import { Injectable, InjectionToken, Injector } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { NaUtils } from '@ng-arthur-mobile/common';
import { map, switchMap, tap, catchError } from 'rxjs/operators';
import { of, throwError } from 'rxjs';

export interface IStartupConfigResource {
  /** 前缀 */
  prefix: string;
  /** 后缀 */
  suffix: string;
}

export const NA_STARTUP_CONFIG = new InjectionToken<IStartupConfigResource>(
  'NA_STARTUP_CONFIG'
);

/**
 * 用于应用启动时
 *
 * 一般用来获取应用所需要的基础数据等
 *
 * @export
 */
@Injectable()
export class NaStartupService {
  private _startupConfig: any = {};
  private initialized = false;
  private cache = new Map<string, string>();

  constructor(private client: HttpClient) { }

  /**
   * 启动加载
   *
   * TODO ssr注入`HttpClient`在使用client时会有异常
   * @param startupConfig 启动配置文件
   */
  // load(startupConfig: IStartupConfigResource): Promise<any | void> {
  //   return new Promise((resolve, reject) => {
  //     const filePath = startupConfig.prefix + startupConfig.suffix;
  //     this.client.get(filePath).subscribe(
  //       (next: any) => {
  //         const rtnData = Object.assign({}, next);
  //         const profiles = next.profiles;
  //         if (profiles && profiles.active) {
  //           const file = startupConfig.prefix + '-' + profiles.active + startupConfig.suffix;
  //           const params = {};
  //           // params[NaConstant.HTTP.RTN_ERROR_PROMPT] = false;
  //           this.client.get(file, {params: params}).subscribe(
  //             data => {
  //               NaUtils.mergeJSON(rtnData, data);
  //               console.log(data, rtnData);
  //               resolve(true);
  //             },
  //             err => {
  //               console.log(err);
  //               reject(err);
  //             },
  //             () => {
  //               this._startupConfig = rtnData;
  //             }
  //           );
  //         }
  //       },
  //       error => {
  //         console.error(`the profiles does not exist or error. please check the profiles active.`, error);
  //         reject(error);
  //       }
  //     );
  //   });
  // }
  load(startupConfig: IStartupConfigResource) {
    const filePath = startupConfig.prefix + startupConfig.suffix;
    return this.client.get(filePath).pipe(
      switchMap((value: any) => {
        const rtnData = Object.assign({}, value);
        const profiles = value.profiles;
        if (profiles && profiles.active) {
          const file = startupConfig.prefix + '-' + profiles.active + startupConfig.suffix;
          const params = {};
          // params[NaConstant.HTTP.RTN_ERROR_PROMPT] = false;
          return this.client.get(file, {
            params: params
          }).pipe(
            map((resp: any) => {
              NaUtils.mergeJSON(rtnData, resp);
              return rtnData;
            })
          );
        } else {
          return of(rtnData);
        }
      }),
      tap(next => {
        this._startupConfig = next;
        this.initialized = true;
      }),
      catchError(err => {
        console.error(`the profiles does not exist or error. please check the profiles active.`, err);
        return throwError(err);
      })
    )
    .toPromise();
  }

  get(key: string) {
    if (!this.initialized) {
      throw new Error('未加载完毕！');
    }
    return this.getValue(this._startupConfig, key);
  }

  private getValue(target: any, key: string): any {
    if (this.cache.has(key)) {
      return this.cache.get(key);
    }
    const keys = key.split('.');
    key = '';
    do {
      key += keys.shift();
      if (NaUtils.isDefined(target) && NaUtils.isDefined(target[key]) && (typeof target[key] === 'object' || !keys.length)) {
        target = target[key];
        key = '';
      } else if (!keys.length) {
        target = undefined;
      } else {
        key += '.';
      }
    } while (keys.length);
    this.cache.set(key, target);
    return target;
  }

//   private find(data: any, key: string) {
//     const keys = key.split('.');
//     let val = data;
//     if (val == null) {
//       alert('pls init config');
//       throw new Error('pls init config, use APP_INITIALIZER');
//     }
//     keys.forEach(k => {
//       if (val) {
//         val = val[k];
//       }
//     });
//     return val;
//   }

}