/**
 * @author Xuezi
 * @email xzj15859722542@hotmail.com
 * @create date 2018-06-14 06:11:20
 * @modify date 2018-06-14 06:11:20
 * @desc [description]
 */
import * as GRPC from 'grpc';
import * as protoLoader from '@grpc/proto-loader';

export class ServiceContainer {
  static services: { service: any, target: Function }[] = [];
  static routes: { target: Function, route: Function, func?: Function }[] = [];
  /**
   * @description registry grpc service
   * @author Xuezi
   * @static
   * @param {Function} target service constructor
   * @param {string} path proto file path
   * @memberof ServiceContainer
   */
  static registryService(target: Function, path: string) {
    let packageDefinition = protoLoader.loadSync(path, {
        keepCase: true,
        longs: String,
        enums: String,
        defaults: true,
        oneofs: true
    });
    let protoDescriptor = GRPC.loadPackageDefinition(packageDefinition);

    const packages = Object.keys(protoDescriptor);
    for (let packageKey of packages) {
      for (let key in protoDescriptor[packageKey]) {
          this._setServiceClient(protoDescriptor[packageKey][key], target);
        // if (protoDescriptor[packageKey][key].hasOwnProperty('service')) {
        //   this.services.push({ service: protoDescriptor[packageKey][key]['service'], target });
        // }
      }
    }
  }

  private static _setServiceClient(service: any, target: Function) {
      if(!service) {
          return;
      }

      if(service.name === 'ServiceClient') {
            this.services.push({service: service['service'], target});
      } else {
          for(const key in service) {
              this._setServiceClient(service[key], target);
          }
      }
  }

  static registryRoute(target: Function, route: Function) {
    if (this.routes.find(r => (r.target === target && r.route === route))) {
      return;
    }

    this.routes.push({ target, route });
  }

  static generateRouteFunc(...args) {
    return this._generateRouteFunc.apply(this, args);
  }

  private static _generateRouteFunc(service: any, route: Function): Function {
    let key = route.name;
    let rawFunc = service[key];
    let {requestStream, responseStream} = rawFunc;

    let func;
    if (requestStream && responseStream) {
      // requestStream: true
      // responseStream: true
      func = async function(call) {
        call.on('data', async function(chunk) {
          try {
            let result = await route(chunk);
            call.write(result);
          } catch (e) {
            call.emit('error', e);
          }
        });

        call.on('error', error => {
          console.error(error);
        });

        call.on('end', () => {
          call.end && call.end();
        });
      };
    } else if (requestStream && !responseStream) {
      // requestStream: true
      // responseStream: false
      func = async function(call) {
        let callback = arguments[1];

        call.on('data', async chunk => {
          try {
            let result = await route(chunk);
            callback(null, result);
          } catch (e) {
            callback(e);
          }
        });

        call.on('error', error => {
          console.error(error);
        });

        call.on('end', () => {
          call.end && call.end();
        });
      };
    } else if (!requestStream && responseStream) {
      // requestStream: false
      // responseStream: true
      func = async function(call) {
        try {
          let result = await route(call.request);
          call.write(result);
        } catch (e) {
          call.emit('error', e);
        }

        call.on('error', error => {
          console.error(error);
        });

        call.on('end', () => {
          call.end && call.end();
        });
      };
    } else {
      // requestStream: false
      // responseStream: false
      func = async function(call) {
        let callback = arguments[1];

        try {
          let result = await route(call.request);
          callback(null,result);
        } catch (e) {
          callback(e);
        }
      };
    }

    return func;
  }

  static getService(target: Function): any[] {
    let services = this.services.filter(service => service.target === target);
    return services;
  }
}