import Foundation
import UIKit
import Display
import AsyncDisplayKit
import ComponentFlow
import SwiftSignalKit
import AccountContext
import TelegramCore
import MultilineTextComponent
import AvatarNode
import TelegramPresentationData
import CheckNode
import BundleIconComponent

final class CountryListItemComponent: Component {
    enum SelectionState: Equatable {
        case none
        case editing(isSelected: Bool, isTinted: Bool)
    }
    
    let context: AccountContext
    let theme: PresentationTheme
    let title: String
    let selectionState: SelectionState
    let hasNext: Bool
    let action: () -> Void
    
    init(
        context: AccountContext,
        theme: PresentationTheme,
        title: String,
        selectionState: SelectionState,
        hasNext: Bool,
        action: @escaping () -> Void
    ) {
        self.context = context
        self.theme = theme
        self.title = title
        self.selectionState = selectionState
        self.hasNext = hasNext
        self.action = action
    }
    
    static func ==(lhs: CountryListItemComponent, rhs: CountryListItemComponent) -> Bool {
        if lhs.context !== rhs.context {
            return false
        }
        if lhs.theme !== rhs.theme {
            return false
        }
        if lhs.title != rhs.title {
            return false
        }
        if lhs.selectionState != rhs.selectionState {
            return false
        }
        if lhs.hasNext != rhs.hasNext {
            return false
        }
        return true
    }
    
    final class View: UIView {
        private let containerButton: HighlightTrackingButton
        
        private let title = ComponentView<Empty>()
        private let separatorLayer: SimpleLayer
        
        private var checkLayer: CheckLayer?
        
        private var component: CountryListItemComponent?
        private weak var state: EmptyComponentState?
        
        override init(frame: CGRect) {
            self.separatorLayer = SimpleLayer()
            
            self.containerButton = HighlightTrackingButton()
                        
            super.init(frame: frame)
            
            self.layer.addSublayer(self.separatorLayer)
            self.addSubview(self.containerButton)
            
            self.containerButton.addTarget(self, action: #selector(self.pressed), for: .touchUpInside)
        }
        
        required init?(coder: NSCoder) {
            fatalError("init(coder:) has not been implemented")
        }
        
        @objc private func pressed() {
            guard let component = self.component else {
                return
            }
            component.action()
        }
        
        func update(component: CountryListItemComponent, availableSize: CGSize, state: EmptyComponentState, environment: Environment<Empty>, transition: Transition) -> CGSize {
            let themeUpdated = self.component?.theme !== component.theme
            
            var hasSelectionUpdated = false
            if let previousComponent = self.component {
                switch previousComponent.selectionState {
                case .none:
                    if case .none = component.selectionState {
                    } else {
                        hasSelectionUpdated = true
                    }
                case .editing:
                    if case .editing = component.selectionState {
                    } else {
                        hasSelectionUpdated = true
                    }
                }
            }
            
            self.component = component
            self.state = state
            
            let contextInset: CGFloat = 0.0
            
            let height: CGFloat = 44.0
            let verticalInset: CGFloat = 0.0
            var leftInset: CGFloat = 16.0
            let rightInset: CGFloat = contextInset * 2.0 + 8.0
            
            if case let .editing(isSelected, isTinted) = component.selectionState {
                leftInset += 44.0
                let checkSize: CGFloat = 22.0
                
