import Cocoa
import Combine

class RecordingWindow: NSWindow {
  
  var pixelDensity: CGFloat {
    self.screen?.backingScaleFactor ?? 1.0
  }
  
  var recordingContentView: RecordingContentView {
    self.contentView as! RecordingContentView
  }
  
  init(_ configuration: CaptureSessionConfiguration, _ button: NSRect?) {
    
    let screens = NSScreen.screens
    var boundingBox = NSZeroRect
    for screen in screens {
        boundingBox = NSUnionRect(boundingBox, screen.frame)
    }
    
    super.init(
      contentRect: boundingBox,
      styleMask: [.borderless],
      backing: .buffered,
      defer: false)

    self.isReleasedWhenClosed = false
    self.collectionBehavior = [.canJoinAllSpaces]
    self.isMovableByWindowBackground = false
    self.isMovable = false
    self.canHide = false
    self.titlebarAppearsTransparent = true
    self.setFrame(boundingBox, display: true)
    self.titleVisibility = .hidden
    let recordingView = RecordingContentView(configuration, frame: boundingBox)
    recordingView.frame = boundingBox
    recordingView.button = button
    self.contentView = recordingView
    self.backgroundColor = NSColor(white: 1.0, alpha: 0.001)
    self.level = .screenSaver
    self.isOpaque = false
    self.hasShadow = false
  }
  
  // MARK: - Window Behavior Overrides
  
  override func resetCursorRects() {
    super.resetCursorRects()
    let cursor = NSCursor.crosshair
    self.contentView?.addCursorRect(self.contentView!.bounds, cursor: cursor)
  }
  
  override var canBecomeKey: Bool {
    return true
  }
  
  override var canBecomeMain: Bool {
    return true
  }
  
  override func resignMain() {
    super.resignMain()
    if (self.contentView as? RecordingContentView)?.state != .recording {
      self.ignoresMouseEvents = false
    }
  }
  
  override func becomeMain() {
    super.becomeMain()
    if (self.contentView as? RecordingContentView)?.state != .recording {
      (self.contentView as? RecordingContentView)?.state = .idle
    }
  }
}

enum RecordingWindowState {
  case passthrough, idle, drawing, moving, resizing, recording;
}

class RecordingContentView: NSView {
  
  init(_ configuration: CaptureSessionConfiguration, frame: NSRect) {
    super.init(frame: frame)
    preventResize = configuration.preventResize
    preventMove = configuration.preventMove
    autoStart = configuration.autoStart
    
    if configuration.x != nil || configuration.y != nil || configuration.width != nil || configuration.height != nil {
      box = NSRect(
        x: configuration.x ?? Int(frame.width / 2.0),
        y: configuration.y ?? Int(frame.height / 2.0),
        width: configuration.width ?? 400,
        height: configuration.height ?? 400
      )
    }
    
    if autoStart {
      DispatchQueue.main.asyncAfter(deadline: .now() + 3.0) {
        NotificationCenter.default.post(name: .startRecording, object: nil, userInfo: nil)
      }
    }
  }
  
  required init?(coder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }
  
  public var button: NSRect? = nil
  @Published public var box: NSRect? = nil
  public var state: RecordingWindowState = .idle
  private var mouseLocation: NSPoint = NSPoint()
  private var origin: NSPoint = NSPoint()
  private var boxOrigin: NSPoint = NSPoint()
  private var preventResize = false
  private var preventMove = false
  private var autoStart = false
  
  private var resizeBox: NSRect? {
    if let box {
      return NSRect(x: box.maxX - 5, y: box.minY - 5, width: 10, height: 10)
    }
    return nil
  }
  
  private var shouldPassthrough: Bool {
    state == .recording || state == .passthrough
  }
  
  // MARK: - State changing API
  
  public func startRecording() {
    state = .recording
    window?.ignoresMouseEvents = true
  }
  
  public func stopRecording() {
    
  }
  
  public func reset() {
    state = .idle
    window?.ignoresMouseEvents = false
  }
  
  public func startPassthrough() {
    state = .passthrough
    window?.ignoresMouseEvents = true
  }
  
  public func stopPassthrough() {
    state = .idle
    window?.ignoresMouseEvents = false
  }
  
