//
//  MetadataProvider.swift
//  VisionCamera
//
//  Created by Marc Rousavy on 19.03.24.
//

import AVFoundation
import CoreLocation
import Foundation

/**
 A Provider for Photo (AVCapturePhoto) EXIF metadata, and Video (AVAssetWriter) metadata.
 */
class MetadataProvider: NSObject, AVCapturePhotoFileDataRepresentationCustomizer {
  /**
   Get or set the location provider to also set GPS tags for captured photos or videos.
   */
  var locationProvider: LocationProvider?

  // MARK: - Photo Metadata

  /**
   Adds AVCapturePhoto's metadata dictionary
   */
  func replacementMetadata(for photo: AVCapturePhoto) -> [String: Any]? {
    var properties = photo.metadata

    // Add branding info
    if var exifDictionary = properties[kCGImagePropertyExifDictionary as String] as? [String: Any] {
      exifDictionary[kCGImagePropertyExifUserComment as String] = "Captured with VisionCamera by mrousavy"
      properties[kCGImagePropertyExifDictionary as String] = exifDictionary
    }

    // Add GPS Location EXIF info
    if let locationProvider,
       let location = locationProvider.location {
      let locationExif = location.toEXIF(heading: locationProvider.heading)
      properties[kCGImagePropertyGPSDictionary as String] = locationExif
    }

    return properties
  }

  // MARK: - Video Metadata

  func createVideoMetadata() -> [AVMetadataItem] {
    var metadata: [AVMetadataItem] = []

    // Add branding metadata
    let brandingMetadata = createBrandingMetadaItem()
    metadata.append(brandingMetadata)

    if let location = locationProvider?.location {
      // Add GPS Location metadata
      let locationMetadata = createLocationMetadataItem(location: location)
      metadata.append(locationMetadata)
    }

    return metadata
  }

  private func createBrandingMetadaItem() -> AVMetadataItem {
    let metadataItem = AVMutableMetadataItem()
    metadataItem.keySpace = .quickTimeMetadata
    metadataItem.key = AVMetadataKey.quickTimeMetadataKeyInformation as NSString
    metadataItem.identifier = .quickTimeMetadataInformation
    metadataItem.value = "Captured with VisionCamera by mrousavy" as NSString
    metadataItem.dataType = kCMMetadataBaseDataType_UTF8 as String
    return metadataItem
  }

  private func createLocationMetadataItem(location: CLLocation) -> AVMetadataItem {
    let metadataItem = AVMutableMetadataItem()
    metadataItem.keySpace = .quickTimeMetadata
    metadataItem.key = AVMetadataKey.quickTimeMetadataKeyLocationISO6709 as NSString
    metadataItem.identifier = .quickTimeMetadataLocationISO6709
    metadataItem.value = location.iso6709String as NSString
    metadataItem.dataType = kCMMetadataDataType_QuickTimeMetadataLocation_ISO6709 as String
    return metadataItem
  }
}