import Foundation
import UIKit
import Display
import ComponentFlow
import SwiftSignalKit
import TelegramCore
import Markdown
import TextFormat
import TelegramPresentationData
import ViewControllerComponent
import SheetComponent
import BalancedTextComponent
import MultilineTextComponent
import BundleIconComponent
import ButtonComponent
import AccountContext
import PresentationDataUtils
import TelegramUIPreferences
import UndoUI
import DeviceAccess

public func requireAgeVerification(context: AccountContext) -> Bool {
    if let value = context.currentAppConfiguration.with({ $0 }).data?["need_age_video_verification"] as? Bool, value {
        return true
    }
    return false
}

public func requireAgeVerification(context: AccountContext, peer: EnginePeer) -> Signal<Bool, NoError> {
    if requireAgeVerification(context: context), peer._asPeer().hasSensitiveContent(platform: "ios") {
        return context.engine.data.get(TelegramEngine.EngineData.Item.Configuration.ContentSettings())
        |> map { contentSettings in
            if !contentSettings.ignoreContentRestrictionReasons.contains("sensitive") {
                return true
            }
            return false
        }
    }
    return .single(false)
}

private final class SheetContent: CombinedComponent {
    typealias EnvironmentType = ViewControllerComponentContainer.Environment
    
    let context: AccountContext
    let dismiss: () -> Void
    
    init(
        context: AccountContext,
        dismiss: @escaping () -> Void
    ) {
        self.context = context
        self.dismiss = dismiss
    }
    
    static func ==(lhs: SheetContent, rhs: SheetContent) -> Bool {
        if lhs.context !== rhs.context {
            return false
        }
        return true
    }
    
    final class State: ComponentState {
        var cachedCloseImage: (UIImage, PresentationTheme)?
    }
    
    func makeState() -> State {
        return State()
    }
        
    static var body: Body {
        let background = Child(RoundedRectangle.self)
        let icon = Child(ZStack<Empty>.self)
        let closeButton = Child(Button.self)
        let title = Child(Text.self)
        let text = Child(BalancedTextComponent.self)
        
        let button = Child(ButtonComponent.self)
        
        return { context in
            let environment = context.environment[EnvironmentType.self]
            let component = context.component
            let state = context.state
            
            let presentationData = component.context.sharedContext.currentPresentationData.with { $0 }
            let theme = presentationData.theme
            //let strings = presentationData.strings
                        
            var contentSize = CGSize(width: context.availableSize.width, height: 18.0)
                        
            let background = background.update(
                component: RoundedRectangle(color: theme.actionSheet.opaqueItemBackgroundColor, cornerRadius: 8.0),
                availableSize: CGSize(width: context.availableSize.width, height: 1000.0),
                transition: .immediate
            )
            context.add(background
                .position(CGPoint(x: context.availableSize.width / 2.0, y: background.size.height / 2.0))
            )

            let icon = icon.update(
                component: ZStack([
                    AnyComponentWithIdentity(
                        id: AnyHashable(0),
                        component: AnyComponent(RoundedRectangle(color: theme.list.itemCheckColors.fillColor, cornerRadius: 45.0, size: CGSize(width: 90.0, height: 90.0)))
                    ),
                    AnyComponentWithIdentity(
                        id: AnyHashable(1),
                        component: AnyComponent(BundleIconComponent(
                            name: "Settings/FaceVerification",
                            tintColor: theme.list.itemCheckColors.foregroundColor
                        ))
                    )
                ]),
                availableSize: CGSize(width: 90.0, height: 90.0),
                transition: .immediate
            )
            context.add(icon
                .position(CGPoint(x: context.availableSize.width / 2.0, y: icon.size.height / 2.0 + 31.0))
            )
            
