import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';

import {
    Observable,
    of,
} from 'rxjs';
import {
    map,
} from 'rxjs/operators';

import {
    languageMap,
} from './language-map.const';

import {
    MEASUREMENTS,
} from './../../../models/index';

@Injectable()
export class LocationService {
    private _location: Observable<string>;

    constructor(
        private _http: HttpClient,
    ) {
        this._location = of(navigator.language);
    }

    public getDefaultCurrencyCode(locationUrl: string): Observable<string> {
        return this._http.get<{
            currency?: {
                code: string,
            },
        }>(locationUrl)
            .pipe(
                map((currencyData) => {
                    return currencyData &&
                        currencyData.currency &&
                        currencyData.currency.code
                        ?
                            currencyData.currency.code
                            :
                            'GBP';
                }),
            );
    }

    public getDefaultLanguage(): Observable<string> {
        return this._location.pipe(
            map((location) => {
                const language = languageMap[location];
                return language ? language : 'en';
            }),
        );
    }

    public getMeasurementSystem(): Observable<string> {
        return this._location.pipe(
            map((location) => (
                location === 'en-US'
                ? MEASUREMENTS.IMPERIAL
                : MEASUREMENTS.METRIC
            )),
        );
    }
}