import Foundation
import UIKit
import AsyncDisplayKit
import Display
import SwiftSignalKit
import Postbox
import TelegramCore

private final class ChannelOwnershipTransferPasswordFieldNode: ASDisplayNode, UITextFieldDelegate {
    private var theme: PresentationTheme
    private let backgroundNode: ASImageNode
    private let textInputNode: TextFieldNode
    private let placeholderNode: ASTextNode
    private var clearOnce: Bool = false
    private let inputActivityNode: ActivityIndicator
    
    private var isChecking = false
    
    var complete: (() -> Void)?
    var textChanged: ((String) -> Void)?
    
    private let backgroundInsets = UIEdgeInsets(top: 8.0, left: 22.0, bottom: 15.0, right: 22.0)
    private let inputInsets = UIEdgeInsets(top: 5.0, left: 11.0, bottom: 5.0, right: 11.0)
    
    var password: String {
        get {
            return self.textInputNode.textField.text ?? ""
        }
        set {
            self.textInputNode.textField.text = newValue
            self.placeholderNode.isHidden = !newValue.isEmpty
        }
    }
    
    var placeholder: String = "" {
        didSet {
            self.placeholderNode.attributedText = NSAttributedString(string: self.placeholder, font: Font.regular(17.0), textColor: self.theme.actionSheet.inputPlaceholderColor)
        }
    }
    
    init(theme: PresentationTheme, placeholder: String) {
        self.theme = theme
        
        self.backgroundNode = ASImageNode()
        self.backgroundNode.isLayerBacked = true
        self.backgroundNode.displaysAsynchronously = false
        self.backgroundNode.displayWithoutProcessing = true
        self.backgroundNode.image = generateStretchableFilledCircleImage(diameter: 16.0, color: theme.actionSheet.inputHollowBackgroundColor, strokeColor: theme.actionSheet.inputBorderColor, strokeWidth: UIScreenPixel)
        
        self.textInputNode = TextFieldNode()

        self.placeholderNode = ASTextNode()
        self.placeholderNode.isUserInteractionEnabled = false
        self.placeholderNode.displaysAsynchronously = false
        self.placeholderNode.attributedText = NSAttributedString(string: placeholder, font: Font.regular(14.0), textColor: self.theme.actionSheet.inputPlaceholderColor)
        
        self.inputActivityNode = ActivityIndicator(type: .custom(theme.list.itemAccentColor, 18.0, 1.5, false))
        
        super.init()
        
        self.addSubnode(self.backgroundNode)
        self.addSubnode(self.textInputNode)
        self.addSubnode(self.placeholderNode)
        self.addSubnode(self.inputActivityNode)
        
        self.inputActivityNode.isHidden = true
    }
    
    override func didLoad() {
        super.didLoad()
        
        self.textInputNode.textField.typingAttributes = [NSAttributedStringKey.font.rawValue: Font.regular(14.0), NSAttributedStringKey.foregroundColor.rawValue: self.theme.actionSheet.inputTextColor]
        self.textInputNode.textField.font = Font.regular(14.0)
        self.textInputNode.textField.textColor = self.theme.list.itemPrimaryTextColor
        self.textInputNode.textField.isSecureTextEntry = true
        self.textInputNode.textField.returnKeyType = .done
        self.textInputNode.textField.keyboardAppearance = theme.chatList.searchBarKeyboardColor.keyboardAppearance
        self.textInputNode.clipsToBounds = true
        self.textInputNode.textField.delegate = self
        self.textInputNode.textField.addTarget(self, action: #selector(self.textFieldTextChanged(_:)), for: .editingChanged)
        self.textInputNode.hitTestSlop = UIEdgeInsets(top: -5.0, left: -5.0, bottom: -5.0, right: -5.0)
    }
    
    func updateTheme(_ theme: PresentationTheme) {
        self.theme = theme
        
        self.backgroundNode.image = generateStretchableFilledCircleImage(diameter: 16.0, color: theme.actionSheet.inputHollowBackgroundColor, strokeColor: theme.actionSheet.inputBorderColor, strokeWidth: UIScreenPixel)
        self.textInputNode.textField.keyboardAppearance = theme.chatList.searchBarKeyboardColor.keyboardAppearance
        self.textInputNode.textField.textColor = theme.list.itemPrimaryTextColor
        self.textInputNode.textField.typingAttributes = [NSAttributedStringKey.font.rawValue: Font.regular(14.0), NSAttributedStringKey.foregroundColor.rawValue: theme.actionSheet.inputTextColor]
        self.placeholderNode.attributedText = NSAttributedString(string: self.placeholderNode.attributedText?.string ?? "", font: Font.regular(14.0), textColor: theme.actionSheet.inputPlaceholderColor)
    }
    
