//
// Copyright 2025 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//

import AuthenticationServices
import SignalServiceKit
import SignalUI
import SwiftUI

class BackupRecordKeyViewController: OWSViewController, OWSNavigationChildController {
    struct Option: OptionSet {
        let rawValue: Int

        /// Show a "continue" button in the view footer. Not compatible with
        /// `.showCreateNewKeyButton`.
        static let showContinueButton = Option(rawValue: 1 << 1)
        /// Show a "create new key" button in the view footer. Not compatible
        /// with `.showContinueButton`.
        static let showCreateNewKeyButton = Option(rawValue: 1 << 2)
    }

    enum AEPMode {
        /// The user's current AEP, which must only be viewed after device auth.
        case current(AccountEntropyPool, LocalDeviceAuthentication.AuthSuccess)
        /// A new candidate AEP.
        case newCandidate(AccountEntropyPool)

        fileprivate var aep: AccountEntropyPool {
            switch self {
            case .current(let aep, _): return aep
            case .newCandidate(let aep): return aep
            }
        }
    }

    var shouldCancelNavigationBack: Bool {
        onBackPressedBlock != nil
    }

    private let displayableAEP: DisplayableAccountEntropyPool
    private let onContinuePressedBlock: (BackupRecordKeyViewController) -> Void
    private let onCreateNewKeyPressedBlock: (BackupRecordKeyViewController) -> Void
    private let onBackPressedBlock: (() -> Void)?
    private let options: [Option]

    /// - Parameter onCreateNewKeyPressed
    /// Called when the user taps the "create new key" button. Only relevant if
    /// the `.showCreateNewKeyButton` option is passed.
    /// - Parameter onContinuePressed
    /// Called when the user taps the "continue" button. Only relevant if the
    /// `.showContinueButton` option is passed.
    init(
        aepMode: AEPMode,
        options: [Option],
        onCreateNewKeyPressed: @escaping (BackupRecordKeyViewController) -> Void = { _ in },
        onContinuePressed: @escaping (BackupRecordKeyViewController) -> Void = { _ in },
        onBackPressed: (() -> Void)? = nil,
    ) {
        self.displayableAEP = DisplayableAccountEntropyPool(aep: aepMode.aep)
        self.onContinuePressedBlock = onContinuePressed
        self.onCreateNewKeyPressedBlock = onCreateNewKeyPressed
        self.onBackPressedBlock = onBackPressed
        self.options = options

        super.init()

        OWSTableViewController2.removeBackButtonText(viewController: self)
    }

    var navbarBackgroundColorOverride: UIColor? {
        .Signal.groupedBackground
    }

    // MARK: -

    override func viewDidLoad() {
        super.viewDidLoad()

        let screenLockUI = AppEnvironment.shared.screenLockUI
        screenLockUI.sensitiveContentDidLoad(inViewController: self)

        view.backgroundColor = .Signal.groupedBackground

        if let onBackPressedBlock {
            navigationItem.hidesBackButton = true
            navigationItem.leftBarButtonItem = .init(
                image: UIImage(named: "chevron-left-bold-28"),
                primaryAction: UIAction { _ in
                    onBackPressedBlock()
                },
            )

            isModalInPresentation = true
        }

        let heroIconView = UIImageView()
        heroIconView.image = .backupsLock
        heroIconView.contentMode = .scaleAspectFit

        let headlineLabel = UILabel.title1Label(text: OWSLocalizedString(
            "BACKUP_RECORD_KEY_TITLE",
            comment: "Title for a view allowing users to record their 'Recovery Key'.",
        ))

        let subheadlineLabel = UILabel.explanationTextLabel(text: OWSLocalizedString(
            "BACKUP_RECORD_KEY_SUBTITLE",
            comment: "Subtitle for a view allowing users to record their 'Recovery Key'.",
        ))

