import {Injectable} from "@angular/core";
import {Http, RequestOptionsArgs, Response, Request, RequestOptions, Headers, RequestMethod} from "@angular/http";
import {Observable} from "rxjs/Observable";
import "rxjs/add/operator/catch";
import "rxjs/add/operator/map";

/**
 * Internal service used by the module to add headers on each http-request and handle unauthorized response
 */
@Injectable()
export class BaseService {

    private api = 'https://www.googleapis.com';

    /**
     * creates the internal smart mirror api service
     * @param config Injected configuration for remote service
     * @param tokenService Injected token service for invalidating the authentication token
     * @param http Injected angular http client used for the remote requests
     */
    constructor(private http: Http) {
    }

    /**
     * Performs a request with `get` http method.
     */
    public get(url: string, token: string, options?: RequestOptionsArgs): Observable<Response> {
        return this.sendRequest({method: RequestMethod.Get, url: url, body: ''}, token, options);
    }

    /**
     * Performs a request with `post` http method.
     */
    public post(url: string, token: string, body: any, options?: RequestOptionsArgs): Observable<Response> {
        return this.sendRequest({method: RequestMethod.Post, url: url, body: body}, token, options);
    }

    /**
     * Performs a request with `put` http method.
     */
    public put(url: string, token: string, body: any, options?: RequestOptionsArgs): Observable<Response> {
        return this.sendRequest({method: RequestMethod.Put, url: url, body: body}, token, options);
    }

    /**
     * Performs a request with `delete` http method.
     */
    public delete(url: string, token: string, options?: RequestOptionsArgs): Observable<Response> {
        return this.sendRequest({method: RequestMethod.Delete, url: url, body: ''}, token, options);
    }

    /**
     * Performs a request with `patch` http method.
     */
    public patch(url: string, token: string, body: any, options?: RequestOptionsArgs): Observable<Response> {
        return this.sendRequest({method: RequestMethod.Patch, url: url, body: body}, token, options);
    }

    /**
     * Performs a request with `head` http method.
     */
    public head(url: string, token: string, options?: RequestOptionsArgs): Observable<Response> {
        return this.sendRequest({method: RequestMethod.Head, url: url, body: ''}, token, options);
    }

    /**
     * Performs a request with `options` http method.
     */
    public options(url: string, token: string, options?: RequestOptionsArgs): Observable<Response> {
        return this.sendRequest({method: RequestMethod.Options, url: url, body: ''}, token, options);
    }

    /**
     * extends the request options with stored authentication token and sends the request to the remove service
     * @param requestOptionsArgs The basic request options arguments
     * @param options Enhanced request options arguments
     * @return {Observable<R|T>} Observable to listen on http response
     */
    private sendRequest(requestOptionsArgs: RequestOptionsArgs, token: string, options?: RequestOptionsArgs): Observable<any> {

        const requestOptions = new RequestOptions(requestOptionsArgs);

        requestOptions.url = this.api + requestOptions.url;

        if (!requestOptions.headers) {
            requestOptions.headers = new Headers();
        }

        requestOptions.headers.set('Authorization', 'Bearer ' + token);

        const request = new Request(Object.assign(requestOptions, options));
        return this.http.request(request)
            .map(res => res);
    }
}