import AVFoundation
import MobileCoreServices
import Photos
import SwiftUI

struct SharingMediaPickerView: View {
    @EnvironmentObject var store: AppStore
    @State private var showCameraPicker = false
    @State private var cameraReady = false

    @State private var selectedItems: [String] = []

    var body: some View {
        let columns = Array(repeating: GridItem(.flexible(), spacing: 0), count: 3)

        VStack(spacing: 0) {
            // List of media
            ScrollView(showsIndicators: false) {
                LazyVGrid(columns: columns, spacing: 0) {
                    // For camera
                    if store.state.sharingState.isCameraAccessGranted {
                        if cameraReady {
                            ZStack {
                                CameraView()
                                    .aspectRatio(1, contentMode: .fit)
                                    .frame(maxWidth: .infinity)
                                Image(systemName: "camera")
                                    .resizable()
                                    .aspectRatio(contentMode: .fit)
                                    .frame(width: 40, height: 40)
                                    .foregroundColor(.white)
                                    .padding(8)
                                    .background(Color.black.opacity(0.5))
                                    .clipShape(Circle())
                                    .padding(8)
                            }
                            .onTapGesture {
                                showCameraPicker = true
                            }
                        } else {
                            ProgressView()
                                .frame(maxWidth: .infinity)
                                .frame(height: 100)
                                .onAppear {
                                    DispatchQueue.main.asyncAfter(deadline: .now() + 0.01) {
                                        cameraReady = true
                                    }
                                }
                        }
                    } else {
                        Button {
                            openAppSettings()
                        } label: {
                            ZStack {
                                Rectangle()
                                    .fill(Color.Material.Background.light)
                                    .overlay {
                                        VStack {
                                            Image(systemName: "camera")
                                                .foregroundColor(.Material.Elements.active)
                                                .font(.system(size: 30))
                                            Text("Allow camera access")
                                                .foregroundColor(.Material.Text.main)
                                                .font(.body3)
                                        }
                                    }
                                    .frame(height: 100)
                            }
                        }
                    }

                    // For gallery
                    if store.state.sharingState.isGalleryAccessGranted {
                        ForEach(store.state.sharingState.galleryItems) { item in
                            GridViewItem(item: item, selected: $selectedItems)
                        }
                    } else {
                        Button {
                            openAppSettings()
                        } label: {
                            ZStack {
                                Rectangle()
                                    .fill(Color.Material.Background.light)
                                    .overlay {
                                        VStack {
                                            Image(systemName: "photo")
                                                .foregroundColor(.Material.Elements.active)
                                                .font(.system(size: 30))
                                            Text("Allow gallery access")
                                                .foregroundColor(.Material.Text.main)
                                                .font(.body3)
                                        }
                                    }
                                    .frame(height: 100)
                            }
                        }
                    }
                }
            }
            .fullScreenCover(isPresented: $showCameraPicker) {
                CameraPicker(sourceType: .camera) { data, type in
                    store.dispatch(.sharingAction(.cameraCaptured(media: data, type: type)))
                    showCameraPicker = false
                    store.dispatch(.sharingAction(.showSharing(false)))
                }
                .edgesIgnoringSafeArea(.all)
            }

            // Send panel
            Rectangle()
                .foregroundColor(.Material.Shape.black)
                .frame(maxWidth: .infinity)
                .frame(height: self.selectedItems.isEmpty ? 0 : 50)
                .overlay {
                    HStack {
                        Text(L10n.Attachment.Send.media)
                            .foregroundColor(.Material.Text.white)
                            .font(.body1)
                        Image(systemName: "arrow.up.circle")
                            .foregroundColor(.Material.Text.white)
                            .font(.body1)
                            .padding(.leading, 8)
                    }
                    .padding()
                }
                .clipped()
                .onTapGesture {
                    store.dispatch(.sharingAction(.shareMedia(ids: selectedItems)))
                    store.dispatch(.sharingAction(.showSharing(false)))
                }
        }
        .onAppear {
            store.dispatch(.sharingAction(.checkCameraAccess))
            store.dispatch(.sharingAction(.checkGalleryAccess))
        }
        .onChange(of: store.state.sharingState.isGalleryAccessGranted) { granted in
            if granted {
                store.dispatch(.fileAction(.fetchItemsFromGallery))
            }
        }
    }
}

