import { Injectable, Logger } from '@nestjs/common';
import {
  S3Client,
  DeleteObjectCommand,
  GetObjectCommand,
  ListObjectsCommand,
  PutObjectCommand,
} from '@aws-sdk/client-s3';
import { getSignedUrl } from '@aws-sdk/s3-request-presigner';
import { Upload } from '@aws-sdk/lib-storage';
import { ConfigService } from '@nestjs/config';

@Injectable()
export class S3Service {
  private s3Client: S3Client;
  private readonly logger = new Logger(S3Service.name);

  constructor(private configService: ConfigService) {
    this.s3Client = new S3Client({
      region: this.configService.get('AWS_REGION'),
      endpoint: this.configService.get('AWS_ENDPOINT_URL'),
      credentials: {
        accessKeyId: this.configService.get('AWS_ACCESS_KEY_ID'),
        secretAccessKey: this.configService.get('AWS_SECRET_ACCESS_KEY'),
      },
      forcePathStyle: true, // Needed for non-AWS S3 compatible services
    });
  }

  async getObject(key: string) {
    try {
      const command = new GetObjectCommand({
        Bucket: this.configService.get('AWS_S3_BUCKET_NAME'),
        Key: key,
      });

      const response = await this.s3Client.send(command);
      return response;
    } catch (error) {
      this.logger.error(`Error getting object from S3: ${error.message}`);
      throw error;
    }
  }
  async uploadFile(file: Express.Multer.File, folder: string): Promise<string> {
    try {
      const key = `${folder}/${Date.now()}-${file.originalname}`;
      
      const command = new PutObjectCommand({
        Bucket: this.configService.get('AWS_S3_BUCKET_NAME'),
        Key: key,
        Body: file.buffer,
        ContentType: file.mimetype,
      });

      await this.s3Client.send(command);
      return key;
    } catch (error) {
      this.logger.error(`Error uploading file to S3: ${error.message}`);
      throw error;
    }
  }

  async deleteFile(key: string): Promise<void> {
    try {
      const command = new DeleteObjectCommand({
        Bucket: this.configService.get('AWS_S3_BUCKET_NAME'),
        Key: key,
      });

      await this.s3Client.send(command);
    } catch (error) {
      this.logger.error(`Error deleting file from S3: ${error.message}`);
      throw error;
    }
  }

    async getFileUrl(key: string): Promise<string> {
    const command = new GetObjectCommand({
      Bucket: this.configService.get('AWS_S3_BUCKET_NAME'),
      Key: key,
    });

    const url = await getSignedUrl(this.s3Client, command, { expiresIn: 3600 }); // URL expires in 1 hour
    return url;
  }

  async testConnection(): Promise<boolean> {
    try {
      await this.getObject('test-connection');
      return true;
    } catch (error) {
      if (error.name === 'NoSuchKey') {
        // This is expected as we're just testing connection
        return true;
      }
      this.logger.error('Failed to connect to S3', error);
      return false;
    }
  }
}