import AVFoundation
import Combine
import Foundation
import Photos
import UIKit

final class SharingMiddleware {
    static let shared = SharingMiddleware()

    // swiftlint:disable:next function_body_length
    func middleware(state _: AppState, action: AppAction) -> AnyPublisher<AppAction, Never> {
        switch action {
        case .sharingAction(.checkCameraAccess):
            return Future<AppAction, Never> { promise in
                let status = AVCaptureDevice.authorizationStatus(for: .video)
                switch status {
                case .authorized:
                    promise(.success(.sharingAction(.setCameraAccess(true))))

                case .notDetermined:
                    AVCaptureDevice.requestAccess(for: .video) { granted in
                        promise(.success(.sharingAction(.setCameraAccess(granted))))
                        // DispatchQueue.main.async {
                        //     self.isCameraAccessGranted = granted
                        // }
                    }

                case .denied, .restricted:
                    promise(.success(.sharingAction(.setCameraAccess(false))))

                @unknown default:
                    promise(.success(.sharingAction(.setCameraAccess(false))))
                }
            }
            .eraseToAnyPublisher()

        case .sharingAction(.checkGalleryAccess):
            return Future<AppAction, Never> { promise in
                let status = PHPhotoLibrary.authorizationStatus()
                switch status {
                case .authorized, .limited:
                    promise(.success(.sharingAction(.setGalleryAccess(true))))

                case .notDetermined:
                    PHPhotoLibrary.requestAuthorization { status in
                        promise(.success(.sharingAction(.setGalleryAccess(status == .authorized))))
                        // DispatchQueue.main.async {
                        //     self.isGalleryAccessGranted = status == .authorized
                        //     if self.isGalleryAccessGranted {
                        //         self.fetchGallery()
                        //     }
                        // }
                    }

                case .denied, .restricted:
                    promise(.success(.sharingAction(.setGalleryAccess(false))))

                @unknown default:
                    promise(.success(.sharingAction(.setGalleryAccess(false))))
                }
            }
            .eraseToAnyPublisher()

        case .sharingAction(.fetchGallery):
            return Future<AppAction, Never> { promise in
                DispatchQueue.global(qos: .background).async {
                    let fetchOptions = PHFetchOptions()
                    fetchOptions.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
                    let assets = PHAsset.fetchAssets(with: fetchOptions)

                    let manager = PHImageManager.default()
                    let option = PHImageRequestOptions()
                    option.isSynchronous = true

                    var items: [SharingGalleryItem] = []
                    let group = DispatchGroup()
                    assets.enumerateObjects { asset, _, _ in
                        if asset.mediaType == .image {
                            group.enter()
                            manager.requestImage(
                                for: asset,
                                targetSize: PHImageManagerMaximumSize,
                                contentMode: .aspectFill,
                                options: option
                            ) { image, _ in
                                if image != nil {
                                    items.append(.init(id: asset.localIdentifier, type: .photo))
                                    group.leave()
                                }
                            }
                        } else if asset.mediaType == .video {
                            group.enter()
                            manager.requestAVAsset(forVideo: asset, options: nil) { avAsset, _, _ in
                                if avAsset != nil {
                                    items.append(.init(id: asset.localIdentifier, type: .video, duration: asset.duration.minAndSec))
                                    group.leave()
                                }
                            }
                        }
                    }
                    group.notify(queue: .main) {
                        promise(.success(.sharingAction(.galleryFetched(items))))
                    }
                }
            }
            .eraseToAnyPublisher()

