//
// Copyright 2022 New Vector Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

import QuickLook
import SwiftUI

struct MediaPickerPreviewScreenScreen: View {
    @ObservedObject var context: MediaPickerPreviewScreenViewModel.Context
    
    var body: some View {
        NavigationStack {
            PreviewView(context: context,
                        fileURL: context.viewState.url,
                        title: context.viewState.title)
                .id(UUID())
                .ignoresSafeArea(edges: .bottom)
                .toolbar { toolbar }
        }
    }
    
    @ToolbarContentBuilder
    private var toolbar: some ToolbarContent {
        ToolbarItem(placement: .cancellationAction) {
            Button { context.send(viewAction: .cancel) } label: {
                Text(L10n.actionCancel)
            }
        }
        ToolbarItem(placement: .confirmationAction) {
            Button { context.send(viewAction: .send) } label: {
                Text(L10n.actionSend)
            }
        }
    }
}

private struct PreviewView: UIViewControllerRepresentable {
    let context: MediaPickerPreviewScreenViewModel.Context
    let fileURL: URL
    let title: String?

    func makeUIViewController(context: Context) -> UINavigationController {
        let previewController = QLPreviewController()
        previewController.dataSource = context.coordinator
        previewController.delegate = context.coordinator

        return UINavigationController(rootViewController: previewController)
    }

    func updateUIViewController(_ uiViewController: UINavigationController, context: Context) { }

    func makeCoordinator() -> Coordinator {
        Coordinator(view: self)
    }
    
    class Coordinator: NSObject, QLPreviewControllerDataSource, QLPreviewControllerDelegate {
        let view: PreviewView

        init(view: PreviewView) {
            self.view = view
        }
        
        // MARK: - QLPreviewControllerDataSource
        
        func numberOfPreviewItems(in controller: QLPreviewController) -> Int {
            1
        }

        func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
            PreviewItem(previewItemURL: view.fileURL, previewItemTitle: view.title)
        }
        
        // MARK: - QLPreviewControllerDelegate
        
        func previewController(_ controller: QLPreviewController, editingModeFor previewItem: QLPreviewItem) -> QLPreviewItemEditingMode {
            .disabled
        }
    }
}

private class PreviewItem: NSObject, QLPreviewItem {
    var previewItemURL: URL?
    var previewItemTitle: String?

    init(previewItemURL: URL?, previewItemTitle: String?) {
        self.previewItemURL = previewItemURL
        self.previewItemTitle = previewItemTitle
    }
}

// MARK: - Previews

struct MediaPickerPreviewScreen_Previews: PreviewProvider {
    static let viewModel = MediaPickerPreviewScreenViewModel(url: URL.picturesDirectory, title: nil)
    static var previews: some View {
        MediaPickerPreviewScreenScreen(context: viewModel.context)
    }
}