import { Injectable, Logger, NotFoundException } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import {
  S3Client,
  PutObjectCommand,
  DeleteObjectCommand,
} from '@aws-sdk/client-s3';
import { getSignedUrl } from '@aws-sdk/s3-request-presigner';
@Injectable()
export class RustfsStorageService {
  private readonly logger = new Logger(RustfsStorageService.name);
  private s3Client: S3Client;
  private bucket: string;
  private endpoint: string;

  constructor(private configService: ConfigService) {
    this.endpoint =
      this.configService.get<string>('rustfsStorage.endpoint') || '';
    const accessKeyId =
      this.configService.get<string>('rustfsStorage.accessKey') || '';
    const secretAccessKey =
      this.configService.get<string>('rustfsStorage.secretKey') || '';
    this.bucket =
      this.configService.get<string>('rustfsStorage.bucket') || 'streamflix';
    const region =
      this.configService.get<string>('rustfsStorage.region') || 'us-east-1';

    this.s3Client = new S3Client({
      region,
      endpoint: this.endpoint,
      credentials: {
        accessKeyId,
        secretAccessKey,
      },
      forcePathStyle: true,
    });
  }

  /**
   * Get folder path based on file type
   */
  private getFolderPath(fileType: string): string {
    const folderMap: Record<string, string> = {
      IMAGE: 'images',
      DOCUMENT: 'documents',
      VIDEO: 'videos',
    };
    return folderMap[fileType.toUpperCase()] || 'others';
  }

  /**
   * Generate presigned upload URL using S3
   */
  async getPresignedUploadUrl(fileName: string, fileType?: string) {
    try {
      const folder = fileType ? this.getFolderPath(fileType) : 'others';
      const timestamp = Date.now();
      const filePath = `${folder}/${timestamp}-${fileName}`;

      const command = new PutObjectCommand({
        Bucket: this.bucket,
        Key: filePath,
      });

      const uploadUrl = await getSignedUrl(this.s3Client, command, {
        expiresIn: 3600,
      });

      const fileUrl = `${this.endpoint}/${this.bucket}/${filePath}`;

      this.logger.log(
        `Generated presigned upload URL for: ${filePath}${fileType ? ` (type: ${fileType})` : ''}`,
      );

      return {
        uploadUrl,
        fileUrl,
        filePath,
        expiresIn: 3600,
        ...(fileType && { fileType }),
      };
    } catch (error) {
      this.logger.error('Failed to generate presigned upload URL', error);
      throw error;
    }
  }

  /**
   * Delete a file from RustFS Storage
   */
  async deleteFile(filePath: string): Promise<any> {
    try {
      const command = new DeleteObjectCommand({
        Bucket: this.bucket,
        Key: filePath,
      });

      const result = await this.s3Client.send(command);

      this.logger.log(`Successfully deleted file: ${filePath}`);
      return {
        success: true,
        deletedPath: filePath,
        result,
      };
    } catch (error) {
      this.logger.error(`Failed to delete file: ${filePath}`, error);
      throw new NotFoundException('File not found or already deleted');
    }
  }

  /**
   * Delete a file by URL
   */
  async deleteFileByUrl(url: string): Promise<any> {
    try {
      const filePath = this.extractFilePathFromUrl(url);

      if (!filePath) {
        throw new NotFoundException('Could not extract file path from URL');
      }

      const result = await this.deleteFile(filePath);

      this.logger.log(`Successfully deleted file from URL: ${url}`);

      return {
        ...result,
        deletedUrl: url,
      };
    } catch (error) {
      if (error instanceof NotFoundException) {
        throw error;
      }
      this.logger.error(`Failed to delete file by URL: ${url}`, error);
      throw new NotFoundException('File not found or already deleted');
    }
  }

  /**
   * Extract file path from RustFS Storage URL
   */
  private extractFilePathFromUrl(url: string): string | null {
    try {
      const urlObj = new URL(url);
      const pathParts = urlObj.pathname.split('/');
      const bucketIndex = pathParts.indexOf(this.bucket);

      if (bucketIndex !== -1 && bucketIndex < pathParts.length - 1) {
        return pathParts.slice(bucketIndex + 1).join('/');
      }

      return pathParts.slice(1).join('/');
    } catch {
      return null;
    }
  }
}