  // MARK: - View Behavior Overrides
  
  override func updateTrackingAreas() {
    super.updateTrackingAreas()
    
    for trackingArea in self.trackingAreas {
      self.removeTrackingArea(trackingArea)
    }

    let options: NSTrackingArea.Options = [.mouseEnteredAndExited, .activeInKeyWindow, .cursorUpdate, .mouseMoved]
    let trackingArea = NSTrackingArea(rect: self.bounds, options: options, owner: self, userInfo: nil)
    self.addTrackingArea(trackingArea)
  }
  
  override func mouseMoved(with event: NSEvent) {
    
    self.mouseLocation = self.convert(event.locationInWindow, from: nil)
    
    if shouldPassthrough {
      NSCursor.arrow.set()
    } else {
      if let box {
        if resizeBox!.contains(mouseLocation) {
          NSCursor.arrow.set()
        } else {
          if box.contains(mouseLocation) {
            NSCursor.openHand.set()
          } else {
            NSCursor.crosshair.set()
          }
        }
        if let button {
          if button.contains(mouseLocation) {
            NSCursor.arrow.set()
          }
        }
      } else {
        NSCursor.crosshair.set()
      }
    }

    self.setNeedsDisplay(self.bounds)
  }
  
  override func mouseDragged(with event: NSEvent) {
    self.mouseLocation = self.convert(event.locationInWindow, from: nil)
    if state == .drawing {
      box = NSRect(
        x: round(min(origin.x, mouseLocation.x)),
        y: round(min(origin.y, mouseLocation.y)),
        width: round(abs(mouseLocation.x - origin.x)),
        height: round(abs(mouseLocation.y - origin.y))
      )
    }
    
    if box != nil {
      if state == .moving {
        NSCursor.closedHand.set()
        box!.origin = NSPoint(
          x: self.boxOrigin.x - self.origin.x + self.mouseLocation.x,
          y: self.boxOrigin.y - self.origin.y + self.mouseLocation.y)
      }
      
      if state == .resizing {
        box = NSRect(
          x: round(min(origin.x, mouseLocation.x)),
          y: round(min(origin.y, mouseLocation.y)),
          width: round(abs(mouseLocation.x - origin.x)),
          height: round(abs(mouseLocation.y - origin.y))
        )
      }
    }
    self.setNeedsDisplay(self.bounds)
  }
  
  override func cursorUpdate(with event: NSEvent) {
    NSCursor.crosshair.set()
  }

  override func hitTest(_ point: NSPoint) -> NSView? {
    return shouldPassthrough ? nil : self
  }
      
  override var acceptsFirstResponder: Bool {
    return true
  }

  override func mouseDown(with event: NSEvent) {
    self.origin = self.convert(event.locationInWindow, from: nil)
    if let box {
      
      if let button {
        if button.contains(origin) {
          NotificationCenter.default.post(name: .startRecording, object: nil, userInfo: nil)
          return
        }
      }
      
      if resizeBox!.contains(origin) && !preventResize {
        self.origin = NSPoint(x: box.minX, y: box.maxY)
        state = .resizing
        return
      }
      if box.contains(origin) && !preventMove {
        state = .moving
        self.boxOrigin = NSPoint(x: box.origin.x, y: box.origin.y)
        return
      }
    }
    
    if preventResize || preventMove {
      return
    }
    
    state = .drawing
  }

  override func mouseUp(with event: NSEvent) {
    if state != .recording {
      state = .idle
    }
  }
  
  override func keyDown(with event: NSEvent) {
    switch event.keyCode {
      case 53:  // Escape key
        NotificationCenter.default.post(name: .reset, object: nil, userInfo: nil)
      default:
        super.keyDown(with: event)
    }
  }
  
  override func flagsChanged(with event: NSEvent) {
    if state == .idle {
      if event.modifierFlags.contains(.shift) {
        startPassthrough()
      } else {
        stopPassthrough()
      }
    }
  }
  
  override func draw(_ dirtyRect: NSRect) {
    if shouldPassthrough {
      NSColor.clear.setFill()
    } else {
      NSColor(white: 1.0, alpha: 0.001).setFill()
    }
    dirtyRect.fill()
    
    let dashLength: CGFloat = 5.0
    let lineWidth = 0.5

    if state == .idle && box == nil {
      let blackLine = NSBezierPath()
      blackLine.lineWidth = lineWidth
      blackLine.setLineDash([dashLength, dashLength], count: 2, phase: 0)
      
      // Vertical line (Black)
      blackLine.move(to: NSPoint(x: self.mouseLocation.x, y: NSMinY(self.bounds)))
      blackLine.line(to: NSPoint(x: self.mouseLocation.x, y: NSMaxY(self.bounds)))
      
      // Horizontal line (Black)
      blackLine.move(to: NSPoint(x: NSMinX(self.bounds), y: self.mouseLocation.y))
      blackLine.line(to: NSPoint(x: NSMaxX(self.bounds), y: self.mouseLocation.y))
      
