import { Injectable, NotFoundException } from '@nestjs/common';

import { getFunctionsOfInstance } from './common/getFunctionsOfInstance';
import { OEMC_METHOD } from './nestjs-oemc.constants';

export interface OemcController {
  controllerAlias: string;
  oemcController: any;
}

export interface OemcMethod {
  methodAlias: string;
  methodName: string;
}

@Injectable()
export class NestjsOemcService {
  private readonly oemcControllers: OemcController[] = [];

  registerOemcController(oemcController: OemcController): void {
    this.oemcControllers.push(oemcController);
  }

  getOemcMethods(controllerAlias: string): OemcMethod[] {
    const oemcController = this.getOemcController(controllerAlias);

    const oemcControllerMethodNames = getFunctionsOfInstance(oemcController.oemcController).filter(
      (oemcFunctionName) => {
        return Reflect.getMetadata(OEMC_METHOD, oemcController.oemcController[oemcFunctionName])
          ? oemcFunctionName
          : null;
      },
    );

    return oemcControllerMethodNames.map((oemcControllerMethodName) => ({
      methodAlias: Reflect.getMetadata(OEMC_METHOD, oemcController.oemcController[oemcControllerMethodName]),
      methodName: oemcControllerMethodName,
    }));
  }

  getOemcControllerNames(): object[] {
    return this.oemcControllers.map((oemcController) => {
      return {
        controllerAlias: oemcController.controllerAlias,
        methods: this.getOemcMethods(oemcController.controllerAlias),
      };
    });
  }

  getOemcController(controllerAlias: string): OemcController {
    const oemcControllers = this.oemcControllers.filter(
      (oemcController) => oemcController.controllerAlias === controllerAlias,
    );
    if (oemcControllers.length > 0) {
      return oemcControllers[0];
    } else {
      throw new NotFoundException(
        `OemcController ${controllerAlias} is Not Found or Not Registered to NestjsOemcService`,
      );
    }
  }

  async executeOemcFunction(controllerAlias: string, methodAlias: string, body: object): Promise<any> {
    const oemcController = this.getOemcController(controllerAlias);
    const oemcMethod = this.getOemcMethods(controllerAlias).find(
      (findingOemcMethod: OemcMethod) => findingOemcMethod.methodAlias === methodAlias,
    );
    if (oemcMethod) {
      return await oemcController.oemcController[oemcMethod.methodName](body);
    } else {
      throw new NotFoundException(
        `OemcMethod ${controllerAlias}.${methodAlias} is Not Found or Not Registed as OemcMethod`,
      );
    }
  }
}