import Foundation
import UIKit
import Display
import AsyncDisplayKit
import TelegramPresentationData
import Postbox
import SyncCore
import AccountContext

private let timezoneOffset: Int32 = {
    let nowTimestamp = Int32(CFAbsoluteTimeGetCurrent() + NSTimeIntervalSince1970)
    var now: time_t = time_t(nowTimestamp)
    var timeinfoNow: tm = tm()
    localtime_r(&now, &timeinfoNow)
    return Int32(timeinfoNow.tm_gmtoff)
}()

private let granularity: Int32 = 60 * 60 * 24

final class ChatMessageDateHeader: ListViewItemHeader {
    private let timestamp: Int32
    private let roundedTimestamp: Int32
    private let scheduled: Bool
    
    let id: Int64
    let presentationData: ChatPresentationData
    let context: AccountContext
    let action: ((Int32) -> Void)?
    
    init(timestamp: Int32, scheduled: Bool, presentationData: ChatPresentationData, context: AccountContext, action: ((Int32) -> Void)? = nil) {
        self.timestamp = timestamp
        self.scheduled = scheduled
        self.presentationData = presentationData
        self.context = context
        self.action = action
        if timestamp == scheduleWhenOnlineTimestamp {
            self.roundedTimestamp = scheduleWhenOnlineTimestamp
        } else if timestamp == Int32.max {
            self.roundedTimestamp = timestamp / (granularity) * (granularity)
        } else {
            self.roundedTimestamp = ((timestamp + timezoneOffset) / (granularity)) * (granularity)
        }
        self.id = Int64(self.roundedTimestamp)
    }
    
    let stickDirection: ListViewItemHeaderStickDirection = .bottom
    
    let height: CGFloat = 34.0
    
    func node() -> ListViewItemHeaderNode {
        return ChatMessageDateHeaderNode(localTimestamp: self.roundedTimestamp, scheduled: self.scheduled, presentationData: self.presentationData, context: self.context, action: self.action)
    }
    
    func updateNode(_ node: ListViewItemHeaderNode, previous: ListViewItemHeader?, next: ListViewItemHeader?) {
        guard let node = node as? ChatMessageDateHeaderNode, let next = next as? ChatMessageDateHeader else {
            return
        }
        node.updatePresentationData(next.presentationData, context: next.context)
    }
}

private func monthAtIndex(_ index: Int, strings: PresentationStrings) -> String {
    switch index {
        case 0:
            return strings.Month_GenJanuary
        case 1:
            return strings.Month_GenFebruary
        case 2:
            return strings.Month_GenMarch
        case 3:
            return strings.Month_GenApril
        case 4:
            return strings.Month_GenMay
        case 5:
            return strings.Month_GenJune
        case 6:
            return strings.Month_GenJuly
        case 7:
            return strings.Month_GenAugust
        case 8:
            return strings.Month_GenSeptember
        case 9:
            return strings.Month_GenOctober
        case 10:
            return strings.Month_GenNovember
        case 11:
            return strings.Month_GenDecember
        default:
            return ""
    }
}

final class ChatMessageDateHeaderNode: ListViewItemHeaderNode {
    let labelNode: TextNode
    let backgroundNode: NavigationBackgroundNode
    let stickBackgroundNode: ASImageNode
    let activateArea: AccessibilityAreaNode
    
    private let localTimestamp: Int32
    private var presentationData: ChatPresentationData
    private let context: AccountContext
    private let text: String
    
    private var flashingOnScrolling = false
    private var stickDistanceFactor: CGFloat = 0.0
    private var action: ((Int32) -> Void)? = nil
    
    init(localTimestamp: Int32, scheduled: Bool, presentationData: ChatPresentationData, context: AccountContext, action: ((Int32) -> Void)? = nil) {
        self.presentationData = presentationData
        self.context = context
        
        self.localTimestamp = localTimestamp
        self.action = action
        
        self.labelNode = TextNode()
        self.labelNode.isUserInteractionEnabled = false
        self.labelNode.displaysAsynchronously = !presentationData.isPreview
        
        self.backgroundNode = NavigationBackgroundNode(color: .clear)
        self.backgroundNode.isUserInteractionEnabled = false
        
        self.stickBackgroundNode = ASImageNode()
        self.stickBackgroundNode.isLayerBacked = true
        self.stickBackgroundNode.displayWithoutProcessing = true
        self.stickBackgroundNode.displaysAsynchronously = false
        
        let nowTimestamp = Int32(CFAbsoluteTimeGetCurrent() + NSTimeIntervalSince1970)
        
        var t: time_t = time_t(localTimestamp)
        var timeinfo: tm = tm()
        gmtime_r(&t, &timeinfo)
        
        var now: time_t = time_t(nowTimestamp)
        var timeinfoNow: tm = tm()
        localtime_r(&now, &timeinfoNow)
        