      NSColor.black.setStroke()
      blackLine.stroke()
      
      let whiteLine = NSBezierPath()
      whiteLine.lineWidth = lineWidth
      whiteLine.setLineDash([dashLength, dashLength], count: 2, phase: dashLength)
      
      // Vertical line (White)
      whiteLine.move(to: NSPoint(x: self.mouseLocation.x, y: NSMinY(self.bounds)))
      whiteLine.line(to: NSPoint(x: self.mouseLocation.x, y: NSMaxY(self.bounds)))
      
      // Horizontal line (White)
      whiteLine.move(to: NSPoint(x: NSMinX(self.bounds), y: self.mouseLocation.y))
      whiteLine.line(to: NSPoint(x: NSMaxX(self.bounds), y: self.mouseLocation.y))
      
      NSColor.white.setStroke()
      whiteLine.stroke()
    }
    
    if let box {
      let blackBox = NSBezierPath()
      blackBox.lineWidth = lineWidth
      blackBox.setLineDash([dashLength, dashLength], count: 2, phase: 0)
      blackBox.move(to: NSPoint(x: box.minX, y: box.minY))
      blackBox.line(to: NSPoint(x: box.maxX, y: box.minY))
      blackBox.line(to: NSPoint(x: box.maxX, y: box.maxY))
      blackBox.line(to: NSPoint(x: box.minX, y: box.maxY))
      blackBox.line(to: NSPoint(x: box.minX, y: box.minY))
      NSColor.black.setStroke()
      blackBox.stroke()
      
      let whiteBox = NSBezierPath()
      whiteBox.lineWidth = lineWidth
      whiteBox.setLineDash([dashLength, dashLength], count: 2, phase: dashLength)
      whiteBox.move(to: NSPoint(x: box.minX, y: box.minY))
      whiteBox.line(to: NSPoint(x: box.maxX, y: box.minY))
      whiteBox.line(to: NSPoint(x: box.maxX, y: box.maxY))
      whiteBox.line(to: NSPoint(x: box.minX, y: box.maxY))
      whiteBox.line(to: NSPoint(x: box.minX, y: box.minY))
      NSColor.white.setStroke()
      whiteBox.stroke()
      
      if state == .recording {
        return
      }
      
      if let resizeBox {
        let clearBox = NSBezierPath()
        clearBox.move(to: NSPoint(x: resizeBox.minX, y: resizeBox.minY))
        clearBox.line(to: NSPoint(x: resizeBox.maxX, y: resizeBox.minY))
        clearBox.line(to: NSPoint(x: resizeBox.maxX, y: resizeBox.maxY))
        clearBox.line(to: NSPoint(x: resizeBox.minX, y: resizeBox.maxY))
        clearBox.line(to: NSPoint(x: resizeBox.minX, y: resizeBox.minY))
        NSColor(white: 0, alpha: 0.2).setFill()
        clearBox.fill()
      }
      
      if state == .moving {
        let string = "\(Int(box.minX)), \(Int(box.maxY))" as NSString
        drawText(string, NSPoint(
          x: box.minX,
          y: box.maxY
        ), true)
      }
      
      if state == .resizing {
        let string = "\(Int(mouseLocation.x)), \(Int(mouseLocation.y))" as NSString
        drawText(string, mouseLocation)
      }
      
      if box.contains(mouseLocation) && state != .resizing {
        return;
      }
    }
    
    // Draw text

    let string = "\(Int(mouseLocation.x)), \(Int(mouseLocation.y))" as NSString
    drawText(string, mouseLocation)
  }
  
  // MARK: - Utilities
  
  private func drawText(_ text: NSString, _ location: NSPoint, _ isBottomRight: Bool = false) {
    
    let textAttributes = [
      NSAttributedString.Key.font: NSFont(name: "Hiragino Mincho ProN", size: 12) ?? NSFont.systemFont(ofSize: 12),
      NSAttributedString.Key.foregroundColor: NSColor.white,
    ]
    let offset = NSPoint(x: 10, y: 10)
    let padding = NSPoint(x: 5, y: 2)
    let size = text.size(withAttributes: textAttributes)
    var rect = NSRect(x: location.x + offset.x, y: location.y + offset.y, width: size.width + 2 * padding.x, height: size.height + 2 * padding.y)
    var textRect = NSRect(x: location.x + offset.x + padding.x, y: location.y + offset.y + padding.y, width: size.width, height: size.height)
    
    if (isBottomRight) {
      rect = rect.offsetBy(dx: -size.width - 2 * offset.x, dy: 0)
      textRect = textRect.offsetBy(dx: -size.width - 2 * offset.x, dy: 0)
    }

    NSColor.black.set()
    rect.fill()

    text.draw(in: textRect, withAttributes: textAttributes)
  }
}