        case .sharingAction(.galleryFetched(let items)):
            return Future<AppAction, Never> { promise in
                DispatchQueue.global(qos: .background).async {
                    let ids = items
                        .filter { $0.thumbnail == nil }
                        .map { $0.id }
                    let assets = PHAsset.fetchAssets(withLocalIdentifiers: ids, options: nil)
                    assets.enumerateObjects { asset, _, _ in
                        let manager = PHImageManager.default()
                        if asset.mediaType == .image {
                            manager.requestImage(
                                for: asset,
                                targetSize: PHImageManagerMaximumSize,
                                contentMode: .aspectFill,
                                options: nil
                            ) { image, _ in
                                image?.scaleAndCropImage(toExampleSize: CGSize(width: Const.galleryGridSize, height: Const.galleryGridSize)) { image in
                                    if let image {
                                        let data = image.jpegData(compressionQuality: 1.0) ?? Data()
                                        DispatchQueue.main.async {
                                            store.dispatch(.sharingAction(.thumbnailUpdated(data, asset.localIdentifier)))
                                        }
                                    }
                                }
                            }
                        } else if asset.mediaType == .video {
                            manager.requestAVAsset(forVideo: asset, options: nil) { avAsset, _, _ in
                                if let avAsset {
                                    let imageGenerator = AVAssetImageGenerator(asset: avAsset)
                                    imageGenerator.appliesPreferredTrackTransform = true
                                    let time = CMTimeMake(value: 1, timescale: 2)
                                    do {
                                        let imageRef = try imageGenerator.copyCGImage(at: time, actualTime: nil)
                                        let thumbnail = UIImage(cgImage: imageRef)
                                        thumbnail.scaleAndCropImage(toExampleSize: CGSize(width: Const.galleryGridSize, height: Const.galleryGridSize), completion: { image in
                                            if let image {
                                                let data = image.jpegData(compressionQuality: 1.0) ?? Data()
                                                DispatchQueue.main.async {
                                                    store.dispatch(.sharingAction(.thumbnailUpdated(data, asset.localIdentifier)))
                                                }
                                            }
                                        })
                                    } catch {
                                        print("Failed to create thumbnail image")
                                    }
                                }
                            }
                        }
                    }
                }
                promise(.success(.empty))
            }
            .eraseToAnyPublisher()

        default:
            return Empty().eraseToAnyPublisher()
        }
    }
}

// private func fetchGallery() {
//     let fetchOptions = PHFetchOptions()
//     fetchOptions.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
//     let assets = PHAsset.fetchAssets(with: fetchOptions)
//
//     let manager = PHImageManager.default()
//     let option = PHImageRequestOptions()
//     option.isSynchronous = true
//
//     assets.enumerateObjects { asset, _, _ in
//         if asset.mediaType == .image {
//             manager.requestImage(
//                 for: asset,
//                 targetSize: PHImageManagerMaximumSize,
//                 contentMode: .aspectFill,
//                 options: option
//             ) { image, _ in
//                 image?.scaleAndCropImage(toExampleSize: CGSize(width: gridSize, height: gridSize), completion: { image in
//                     if let image {
//                         DispatchQueue.main.async {
//                             self.thumbnails.append(ThumbnailView(id: asset.localIdentifier, image: image, gridSize: gridSize, selected: $selectedMedia))
//                         }
//                     }
//                 })
//             }
//         } else if asset.mediaType == .video {
//             manager.requestAVAsset(forVideo: asset, options: nil) { avAsset, _, _ in
//                 if let avAsset {
//                     let imageGenerator = AVAssetImageGenerator(asset: avAsset)
//                     imageGenerator.appliesPreferredTrackTransform = true
//                     let time = CMTimeMake(value: 1, timescale: 2)
//                     do {
//                         let imageRef = try imageGenerator.copyCGImage(at: time, actualTime: nil)
//                         let thumbnail = UIImage(cgImage: imageRef)
//                         thumbnail.scaleAndCropImage(toExampleSize: CGSize(width: gridSize, height: gridSize), completion: { image in
//                             if let image {
//                                 DispatchQueue.main.async {
//                                     self.thumbnails.append(ThumbnailView(id: asset.localIdentifier, image: image, gridSize: gridSize, selected: $selectedMedia, duration: asset.duration.minAndSec))
//                                 }
//                             }
//                         })
//                     } catch {
//                         print("Failed to create thumbnail image")
//                     }
//                 }
//             }
//         }
//     }
// }