            let closeImage: UIImage
            if let (image, cacheTheme) = state.cachedCloseImage, theme === cacheTheme {
                closeImage = image
            } else {
                closeImage = generateCloseButtonImage(backgroundColor: UIColor(rgb: 0x808084, alpha: 0.1), foregroundColor: theme.actionSheet.inputClearButtonColor)!
                state.cachedCloseImage = (closeImage, theme)
            }
            let closeButton = closeButton.update(
                component: Button(
                    content: AnyComponent(Image(image: closeImage)),
                    action: {
                        component.dismiss()
                    }
                ),
                availableSize: CGSize(width: 30.0, height: 30.0),
                transition: .immediate
            )
            context.add(closeButton
                .position(CGPoint(x: context.availableSize.width - closeButton.size.width, y: 28.0))
            )
            
            let constrainedTitleWidth = context.availableSize.width - 16.0 * 2.0
            
            contentSize.height += 124.0
            
            let title = title.update(
                component: Text(text: "Age Verification", font: Font.bold(24.0), color: theme.list.itemPrimaryTextColor),
                availableSize: CGSize(width: constrainedTitleWidth, height: context.availableSize.height),
                transition: .immediate
            )
            context.add(title
                .position(CGPoint(x: context.availableSize.width / 2.0, y: contentSize.height + title.size.height / 2.0))
            )
            contentSize.height += title.size.height
            contentSize.height += 13.0
                          
            let textFont = Font.regular(15.0)
            let boldTextFont = Font.semibold(15.0)
            let textColor = theme.actionSheet.primaryTextColor
            let linkColor = theme.actionSheet.controlAccentColor
            let markdownAttributes = MarkdownAttributes(body: MarkdownAttributeSet(font: textFont, textColor: textColor), bold: MarkdownAttributeSet(font: boldTextFont, textColor: textColor), link: MarkdownAttributeSet(font: textFont, textColor: linkColor), linkAttribute: { contents in
                return (TelegramTextAttributes.URL, contents)
            })
            
            let textString = "To access this content, you must confirm you are at least **18** years old as required by UK law.\n\nThis is a one-time process using your phone's camera. Your selfie will not be stored by Telegram."
            
            let text = text.update(
                component: BalancedTextComponent(
                    text: .markdown(
                        text: textString,
                        attributes: markdownAttributes
                    ),
                    horizontalAlignment: .center,
                    maximumNumberOfLines: 0,
                    lineSpacing: 0.2
                ),
                availableSize: CGSize(width: constrainedTitleWidth, height: context.availableSize.height),
                transition: .immediate
            )
            context.add(text
                .position(CGPoint(x: context.availableSize.width / 2.0, y: contentSize.height + text.size.height / 2.0))
            )
            contentSize.height += text.size.height
            contentSize.height += 23.0
                        
            let controller = environment.controller() as? AgeVerificationScreen
                        
            let button = button.update(
                component: ButtonComponent(
                    background: ButtonComponent.Background(
                        color: theme.list.itemCheckColors.fillColor,
                        foreground: theme.list.itemCheckColors.foregroundColor,
                        pressedColor: theme.list.itemCheckColors.fillColor.withMultipliedAlpha(0.9),
                        cornerRadius: 10.0
                    ),
                    content: AnyComponentWithIdentity(
                        id: AnyHashable(0),
                        component: AnyComponent(MultilineTextComponent(text: .plain(NSMutableAttributedString(string: "Verify My Age", font: Font.semibold(17.0), textColor: theme.list.itemCheckColors.foregroundColor, paragraphAlignment: .center))))
                    ),
                    isEnabled: true,
                    displaysProgress: false,
                    action: { [weak controller] in
                        controller?.complete(result: true)
                    }
                ),
                availableSize: CGSize(width: context.availableSize.width - 16.0 * 2.0, height: 50),
                transition: .immediate
            )
            context.add(button
                .clipsToBounds(true)
                .cornerRadius(10.0)
                .position(CGPoint(x: context.availableSize.width / 2.0, y: contentSize.height + button.size.height / 2.0))
            )
            contentSize.height += button.size.height
 
            contentSize.height += 48.0
            
            return contentSize
        }
    }
}

private final class AgeVerificationSheetComponent: CombinedComponent {
    typealias EnvironmentType = ViewControllerComponentContainer.Environment
    
