import Foundation
import UIKit
import Display
import AsyncDisplayKit
import ComponentFlow
import TelegramPresentationData
import ComponentDisplayAdapters
import SearchUI
import AccountContext
import TelegramCore

public final class ChatListNavigationBar: Component {
    public let context: AccountContext
    public let theme: PresentationTheme
    public let strings: PresentationStrings
    public let statusBarHeight: CGFloat
    public let sideInset: CGFloat
    public let isSearchActive: Bool
    public let primaryContent: ChatListHeaderComponent.Content?
    public let secondaryContent: ChatListHeaderComponent.Content?
    public let secondaryTransition: CGFloat
    public let storySubscriptions: EngineStorySubscriptions?
    public let activateSearch: (NavigationBarSearchContentNode) -> Void
    public let openStatusSetup: (UIView) -> Void
    
    public init(
        context: AccountContext,
        theme: PresentationTheme,
        strings: PresentationStrings,
        statusBarHeight: CGFloat,
        sideInset: CGFloat,
        isSearchActive: Bool,
        primaryContent: ChatListHeaderComponent.Content?,
        secondaryContent: ChatListHeaderComponent.Content?,
        secondaryTransition: CGFloat,
        storySubscriptions: EngineStorySubscriptions?,
        activateSearch: @escaping (NavigationBarSearchContentNode) -> Void,
        openStatusSetup: @escaping (UIView) -> Void
    ) {
        self.context = context
        self.theme = theme
        self.strings = strings
        self.statusBarHeight = statusBarHeight
        self.sideInset = sideInset
        self.isSearchActive = isSearchActive
        self.primaryContent = primaryContent
        self.secondaryContent = secondaryContent
        self.secondaryTransition = secondaryTransition
        self.storySubscriptions = storySubscriptions
        self.activateSearch = activateSearch
        self.openStatusSetup = openStatusSetup
    }

    public static func ==(lhs: ChatListNavigationBar, rhs: ChatListNavigationBar) -> Bool {
        if lhs.context !== rhs.context {
            return false
        }
        if lhs.theme !== rhs.theme {
            return false
        }
        if lhs.strings !== rhs.strings {
            return false
        }
        if lhs.statusBarHeight != rhs.statusBarHeight {
            return false
        }
        if lhs.sideInset != rhs.sideInset {
            return false
        }
        if lhs.isSearchActive != rhs.isSearchActive {
            return false
        }
        if lhs.primaryContent != rhs.primaryContent {
            return false
        }
        if lhs.secondaryContent != rhs.secondaryContent {
            return false
        }
        if lhs.secondaryTransition != rhs.secondaryTransition {
            return false
        }
        if lhs.storySubscriptions != rhs.storySubscriptions {
            return false
        }
        return true
    }
    
    private struct CurrentLayout {
        var size: CGSize
        
        init(size: CGSize) {
            self.size = size
        }
    }

    public final class View: UIView {
        private let backgroundView: BlurredBackgroundView
        private let separatorLayer: SimpleLayer
        
        public let headerContent = ComponentView<Empty>()
        
        public private(set) var searchContentNode: NavigationBarSearchContentNode?
        
        private var component: ChatListNavigationBar?
        private weak var state: EmptyComponentState?
        
        private var scrollTheme: PresentationTheme?
        private var scrollStrings: PresentationStrings?
        
        private var currentLayout: CurrentLayout?
        private var rawScrollOffset: CGFloat?
        private var clippedScrollOffset: CGFloat?
        
        public var deferScrollApplication: Bool = false
        private var hasDeferredScrollOffset: Bool = false
        
        public private(set) var effectiveStoriesInsetHeight: CGFloat = 0.0
        
        override public init(frame: CGRect) {
            self.backgroundView = BlurredBackgroundView(color: .clear, enableBlur: true)
            self.separatorLayer = SimpleLayer()
            
            super.init(frame: frame)
            
            self.addSubview(self.backgroundView)
            self.layer.addSublayer(self.separatorLayer)
        }
        
        required init?(coder: NSCoder) {
            fatalError("init(coder:) has not been implemented")
        }
        
