import ExpoModulesCore
import Photos
import PhotosUI

public class LivePhotoModule: Module {
  public func definition() -> ModuleDefinition {
    Name("LivePhoto")

    /// Generate a Live Photo from an image + animation config and save to photo library.
    /// Returns the local identifier of the saved PHAsset.
    AsyncFunction("exportLivePhoto") { (configJson: String, promise: Promise) in
      guard let data = configJson.data(using: .utf8),
            let config = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
            let sourceUri = config["sourceUri"] as? String else {
        promise.reject("INVALID_CONFIG", "Invalid wallpaper config JSON")
        return
      }

      let shaderId = config["animation"] as? String ?? "ken-burns"
      let uniforms = config["uniforms"] as? [String: Double] ?? [:]
      let intensity = Float(uniforms["intensity"] ?? 0.5)
      let speed = Float(uniforms["speed"] ?? 0.3)
      let direction = Float(uniforms["direction"] ?? 0.0)

      // Resolve image path
      let imagePath: String
      if sourceUri.hasPrefix("file://") {
        imagePath = String(sourceUri.dropFirst(7))
      } else {
        imagePath = sourceUri
      }

      guard let image = UIImage(contentsOfFile: imagePath) else {
        promise.reject("IMAGE_NOT_FOUND", "Could not load image at \(imagePath)")
        return
      }

      let screenSize = UIScreen.main.bounds.size
      let scale = UIScreen.main.scale
      let targetSize = CGSize(width: screenSize.width * scale, height: screenSize.height * scale)

      Task {
        do {
          let exporter = LivePhotoExporter()
          let assetId = try await exporter.export(
            image: image,
            targetSize: targetSize,
            shaderId: shaderId,
            intensity: intensity,
            speed: speed,
            direction: direction
          )
          promise.resolve(assetId)
        } catch {
          promise.reject("EXPORT_FAILED", error.localizedDescription)
        }
      }
    }

    /// Check if the photo library is accessible.
    AsyncFunction("checkPermission") { () -> String in
      let status = PHPhotoLibrary.authorizationStatus(for: .readWrite)
      switch status {
      case .authorized, .limited: return "granted"
      case .denied, .restricted: return "denied"
      case .notDetermined: return "undetermined"
      @unknown default: return "unknown"
      }
    }

    /// Request photo library write permission.
    AsyncFunction("requestPermission") { (promise: Promise) in
      PHPhotoLibrary.requestAuthorization(for: .readWrite) { status in
        switch status {
        case .authorized, .limited: promise.resolve("granted")
        case .denied, .restricted: promise.resolve("denied")
        default: promise.resolve("denied")
        }
      }
    }
  }
}