import SwiftUI
import SwiftData
import Cocoa
import Combine
import AVFoundation

@main
struct CapturaApp: App {
  
    @NSApplicationDelegateAdaptor(CapturaAppDelegate.self) var appDelegate

    var body: some Scene {
        WindowGroup {
          PreferencesScreen()
              .handlesExternalEvents(preferring: Set(arrayLiteral: "PreferencesScreen"), allowing: Set(arrayLiteral: "*"))
              .frame(width: 650, height: 450)
        }
        .handlesExternalEvents(matching: Set(arrayLiteral: "PreferencesScreen"))
        .modelContainer(for: CapturaRemoteFile.self)
      }
}

class CapturaAppDelegate: NSObject, NSApplicationDelegate, NSMenuDelegate {
    
  @Environment(\.openURL) var openURL
  var statusItem: NSStatusItem!
  var captureState: CaptureState = .idle
  var recordingWindow: RecordingWindow? = nil
  var preferencesWindow: PreferencesWindow? = nil
  var boxListener: AnyCancellable? = nil
  var popover: NSPopover? = nil
  var helpShown = false
  var captureSession: CapturaCaptureSession? = nil
  var images: [CGImage] = []
  var outputFile: CapturaFile? = nil
  var gifCallbackTimer = ContinuousClock.now
  var fps = CapturaSettings.frameRate
  var pixelDensity: CGFloat = 1.0
  var stopTimer: DispatchWorkItem?
  
  func applicationDidFinishLaunching(_ notification: Notification) {
    setupMenu()
    NotificationCenter.default.addObserver(
      self,
      selector: #selector(self.didReceiveNotification(_:)),
      name: nil,
      object: nil)
    closeWindow()
  }
  
  // MARK: - Setup Functions
  
  
  private func setupMenu() {
    statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.variableLength)
    
    if let button = statusItem.button {
      button.image = NSImage(systemSymbolName: "rectangle.dashed.badge.record", accessibilityDescription: "Captura")
    }
    
    statusItem.isVisible = true
    statusItem.menu = NSMenu()
    statusItem.menu?.delegate = self
    
    // Create the Popover
    popover = NSPopover()
    popover?.contentViewController = HelpPopoverViewController()
    popover?.behavior = .transient
    
    
    let recordItem = NSMenuItem(title: "Record", action: #selector(CapturaAppDelegate.onClickStartRecording), keyEquivalent: "6")
    recordItem.keyEquivalentModifierMask = [.command, .shift]
    statusItem.menu?.addItem(recordItem)
    statusItem.menu?.addItem(NSMenuItem.separator())
    
    let preferencesItem = NSMenuItem(title: "Preferences", action: #selector(CapturaAppDelegate.onOpenPreferences), keyEquivalent: "")
    statusItem.menu?.addItem(preferencesItem)
    
    let quitItem = NSMenuItem(title: "Quit", action: #selector(CapturaAppDelegate.onQuit), keyEquivalent: "")
    statusItem.menu?.addItem(quitItem)
  }
  
  private func closeWindow() {
    if let window = NSApplication.shared.windows.first {
      window.close()
    }
  }
  
  // MARK: - UI Event Handlers
  
  func menuWillOpen(_ menu: NSMenu) {
    if captureState != .idle {
      menu.cancelTracking()
      if captureState == .recording {
        NotificationCenter.default.post(name: .stopRecording, object: nil, userInfo: nil)
      }
    }
  }
  
  @objc private func onClickStartRecording() {
    NotificationCenter.default.post(name: .startAreaSelection, object: nil, userInfo: nil)
  }
  
  @objc private func onOpenPreferences() {
    NSApp.activate(ignoringOtherApps: true)
    if preferencesWindow == nil {
      preferencesWindow =  PreferencesWindow()
    } else {
      preferencesWindow?.makeKeyAndOrderFront(nil)
    }
  }
  
  @objc private func onQuit() {
    NSApplication.shared.terminate(self)
  }
  
  // MARK: - App State Event Listeners
  
  @objc func didReceiveNotification(_ notification: Notification) {
    switch(notification.name) {
    case .startAreaSelection:
      startAreaSelection()
    case .startRecording:
      startRecording()
    case .stopRecording:
      stopRecording()
    case .finalizeRecording:
      DispatchQueue.main.async {
        self.finalizeRecording()
      }
    case .reset:
      reset()
    case .failedToStart:
      failedToStart()
    case .receivedFrame:
      if let frame = notification.userInfo?["frame"] {
        receivedFrame(frame as! CVImageBuffer)
      }
    default:
      return
    }
  }
  
  
  func startAreaSelection() {
    helpShown = false
    NSApp.activate(ignoringOtherApps: true)
    if captureState != .selectingArea {
      captureState = .selectingArea
      if let button = statusItem.button {
        let rectInWindow = button.convert(button.bounds, to: nil)
        let rectInScreen = button.window?.convertToScreen(rectInWindow)
        recordingWindow = RecordingWindow(rectInScreen)
        boxListener = recordingWindow?.recordingContentView.$box
          .debounce(for: .seconds(0.3), scheduler: RunLoop.main)
          .sink { newValue in
            if newValue != nil {
              self.updateImage()
              if !self.helpShown {
                self.helpShown = true
                self.showPopoverWithMessage("Click here when you're ready to record.")
              }
            }
          }
      }
    }
  }
  