        override public func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
            if !self.backgroundView.frame.contains(point) {
                return nil
            }
            
            guard let result = super.hitTest(point, with: event) else {
                return nil
            }
            return result
        }
        
        public func applyCurrentScroll(transition: Transition) {
            if let rawScrollOffset = self.rawScrollOffset, self.hasDeferredScrollOffset {
                self.applyScroll(offset: rawScrollOffset, transition: transition)
            }
        }
        
        public func applyScroll(offset: CGFloat, transition: Transition) {
            self.rawScrollOffset = offset
            
            if self.deferScrollApplication {
                self.hasDeferredScrollOffset = true
                return
            }
            
            guard let component = self.component, let currentLayout = self.currentLayout else {
                return
            }
            
            let themeUpdated = component.theme !== self.scrollTheme || component.strings !== self.scrollStrings
            
            self.scrollTheme = component.theme
            self.scrollStrings = component.strings
            
            let searchOffsetDistance: CGFloat = navigationBarSearchContentHeight
            let defaultStoriesOffsetDistance: CGFloat = 94.0
            let effectiveStoriesOffsetDistance: CGFloat
            
            var minContentOffset: CGFloat = navigationBarSearchContentHeight
            if !component.isSearchActive, let storySubscriptions = component.storySubscriptions, !storySubscriptions.items.isEmpty {
                effectiveStoriesOffsetDistance = defaultStoriesOffsetDistance * (1.0 - component.secondaryTransition)
                minContentOffset += effectiveStoriesOffsetDistance
            } else {
                effectiveStoriesOffsetDistance = 0.0
            }
            
            let clippedScrollOffset = min(minContentOffset, offset)
            if self.clippedScrollOffset == clippedScrollOffset && !self.hasDeferredScrollOffset {
                return
            }
            self.hasDeferredScrollOffset = false
            self.clippedScrollOffset = clippedScrollOffset
            
            let visibleSize = CGSize(width: currentLayout.size.width, height: max(0.0, currentLayout.size.height - clippedScrollOffset))
            
            self.backgroundView.update(size: visibleSize, transition: transition.containedViewLayoutTransition)
            transition.setFrame(view: self.backgroundView, frame: CGRect(origin: CGPoint(), size: visibleSize))
            transition.setFrame(layer: self.separatorLayer, frame: CGRect(origin: CGPoint(x: 0.0, y: visibleSize.height), size: CGSize(width: visibleSize.width, height: UIScreenPixel)))
            
            let searchContentNode: NavigationBarSearchContentNode
            if let current = self.searchContentNode {
                searchContentNode = current
                
                if themeUpdated {
                    let placeholder: String
                    let compactPlaceholder: String
                    
                    placeholder = component.strings.Common_Search
                    compactPlaceholder = component.strings.Common_Search
                    
                    searchContentNode.updateThemeAndPlaceholder(theme: component.theme, placeholder: placeholder, compactPlaceholder: compactPlaceholder)
                }
            } else {
                let placeholder: String
                let compactPlaceholder: String
                
                placeholder = component.strings.Common_Search
                compactPlaceholder = component.strings.Common_Search
                
                //TODO:localize
                searchContentNode = NavigationBarSearchContentNode(
                    theme: component.theme,
                    placeholder: placeholder,
                    compactPlaceholder: compactPlaceholder,
                    activate: { [weak self] in
                        guard let self, let component = self.component, let searchContentNode = self.searchContentNode else {
                            return
                        }
                        component.activateSearch(searchContentNode)
                    }
                )
                self.searchContentNode = searchContentNode
                self.addSubview(searchContentNode.view)
            }
            
            let clippedStoriesOffset = max(0.0, min(clippedScrollOffset, defaultStoriesOffsetDistance))
            let storiesOffsetFraction: CGFloat
            if let storySubscriptions = component.storySubscriptions, !storySubscriptions.items.isEmpty {
                storiesOffsetFraction = clippedStoriesOffset / defaultStoriesOffsetDistance
            } else {
                storiesOffsetFraction = 1.0
            }
            