        var text: String
        if timeinfo.tm_year == timeinfoNow.tm_year {
            if timeinfo.tm_yday == timeinfoNow.tm_yday {
                text = presentationData.strings.Weekday_Today
            } else {
                text = presentationData.strings.Date_ChatDateHeader(monthAtIndex(Int(timeinfo.tm_mon), strings: presentationData.strings), "\(timeinfo.tm_mday)").0
            }
        } else {
            text = presentationData.strings.Date_ChatDateHeaderYear(monthAtIndex(Int(timeinfo.tm_mon), strings: presentationData.strings), "\(timeinfo.tm_mday)", "\(1900 + timeinfo.tm_year)").0
        }
        
        if scheduled {
            if localTimestamp == scheduleWhenOnlineTimestamp {
                text = presentationData.strings.ScheduledMessages_ScheduledOnline
            } else if timeinfo.tm_year == timeinfoNow.tm_year && timeinfo.tm_yday == timeinfoNow.tm_yday {
                text = presentationData.strings.ScheduledMessages_ScheduledToday
            } else {
                text = presentationData.strings.ScheduledMessages_ScheduledDate(text).0
            }
        }
        self.text = text
        
        self.activateArea = AccessibilityAreaNode()
        self.activateArea.accessibilityTraits = .staticText
        
        super.init(layerBacked: false, dynamicBounce: true, isRotated: true, seeThrough: false)
        
        self.transform = CATransform3DMakeRotation(CGFloat.pi, 0.0, 0.0, 1.0)
        
        let graphics = PresentationResourcesChat.principalGraphics(theme: presentationData.theme.theme, wallpaper: presentationData.theme.wallpaper, bubbleCorners: presentationData.chatBubbleCorners)
        
        //self.backgroundNode.image = graphics.dateStaticBackground
        self.backgroundNode.updateColor(color: selectDateFillStaticColor(theme: presentationData.theme.theme, wallpaper: presentationData.theme.wallpaper), enableBlur: dateFillNeedsBlur(theme: presentationData.theme.theme, wallpaper: presentationData.theme.wallpaper), transition: .immediate)
        self.stickBackgroundNode.image = graphics.dateFloatingBackground
        self.stickBackgroundNode.alpha = 0.0
        //self.backgroundNode.addSubnode(self.stickBackgroundNode)
        self.addSubnode(self.backgroundNode)
        self.addSubnode(self.labelNode)
        
        self.addSubnode(self.activateArea)
        
        let titleFont = Font.medium(min(18.0, floor(presentationData.fontSize.baseDisplaySize * 13.0 / 17.0)))
        
        let attributedString = NSAttributedString(string: text, font: titleFont, textColor: bubbleVariableColor(variableColor: presentationData.theme.theme.chat.serviceMessage.dateTextColor, wallpaper: presentationData.theme.wallpaper))
        let labelLayout = TextNode.asyncLayout(self.labelNode)
        
        self.activateArea.accessibilityLabel = text
        
        let (size, apply) = labelLayout(TextNodeLayoutArguments(attributedString: attributedString, backgroundColor: nil, maximumNumberOfLines: 1, truncationType: .end, constrainedSize: CGSize(width: 320.0, height: CGFloat.greatestFiniteMagnitude), alignment: .natural, cutout: nil, insets: UIEdgeInsets()))
        let _ = apply()
        self.labelNode.frame = CGRect(origin: CGPoint(), size: size.size)
    }

    override func didLoad() {
        super.didLoad()
        
        self.view.addGestureRecognizer(ListViewTapGestureRecognizer(target: self, action: #selector(self.tapGesture(_:))))
    }
    
    func updatePresentationData(_ presentationData: ChatPresentationData, context: AccountContext) {
        let previousPresentationData = self.presentationData
        self.presentationData = presentationData
        
        let graphics = PresentationResourcesChat.principalGraphics(theme: presentationData.theme.theme, wallpaper: presentationData.theme.wallpaper, bubbleCorners: presentationData.chatBubbleCorners)
        
        //self.backgroundNode.image = graphics.dateStaticBackground
        self.backgroundNode.updateColor(color: selectDateFillStaticColor(theme: presentationData.theme.theme, wallpaper: presentationData.theme.wallpaper), enableBlur: dateFillNeedsBlur(theme: presentationData.theme.theme, wallpaper: presentationData.theme.wallpaper), transition: .immediate)
        self.stickBackgroundNode.image = graphics.dateFloatingBackground
        
        let titleFont = Font.medium(min(18.0, floor(presentationData.fontSize.baseDisplaySize * 13.0 / 17.0)))
        
