import Foundation
import UIKit
import TelegramCore
import Postbox
import SwiftSignalKit
import Display
import TelegramPresentationData
import TelegramUIPreferences
import AccountContext

public struct InstantPageSourceLocation {
    public var userLocation: MediaResourceUserLocation
    public var peerType: MediaAutoDownloadPeerType
    
    public init(userLocation: MediaResourceUserLocation, peerType: MediaAutoDownloadPeerType) {
        self.userLocation = userLocation
        self.peerType = peerType
    }
}

public func instantPageAndAnchor(message: Message) -> (TelegramMediaWebpage, String?)? {
    for media in message.media {
        if let webpage = media as? TelegramMediaWebpage, case let .Loaded(content) = webpage.content {
            if let _ = content.instantPage {
                var textUrl: String?
                if let pageUrl = URL(string: content.url) {
                    inner: for attribute in message.attributes {
                        if let attribute = attribute as? TextEntitiesMessageAttribute {
                            for entity in attribute.entities {
                                switch entity.type {
                                    case let .TextUrl(url):
                                        if let parsedUrl = URL(string: url) {
                                            if pageUrl.scheme == parsedUrl.scheme && pageUrl.host == parsedUrl.host && pageUrl.path == parsedUrl.path {
                                                textUrl = url
                                            }
                                    }
                                    case .Url:
                                        let nsText = message.text as NSString
                                        var entityRange = NSRange(location: entity.range.lowerBound, length: entity.range.upperBound - entity.range.lowerBound)
                                        if entityRange.location + entityRange.length > nsText.length {
                                            entityRange.location = max(0, nsText.length - entityRange.length)
                                            entityRange.length = nsText.length - entityRange.location
                                        }
                                        let url = nsText.substring(with: entityRange)
                                        if let parsedUrl = URL(string: url) {
                                            if pageUrl.scheme == parsedUrl.scheme && pageUrl.host == parsedUrl.host && pageUrl.path == parsedUrl.path {
                                                textUrl = url
                                            }
                                    }
                                    default:
                                        break
                                }
                            }
                            break inner
                        }
                    }
                }
                var anchor: String?
                if let textUrl = textUrl, let anchorRange = textUrl.range(of: "#") {
                    anchor = String(textUrl[anchorRange.upperBound...])
                }
                
                return (webpage, anchor)
            }
            break
        }
    }
    return nil
}

public final class InstantPageController: ViewController {
    private let context: AccountContext
    private var webPage: TelegramMediaWebpage
    private let sourceLocation: InstantPageSourceLocation
    private let anchor: String?
    
    private var presentationData: PresentationData
    
    private let _ready = Promise<Bool>()
    override public var ready: Promise<Bool> {
        return self._ready
    }
    
    private var controllerNode: InstantPageControllerNode {
        return self.displayNode as! InstantPageControllerNode
    }
    
    private var webpageDisposable: Disposable?
    private var storedStateDisposable: Disposable?
    
    private var settings: InstantPagePresentationSettings?
    private var settingsDisposable: Disposable?
    private var themeSettings: PresentationThemeSettings?
    
    public init(context: AccountContext, webPage: TelegramMediaWebpage, sourceLocation: InstantPageSourceLocation, anchor: String? = nil) {
        self.context = context
        self.presentationData = context.sharedContext.currentPresentationData.with { $0 }
        
        self.webPage = webPage
        self.anchor = anchor
        self.sourceLocation = sourceLocation
        
        super.init(navigationBarPresentationData: nil)
        
        self.navigationPresentation = .modalInLargeLayout
        
        self.statusBar.statusBarStyle = .White
        
        self.webpageDisposable = (actualizedWebpage(postbox: self.context.account.postbox, network: self.context.account.network, webpage: webPage) |> deliverOnMainQueue).start(next: { [weak self] result in
            if let strongSelf = self {
                strongSelf.webPage = result
                if strongSelf.isNodeLoaded {
                    strongSelf.controllerNode.updateWebPage(result, anchor: strongSelf.anchor)
                }
            }
        })
        
