import {
  isObject,
  isNumber,
  isNil,
  isSymbol,
} from '@nestjs/common/utils/shared.utils';
/* eslint-disable @typescript-eslint/no-use-before-define */
import {
  PATTERN_HANDLER_METADATA,
  PATTERN_METADATA,
  TRANSPORT_METADATA,
  PATTERN_EXTRAS_METADATA,
} from '../constants';
import { PatternHandler } from '../enums/pattern-handler.enum';
import { PatternMetadata } from '../interfaces/pattern-metadata.interface';
import { Transport } from '../enums';

export enum GrpcMethodStreamingType {
  NO_STREAMING = 'no_stream',
  RX_STREAMING = 'rx_stream',
  PT_STREAMING = 'pt_stream',
}

/**
 * Subscribes to incoming messages which fulfils chosen pattern.
 */
export const MessagePattern: {
  <T = PatternMetadata | string>(metadata?: T): MethodDecorator;
  <T = PatternMetadata | string>(
    metadata?: T,
    transport?: Transport | symbol,
  ): MethodDecorator;
  <T = PatternMetadata | string>(
    metadata?: T,
    extras?: Record<string, any>,
  ): MethodDecorator;
  <T = PatternMetadata | string>(
    metadata?: T,
    transport?: Transport | symbol,
    extras?: Record<string, any>,
  ): MethodDecorator;
} = <T = PatternMetadata | string>(
  metadata?: T,
  transportOrExtras?: Transport | symbol | Record<string, any>,
  maybeExtras?: Record<string, any>,
): MethodDecorator => {
  let transport: Transport | symbol;
  let extras: Record<string, any>;
  if (
    (isNumber(transportOrExtras) || isSymbol(transportOrExtras)) &&
    isNil(maybeExtras)
  ) {
    transport = transportOrExtras;
  } else if (isObject(transportOrExtras) && isNil(maybeExtras)) {
    extras = transportOrExtras;
  } else {
    transport = transportOrExtras as Transport | symbol;
    extras = maybeExtras;
  }
  return (
    target: object,
    key: string | symbol,
    descriptor: PropertyDescriptor,
  ) => {
    Reflect.defineMetadata(
      PATTERN_METADATA,
      [].concat(metadata),
      descriptor.value,
    );
    Reflect.defineMetadata(
      PATTERN_HANDLER_METADATA,
      PatternHandler.MESSAGE,
      descriptor.value,
    );
    Reflect.defineMetadata(TRANSPORT_METADATA, transport, descriptor.value);
    Reflect.defineMetadata(PATTERN_EXTRAS_METADATA, extras, descriptor.value);
    return descriptor;
  };
};

/**
 * Registers gRPC method handler for specified service.
 */
export function GrpcMethod(service?: string): MethodDecorator;
export function GrpcMethod(service: string, method?: string): MethodDecorator;
export function GrpcMethod(service: string, method?: string): MethodDecorator {
  return (
    target: object,
    key: string | symbol,
    descriptor: PropertyDescriptor,
  ) => {
    const metadata = createGrpcMethodMetadata(target, key, service, method);
    return MessagePattern(metadata, Transport.GRPC)(target, key, descriptor);
  };
}

/**
 * Registers gRPC call through RX handler for service and method
 *
 * @param service String parameter reflecting the name of service definition from proto file
 */
export function GrpcStreamMethod(service?: string): MethodDecorator;
/**
 * @param service String parameter reflecting the name of service definition from proto file
 * @param method Optional string parameter reflecting the name of method inside of a service definition coming after rpc keyword
 */
export function GrpcStreamMethod(
  service: string,
  method?: string,
): MethodDecorator;
export function GrpcStreamMethod(
  service: string,
  method?: string,
): MethodDecorator {
  return (
    target: object,
    key: string | symbol,
    descriptor: PropertyDescriptor,
  ) => {
    const metadata = createGrpcMethodMetadata(
      target,
      key,
      service,
      method,
      GrpcMethodStreamingType.RX_STREAMING,
    );
    return MessagePattern(metadata, Transport.GRPC)(target, key, descriptor);
  };
}

/**
 * Registers gRPC call pass through handler for service and method
 *
 * @param service String parameter reflecting the name of service definition from proto file
 */
export function GrpcStreamCall(service?: string): MethodDecorator;
/**
 * @param service String parameter reflecting the name of service definition from proto file
 * @param method Optional string parameter reflecting the name of method inside of a service definition coming after rpc keyword
 */
export function GrpcStreamCall(
  service: string,
  method?: string,
): MethodDecorator;
export function GrpcStreamCall(
  service: string,
  method?: string,
): MethodDecorator {
  return (
    target: object,
    key: string | symbol,
    descriptor: PropertyDescriptor,
  ) => {
    const metadata = createGrpcMethodMetadata(
      target,
      key,
      service,
      method,
      GrpcMethodStreamingType.PT_STREAMING,
    );
    return MessagePattern(metadata, Transport.GRPC)(target, key, descriptor);
  };
}

export function createGrpcMethodMetadata(
  target: object,
  key: string | symbol,
  service: string | undefined,
  method: string | undefined,
  streaming = GrpcMethodStreamingType.NO_STREAMING,
) {
  const capitalizeFirstLetter = (str: string) =>
    str.charAt(0).toUpperCase() + str.slice(1);

  if (!service) {
    const { name } = target.constructor;
    return {
      service: name,
      rpc: capitalizeFirstLetter(key as string),
      streaming,
    };
  }
  if (service && !method) {
    return { service, rpc: capitalizeFirstLetter(key as string), streaming };
  }
  return { service, rpc: method, streaming };
}