    func updateIsChecking(_ isChecking: Bool) {
        self.isChecking = isChecking
        self.inputActivityNode.isHidden = !isChecking
    }
    
    func updateIsInvalid() {
        self.clearOnce = true
    }
    
    func updateLayout(width: CGFloat, transition: ContainedViewLayoutTransition) -> CGFloat {
        let backgroundInsets = self.backgroundInsets
        let inputInsets = self.inputInsets
        
        let textFieldHeight: CGFloat = 30.0
        let panelHeight = textFieldHeight + backgroundInsets.top + backgroundInsets.bottom
        
        let backgroundFrame = CGRect(origin: CGPoint(x: backgroundInsets.left, y: backgroundInsets.top), size: CGSize(width: width - backgroundInsets.left - backgroundInsets.right, height: panelHeight - backgroundInsets.top - backgroundInsets.bottom))
        transition.updateFrame(node: self.backgroundNode, frame: backgroundFrame)
        
        let placeholderSize = self.placeholderNode.measure(backgroundFrame.size)
        transition.updateFrame(node: self.placeholderNode, frame: CGRect(origin: CGPoint(x: backgroundFrame.minX + inputInsets.left, y: backgroundFrame.minY + floor((backgroundFrame.size.height - placeholderSize.height) / 2.0)), size: placeholderSize))
        
        transition.updateFrame(node: self.textInputNode, frame: CGRect(origin: CGPoint(x: backgroundFrame.minX + inputInsets.left, y: backgroundFrame.minY), size: CGSize(width: backgroundFrame.size.width - inputInsets.left - inputInsets.right, height: backgroundFrame.size.height)))
        
        let activitySize = CGSize(width: 18.0, height: 18.0)
        transition.updateFrame(node: self.inputActivityNode, frame: CGRect(origin: CGPoint(x: backgroundFrame.maxX - activitySize.width - 6.0, y: backgroundFrame.minY + floor((backgroundFrame.height - activitySize.height) / 2.0)), size: activitySize))
        
        return panelHeight
    }
    
    func activateInput() {
        self.textInputNode.becomeFirstResponder()
    }
    
    func deactivateInput() {
        self.textInputNode.resignFirstResponder()
    }
    
    @objc func editableTextNodeDidUpdateText(_ editableTextNode: ASEditableTextNode) {
        self.textChanged?(editableTextNode.textView.text)
        self.placeholderNode.isHidden = !(editableTextNode.textView.text ?? "").isEmpty
    }
    
    @objc func textFieldTextChanged(_ textField: UITextField) {
        let text = textField.text ?? ""
        self.textChanged?(text)
        self.placeholderNode.isHidden = !text.isEmpty
    }
    
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        if self.isChecking {
            return false
        }
        
        if string == "\n" {
            self.complete?()
            return false
        }
        
        if self.clearOnce {
            self.clearOnce = false
            if range.length > string.count {
                textField.text = ""
                return false
            }
        }
        
        return true
    }
}

private final class ChannelOwnershipTransferAlertContentNode: AlertContentNode {
    private let strings: PresentationStrings
    
    private let titleNode: ASTextNode
    private let textNode: ASTextNode
    let inputFieldNode: ChannelOwnershipTransferPasswordFieldNode
    
    private let actionNodesSeparator: ASDisplayNode
    private let actionNodes: [TextAlertContentActionNode]
    private let actionVerticalSeparators: [ASDisplayNode]
    
    private let disposable = MetaDisposable()
    
    private var validLayout: CGSize?
    
