import { Injectable, Injector, InjectionToken, Inject } from '@angular/core';
import { NaStartupService } from '@ng-arthur-mobile/core';
import { Observable } from 'rxjs';
import { HttpResponse, HttpClient, HttpRequest } from '@angular/common/http';
import { DOCUMENT } from '@angular/common';
import { tap } from 'rxjs/operators';
import { INaHttpConfig, NaHttpConfig } from './na-http-config';


export const NA_HTTP_CONFIG = new InjectionToken<INaHttpConfig>(
  'NA_HTTP_CONFIG'
);

@Injectable()
export class NaHttpService {
  public static METHOD = ['POST', 'PUT', 'PATCH'];
  private _httpConfig: INaHttpConfig;

  constructor(protected injector: Injector, private startupService: NaStartupService, private http: HttpClient, @Inject(DOCUMENT) private _doc: any) {
    this._httpConfig = new NaHttpConfig();
    const injectorConfig = this.injector.get(NA_HTTP_CONFIG, {});
    Object.assign(this._httpConfig, injectorConfig);
  }

  httpConfig(req: HttpRequest<any>): INaHttpConfig {
    if (req) {
      Object.keys(this._httpConfig).forEach(key => {
        let value = this._httpConfig[key];
        if (NaHttpService.METHOD.indexOf(req.method) >= 0) {
          if (req.body[key]) {
            value = req.body[key];
          }
        } else {
          if (req.params.get(key)) {
            value = req.params.get(key);
          }
        }
        this._httpConfig[key] = value;
      });
    }
    return this._httpConfig;
  }

  get baseUrl(): string {
    const _baseUrl = this._httpConfig.BASE_URL;
    if (typeof _baseUrl === 'string') {
      return this.startupService.get(_baseUrl) || _baseUrl;
    } else if (_baseUrl instanceof Array) {
      return this.concat(_baseUrl).substr(1);
    }
  }

  getUrl(key: string, baseUrl: boolean = true) {
    const value = this.startupService.get(key) || key;
    if (baseUrl) {
      return this.concatUrl(this.baseUrl, value);
    }
    return value;
  }

  concatUrl(urlPrefix: string, urlSuffix: string) {
    if (urlPrefix == null && urlSuffix != null) {
      return urlSuffix;
    }
    if (urlPrefix != null && urlSuffix == null) {
      return urlPrefix;
    }
    if (typeof urlPrefix !== 'string') {
      throw new Error('merge the url error. use string, now: ' + JSON.stringify(urlPrefix));
    }
    if (typeof urlSuffix !== 'string') {
      throw new Error('merge the url error. use string, now: ' + JSON.stringify(urlSuffix));
    }
    if (urlPrefix.endsWith('/') && urlSuffix.startsWith('/')) {
      return urlPrefix + urlSuffix.substr(1);
    }
    if (urlPrefix.endsWith('/') || urlSuffix.startsWith('/')) {
      return urlPrefix + urlSuffix;
    }
    return urlPrefix + '/' + urlSuffix;
  }
  private concat(args: string[]): string {
    let newStr = '';
    args.forEach(arg => {
      newStr = this.concatUrl(newStr, this.startupService.get(arg) || arg);
    });
    return newStr;
  }

  download(url: string, body: any, filename?: string): Observable<HttpResponse<Blob>> {
    return this.http.post(url, body, {
      observe: 'response',
      responseType: 'blob'
    }).pipe(
      tap(data => {
          const headers = data.headers;
          const blob = new Blob([data.body], {type: headers.get('Content-Type')});
          if (filename) {
            this.innerDownload(filename, blob);
          } else {
            // decodeURIComponent 解决中文乱码
            const contentDisposition = headers.get('Content-Disposition');
            if (contentDisposition) {
              filename = decodeURIComponent(contentDisposition.split('filename=')[1]);
              this.innerDownload(filename, blob);
            } else {
              console.error('download failed. filename is null, Please check the \'access-control-expose-headers: content-disposition\' and headers[\'Content-Disposition\'] filename=');
            }
          }
        }
      )
    );
  }

  private innerDownload(filename: string, blob: Blob) {
    if ('msSaveOrOpenBlob' in navigator) {// IE导出
      window.navigator.msSaveOrOpenBlob(blob, filename);
    } else {
      const link = this._doc.createElement('a');
      link.setAttribute('href', window.URL.createObjectURL(blob));
      link.setAttribute('download', filename);
      link.style.visibility = 'hidden';
      this._doc.body.appendChild(link);
      link.click();
      this._doc.body.removeChild(link);
    }
  }
}