        let aepTextView = AccountEntropyPoolTextView(mode: .display(displayableAEP))
        aepTextView.backgroundColor = .Signal.secondaryGroupedBackground

        var topButtons: [UIButton] = [
            UIButton(
                configuration: .smallSecondary(title: OWSLocalizedString(
                    "BACKUP_RECORD_KEY_COPY_TO_CLIPBOARD_BUTTON_TITLE",
                    comment: "Title for a button allowing users to copy their 'Recovery Key' to the clipboard.",
                )),
                primaryAction: UIAction { [weak self] _ in
                    self?.copyToClipboardWithConfirmation()
                },
            ),
        ]
        if #available(iOS 26.2, *) {
            let saveToPasswordManagerButton = UIButton(
                configuration: .smallSecondary(title: OWSLocalizedString(
                    "BACKUP_RECORD_KEY_PASSWORD_MANAGER_BUTTON_TITLE",
                    comment: "Title for a button allowing users to save their 'Recovery Key' to a password manager.",
                )),
                primaryAction: UIAction { [weak self] _ in
                    self?.saveToPasswordManagerWithConfirmation()
                },
            )
            topButtons.append(saveToPasswordManagerButton)
        }

        var bottomButtons = [UIButton]()
        if options.contains(.showCreateNewKeyButton) {
            let createNewKeyButton = UIButton(
                configuration: .largeSecondary(title: OWSLocalizedString(
                    "BACKUP_RECORD_KEY_CREATE_NEW_KEY_BUTTON_TITLE",
                    comment: "Title for a button allowing users to create a new 'Recovery Key'.",
                )),
                primaryAction: UIAction { [weak self] _ in
                    guard let self else { return }
                    onCreateNewKeyPressedBlock(self)
                },
            )

            bottomButtons.append(createNewKeyButton)
        }
        if options.contains(.showContinueButton) {
            let continueButton = UIButton(
                configuration: .largePrimary(title: CommonStrings.continueButton),
                primaryAction: UIAction { [weak self] _ in
                    guard let self else { return }
                    onContinuePressedBlock(self)
                },
            )

            bottomButtons.append(continueButton)
        }

        let stackView = addStaticContentStackView(
            arrangedSubviews: [
                heroIconView,
                headlineLabel,
                subheadlineLabel,
                aepTextView,
                topButtons.enclosedInVerticalStackView(isFullWidthButtons: false),
                .vStretchingSpacer(),
                bottomButtons.enclosedInVerticalStackView(isFullWidthButtons: options.contains(.showContinueButton)),
            ],
            isScrollable: true,
        )
        stackView.spacing = 24
        stackView.setCustomSpacing(32, after: aepTextView)
    }

    private func copyToClipboardWithConfirmation() {
        let warningSheet = BackupNeverShareRecoveryKeySheet(
            primaryButton: HeroSheetViewController.Button(
                title: OWSLocalizedString(
                    "BACKUP_RECORD_KEY_COPY_WARNING_SHEET_PRIMARY_BUTTON_TITLE",
                    comment: "Title for the primary button in a warning sheet shown before copying the user's 'Recovery Key' to the clipboard, which acknowledges the warning and proceeds with the copy.",
                ),
                action: { sheet in
                    sheet.dismiss(animated: true) { [weak self] in
                        guard let self else { return }
                        copyToClipboard()
                    }
                },
            ),
            secondaryButton: nil,
        )

        present(warningSheet, animated: true)
    }

    private func copyToClipboard() {
        UIPasteboard.general.setItems(
            [[UIPasteboard.typeAutomatic: displayableAEP.displayString]],
            options: [.expirationDate: Date().addingTimeInterval(60)],
        )

        let toast = ToastController(
            text: OWSLocalizedString(
                "BACKUP_KEY_COPIED_MESSAGE_TOAST",
                comment: "Toast indicating that the user has copied their recovery key.",
            ),
            image: .copy,
        )
        toast.presentToastView(from: .bottom, of: view, inset: view.safeAreaInsets.bottom + 8)
    }

