open-brainy/src/augmentations/intelligentImport/handlers/imageHandler.ts

/**
 * Image Import Handler
 *
 * Handles image files with:
 * - EXIF metadata extraction (camera, GPS, timestamps) via exifr
 * - Image metadata (dimensions, format) via probe-image-size
 * - Support for JPEG, PNG, WebP, GIF, TIFF, BMP, SVG
 *
 * NO NATIVE DEPENDENCIES - Pure JavaScript implementation
 * Replaces Sharp with lightweight pure-JS alternatives
 */

import { BaseFormatHandler } from './base.js'
import type { FormatHandlerOptions, ProcessedData } from '../types.js'
import exifr from 'exifr'
import probeImageSize from 'probe-image-size'
import { Readable } from 'stream'

export interface ImageMetadata {
  /** Image dimensions */
  width: number
  height: number

  /** Image format (jpeg, png, webp, etc.) */
  format: string

  /** File size in bytes */
  size: number

  /** Orientation (EXIF) */
  orientation?: number

  /** MIME type */
  mimeType?: string
}

export interface EXIFData {
  /** Camera make (e.g., "Canon", "Nikon") */
  make?: string

  /** Camera model */
  model?: string

  /** Lens information */
  lens?: string

  /** Date/time original */
  dateTimeOriginal?: Date

  /** GPS latitude */
  latitude?: number

  /** GPS longitude */
  longitude?: number

  /** GPS altitude in meters */
  altitude?: number

  /** Exposure time (e.g., "1/250") */
  exposureTime?: number

  /** F-number (e.g., 2.8) */
  fNumber?: number

  /** ISO speed */
  iso?: number

  /** Focal length in mm */
  focalLength?: number

  /** Flash fired */
  flash?: boolean

  /** Copyright */
  copyright?: string

  /** Artist/photographer */
  artist?: string

  /** Image description */
  imageDescription?: string

  /** Software used */
  software?: string
}

export interface ImageHandlerOptions extends FormatHandlerOptions {
  /** Extract EXIF data (default: true) */
  extractEXIF?: boolean
}

/**
 * ImageImportHandler
 *
 * Processes image files and extracts rich metadata including EXIF data.
 * Enables developers to import images into the knowledge graph with
 * full metadata extraction.
 *
 * Pure JavaScript implementation (no native dependencies)
 */
export class ImageHandler extends BaseFormatHandler {
  readonly format = 'image'

  /**
   * Check if this handler can process the given data
   */
  canHandle(data: Buffer | string | { filename?: string; ext?: string }): boolean {
    // Check by filename/extension
    if (typeof data === 'object' && 'filename' in data) {
      const mimeType = this.getMimeType(data)
      return this.mimeTypeMatches(mimeType, ['image/*'])
    }

    // Check by extension
    if (typeof data === 'object' && 'ext' in data && data.ext) {
      return this.isImageExtension(data.ext)
    }

    // Check by data (Buffer magic bytes)
    if (Buffer.isBuffer(data)) {
      return this.detectImageFormat(data) !== null
    }

    return false
  }

  /**
   * Process image file
   */
  async process(
    data: Buffer | string,
    options: ImageHandlerOptions = {}
  ): Promise<ProcessedData> {
    const startTime = Date.now()

    try {
      // Convert to Buffer
      const buffer = Buffer.isBuffer(data) ? data : Buffer.from(data, 'base64')

      // Extract image metadata
      const metadata = await this.extractMetadata(buffer)

      // Extract EXIF data (default: enabled)
      let exifData: EXIFData | undefined
      if (options.extractEXIF !== false) {
        exifData = await this.extractEXIF(buffer)
      }

      // Calculate processing time
      const processingTime = Date.now() - startTime

      // Generate descriptive name
      const imageName = options.filename
        ? options.filename.replace(/\.[^/.]+$/, '') // Remove extension
        : `${metadata.format.toUpperCase()} Image ${metadata.width}x${metadata.height}`

      // Return structured data
      return {
        format: 'image',
        data: [
          {
            name: imageName,
            type: 'media',
            metadata: {
              ...metadata,
              subtype: 'image',
              exif: exifData
            }
          }
        ],
        metadata: {
          rowCount: 1,
          fields: ['type', 'metadata'],
          processingTime,
          imageMetadata: metadata,
          exifData
        },
        filename: options.filename
      }
    } catch (error) {
      throw new Error(
        `Image processing failed: ${error instanceof Error ? error.message : String(error)}`
      )
    }
  }

