") {
                let languageEventuallyUsed: string;
                for (let i = 0; i < data.languages.length && languageEventuallyUsed === undefined; i++) {
                    const l = data.languages[i];
                    if (l !== undefined) {
                        try {
                            this.setLocale(l);
                            languageEventuallyUsed = l;
                        } catch (e) {
                            console.error(e.toString());
                        }
                    }
                }
                // confirm to setup service which language was eventually used at app startup (triggers nothing more)
                this.applicationSetupService.language = languageEventuallyUsed;
            }
        }
    }
}