import 'dart:async';
import 'dart:math';

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart';

import 'package:pong/pong_menu.dart';

void main() {
  // Run the PongGame app
  runApp(const PongGame());
}

class PongGame extends StatelessWidget {
  const PongGame({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // Set the app title and theme
      title: 'Pong Game',
      theme: ThemeData(
          scaffoldBackgroundColor: const Color.fromARGB(255, 41, 38, 38)),
      // Set the initial screen to the StartScreen
      home: const StartScreen(),
    );
  }
}

class StartScreen extends StatelessWidget {
  const StartScreen({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: GestureDetector(
        onTap: () {
          // Navigate to the GameScreen when tapped
          Navigator.of(context).push(MaterialPageRoute(
            builder: (context) {
              return const GameScreen();
            },
          ));
        },
        child: const Center(
          // Display a message prompting the user to touch the screen to begin
          child: Text(
            'Berühren um zu beginnen!',
            style: TextStyle(
              fontSize: 30,
              fontWeight: FontWeight.bold,
              color: Colors.white,
            ),
          ),
        ),
      ),
    );
  }
}

class GameScreen extends StatefulWidget {
  const GameScreen({super.key});

  @override
  State<GameScreen> createState() => GameScreenState();
}

class GameScreenState extends State<GameScreen> {
  // Constants defining properties of the game
  final ballSize = 20.0;
  final racketWidth = 100.0;
  final racketHeight = 10.0;
  final racketBottomOffset = 100.0;
  bool isPaused = false;

  // Initial speed of the ball
  final initialBallSpeed = 3.0;

  // Variables to track ball and racket positions, speed, score, and game state
  double ballPositionX = 0;
  double ballPositionY = 0;
  double ballSpeedX = 0;
  double ballSpeedY = 0;
  double racketX = 20;
  int score = 0;

  // Ticker for updating the game state
  late Ticker ticker;
  double ballSpeedMultiplier = 1.1;

  @override
  void initState() {
    super.initState();
    // Initialize the game state when the widget is created
    startGame();
  }

  // Initialize the game state
  void startGame() {
    final random = Random();
    ballPositionX = 0;
    ballPositionY = 0;
    ballSpeedX = initialBallSpeed;
    ballSpeedY = initialBallSpeed;
    ballSpeedMultiplier = 1.1;
    racketX = 200;
    score = 0;

    // Randomize initial ball direction
    if (random.nextBool()) ballSpeedX = -ballSpeedX;
    if (random.nextBool()) ballSpeedY = -ballSpeedY;

    // Start the game loop after a delay
    continueGame();
  }

  // Stop the game loop
  void stopGame() {
    ticker.dispose();
  }

  // Continue the game loop with a delay
  void continueGame() {
    if (!isPaused) {
      Future.delayed(const Duration(seconds: 1), () {
        ticker = Ticker((elapsed) {
          setState(() {
            moveBall(ballSpeedMultiplier);
          });
        });
        ticker.start();
      });
    }
  }

  void moveBall(double ballSpeedMultiplier) {
    // Update ball position based on speed and direction
    ballPositionX += ballSpeedX * ballSpeedMultiplier;
    ballPositionY += ballSpeedY * ballSpeedMultiplier;

    // Get the screen size
    final Size screenSize = MediaQuery.of(context).size;

    // Check for collisions with horizontal walls and bounce the ball
    if (ballPositionX < 0 || ballPositionX > screenSize.width - ballSize) {
      ballSpeedX = -ballSpeedX;
    }

    // Check for collision with the top wall and bounce the ball
    if (ballPositionY < 0) {
      ballSpeedY = -ballSpeedY;
    }

    // Check if the ball has touched the floor
    var ballTouchesFloor = ballPositionY > screenSize.height - ballSize;

    // Check if the ball collides with the racket
    var ballCollidesWithRacket =
        ballPositionY + ballSize >= screenSize.height - racketBottomOffset &&
            ballPositionY <= screenSize.height - racketBottomOffset &&
            ballPositionX + ballSize >= racketX &&
            ballPositionX <= racketX + racketWidth;

