import SwiftUI
import PhotosUI
import AVFoundation
import os.log

struct VideoPicker: UIViewControllerRepresentable {
    @Binding var selectedVideoURL: URL?
    @Binding var thumbnailImage: UIImage?
    var onDismiss: (() -> Void)?
    
    func makeUIViewController(context: Context) -> PHPickerViewController {
        var configuration = PHPickerConfiguration(photoLibrary: PHPhotoLibrary.shared())
        configuration.filter = .videos
        configuration.selectionLimit = 1
        configuration.preferredAssetRepresentationMode = .current
        
        let picker = PHPickerViewController(configuration: configuration)
        picker.delegate = context.coordinator
        return picker
    }
    
    func updateUIViewController(_ uiViewController: PHPickerViewController, context: Context) {}
    
    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }
    
    class Coordinator: NSObject, PHPickerViewControllerDelegate {
        let parent: VideoPicker
        private let logger = Logger(subsystem: Bundle.main.bundleIdentifier ?? "com.example.app", category: "VideoPicker")
        
        init(_ parent: VideoPicker) {
            self.parent = parent
        }
        
        func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
            guard let result = results.first else {
                parent.onDismiss?()
                return
            }
            
            // 获取视频URL
            result.itemProvider.loadFileRepresentation(forTypeIdentifier: UTType.movie.identifier) { [weak self] url, error in
                guard let self = self, let videoURL = url, error == nil else {
                    self?.logger.error("Failed to load video: \(error?.localizedDescription ?? "Unknown error")")
                    DispatchQueue.main.async {
                        self?.parent.onDismiss?()
                    }
                    return
                }
                
                // 创建临时文件URL
                let tempDirectory = FileManager.default.temporaryDirectory
                let targetURL = tempDirectory.appendingPathComponent("\(UUID().uuidString).\(videoURL.pathExtension)")
                
                do {
                    // 将视频复制到临时目录
                    if FileManager.default.fileExists(atPath: targetURL.path) {
                        try FileManager.default.removeItem(at: targetURL)
                    }
                    try FileManager.default.copyItem(at: videoURL, to: targetURL)
                    
                    // 提取视频首帧
                    MediaUtils.extractFirstFrame(from: targetURL) { [weak self] result in
                        switch result {
                        case .success(let image):
                            DispatchQueue.main.async {
                                self?.parent.thumbnailImage = image
                                self?.parent.selectedVideoURL = targetURL
                                self?.parent.onDismiss?()
                            }
                        case .failure(let error):
                            self?.logger.error("Failed to extract video thumbnail: \(error.localizedDescription)")
                            DispatchQueue.main.async {
                                self?.parent.onDismiss?()
                            }
                        }
                    }
                } catch {
                    self.logger.error("Failed to copy video file: \(error.localizedDescription)")
                    DispatchQueue.main.async {
                        self.parent.onDismiss?()
                    }
                }
            }
        }
    }
}