//
// Copyright 2019 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//

import SignalServiceKit
import SignalUI
import SwiftUI

class ProvisioningQRCodeViewController: ProvisioningBaseViewController, ProvisioningSocketManagerUIDelegate {
    private let provisioningQRCodeViewModel: RotatingQRCodeView.Model
    private let provisioningSocketManager: ProvisioningSocketManager

    init(
        provisioningController: ProvisioningController,
        provisioningSocketManager: ProvisioningSocketManager,
    ) {
        provisioningQRCodeViewModel = RotatingQRCodeView.Model(
            urlDisplayMode: .loading,
            onRefreshButtonPressed: { [weak provisioningSocketManager] in
                provisioningSocketManager?.reset()
            },
        )
        self.provisioningSocketManager = provisioningSocketManager

        super.init(provisioningController: provisioningController)

        provisioningSocketManager.delegate = self
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        navigationItem.hidesBackButton = true

        let qrCodeViewHostingContainer = HostingContainer(wrappedView: ProvisioningQRCodeView(
            model: provisioningQRCodeViewModel,
        ))

        addChild(qrCodeViewHostingContainer)
        view.addSubview(qrCodeViewHostingContainer.view)
        qrCodeViewHostingContainer.view.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            qrCodeViewHostingContainer.view.topAnchor.constraint(equalTo: contentLayoutGuide.topAnchor),
            qrCodeViewHostingContainer.view.leadingAnchor.constraint(equalTo: contentLayoutGuide.leadingAnchor),
            qrCodeViewHostingContainer.view.bottomAnchor.constraint(equalTo: contentLayoutGuide.bottomAnchor),
            qrCodeViewHostingContainer.view.trailingAnchor.constraint(equalTo: contentLayoutGuide.trailingAnchor),
        ])
        qrCodeViewHostingContainer.didMove(toParent: self)

        provisioningQRCodeViewModel.updateURLDisplayMode(.loading)
        provisioningSocketManager.start()
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        provisioningSocketManager.stop()
    }

    // MARK: -

    func reset() {
        provisioningSocketManager.stop()
        provisioningQRCodeViewModel.updateURLDisplayMode(.loading)
        provisioningSocketManager.start()
    }

    func provisioningSocketManager(_ provisioningSocketManager: ProvisioningSocketManager, didUpdateProvisioningURL url: URL) {
        provisioningQRCodeViewModel.updateURLDisplayMode(.loaded(url))
    }

    func provisioningSocketManagerDidPauseQRRotation(_ provisioningSocketManager: ProvisioningSocketManager) {
        provisioningQRCodeViewModel.updateURLDisplayMode(.refreshButton)
    }
}

// MARK: -

private struct ProvisioningQRCodeView: View {
    @ObservedObject var model: RotatingQRCodeView.Model

    var body: some View {
        GeometryReader { overallGeometry in
            VStack(spacing: 12) {
                Text(OWSLocalizedString(
                    "SECONDARY_ONBOARDING_SCAN_CODE_TITLE",
                    comment: "header text while displaying a QR code which, when scanned, will link this device.",
                ))
                .font(.title)
                .fontWeight(.semibold)
                .foregroundStyle(Color.Signal.label)

                Text(OWSLocalizedString(
                    "SECONDARY_ONBOARDING_SCAN_CODE_BODY",
                    comment: "body text while displaying a QR code which, when scanned, will link this device.",
                ))
                .font(.body)
                .foregroundStyle(Color.Signal.secondaryLabel)

                Spacer()
                    .frame(height: overallGeometry.size.height * 0.05)

                RotatingQRCodeView(model: self.model)

                Spacer()
                    .frame(height: overallGeometry.size.height * (overallGeometry.size.isLandscape ? 0.05 : 0.1))

#if TESTABLE_BUILD
                if
                    #available(iOS 16.0, *),
                    let provisioningUrl = model.qrCodeViewModel.qrCodeURL
                {
                    // If on a physical device, this postfixing with some text
                    // allows one to AirDrop the URL to macOS to be copied into
                    // a simulator, instead of having macOS automatically try
                    // and open the URL (which Signal Desktop will try, and
                    // fail, to handle).
                    ShareLink(item: "\(provisioningUrl) DELETETHIS") {
                        Text(LocalizationNotNeeded(
                            "Debug only: Share URL",
                        ))
                    }
                    .simultaneousGesture(TapGesture().onEnded {
                        // When tapped, also copy to the clipboard for easy
                        // extraction from a simulator.
                        UIPasteboard.general.url = provisioningUrl
                    })

                    Button(LocalizationNotNeeded("Debug only: Copy URL")) {
                        UIPasteboard.general.url = provisioningUrl
                    }
                }
#endif

                Link(
                    OWSLocalizedString(
                        "SECONDARY_ONBOARDING_SCAN_CODE_HELP_TEXT",
                        comment: "Link text for page with troubleshooting info shown on the QR scanning screen",
                    ),
                    destination: URL.Support.troubleshootingMultipleDevices,
                )
                .buttonStyle(Registration.UI.MediumSecondaryButtonStyle())
                .padding(.bottom, NSDirectionalEdgeInsets.buttonContainerLayoutMargins.bottom)
            }
            .multilineTextAlignment(.center)
        }
    }
}

// MARK: -

private struct PreviewView: View {
    let urlDisplayMode: RotatingQRCodeView.Model.URLDisplayMode

    var body: some View {
        ProvisioningQRCodeView(
            model: RotatingQRCodeView.Model(
                urlDisplayMode: urlDisplayMode,
                onRefreshButtonPressed: {},
            ),
        )
        .padding(112)
    }
}

#Preview("Loaded") {
    PreviewView(urlDisplayMode: .loaded(URL(string: "https://signal.org")!))
}

#Preview("Loading") {
    PreviewView(urlDisplayMode: .loading)
}

#Preview("Refresh Button") {
    PreviewView(urlDisplayMode: .refreshButton)
}