    private let context: AccountContext
    
    init(
        context: AccountContext
    ) {
        self.context = context
    }
    
    static func ==(lhs: AgeVerificationSheetComponent, rhs: AgeVerificationSheetComponent) -> Bool {
        if lhs.context !== rhs.context {
            return false
        }
        return true
    }
    
    static var body: Body {
        let sheet = Child(SheetComponent<(EnvironmentType)>.self)
        let animateOut = StoredActionSlot(Action<Void>.self)
        
        return { context in
            let environment = context.environment[EnvironmentType.self]
            
            let controller = environment.controller
            
            let sheet = sheet.update(
                component: SheetComponent<EnvironmentType>(
                    content: AnyComponent<EnvironmentType>(SheetContent(
                        context: context.component.context,
                        dismiss: {
                            animateOut.invoke(Action { _ in
                                if let controller = controller() as? AgeVerificationScreen {
                                    controller.complete(result: false)
                                    controller.dismiss(completion: nil)
                                }
                            })
                        }
                    )),
                    backgroundColor: .color(environment.theme.list.modalBlocksBackgroundColor),
                    followContentSizeChanges: true,
                    clipsContent: true,
                    animateOut: animateOut
                ),
                environment: {
                    environment
                    SheetComponentEnvironment(
                        isDisplaying: environment.value.isVisible,
                        isCentered: environment.metrics.widthClass == .regular,
                        hasInputHeight: !environment.inputHeight.isZero,
                        regularMetricsSize: CGSize(width: 430.0, height: 900.0),
                        dismiss: { animated in
                            if animated {
                                animateOut.invoke(Action { _ in
                                    if let controller = controller() as? AgeVerificationScreen {
                                        controller.complete(result: false)
                                        controller.dismiss(completion: nil)
                                    }
                                })
                            } else {
                                if let controller = controller() as? AgeVerificationScreen {
                                    controller.complete(result: false)
                                    controller.dismiss(completion: nil)
                                }
                            }
                        }
                    )
                },
                availableSize: context.availableSize,
                transition: context.transition
            )
            
            context.add(sheet
                .position(CGPoint(x: context.availableSize.width / 2.0, y: context.availableSize.height / 2.0))
            )
            
            return context.availableSize
        }
    }
}

public final class AgeVerificationScreen: ViewControllerComponentContainer {
    private let context: AccountContext
    private let completion: (Bool, Signal<AgeVerificationAvailability, NoError>) -> Void
        
    private let promise = Promise<AgeVerificationAvailability>()
    
    public init(
        context: AccountContext,
        completion: @escaping (Bool, Signal<AgeVerificationAvailability, NoError>) -> Void
    ) {
        self.context = context
        self.completion = completion
                
        self.promise.set(ageVerificationAvailability(context: context))
        
        super.init(
            context: context,
            component: AgeVerificationSheetComponent(
                context: context
            ),
            navigationBarAppearance: .none,
            statusBarStyle: .ignore,
            theme: .default
        )
        
        self.navigationPresentation = .flatModal
    }
        
    required public init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    private var didComplete = false
    fileprivate func complete(result: Bool) {
        guard !self.didComplete else {
            return
        }
        
        if result {
            let context = self.context
            let presentationData = context.sharedContext.currentPresentationData.with { $0 }
            DeviceAccess.authorizeAccess(to: .camera(.ageVerification), presentationData: presentationData, present: { c, a in
                c.presentationArguments = a
                context.sharedContext.mainWindow?.present(c, on: .root)
            }, openSettings: {
                context.sharedContext.applicationBindings.openSettings()
            }, { [weak self] granted in
                guard let self, granted else {
                    return
                }
                self.didComplete = true
                self.completion(true, self.promise.get())
                self.dismissAnimated()
            })
        } else {
            self.didComplete = true
            self.completion(false, self.promise.get())
        }
    }
    
    public func dismissAnimated() {
        if let view = self.node.hostView.findTaggedView(tag: SheetComponent<ViewControllerComponentContainer.Environment>.View.Tag()) as? SheetComponent<ViewControllerComponentContainer.Environment>.View {
            view.dismissAnimated()
        }
    }
}