private struct GridViewItem: View {
    let item: SharingGalleryItem
    @Binding var selected: [String]
    @State var isSelected = false

    var body: some View {
        if let data = item.thumbnail {
            ZStack {
                Image(uiImage: UIImage(data: data) ?? UIImage())
                    .resizable()
                    .aspectRatio(contentMode: .fill)
                    .frame(width: Const.galleryGridSize, height: Const.galleryGridSize)
                    .clipped()
                if let duration = item.duration {
                    VStack {
                        Spacer()
                        HStack {
                            Spacer()
                            Text(duration)
                                .foregroundColor(.Material.Text.white)
                                .font(.sub1)
                                .shadow(color: .black, radius: 2)
                                .padding(4)
                        }
                    }
                }
                if isSelected {
                    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 {
                isSelected.toggle()
                if isSelected {
                    selected.append(item.id)
                } else {
                    selected.removeAll { $0 == item.id }
                }
            }
        } else {
            ZStack {
                Rectangle()
                    .fill(Color.Material.Background.light)
                    .overlay {
                        ProgressView()
                            .foregroundColor(.Material.Elements.active)
                    }
                    .frame(width: Const.galleryGridSize, height: Const.galleryGridSize)
            }
        }
    }
}

class CameraUIView: UIView {
    var previewLayer: AVCaptureVideoPreviewLayer?

    override func layoutSubviews() {
        super.layoutSubviews()
        previewLayer?.frame = bounds
    }
}

struct CameraView: UIViewRepresentable {
    func makeUIView(context _: Context) -> CameraUIView {
        let view = CameraUIView()

        let captureSession = AVCaptureSession()
        guard let captureDevice = AVCaptureDevice.default(for: .video) else { return view }
        guard let input = try? AVCaptureDeviceInput(device: captureDevice) else { return view }
        captureSession.addInput(input)

        let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
        previewLayer.videoGravity = .resizeAspectFill
        view.layer.addSublayer(previewLayer)
        view.previewLayer = previewLayer

        captureSession.startRunning()

        return view
    }

    func updateUIView(_ uiView: CameraUIView, context _: Context) {
        uiView.previewLayer?.frame = uiView.bounds
    }
}

struct CameraPicker: UIViewControllerRepresentable {
    var sourceType: UIImagePickerController.SourceType
    var completionHandler: (Data, SharingCameraMediaType) -> Void

    func makeUIViewController(context: Context) -> UIImagePickerController {
        let picker = UIImagePickerController()
        picker.sourceType = sourceType
        picker.delegate = context.coordinator
        picker.mediaTypes = [UTType.movie.identifier, UTType.image.identifier]
        picker.videoQuality = .typeHigh
        picker.videoMaximumDuration = Const.videoDurationLimit
        picker.view.backgroundColor = .clear
        return picker
    }

    func updateUIViewController(_: UIImagePickerController, context _: Context) {}

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    class Coordinator: NSObject, UINavigationControllerDelegate, UIImagePickerControllerDelegate {
        let parent: CameraPicker

        init(_ parent: CameraPicker) {
            self.parent = parent
        }

        func imagePickerController(_: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey: Any]) {
            // swiftlint:disable:next force_cast
            let mediaType = info[.mediaType] as! String

            if mediaType == UTType.image.identifier {
                if let image = info[.originalImage] as? UIImage {
                    let data = image.jpegData(compressionQuality: 1.0) ?? Data()
                    parent.completionHandler(data, .photo)
                }
            } else if mediaType == UTType.movie.identifier {
                if let url = info[.mediaURL] as? URL {
                    let data = try? Data(contentsOf: url)
                    parent.completionHandler(data ?? Data(), .video)
                }
            }
        }
    }
}