    @available(iOS 26.2, *)
    private func saveToPasswordManagerWithConfirmation() {
        guard let window = view.window else {
            owsFailDebug("Missing window!")
            return
        }

        let actionSheet = ActionSheetController(
            title: OWSLocalizedString(
                "BACKUP_RECORD_KEY_PASSWORD_MANAGER_CONFIRM_TITLE",
                comment: "Title for a confirmation sheet shown before saving the user's 'Recovery Key' to a password manager.",
            ),
            message: OWSLocalizedString(
                "BACKUP_RECORD_KEY_PASSWORD_MANAGER_CONFIRM_MESSAGE",
                comment: "Message for a confirmation sheet shown before saving the user's 'Recovery Key' to a password manager, advising them to only use a password manager they trust.",
            ),
        )
        actionSheet.addAction(ActionSheetAction(
            title: CommonStrings.continueButton,
            handler: { [self] _ in
                Task {
                    await _saveToPasswordManager(window: window)
                }
            },
        ))
        actionSheet.addAction(.cancel)

        presentActionSheet(actionSheet)
    }

    @available(iOS 26.2, *)
    private func _saveToPasswordManager(window: ASPresentationAnchor) async {
        do {
            let credentialDataManager = ASCredentialDataManager()
            let credentialName = OWSLocalizedString(
                "BACKUP_RECORD_KEY_PASSWORD_MANAGER_CREDENTIAL_NAME",
                comment: "Name used as both the username and title for the user's 'Recovery Key' credential when saving it to a password manager.",
            )
            let password = ASPasswordCredential(
                user: credentialName,
                password: displayableAEP.displayString,
            )
            let scope = ASAutoFillURLScope(host: "signal.org")

            try await credentialDataManager.save(
                password: password,
                for: scope,
                title: credentialName,
                anchor: window,
            )

            presentToast(text: OWSLocalizedString(
                "BACKUP_RECORD_KEY_PASSWORD_MANAGER_SUCCESS_TOAST",
                comment: "Toast shown after the user successfully saves their 'Recovery Key' to a password manager.",
            ))
        } catch {
            Logger.warn("Failed to save to password manager! \(error)")

            let actionSheet = ActionSheetController(
                title: OWSLocalizedString(
                    "BACKUP_RECORD_KEY_PASSWORD_MANAGER_ERROR_TITLE",
                    comment: "Title for an error sheet shown when saving the user's 'Recovery Key' to a password manager fails.",
                ),
                message: OWSLocalizedString(
                    "BACKUP_RECORD_KEY_PASSWORD_MANAGER_ERROR_MESSAGE",
                    comment: "Message for an error sheet shown when saving the user's 'Recovery Key' to a password manager fails, suggesting that they may not have a supported password manager configured.",
                ),
            )
            actionSheet.addAction(.ok)

            presentActionSheet(actionSheet)
        }
    }
}

// MARK: -

#if DEBUG

private extension BackupRecordKeyViewController {
    static func forPreview(
        aepMode: AEPMode,
        options: [Option],
    ) -> BackupRecordKeyViewController {
        return BackupRecordKeyViewController(
            aepMode: aepMode,
            options: options,
            onCreateNewKeyPressed: { _ in print("Create New Key!") },
            onContinuePressed: { _ in print("Continue!") },
        )
    }
}

@available(iOS 17, *)
#Preview("CreateNewKey") {
    UINavigationController(rootViewController: BackupRecordKeyViewController.forPreview(
        aepMode: .newCandidate(AccountEntropyPool()),
        options: [.showCreateNewKeyButton],
    ))
}

@available(iOS 17, *)
#Preview("ContinueButton") {
    UINavigationController(rootViewController: BackupRecordKeyViewController.forPreview(
        aepMode: .newCandidate(AccountEntropyPool()),
        options: [.showContinueButton],
    ))
}

#endif