    private let hapticFeedback = HapticFeedback()
    
    var complete: (() -> Void)? {
        didSet {
            self.inputFieldNode.complete = self.complete
        }
    }
    
    override var dismissOnOutsideTap: Bool {
        return self.isUserInteractionEnabled
    }
    
    init(theme: AlertControllerTheme, ptheme: PresentationTheme, strings: PresentationStrings, actions: [TextAlertAction]) {
        self.strings = strings
        
        self.titleNode = ASTextNode()
        self.titleNode.maximumNumberOfLines = 2
        self.textNode = ASTextNode()
        self.textNode.maximumNumberOfLines = 2
        
        self.inputFieldNode = ChannelOwnershipTransferPasswordFieldNode(theme: ptheme, placeholder: strings.Channel_OwnershipTransfer_PasswordPlaceholder)
        
        self.actionNodesSeparator = ASDisplayNode()
        self.actionNodesSeparator.isLayerBacked = true
        
        self.actionNodes = actions.map { action -> TextAlertContentActionNode in
            return TextAlertContentActionNode(theme: theme, action: action)
        }
        
        var actionVerticalSeparators: [ASDisplayNode] = []
        if actions.count > 1 {
            for _ in 0 ..< actions.count - 1 {
                let separatorNode = ASDisplayNode()
                separatorNode.isLayerBacked = true
                actionVerticalSeparators.append(separatorNode)
            }
        }
        self.actionVerticalSeparators = actionVerticalSeparators
        
        super.init()
        
        self.addSubnode(self.titleNode)
        self.addSubnode(self.textNode)
        
        self.addSubnode(self.inputFieldNode)
        
        self.addSubnode(self.actionNodesSeparator)
        
        for actionNode in self.actionNodes {
            self.addSubnode(actionNode)
        }
        self.actionNodes.last?.actionEnabled = false
        
        for separatorNode in self.actionVerticalSeparators {
            self.addSubnode(separatorNode)
        }
        
        self.inputFieldNode.textChanged = { [weak self] text in
            if let strongSelf = self, let lastNode = strongSelf.actionNodes.last {
                lastNode.actionEnabled = !text.isEmpty
            }
        }
        
        self.updateTheme(theme)
    }
    
    deinit {
        self.disposable.dispose()
    }
    
    func dismissInput() {
        self.inputFieldNode.deactivateInput()
    }
    
    var password: String {
        return self.inputFieldNode.password
    }
    
    func updateIsChecking(_ checking: Bool) {
        self.inputFieldNode.updateIsChecking(checking)
    }
    
    override func updateTheme(_ theme: AlertControllerTheme) {
        self.titleNode.attributedText = NSAttributedString(string: self.strings.Channel_OwnershipTransfer_EnterPassword, font: Font.bold(17.0), textColor: theme.primaryColor, paragraphAlignment: .center)
        self.textNode.attributedText = NSAttributedString(string: self.strings.Channel_OwnershipTransfer_EnterPasswordText, font: Font.regular(13.0), textColor: theme.primaryColor, paragraphAlignment: .center)
        
        self.actionNodesSeparator.backgroundColor = theme.separatorColor
        for actionNode in self.actionNodes {
            actionNode.updateTheme(theme)
        }
        for separatorNode in self.actionVerticalSeparators {
            separatorNode.backgroundColor = theme.separatorColor
        }
        
        if let size = self.validLayout {
            _ = self.updateLayout(size: size, transition: .immediate)
        }
    }
    
    override func updateLayout(size: CGSize, transition: ContainedViewLayoutTransition) -> CGSize {
        var size = size
        size.width = min(size.width, 270.0)
        let measureSize = CGSize(width: size.width - 16.0 * 2.0, height: CGFloat.greatestFiniteMagnitude)
        
        let hadValidLayout = self.validLayout != nil
        
        self.validLayout = size
        
        var origin: CGPoint = CGPoint(x: 0.0, y: 20.0)
        
        let titleSize = self.titleNode.measure(measureSize)
        transition.updateFrame(node: self.titleNode, frame: CGRect(origin: CGPoint(x: floorToScreenPixels((size.width - titleSize.width) / 2.0), y: origin.y), size: titleSize))
        origin.y += titleSize.height + 4.0
        
        let textSize = self.textNode.measure(measureSize)
        transition.updateFrame(node: self.textNode, frame: CGRect(origin: CGPoint(x: floorToScreenPixels((size.width - textSize.width) / 2.0), y: origin.y), size: textSize))
        origin.y += textSize.height + 6.0
        