        let attributedString = NSAttributedString(string: self.text, font: titleFont, textColor: bubbleVariableColor(variableColor: presentationData.theme.theme.chat.serviceMessage.dateTextColor, wallpaper: presentationData.theme.wallpaper))
        let labelLayout = TextNode.asyncLayout(self.labelNode)
        
        let (size, apply) = labelLayout(TextNodeLayoutArguments(attributedString: attributedString, backgroundColor: nil, maximumNumberOfLines: 1, truncationType: .end, constrainedSize: CGSize(width: 320.0, height: CGFloat.greatestFiniteMagnitude), alignment: .natural, cutout: nil, insets: UIEdgeInsets()))
        let _ = apply()
        
        if presentationData.fontSize != previousPresentationData.fontSize {
            self.labelNode.bounds = CGRect(origin: CGPoint(), size: size.size)
        }

        self.setNeedsLayout()
    }
    
    func updateBackgroundColor(color: UIColor, enableBlur: Bool) {
        self.backgroundNode.updateColor(color: color, enableBlur: enableBlur, transition: .immediate)
        /*let chatDateSize: CGFloat = 20.0
        self.backgroundNode.image = generateImage(CGSize(width: chatDateSize, height: chatDateSize), contextGenerator: { size, context -> Void in
            context.clear(CGRect(origin: CGPoint(), size: size))
            context.setFillColor(color.cgColor)
            context.fillEllipse(in: CGRect(origin: CGPoint(), size: size))
        })!.stretchableImage(withLeftCapWidth: Int(chatDateSize) / 2, topCapHeight: Int(chatDateSize) / 2)*/
    }
    
    override func updateLayout(size: CGSize, leftInset: CGFloat, rightInset: CGFloat) {
        let chatDateSize: CGFloat = 20.0
        let chatDateInset: CGFloat = 6.0
        
        let labelSize = self.labelNode.bounds.size
        let backgroundSize = CGSize(width: labelSize.width + chatDateInset * 2.0, height: chatDateSize)
        
        let backgroundFrame = CGRect(origin: CGPoint(x: floorToScreenPixels((size.width - backgroundSize.width) / 2.0), y: (34.0 - chatDateSize) / 2.0), size: backgroundSize)
        self.stickBackgroundNode.frame = CGRect(origin: CGPoint(), size: backgroundFrame.size)
        self.backgroundNode.frame = backgroundFrame
        self.backgroundNode.update(size: backgroundFrame.size, cornerRadius: backgroundFrame.size.height / 2.0, transition: .immediate)
        self.labelNode.frame = CGRect(origin: CGPoint(x: backgroundFrame.origin.x + chatDateInset, y: backgroundFrame.origin.y + floorToScreenPixels((backgroundSize.height - labelSize.height) / 2.0)), size: labelSize)
        
        self.activateArea.frame = backgroundFrame
    }
    
    override func updateStickDistanceFactor(_ factor: CGFloat, transition: ContainedViewLayoutTransition) {
        if !self.stickDistanceFactor.isEqual(to: factor) {
            self.stickBackgroundNode.alpha = factor
            
            let wasZero = self.stickDistanceFactor < 0.5
            let isZero = factor < 0.5
            self.stickDistanceFactor = factor
            
            if wasZero != isZero {
                var animated = true
                if case .immediate = transition {
                    animated = false
                }
                self.updateFlashing(animated: animated)
            }
        }
    }
    
    override func updateFlashingOnScrolling(_ isFlashingOnScrolling: Bool, animated: Bool) {
        self.flashingOnScrolling = isFlashingOnScrolling
        self.updateFlashing(animated: animated)
    }
    
    private func updateFlashing(animated: Bool) {
        let flashing = self.flashingOnScrolling || self.stickDistanceFactor < 0.5
        
        let alpha: CGFloat = flashing ? 1.0 : 0.0
        let previousAlpha = self.backgroundNode.alpha
        
        if !previousAlpha.isEqual(to: alpha) {
            self.backgroundNode.alpha = alpha
            self.labelNode.alpha = alpha
            if animated {
                let duration: Double = flashing ? 0.3 : 0.4
                self.backgroundNode.layer.animateAlpha(from: previousAlpha, to: alpha, duration: duration)
                self.labelNode.layer.animateAlpha(from: previousAlpha, to: alpha, duration: duration)
            }
        }
    }

    override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
        if !self.bounds.contains(point) {
            return nil
        }
        if self.labelNode.alpha.isZero {
            return nil
        }
        if self.backgroundNode.frame.contains(point) {
            return self.view
        }
        return nil
    }
    
    override func touchesCancelled(_ touches: Set<UITouch>?, with event: UIEvent?) {
        super.touchesCancelled(touches, with: event)
    }
    
    @objc func tapGesture(_ recognizer: ListViewTapGestureRecognizer) {
        if case .ended = recognizer.state {
            self.action?(self.localTimestamp)
        }
    }
}