            let searchSize = CGSize(width: currentLayout.size.width, height: navigationBarSearchContentHeight)
            let searchFrame = CGRect(origin: CGPoint(x: 0.0, y: visibleSize.height - 0.0 - searchSize.height), size: searchSize)
            
            let clippedSearchOffset = max(0.0, min(clippedScrollOffset - effectiveStoriesOffsetDistance, searchOffsetDistance))
            let searchOffsetFraction = clippedSearchOffset / searchOffsetDistance
            searchContentNode.expansionProgress = 1.0 - searchOffsetFraction
            
            transition.setFrame(view: searchContentNode.view, frame: searchFrame)
            searchContentNode.updateLayout(size: searchSize, leftInset: component.sideInset, rightInset: component.sideInset, transition: transition.containedViewLayoutTransition)
            
            let headerContentSize = self.headerContent.update(
                transition: transition,
                component: AnyComponent(ChatListHeaderComponent(
                    sideInset: component.sideInset + 16.0,
                    primaryContent: component.primaryContent,
                    secondaryContent: component.secondaryContent,
                    secondaryTransition: component.secondaryTransition,
                    networkStatus: nil,
                    storySubscriptions: component.storySubscriptions,
                    storiesFraction: 1.0 - storiesOffsetFraction,
                    context: component.context,
                    theme: component.theme,
                    strings: component.strings,
                    openStatusSetup: { [weak self] sourceView in
                        guard let self, let component = self.component else {
                            return
                        }
                        component.openStatusSetup(sourceView)
                    },
                    toggleIsLocked: { [weak self] in
                        guard let self, let component = self.component else {
                            return
                        }
                        component.context.sharedContext.appLockContext.lock()
                    }
                )),
                environment: {},
                containerSize: CGSize(width: currentLayout.size.width, height: 44.0)
            )
            let headerContentY: CGFloat
            if component.isSearchActive {
                headerContentY = -headerContentSize.height - effectiveStoriesOffsetDistance
            } else {
                if component.statusBarHeight < 1.0 {
                    headerContentY = 0.0
                } else {
                    headerContentY = component.statusBarHeight + 12.0
                }
            }
            let headerContentFrame = CGRect(origin: CGPoint(x: 0.0, y: headerContentY), size: headerContentSize)
            if let headerContentView = self.headerContent.view {
                if headerContentView.superview == nil {
                    self.addSubview(headerContentView)
                }
                transition.setFrame(view: headerContentView, frame: headerContentFrame)
            }
        }
        
        func update(component: ChatListNavigationBar, availableSize: CGSize, state: EmptyComponentState, environment: Environment<Empty>, transition: Transition) -> CGSize {
            let themeUpdated = self.component?.theme !== component.theme
            
            self.component = component
            self.state = state
            
            if themeUpdated {
                self.backgroundView.updateColor(color: component.theme.rootController.navigationBar.blurredBackgroundColor, transition: .immediate)
                self.separatorLayer.backgroundColor = component.theme.rootController.navigationBar.separatorColor.cgColor
            }
            
            var contentHeight = component.statusBarHeight
            
            if component.statusBarHeight >= 1.0 {
                contentHeight += 10.0
            }
            contentHeight += 44.0
            
            if component.isSearchActive {
                if component.statusBarHeight < 1.0 {
                    contentHeight += 8.0
                }
                self.effectiveStoriesInsetHeight = 0.0
            } else {
                if let storySubscriptions = component.storySubscriptions, !storySubscriptions.items.isEmpty {
                    let storiesHeight: CGFloat = 94.0 * (1.0 - component.secondaryTransition)
                    contentHeight += storiesHeight
                    self.effectiveStoriesInsetHeight = storiesHeight
                } else {
                    self.effectiveStoriesInsetHeight = 0.0
                }
                
                contentHeight += navigationBarSearchContentHeight
            }
            
            let size = CGSize(width: availableSize.width, height: contentHeight)
            self.currentLayout = CurrentLayout(size: size)
            
            self.hasDeferredScrollOffset = true
            
            return size
        }
    }
    
    public func makeView() -> View {
        return View(frame: CGRect())
    }

    public 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)
    }
}