                let checkLayer: CheckLayer
                if let current = self.checkLayer {
                    checkLayer = current
                    if themeUpdated {
                        var theme = CheckNodeTheme(theme: component.theme, style: .plain)
                        if isTinted {
                            theme.backgroundColor = theme.backgroundColor.mixedWith(component.theme.list.itemBlocksBackgroundColor, alpha: 0.5)
                        }
                        checkLayer.theme = theme
                    }
                    checkLayer.setSelected(isSelected, animated: !transition.animation.isImmediate)
                } else {
                    var theme = CheckNodeTheme(theme: component.theme, style: .plain)
                    if isTinted {
                        theme.backgroundColor = theme.backgroundColor.mixedWith(component.theme.list.itemBlocksBackgroundColor, alpha: 0.5)
                    }
                    checkLayer = CheckLayer(theme: theme)
                    self.checkLayer = checkLayer
                    self.containerButton.layer.addSublayer(checkLayer)
                    checkLayer.frame = CGRect(origin: CGPoint(x: -checkSize, y: floor((height - verticalInset * 2.0 - checkSize) / 2.0)), size: CGSize(width: checkSize, height: checkSize))
                    checkLayer.setSelected(isSelected, animated: false)
                    checkLayer.setNeedsDisplay()
                }
                transition.setFrame(layer: checkLayer, frame: CGRect(origin: CGPoint(x: floor((54.0 - checkSize) * 0.5), y: floor((height - verticalInset * 2.0 - checkSize) / 2.0)), size: CGSize(width: checkSize, height: checkSize)))
            } else {
                if let checkLayer = self.checkLayer {
                    self.checkLayer = nil
                    transition.setPosition(layer: checkLayer, position: CGPoint(x: -checkLayer.bounds.width * 0.5, y: checkLayer.position.y), completion: { [weak checkLayer] _ in
                        checkLayer?.removeFromSuperlayer()
                    })
                }
            }
            
            let previousTitleFrame = self.title.view?.frame
            var previousTitleContents: UIView?
            if hasSelectionUpdated && !"".isEmpty {
                previousTitleContents = self.title.view?.snapshotView(afterScreenUpdates: false)
            }
            
            let titleSize = self.title.update(
                transition: .immediate,
                component: AnyComponent(MultilineTextComponent(
                    text: .plain(NSAttributedString(string: component.title, font: Font.regular(17.0), textColor: component.theme.list.itemPrimaryTextColor))
                )),
                environment: {},
                containerSize: CGSize(width: availableSize.width - leftInset - rightInset, height: 100.0)
            )
            
            let centralContentHeight: CGFloat = titleSize.height
            
            let titleFrame = CGRect(origin: CGPoint(x: leftInset, y: floor((height - verticalInset * 2.0 - centralContentHeight) / 2.0)), size: titleSize)
            if let titleView = self.title.view {
                if titleView.superview == nil {
                    titleView.isUserInteractionEnabled = false
                    self.containerButton.addSubview(titleView)
                }
                titleView.frame = titleFrame
                if let previousTitleFrame, previousTitleFrame.origin.x != titleFrame.origin.x {
                    transition.animatePosition(view: titleView, from: CGPoint(x: previousTitleFrame.origin.x - titleFrame.origin.x, y: 0.0), to: CGPoint(), additive: true)
                }
                
                if let previousTitleFrame, let previousTitleContents, previousTitleFrame.size != titleSize {
                    previousTitleContents.frame = CGRect(origin: previousTitleFrame.origin, size: previousTitleFrame.size)
                    self.addSubview(previousTitleContents)
                    
                    transition.setFrame(view: previousTitleContents, frame: CGRect(origin: titleFrame.origin, size: previousTitleFrame.size))
                    transition.setAlpha(view: previousTitleContents, alpha: 0.0, completion: { [weak previousTitleContents] _ in
                        previousTitleContents?.removeFromSuperview()
                    })
                    transition.animateAlpha(view: titleView, from: 0.0, to: 1.0)
                }
            }
           
            if themeUpdated {
                self.separatorLayer.backgroundColor = component.theme.list.itemPlainSeparatorColor.cgColor
            }
            let separatorLeftInset = leftInset + 44.0
            transition.setFrame(layer: self.separatorLayer, frame: CGRect(origin: CGPoint(x: separatorLeftInset, y: height), size: CGSize(width: availableSize.width - separatorLeftInset, height: UIScreenPixel)))
            self.separatorLayer.isHidden = !component.hasNext
            
            let containerFrame = CGRect(origin: CGPoint(x: contextInset, y: verticalInset), size: CGSize(width: availableSize.width - contextInset * 2.0, height: height - verticalInset * 2.0))
            transition.setFrame(view: self.containerButton, frame: containerFrame)
            
            return CGSize(width: availableSize.width, height: height)
        }
    }
    
    func makeView() -> View {
        return View(frame: CGRect())
    }
    
    func update(view: View, availableSize: CGSize, state: EmptyComponentState, environment: Environment<Empty>, transition: Transition) -> CGSize {
        return view.update(component: self, availableSize: availableSize, state: state, environment: environment, transition: transition)
    }
}