  /**
   * Extract image metadata using probe-image-size (pure JS)
   */
  private async extractMetadata(buffer: Buffer): Promise<ImageMetadata> {
    try {
      // Convert Buffer to Stream for probe-image-size
      const stream = Readable.from(buffer)
      const result = await probeImageSize(stream)

      return {
        width: result.width,
        height: result.height,
        format: result.type, // 'jpeg', 'png', 'webp', etc.
        size: buffer.length,
        mimeType: result.mime,
        orientation: result.orientation
      }
    } catch (error) {
      // Fallback: Try to detect format from magic bytes
      const detectedFormat = this.detectImageFormat(buffer)

      return {
        width: 0,
        height: 0,
        format: detectedFormat || 'unknown',
        size: buffer.length,
        mimeType: detectedFormat ? `image/${detectedFormat}` : undefined
      }
    }
  }

  /**
   * Extract EXIF data using exifr (pure JS)
   */
  private async extractEXIF(buffer: Buffer): Promise<EXIFData | undefined> {
    try {
      const exif = await exifr.parse(buffer, {
        pick: [
          'Make',
          'Model',
          'LensModel',
          'DateTimeOriginal',
          'latitude',
          'longitude',
          'GPSAltitude',
          'ExposureTime',
          'FNumber',
          'ISO',
          'FocalLength',
          'Flash',
          'Copyright',
          'Artist',
          'ImageDescription',
          'Software'
        ]
      })

      if (!exif) return undefined

      return {
        make: exif.Make,
        model: exif.Model,
        lens: exif.LensModel,
        dateTimeOriginal: exif.DateTimeOriginal,
        latitude: exif.latitude,
        longitude: exif.longitude,
        altitude: exif.GPSAltitude,
        exposureTime: exif.ExposureTime,
        fNumber: exif.FNumber,
        iso: exif.ISO,
        focalLength: exif.FocalLength,
        flash: exif.Flash !== undefined ? Boolean(exif.Flash & 1) : undefined,
        copyright: exif.Copyright,
        artist: exif.Artist,
        imageDescription: exif.ImageDescription,
        software: exif.Software
      }
    } catch (error) {
      // EXIF extraction can fail for non-JPEG images or corrupt data
      return undefined
    }
  }

  /**
   * Detect image format from magic bytes
   */
  private detectImageFormat(buffer: Buffer): string | null {
    if (buffer.length < 4) return null

    // JPEG: FF D8 FF
    if (buffer[0] === 0xff && buffer[1] === 0xd8 && buffer[2] === 0xff) {
      return 'jpeg'
    }

    // PNG: 89 50 4E 47
    if (
      buffer[0] === 0x89 &&
      buffer[1] === 0x50 &&
      buffer[2] === 0x4e &&
      buffer[3] === 0x47
    ) {
      return 'png'
    }

    // GIF: 47 49 46
    if (buffer[0] === 0x47 && buffer[1] === 0x49 && buffer[2] === 0x46) {
      return 'gif'
    }

    // WebP: 52 49 46 46 ... 57 45 42 50
    if (
      buffer[0] === 0x52 &&
      buffer[1] === 0x49 &&
      buffer[2] === 0x46 &&
      buffer[3] === 0x46 &&
      buffer.length >= 12 &&
      buffer[8] === 0x57 &&
      buffer[9] === 0x45 &&
      buffer[10] === 0x42 &&
      buffer[11] === 0x50
    ) {
      return 'webp'
    }

    // TIFF: 49 49 2A 00 (little-endian) or 4D 4D 00 2A (big-endian)
    if (
      (buffer[0] === 0x49 && buffer[1] === 0x49 && buffer[2] === 0x2a && buffer[3] === 0x00) ||
      (buffer[0] === 0x4d && buffer[1] === 0x4d && buffer[2] === 0x00 && buffer[3] === 0x2a)
    ) {
      return 'tiff'
    }

    // BMP: 42 4D
    if (buffer[0] === 0x42 && buffer[1] === 0x4d) {
      return 'bmp'
    }

    return null
  }

  /**
   * Detect if extension is an image format
   */
  private isImageExtension(ext: string): boolean {
    const imageExts = [
      '.jpg',
      '.jpeg',
      '.png',
      '.gif',
      '.webp',
      '.tiff',
      '.tif',
      '.bmp',
      '.svg',
      '.heic',
      '.heif',
      '.avif'
    ]

    const normalized = ext.toLowerCase()
    const withDot = normalized.startsWith('.') ? normalized : `.${normalized}`
    return imageExts.includes(withDot)
  }
}