//     private func sendGalleryMedia(ids _: [String]) {
//         var media: [AttachmentItem] = []
//         let dispatchGroup = DispatchGroup()
//
//         let asset = PHAsset.fetchAssets(withLocalIdentifiers: ids, options: nil)
//         asset.enumerateObjects { asset, _, _ in
//             dispatchGroup.enter()
//             if asset.mediaType == .image {
//                 let manager = PHImageManager.default()
//                 let option = PHImageRequestOptions()
//                 option.isSynchronous = true
//
//                 manager.requestImage(
//                     for: asset,
//                     targetSize: PHImageManagerMaximumSize,
//                     contentMode: .aspectFill,
//                     options: option
//                 ) { image, _ in
//                     if let image {
//                         let data = image.jpegData(compressionQuality: 1.0) ?? Data()
//                         media.append(.init(type: .image, data: data, string: ""))
//                     }
//                     dispatchGroup.leave()
//                 }
//             } else if asset.mediaType == .video {
//                 let manager = PHImageManager.default()
//                 let option = PHVideoRequestOptions()
//                 option.version = .current
//                 option.deliveryMode = .highQualityFormat
//
//                 manager.requestAVAsset(forVideo: asset, options: option) { avAsset, _, _ in
//                     if let avAsset {
//                         let url = (avAsset as? AVURLAsset)?.url
//                         let data = try? Data(contentsOf: url ?? URL(fileURLWithPath: ""))
//                         media.append(.init(type: .movie, data: data ?? Data(), string: ""))
//                     }
//                     dispatchGroup.leave()
//                 }
//             }
//         }
//         dispatchGroup.notify(queue: .main) {
//             store.dispatch(.conversationAction(.sendAttachment(.init(
//                 id: UUID().uuidString,
//                 items: media
//             ))))
//         }
//     }
// }
//
// private struct ThumbnailView: Identifiable, View {
//     let id: String
//     let gridSize: CGFloat
//     let duration: String?
//
//     @State private var image: UIImage
//     @State private var ready = false
//     @State private var selected = false
//     @Binding var selectedMedia: [SelectedMedia]
//
//     init(id: String, image: UIImage, gridSize: CGFloat, selected: Binding<[SelectedMedia]>, duration: String? = nil) {
//         self.id = id
//         self.image = image
//         self.gridSize = gridSize
//         _selectedMedia = selected
//         self.duration = duration
//     }
//
//     var body: some View {
//         if ready {
//             ZStack {
//                 Image(uiImage: image)
//                     .resizable()
//                     .aspectRatio(contentMode: .fill)
//                     .frame(width: gridSize, height: gridSize)
//                     .clipped()
//                 if let duration {
//                     VStack {
//                         Spacer()
//                         HStack {
//                             Spacer()
//                             Text(duration)
//                                 .foregroundColor(.Material.Text.white)
//                                 .font(.sub1)
//                                 .shadow(color: .black, radius: 2)
//                                 .padding(4)
//                         }
//                     }
//                 }
//                 if selected {
//                     VStack {
//                         HStack {
//                             Spacer()
//                             Circle()
//                                 .frame(width: 30, height: 30)
//                                 .shadow(color: .black, radius: 2)
//                                 .foregroundColor(.Material.Shape.white)
//                                 .overlay {
//                                     Image(systemName: "checkmark")
//                                         .foregroundColor(.Material.Elements.active)
//                                         .font(.body3)
//                                 }
//                                 .padding(4)
//                         }
//                         Spacer()
//                     }
//                 }
//             }
//             .onTapGesture {
//                 withAnimation {
//                     selected.toggle()
//                     if selected {
//                         selectedMedia.append(SelectedMedia(id: id))
//                     } else {
//                         selectedMedia.removeAll { $0.id == id }
//                     }
//                 }
//             }
//         } else {
//             ZStack {
//                 Rectangle()
//                     .fill(Color.Material.Background.light)
//                     .overlay {
//                         ProgressView()
//                     }
//                     .frame(width: gridSize, height: gridSize)
//             }
//             .onAppear {
//                 image.scaleAndCropImage(toExampleSize: CGSize(width: gridSize, height: gridSize), completion: { image in
//                     if let image {
//                         self.image = image
//                         ready = true
//                     }
//                 })
//             }
//         }
//     }
// }