        let actionButtonHeight: CGFloat = 44.0
        var minActionsWidth: CGFloat = 0.0
        let maxActionWidth: CGFloat = floor(size.width / CGFloat(self.actionNodes.count))
        let actionTitleInsets: CGFloat = 8.0
        
        var effectiveActionLayout = TextAlertContentActionLayout.horizontal
        for actionNode in self.actionNodes {
            let actionTitleSize = actionNode.titleNode.measure(CGSize(width: maxActionWidth, height: actionButtonHeight))
            if case .horizontal = effectiveActionLayout, actionTitleSize.height > actionButtonHeight * 0.6667 {
                effectiveActionLayout = .vertical
            }
            switch effectiveActionLayout {
                case .horizontal:
                    minActionsWidth += actionTitleSize.width + actionTitleInsets
                case .vertical:
                    minActionsWidth = max(minActionsWidth, actionTitleSize.width + actionTitleInsets)
            }
        }
        
        let insets = UIEdgeInsets(top: 18.0, left: 18.0, bottom: 18.0, right: 18.0)
        
        var contentWidth = max(titleSize.width, minActionsWidth)
        contentWidth = max(contentWidth, 234.0)
        
        var actionsHeight: CGFloat = 0.0
        switch effectiveActionLayout {
            case .horizontal:
                actionsHeight = actionButtonHeight
            case .vertical:
                actionsHeight = actionButtonHeight * CGFloat(self.actionNodes.count)
        }
        
        let resultWidth = contentWidth + insets.left + insets.right
        
        let inputFieldWidth = resultWidth
        let inputFieldHeight = self.inputFieldNode.updateLayout(width: inputFieldWidth, transition: transition)
        let inputHeight = inputFieldHeight
        transition.updateFrame(node: self.inputFieldNode, frame: CGRect(x: 0.0, y: origin.y, width: resultWidth, height: inputFieldHeight))
        transition.updateAlpha(node: self.inputFieldNode, alpha: inputHeight > 0.0 ? 1.0 : 0.0)
        
        let resultSize = CGSize(width: resultWidth, height: titleSize.height + textSize.height + actionsHeight + inputHeight + insets.top + insets.bottom)
        
        transition.updateFrame(node: self.actionNodesSeparator, frame: CGRect(origin: CGPoint(x: 0.0, y: resultSize.height - actionsHeight - UIScreenPixel), size: CGSize(width: resultSize.width, height: UIScreenPixel)))
        
        var actionOffset: CGFloat = 0.0
        let actionWidth: CGFloat = floor(resultSize.width / CGFloat(self.actionNodes.count))
        var separatorIndex = -1
        var nodeIndex = 0
        for actionNode in self.actionNodes {
            if separatorIndex >= 0 {
                let separatorNode = self.actionVerticalSeparators[separatorIndex]
                switch effectiveActionLayout {
                    case .horizontal:
                        transition.updateFrame(node: separatorNode, frame: CGRect(origin: CGPoint(x: actionOffset - UIScreenPixel, y: resultSize.height - actionsHeight), size: CGSize(width: UIScreenPixel, height: actionsHeight - UIScreenPixel)))
                    case .vertical:
                        transition.updateFrame(node: separatorNode, frame: CGRect(origin: CGPoint(x: 0.0, y: resultSize.height - actionsHeight + actionOffset - UIScreenPixel), size: CGSize(width: resultSize.width, height: UIScreenPixel)))
                }
            }
            separatorIndex += 1
            
            let currentActionWidth: CGFloat
            switch effectiveActionLayout {
            case .horizontal:
                if nodeIndex == self.actionNodes.count - 1 {
                    currentActionWidth = resultSize.width - actionOffset
                } else {
                    currentActionWidth = actionWidth
                }
            case .vertical:
                currentActionWidth = resultSize.width
            }
            
            let actionNodeFrame: CGRect
            switch effectiveActionLayout {
                case .horizontal:
                    actionNodeFrame = CGRect(origin: CGPoint(x: actionOffset, y: resultSize.height - actionsHeight), size: CGSize(width: currentActionWidth, height: actionButtonHeight))
                    actionOffset += currentActionWidth
                case .vertical:
                    actionNodeFrame = CGRect(origin: CGPoint(x: 0.0, y: resultSize.height - actionsHeight + actionOffset), size: CGSize(width: currentActionWidth, height: actionButtonHeight))
                    actionOffset += actionButtonHeight
            }
            
