import { Injectable, Logger, NotFoundException } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { v2 as cloudinary } from 'cloudinary';

@Injectable()
export class CloudinaryService {
  private readonly logger = new Logger(CloudinaryService.name);

  constructor(private configService: ConfigService) {
    cloudinary.config({
      cloud_name: this.configService.get<string>('cloudinary.cloudName'),
      api_key: this.configService.get<string>('cloudinary.apiKey'),
      api_secret: this.configService.get<string>('cloudinary.apiSecret'),
    });
  }

  /**
   * Get folder path based on file type
   * @param fileType - The file type (IMAGE, DOCUMENT, VIDEO)
   * @returns Folder path for the file type
   */
  private getFolderPath(fileType: string): string {
    const baseFolder =
      this.configService.get<string>('cloudinary.uploadFolder') || 'StreamFlix';
    const folderMap: Record<string, string> = {
      IMAGE: `${baseFolder}/images`,
      DOCUMENT: `${baseFolder}/documents`,
      VIDEO: `${baseFolder}/videos`,
    };
    return folderMap[fileType.toUpperCase()] || `${baseFolder}/others`;
  }

  /**
   * Get resource type based on file type
   * @param fileType - The file type (IMAGE, DOCUMENT, VIDEO)
   * @returns Cloudinary resource type
   */
  private getResourceType(fileType: string): string {
    const resourceMap: Record<string, string> = {
      IMAGE: 'image',
      DOCUMENT: 'raw',
      VIDEO: 'video',
    };
    return resourceMap[fileType.toUpperCase()] || 'auto';
  }

  /**
   * Get signed upload parameters for client-side upload
   * @param fileType - Optional file type restriction (IMAGE, DOCUMENT, VIDEO)
   * @param publicId - Optional custom public_id for the file
   * @returns Signed upload parameters (signature, timestamp, folder, etc.)
   */
  getSignedUploadParams(fileType?: string, publicId?: string) {
    try {
      const timestamp = Math.round(new Date().getTime() / 1000);
      const folder = fileType
        ? this.getFolderPath(fileType)
        : this.configService.get<string>('cloudinary.uploadFolder') ||
          'StreamFlix';
      const resourceType = fileType ? this.getResourceType(fileType) : 'auto';

      // Parameters to sign (MUST match what frontend sends)
      const paramsToSign: Record<string, any> = {
        timestamp,
        folder,
      };

      // If publicId is provided, include it in signature
      if (publicId) {
        paramsToSign.public_id = publicId;
      }

      // Generate signature
      const signature = cloudinary.utils.api_sign_request(
        paramsToSign,
        this.configService.get<string>('cloudinary.apiSecret') || '',
      );

      this.logger.log(
        `Generated signed upload parameters for Cloudinary${fileType ? ` (type: ${fileType}, folder: ${folder})` : ''}${publicId ? `, publicId: ${publicId}` : ''}`,
      );

      return {
        signature,
        timestamp,
        folder,
        resourceType,
        ...(publicId && { publicId }),
        ...(fileType && { fileType }),
      };
    } catch (error) {
      this.logger.error('Failed to generate signed upload parameters', error);
      throw error;
    }
  }

  /**
   * Delete a file from Cloudinary by public ID
   * @param publicId - The Cloudinary public ID
   * @param resourceType - The resource type (image, video, raw)
   * @returns Deletion result
   */
  async deleteFile(
    publicId: string,
    resourceType: string = 'image',
  ): Promise<any> {
    try {
      const result = await cloudinary.uploader.destroy(publicId, {
        resource_type: resourceType,
        invalidate: true, // Invalidate CDN cache
      });

      this.logger.log(`Successfully deleted file: ${publicId}`);
      return result;
    } catch (error) {
      this.logger.error(`Failed to delete file: ${publicId}`, error);
      throw error;
    }
  }

  /**
   * Delete a file from Cloudinary by URL
   * @param url - The Cloudinary file URL
   * @returns Deletion result
   */
  async deleteFileByUrl(url: string): Promise<any> {
    try {
      // Extract public ID from URL
      // Example: https://res.cloudinary.com/dcvbvmpfu/image/upload/v1234567890/StreamFlix/images/file.jpg
      // Extract: StreamFlix/images/file
      const publicId = this.extractPublicIdFromUrl(url);

      if (!publicId) {
        throw new NotFoundException('Could not extract public ID from URL');
      }

      // Determine resource type from URL
      const resourceType = this.extractResourceTypeFromUrl(url);

      const result = await this.deleteFile(publicId, resourceType);

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

      return {
        ...result,
        deletedUrl: url,
        publicId,
      };
    } 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 public ID from Cloudinary URL
   * @param url - The Cloudinary URL
   * @returns Public ID
   */
  private extractPublicIdFromUrl(url: string): string | null {
    try {
      // Match pattern: /upload/v{version}/{public_id}.{extension}
      const match = url.match(/\/upload\/(?:v\d+\/)?(.+)\.\w+$/);
      return match ? match[1] : null;
    } catch {
      return null;
    }
  }

  /**
   * Extract resource type from Cloudinary URL
   * @param url - The Cloudinary URL
   * @returns Resource type (image, video, raw)
   */
  private extractResourceTypeFromUrl(url: string): string {
    if (url.includes('/image/upload/')) return 'image';
    if (url.includes('/video/upload/')) return 'video';
    if (url.includes('/raw/upload/')) return 'raw';
    return 'image'; // default
  }

  /**
   * Get file details from Cloudinary
   * @param publicId - The Cloudinary public ID
   * @param resourceType - The resource type
   * @returns File details
   */
  async getFileDetails(
    publicId: string,
    resourceType: string = 'image',
  ): Promise<any> {
    try {
      const result = await cloudinary.api.resource(publicId, {
        resource_type: resourceType,
      });
      return result;
    } catch (error) {
      this.logger.error(`Failed to get file details for: ${publicId}`, error);
      throw new NotFoundException('File not found');
    }
  }

  /**
   * Get file details from Cloudinary by URL
   * @param url - The Cloudinary file URL
   * @returns File details
   */
  async getFileDetailsByUrl(url: string): Promise<any> {
    try {
      const publicId = this.extractPublicIdFromUrl(url);

      if (!publicId) {
        throw new NotFoundException('Could not extract public ID from URL');
      }

      const resourceType = this.extractResourceTypeFromUrl(url);
      const result = await this.getFileDetails(publicId, resourceType);

      this.logger.log(`Retrieved file details for URL: ${url}`);
      return result;
    } catch (error) {
      if (error instanceof NotFoundException) {
        throw error;
      }
      this.logger.error(`Failed to get file details by URL: ${url}`, error);
      throw new NotFoundException('File not found');
    }
  }
}