  func startRecording() {
    captureState = .recording
    updateImage()
    fps = CapturaSettings.frameRate
    outputFile = nil
    images = [];
    pixelDensity = recordingWindow?.pixelDensity ?? 1.0
    recordingWindow?.recordingContentView.startRecording()
    if let box = recordingWindow?.recordingContentView.box {
      if let screen = recordingWindow?.screen {
        captureSession = CapturaCaptureSession(screen, box: box)
        
        if let captureSession {

          stopTimer = DispatchWorkItem {
            self.stopRecording()
          }
          DispatchQueue.main.asyncAfter(deadline: .now() + 300, execute: stopTimer!)
          
          outputFile = CapturaFile()
          if CapturaSettings.shouldSaveMp4 {
            captureSession.startRecording(to: outputFile!.mp4URL)
          } else {
            captureSession.startRunning()
          }
          return
        }
      }
    }
    NotificationCenter.default.post(name: .failedToStart, object: nil, userInfo: nil)
  }
  
  func stopRecording() {
    captureState = .uploading
    updateImage()
    stop()
    
    if !CapturaSettings.shouldSaveMp4 {
      NotificationCenter.default.post(name: .finalizeRecording, object: nil, userInfo: nil)
      return
    }
    
    Task.detached {
      if let outputFile = self.outputFile {
        await GifRenderer.render(self.images, at: self.fps, to: outputFile.gifURL)
        NotificationCenter.default.post(name: .finalizeRecording, object: nil, userInfo: nil)
      }
    }
  }
  
  func finalizeRecording() {
    captureState = .uploaded
    copyToClipboard()
    updateImage()
    DispatchQueue.main.asyncAfter(deadline: .now() + 2.0) {
      NotificationCenter.default.post(name: .reset, object: nil, userInfo: nil)
    }
  }
  
  func reset() {
    captureState = .idle
    updateImage()
    stop()
  }
  
  func receivedFrame(_ frame: CVImageBuffer) {
    let now = ContinuousClock.now
    
    if now - gifCallbackTimer > .nanoseconds(1_000_000_000 / UInt64(fps)) {
      gifCallbackTimer = now
      DispatchQueue.main.async {
        if let cgImage = frame.cgImage?.resize(by: self.pixelDensity) {
          self.images.append(cgImage)
        }
      }
    }
  }
  
  func failedToStart() {
    captureState = .error
    updateImage()
    requestPermissionToRecord()
    stop()
    DispatchQueue.main.asyncAfter(deadline: .now() + 2.0) {
      NotificationCenter.default.post(name: .reset, object: nil, userInfo: nil)
    }
  }
  
  // MARK: - Presentation Helpers
  
  
  private func requestPermissionToRecord() {
    showPopoverWithMessage("Please grant Captura permission to record")
    if let url = URL(string: "x-apple.systempreferences:com.apple.preference.security?Privacy_ScreenRecording") {
      NSWorkspace.shared.open(url)
    }
  }
  
  private func showPopoverWithMessage(_ message: String) {
    if let button = statusItem.button {
      (self.popover?.contentViewController as? HelpPopoverViewController)?.updateLabel(message)
      self.popover?.show(relativeTo: button.bounds, of: button, preferredEdge: NSRectEdge.minY)
      DispatchQueue.main.asyncAfter(deadline: .now() + 2.0) {
        self.popover?.performClose(nil)
      }
    }
  }
  
  private func updateImage() {
    if let button = statusItem.button {
      let image: String = switch captureState {
      case .idle:
        "rectangle.dashed.badge.record"
      case .selectingArea:
        "circle.rectangle.dashed"
      case .recording:
        "checkmark.rectangle"
      case .uploading:
        "dock.arrow.up.rectangle"
      case .uploaded:
        "checkmark.rectangle.fill"
      case .error:
        "xmark.rectangle.fill"
      }
      button.image = NSImage(systemSymbolName: image, accessibilityDescription: "Captura")
    }
  }
  
  private func stop() {
    stopTimer?.cancel()
    captureSession?.stopRunning()
    captureSession = nil
    boxListener?.cancel()
    recordingWindow?.close()
    recordingWindow = nil
  }
  
  private func copyToClipboard() {
    let fileType: NSPasteboard.PasteboardType = .init(rawValue: CapturaSettings.shouldSaveGif ? "com.compuserve.gif" : "public.mpeg-4")
    if let url = CapturaSettings.shouldSaveGif ? outputFile?.gifURL : outputFile?.mp4URL {
      if let data = try? Data(contentsOf: url) {
        let pasteboard = NSPasteboard.general
        pasteboard.declareTypes([fileType], owner: nil)
        pasteboard.setData(data, forType: fileType)
      }
    }
  }
}