            transition.updateFrame(node: actionNode, frame: actionNodeFrame)
            
            nodeIndex += 1
        }
        
        if !hadValidLayout {
            self.inputFieldNode.activateInput()
        }
        
        return resultSize
    }
    
    func animateError() {
        self.inputFieldNode.updateIsInvalid()
        self.inputFieldNode.layer.addShakeAnimation()
        self.hapticFeedback.error()
    }
}

private func commitChannelOwnershipTransferController(context: AccountContext, channel: TelegramChannel, member: TelegramUser, completion: @escaping () -> Void) -> ViewController {
    let presentationData = context.sharedContext.currentPresentationData.with { $0 }
    
    var dismissImpl: (() -> Void)?
    var proceedImpl: (() -> Void)?
    
    let disposable = MetaDisposable()
    
    let contentNode = ChannelOwnershipTransferAlertContentNode(theme: AlertControllerTheme(presentationTheme: presentationData.theme), ptheme: presentationData.theme, strings: presentationData.strings, actions: [TextAlertAction(type: .genericAction, title: presentationData.strings.Common_Cancel, action: {
        dismissImpl?()
    }), TextAlertAction(type: .defaultAction, title: presentationData.strings.Common_Done, action: {
        proceedImpl?()
    })])
    
    let controller = AlertController(theme: AlertControllerTheme(presentationTheme: presentationData.theme), contentNode: contentNode)
    let presentationDataDisposable = context.sharedContext.presentationData.start(next: { [weak controller, weak contentNode] presentationData in
        controller?.theme = AlertControllerTheme(presentationTheme: presentationData.theme)
        contentNode?.inputFieldNode.updateTheme(presentationData.theme)
    })
    controller.dismissed = {
        presentationDataDisposable.dispose()
        disposable.dispose()
    }
    dismissImpl = { [weak controller, weak contentNode] in
        contentNode?.dismissInput()
        controller?.dismissAnimated()
    }
    proceedImpl = { [weak contentNode] in
        guard let contentNode = contentNode else {
            return
        }
        contentNode.updateIsChecking(true)
        disposable.set((updateChannelOwnership(postbox: context.account.postbox, network: context.account.network, accountStateManager: context.account.stateManager, channelId: channel.id, memberId: member.id, password: contentNode.password) |> deliverOnMainQueue).start(error: { [weak contentNode] error in
            contentNode?.updateIsChecking(false)
            contentNode?.animateError()
        }, completed: {
            dismissImpl?()
            completion()
        }))
    }
    return controller
}

private func confirmChannelOwnershipTransferController(context: AccountContext, channel: TelegramChannel, member: TelegramUser, present: @escaping (ViewController, Any?) -> Void, completion: @escaping () -> Void) -> ViewController {
    let presentationData = context.sharedContext.currentPresentationData.with { $0 }
    let theme = AlertControllerTheme(presentationTheme: presentationData.theme)
    
    var title: String
    var text: String
    if case .group = channel.info {
        title = presentationData.strings.Group_OwnershipTransfer_Title
        text = presentationData.strings.Group_OwnershipTransfer_DescriptionInfo(channel.displayTitle, member.displayTitle).0
    } else {
        title = presentationData.strings.Channel_OwnershipTransfer_Title
        text = presentationData.strings.Channel_OwnershipTransfer_DescriptionInfo(channel.displayTitle, member.displayTitle).0
    }
    
    let attributedTitle = NSAttributedString(string: title, font: Font.medium(17.0), textColor: theme.primaryColor, paragraphAlignment: .center)
    let body = MarkdownAttributeSet(font: Font.regular(13.0), textColor: theme.primaryColor)
    let bold = MarkdownAttributeSet(font: Font.semibold(13.0), textColor: theme.primaryColor)
    let attributedText = parseMarkdownIntoAttributedString(text, attributes: MarkdownAttributes(body: body, bold: bold, link: body, linkAttribute: { _ in return nil }), textAlignment: .center)
    
    var dismissImpl: (() -> Void)?
    