        self.settingsDisposable = (self.context.sharedContext.accountManager.sharedData(keys: [ApplicationSpecificSharedDataKeys.instantPagePresentationSettings, ApplicationSpecificSharedDataKeys.presentationThemeSettings])
        |> deliverOnMainQueue).start(next: { [weak self] sharedData in
            if let strongSelf = self {
                let settings: InstantPagePresentationSettings
                if let current = sharedData.entries[ApplicationSpecificSharedDataKeys.instantPagePresentationSettings]?.get(InstantPagePresentationSettings.self) {
                    settings = current
                } else {
                    settings = InstantPagePresentationSettings.defaultSettings
                }
                let themeSettings: PresentationThemeSettings
                if let current = sharedData.entries[ApplicationSpecificSharedDataKeys.presentationThemeSettings]?.get(PresentationThemeSettings.self) {
                    themeSettings = current
                } else {
                    themeSettings = PresentationThemeSettings.defaultSettings
                }
                
                strongSelf.settings = settings
                strongSelf.themeSettings = themeSettings
                if strongSelf.isNodeLoaded {
                    strongSelf.controllerNode.update(settings: settings, themeSettings: themeSettings, strings: strongSelf.presentationData.strings)
                }
            }
        })
    }
    
    required public init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    deinit {
        self.webpageDisposable?.dispose()
        self.storedStateDisposable?.dispose()
        self.settingsDisposable?.dispose()
    }
    
    override public func viewWillDisappear(_ animated: Bool) {
        let _ = updateInstantPageStoredStateInteractively(engine: self.context.engine, webPage: self.webPage, state: self.controllerNode.currentState).start()
    }
    
    override public func loadDisplayNode() {
        self.displayNode = InstantPageControllerNode(controller: self, context: self.context, settings: self.settings, themeSettings: self.themeSettings, presentationTheme: self.presentationData.theme, strings: self.presentationData.strings, dateTimeFormat: self.presentationData.dateTimeFormat, nameDisplayOrder: self.presentationData.nameDisplayOrder, autoNightModeTriggered: self.presentationData.autoNightModeTriggered, statusBar: self.statusBar, sourceLocation: self.sourceLocation, getNavigationController: { [weak self] in
            return self?.navigationController as? NavigationController
        }, present: { [weak self] c, a in
            self?.present(c, in: .window(.root), with: a, blockInteraction: true)
        }, pushController: { [weak self] c in
            (self?.navigationController as? NavigationController)?.pushViewController(c)
        }, openPeer: { [weak self] peer in
            if let strongSelf = self, let navigationController = strongSelf.navigationController as? NavigationController {
                strongSelf.context.sharedContext.navigateToChatController(NavigateToChatControllerParams(navigationController: navigationController, context: strongSelf.context, chatLocation: .peer(peer), animated: true))
            }
        }, navigateBack: { [weak self] in
            if let strongSelf = self, let controllers = strongSelf.navigationController?.viewControllers.reversed() {
                for controller in controllers {
                    if !(controller is InstantPageController) {
                        strongSelf.navigationController?.popToViewController(controller, animated: true)
                        return
                    }
                }
                strongSelf.navigationController?.popViewController(animated: true)
            }
        })
        
        self.storedStateDisposable = (instantPageStoredState(engine: self.context.engine, webPage: self.webPage)
        |> deliverOnMainQueue).start(next: { [weak self] state in
            if let strongSelf = self {
                strongSelf.controllerNode.updateWebPage(strongSelf.webPage, anchor: strongSelf.anchor, state: state)
                strongSelf._ready.set(.single(true))
            }
        })
        
        self.displayNodeDidLoad()
    }
    
    override public func containerLayoutUpdated(_ layout: ContainerViewLayout, transition: ContainedViewLayoutTransition) {
        super.containerLayoutUpdated(layout, transition: transition)
        
        self.controllerNode.containerLayoutUpdated(layout, navigationBarHeight: self.navigationLayout(layout: layout).navigationFrame.maxY, transition: transition)
    }
}