import {
  OnModuleInit,
  Inject,
  Injectable,
  HttpException,
  HttpStatus,
  InternalServerErrorException,
} from '@nestjs/common';

import { firstValueFrom, lastValueFrom, ReplaySubject } from 'rxjs';
import { Link } from '@dadosfera/protospack-v2/dist/lib/Duc/interfaces/entities';
import { DucClient } from '../duc/client.config';
import { ClientGrpc } from '@nestjs/microservices';
import { ProtoServices } from '@dadosfera/protospack-v2/dist/lib/Duc';
import { CustomerUpdateRequest } from '@dadosfera/protospack-v2/dist/lib/Duc/interfaces/messages';
import { ThemeProtoService } from '@dadosfera/protospack-v2/dist/lib/Duc/interfaces/write-service';
import { ThemeRequest } from '@dadosfera/protospack-v2/dist/lib/Duc/interfaces/messages';
import { CustomerThemeRequest, CustomerThemeResponse } from './dtos/customers';
import DadosferaLogger from '@dadosfera/dadosfera-logs';
import { resolve } from 'path';
import { Readable } from 'stream';

type Files = {
  logo: Express.Multer.File,
  logoLogin: Express.Multer.File,
}

@Injectable()
export class ThemeService implements OnModuleInit {
  private themeService: ThemeProtoService;
  private logger: DadosferaLogger;

  constructor(
    @Inject(DucClient.name) private readonly grpcClient: ClientGrpc,
    @Inject(DadosferaLogger)
    dadosferaLogger: DadosferaLogger,
  ) {
    this.logger = dadosferaLogger.logger;
  }

  onModuleInit() {
    this.themeService = this.grpcClient.getService<ThemeProtoService>(
      ProtoServices.ThemeProtoService,
    );
  }

  async resetTheme(id: string) {
    const { theme } = await firstValueFrom(
      this.themeService.ResetCustomerTheme({
        id
      }),
    );

     return {
      theme
    }
  }

  async createThemeByCustomer(id: string, theme: CustomerThemeRequest & Files) {
    if (!id) {
      this.logger.error('Error - saveCustomertheme - not found id:' + id);
      throw new HttpException(null, HttpStatus.BAD_REQUEST);
    }

    const customerThemeRequest$ = new ReplaySubject<ThemeRequest>();

    customerThemeRequest$.next({
      customerId: id,
      displayName: theme.displayName,
      backgroundColor: theme.backgroundColor,
      textColor: theme.textColor,
      isMetadata: true,
      filename: '',
      chunk: Buffer.alloc(0)
    })

    if(theme.logo) {
      await this.sendFile(theme.logo, customerThemeRequest$);
    }

    if(theme.logoLogin) {
      await this.sendFile(theme.logoLogin, customerThemeRequest$);
    }
    customerThemeRequest$.complete();

    const stream = this.themeService.CustomerCreateTheme(customerThemeRequest$);

    return lastValueFrom(stream);
  }

  async getThemeByCustomer(id: string): Promise<CustomerThemeResponse> {
    if (!id) {
      this.logger.error('Error - getCustomerTheme - not found id:' + id);
      throw new HttpException(null, HttpStatus.BAD_REQUEST);
    }

    const { theme } = await firstValueFrom(
      this.themeService.CustomerGetTheme({
        id
      }),
    );

    return {
      theme
    }
  }

   private async sendFile(file: Express.Multer.File, stream$: ReplaySubject<ThemeRequest>) {
    const chunkSize = 4 * 1024 * 1024;
    const bufferStream = new CustomBufferStream(file.buffer, chunkSize);
    const parseMimitypeForExtension = {
      'image/jpeg': '.jpeg',
      'image/jpg': '.jpg',
      'image/png': '.png',
      'image/svg+xml': '.svg',
    }

    const extension = parseMimitypeForExtension[file.mimetype];

    return new Promise((resolve, reject) => {
      bufferStream.on('data', (chunk) => {
        const filename = file.fieldname.concat(extension);
        stream$.next({
          customerId: '',
          displayName: '',
          backgroundColor: '',
          textColor: '',
          isMetadata: false,
          filename: filename,
          chunk: chunk
        });
      });

      bufferStream.on('end', () => {
        resolve(file.filename)
      });

      bufferStream.on('error', (err) => {
        reject(err);
      });
    });
  }

}

class CustomBufferStream extends Readable {
  buffer: Buffer;
  offset: number;
  chunkSize: number;

  constructor(buffer: Buffer, chunkSize: number) {
    super({ highWaterMark: chunkSize }); // Configura o tamanho do chunk
    this.buffer = buffer;
    this.offset = 0;
    this.chunkSize = chunkSize;
  }

  _read() {
    if (this.offset < this.buffer.length) {
      const end = Math.min(this.offset + this.chunkSize, this.buffer.length);

      const copiedBuf = Uint8Array.prototype.slice.call(this.buffer);
      const chunk = copiedBuf.slice(this.offset, end);
      this.offset = end;
      this.push(chunk);
    } else {
      this.push(null);
    }
  }
}