import { Injectable, Logger, NotFoundException } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import ImageKit from 'imagekit';

@Injectable()
export class ImagekitioService {
  private readonly logger = new Logger(ImagekitioService.name);
  private imagekit: ImageKit;

  constructor(private configService: ConfigService) {
    this.imagekit = new ImageKit({
      publicKey: this.configService.get<string>('imagekitio.publicKey') || '',
      privateKey: this.configService.get<string>('imagekitio.privateKey') || '',
      urlEndpoint:
        this.configService.get<string>('imagekitio.urlEndpoint') || '',
    });
  }

  /**
   * 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 folderMap: Record<string, string> = {
      IMAGE: 'images',
      DOCUMENT: 'documents',
      VIDEO: 'videos',
    };
    return folderMap[fileType.toUpperCase()] || 'others';
  }

  /**
   * Get authentication parameters for client-side upload
   * @param fileType - Optional file type restriction (IMAGE, DOCUMENT, VIDEO)
   * @returns Authentication parameters (token, expire, signature, folder)
   */
  getAuthenticationParameters(fileType?: string) {
    try {
      // Determine folder based on file type
      const folder = fileType ? this.getFolderPath(fileType) : 'others';

      // Generate auth params
      const authParams = this.imagekit.getAuthenticationParameters();

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

      return {
        ...authParams,
        folder, // Folder where file should be uploaded
        ...(fileType && { fileType }),
      };
    } catch (error) {
      this.logger.error('Failed to generate authentication parameters', error);
      throw error;
    }
  }

  /**
   * Clean URL by removing query parameters
   * @param url - The URL to clean
   * @returns Clean URL without query parameters
   */
  private cleanUrl(url: string): string {
    return url.split('?')[0];
  }

  /**
   * Get file ID from ImageKit URL
   * @param url - The ImageKit file URL
   * @returns File details including fileId
   */
  async getFileIdByUrl(url: string): Promise<any> {
    try {
      // Clean URL (remove query parameters like ?updatedAt=...)
      const cleanUrl = this.cleanUrl(url);

      const urlEndpoint = this.configService.get<string>(
        'imagekitio.urlEndpoint',
      );
      if (!cleanUrl.startsWith(urlEndpoint || '')) {
        throw new NotFoundException(
          'Invalid ImageKit URL - does not match your URL endpoint',
        );
      }

      // Extract file path from URL
      const filePath = cleanUrl.replace(urlEndpoint || '', '');

      // Extract filename from path (last part after /)
      const fileName = filePath.split('/').pop() || '';

      if (!fileName) {
        throw new NotFoundException('Could not extract filename from URL');
      }

      // Search by filename
      const files = await this.imagekit.listFiles({
        searchQuery: `name="${fileName}"`,
      });

      if (!files || files.length === 0) {
        this.logger.warn(`File not found: ${fileName}`);
        throw new NotFoundException('File not found or already deleted');
      }

      // Find exact match by comparing clean URLs
      const exactMatch = files.find(
        (file: any) => this.cleanUrl(file.url) === cleanUrl,
      );

      if (!exactMatch) {
        this.logger.warn(`No exact match found for: ${fileName}`);
        throw new NotFoundException('File not found or already deleted');
      }

      this.logger.log(`Found file: ${fileName}`);
      return exactMatch;
    } catch (error) {
      if (error instanceof NotFoundException) {
        throw error;
      }
      this.logger.error(`Failed to get file ID for URL: ${url}`, error);
      throw new NotFoundException('File not found or already deleted');
    }
  }

  /**
   * Purge CDN cache for a URL
   * @param url - The ImageKit file URL to purge from cache
   * @returns Purge result
   */
  async purgeCdnCache(url: string): Promise<any> {
    try {
      const cleanUrl = this.cleanUrl(url);
      const result = await this.imagekit.purgeCache(cleanUrl);
      this.logger.log(`Successfully purged CDN cache for: ${cleanUrl}`);
      return result;
    } catch (error) {
      this.logger.error(`Failed to purge CDN cache for URL: ${url}`, error);
      throw error;
    }
  }

  /**
   * Delete a file from ImageKit by URL and purge CDN cache
   * @param url - The ImageKit file URL
   * @returns Deletion result
   */
  async deleteFileByUrl(url: string): Promise<any> {
    // First, get the file ID from the URL (this will throw NotFoundException if not found)
    const fileDetails = await this.getFileIdByUrl(url);

    if (!fileDetails || !fileDetails.fileId) {
      throw new NotFoundException('Could not retrieve file ID from URL');
    }

    // Delete the file using the file ID
    const result = await this.deleteFile(fileDetails.fileId);

    // Purge CDN cache to make deletion immediate
    try {
      await this.purgeCdnCache(url);
      this.logger.log(
        `Successfully deleted file and purged cache for URL: ${url}`,
      );
    } catch {
      this.logger.warn(
        `File deleted but CDN cache purge failed for: ${url}. Cache will expire naturally.`,
      );
    }

    return {
      ...result,
      deletedUrl: url,
      fileId: fileDetails.fileId,
    };
  }

  /**
   * Delete a file from ImageKit (private method used internally)
   * @param fileId - The file ID to delete
   * @returns Deletion result
   */
  private async deleteFile(fileId: string): Promise<any> {
    try {
      const result = await this.imagekit.deleteFile(fileId);
      this.logger.log(`Successfully deleted file with ID: ${fileId}`);
      return result;
    } catch (error) {
      this.logger.error(`Failed to delete file with ID: ${fileId}`, error);
      throw error;
    }
  }
}