func generateCloseButtonImage(backgroundColor: UIColor, foregroundColor: UIColor) -> UIImage? {
    return generateImage(CGSize(width: 30.0, height: 30.0), contextGenerator: { size, context in
        context.clear(CGRect(origin: CGPoint(), size: size))
        
        context.setFillColor(backgroundColor.cgColor)
        context.fillEllipse(in: CGRect(origin: CGPoint(), size: size))
        
        context.setLineWidth(2.0)
        context.setLineCap(.round)
        context.setStrokeColor(foregroundColor.cgColor)
        
        context.move(to: CGPoint(x: 10.0, y: 10.0))
        context.addLine(to: CGPoint(x: 20.0, y: 20.0))
        context.strokePath()
        
        context.move(to: CGPoint(x: 20.0, y: 10.0))
        context.addLine(to: CGPoint(x: 10.0, y: 20.0))
        context.strokePath()
    })
}

public func presentAgeVerification(context: AccountContext, parentController: ViewController, completion: @escaping () -> Void) {
    let presentationData = context.sharedContext.currentPresentationData.with { $0 }
    let _ = (context.engine.data.get(
        TelegramEngine.EngineData.Item.Configuration.ApplicationSpecificPreference(key: ApplicationSpecificPreferencesKeys.ageVerificationState)
    ) |> deliverOnMainQueue).start(next: { [weak parentController] ageVerificationStatePreference in
        let state = ageVerificationStatePreference?.get(AgeVerificationState.self) ?? AgeVerificationState.default
        if state.verificationPassed {
            completion()
        } else {
            let infoScreen = AgeVerificationScreen(context: context, completion: { [weak parentController] check, availability in
                if check {
                    let scanScreen = FaceScanScreen(context: context, availability: availability, completion: { [weak parentController] passed in
                        if passed {
                            let _ = updateAgeVerificationState(engine: context.engine, { _ in
                                return AgeVerificationState(verificationPassed: passed)
                            }).start()
                            completion()
                
                            let navigationController = parentController?.navigationController
                            Queue.mainQueue().after(2.0) {
                                let controller = UndoOverlayController(presentationData: presentationData, content: .actionSucceeded(title: "Age check passed!", text: "You can now view this content.", cancel: nil, destructive: false), action: { _ in return true })
                                (navigationController?.viewControllers.last as? ViewController)?.present(controller, in: .window(.root))
                            }
                        } else {
                            let controller = UndoOverlayController(presentationData: presentationData, content: .universal(animation: "anim_banned", scale: 0.066, colors: [:], title: "Age check failed!", text: "Sorry, you can't view this content.", customUndoText: nil, timeout: nil), action: { _ in return true })
                            parentController?.present(controller, in: .window(.root))
                        }
                    })
                    parentController?.push(scanScreen)
                }
            })
            parentController?.push(infoScreen)
        }
    })
}

public func updateAgeVerificationState(engine: TelegramEngine, _ f: @escaping (AgeVerificationState) -> AgeVerificationState) -> Signal<Never, NoError> {
    return engine.preferences.update(id: ApplicationSpecificPreferencesKeys.ageVerificationState, { entry in
        let currentSettings: AgeVerificationState
        if let entry = entry?.get(AgeVerificationState.self) {
            currentSettings = entry
        } else {
            currentSettings = .default
        }
        return SharedPreferencesEntry(f(currentSettings))
    })
}

public struct AgeVerificationState: Equatable, Codable {
    public var verificationPassed: Bool
    
    public static var `default`: AgeVerificationState {
        return AgeVerificationState(verificationPassed: false)
    }
    
    public init(verificationPassed: Bool) {
        self.verificationPassed = verificationPassed
    }
    
    public init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: StringCodingKey.self)

        self.verificationPassed = (try container.decode(Int32.self, forKey: "verificationPassed")) != 0
    }
    
    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: StringCodingKey.self)

        try container.encode((self.verificationPassed ? 1 : 0) as Int32, forKey: "verificationPassed")
    }
}