    let controller = richTextAlertController(context: context, title: attributedTitle, text: attributedText, actions: [TextAlertAction(type: .genericAction, title: presentationData.strings.Channel_OwnershipTransfer_ChangeOwner, action: {
        dismissImpl?()
        present(commitChannelOwnershipTransferController(context: context, channel: channel, member: member, completion: completion), nil)
    }), TextAlertAction(type: .defaultAction, title: presentationData.strings.Common_Cancel, action: {
        dismissImpl?()
    })], actionLayout: .vertical)
    dismissImpl = { [weak controller] in
        controller?.dismissAnimated()
    }
    return controller
}

func channelOwnershipTransferController(context: AccountContext, channel: TelegramChannel, member: TelegramUser, initialError: ChannelOwnershipTransferError, present: @escaping (ViewController, Any?) -> Void, completion: @escaping () -> Void) -> ViewController {
    let presentationData = context.sharedContext.currentPresentationData.with { $0 }
    let theme = AlertControllerTheme(presentationTheme: presentationData.theme)
    
    var title: NSAttributedString? = NSAttributedString(string: presentationData.strings.OwnershipTransfer_SecurityCheck, font: Font.medium(17.0), textColor: theme.primaryColor, paragraphAlignment: .center)
    
    var text = presentationData.strings.OwnershipTransfer_SecurityRequirements
    var isGroup = false
    if case .group = channel.info {
        isGroup = true
    }
    
    var dismissImpl: (() -> Void)?
    var actions: [TextAlertAction] = []
    
    switch initialError {
        case .requestPassword:
            return confirmChannelOwnershipTransferController(context: context, channel: channel, member: member, present: present, completion: completion)
        case .twoStepAuthTooFresh, .authSessionTooFresh:
            text = text + presentationData.strings.OwnershipTransfer_ComeBackLater
            actions = [TextAlertAction(type: .defaultAction, title: presentationData.strings.Common_OK, action: {})]
        case .twoStepAuthMissing:
            actions = [TextAlertAction(type: .genericAction, title: presentationData.strings.OwnershipTransfer_SetupTwoStepAuth, action: {
                let controller = SetupTwoStepVerificationController(context: context, initialState: .automatic, stateUpdated: { update, shouldDismiss, controller in
                    if shouldDismiss {
                        controller.dismiss()
                    }
                })
                present(controller, ViewControllerPresentationArguments(presentationAnimation: .modalSheet))
            }), TextAlertAction(type: .defaultAction, title: presentationData.strings.Common_Cancel, action: {})]
        case .adminsTooMuch:
            title = nil
            text = isGroup ? presentationData.strings.Group_OwnershipTransfer_ErrorAdminsTooMuch :  presentationData.strings.Channel_OwnershipTransfer_ErrorAdminsTooMuch
            actions = [TextAlertAction(type: .defaultAction, title: presentationData.strings.Common_OK, action: {})]
        case .userPublicChannelsTooMuch:
            title = nil
            text = presentationData.strings.Channel_OwnershipTransfer_ErrorPublicChannelsTooMuch
            actions = [TextAlertAction(type: .defaultAction, title: presentationData.strings.Common_OK, action: {})]
        case .userBlocked, .restricted:
            title = nil
            text = isGroup ? presentationData.strings.Group_OwnershipTransfer_ErrorPrivacyRestricted :  presentationData.strings.Channel_OwnershipTransfer_ErrorPrivacyRestricted
            actions = [TextAlertAction(type: .defaultAction, title: presentationData.strings.Common_OK, action: {})]
        default:
            title = nil
            text = presentationData.strings.Login_UnknownError
            actions = [TextAlertAction(type: .defaultAction, title: presentationData.strings.Common_OK, action: {})]
    }
    
    let body = MarkdownAttributeSet(font: Font.regular(13.0), textColor: theme.primaryColor)
    let bold = MarkdownAttributeSet(font: Font.semibold(13.0), textColor: theme.primaryColor)
    let attributedText = parseMarkdownIntoAttributedString(text, attributes: MarkdownAttributes(body: body, bold: bold, link: body, linkAttribute: { _ in return nil }), textAlignment: .center)
    
    let controller = richTextAlertController(context: context, title: title, text: attributedText, actions: actions)
    dismissImpl = { [weak controller] in
        controller?.dismissAnimated()
    }
    return controller
}