    // Handle collision with the racket
    if (ballCollidesWithRacket) {
      // Check if the ball hits the top of the racket
      if (ballPositionY <= screenSize.height - racketBottomOffset) {
        ballSpeedY =
            -ballSpeedY * ballSpeedMultiplier; // Bounce the ball upward
        setState(() {
          score += 1; // Increase the score
          debugPrint('ballSpeedMultiplier: $ballSpeedMultiplier');
        });

        ballPositionY = screenSize.height - racketBottomOffset - ballSize;
        // Adjust the Y position to stay above the racket
      } else {
        ballSpeedX =
            -ballSpeedX * ballSpeedMultiplier; // Bounce the ball backward

        // Adjust the Y position to prevent the ball from going through the racket
        double adjustedY = screenSize.height - racketBottomOffset - ballSize;
        if (ballPositionY < adjustedY) {
          ballPositionY = adjustedY;
        }
      }

      // Handle game over condition if the ball touches the floor
    } else if (ballTouchesFloor) {
      debugPrint('Game over');
      stopGame();
      showDialog(
        context: context,
        barrierDismissible: false,
        builder: (BuildContext context) {
          return PongMenu(
            title: 'Game over!',
            subTitle: 'Deine Punkte: $score',
            child: CupertinoButton(
              child: const Text('Nochmal spielen'),
              onPressed: () {
                Navigator.of(context).pop();
                startGame();
              },
            ),
          );
        },
      );
    }
  }

  void moveRacket(double x) {
    // Move the racket horizontally based on the user's touch position
    setState(() {
      racketX = x - racketWidth / 2;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: [
          GestureDetector(
            // Listen for horizontal drag updates to move the racket
            onHorizontalDragUpdate: (details) {
              moveRacket(details.globalPosition.dx);
            },
            child: CustomPaint(
              painter: PongGamePainter(
                racketHeight: racketHeight,
                racketWidth: racketWidth,
                racketX: racketX,
                racketBottomOffset: racketBottomOffset,
                ballSize: ballSize,
                ballX: ballPositionX,
                ballY: ballPositionY,
              ),
              size: Size.infinite,
            ),
          ),
          Center(
            // Display the player's score in the center of the screen
            child: Text(
              'Punkte: $score',
              style: const TextStyle(
                fontSize: 30,
                fontWeight: FontWeight.bold,
              ),
            ),
          ),
          Positioned(
            top: 40,
            right: 20,
            child: IconButton(
              icon: const Icon(
                CupertinoIcons.pause,
                size: 30,
                color: Colors.white,
              ),
              onPressed: () {
                // Pause the game and show dialog
                stopGame();
                showDialog(
                    context: context,
                    barrierDismissible: false,
                    builder: (BuildContext context) {
                      return PongMenu(
                        title: 'Pause',
                        subTitle: 'Deine Punkte: $score',
                        child: CupertinoButton(
                          onPressed: () {
                            // Continues the game
                            Navigator.of(context).pop();
                            isPaused = false;
                            continueGame();
                          },
                          child: const Text('Fortfahren'),
                        ),
                      );
                    });
              },
            ),
          )
        ],
      ),
    );
  }
}

class PongGamePainter extends CustomPainter {
  final double ballSize;
  final double ballX;
  final double ballY;

  final double racketX;
  final double racketWidth;
  final double racketHeight;
  final double racketBottomOffset;

  // Constructor to initialize the painter with required properties
  PongGamePainter({
    required this.ballSize,
    required this.ballX,
    required this.ballY,
    required this.racketX,
    required this.racketWidth,
    required this.racketHeight,
    required this.racketBottomOffset,
  });

  @override
  void paint(Canvas canvas, Size size) {
    // Paint object for drawing the racket
    final racketPaint = Paint()..color = Colors.white;
    // Paint object for drawing the ball
    final ballPaint = Paint()..color = Colors.white;

    // Draw the ball as an oval on the canvas
    canvas.drawOval(
      Rect.fromLTWH(ballX, ballY, ballSize, ballSize),
      ballPaint,
    );

    // Draw the racket as a rectangle on the canvas
    canvas.drawRect(
      Rect.fromLTWH(
        racketX,
        size.height - racketHeight - racketBottomOffset,
        racketWidth,
        racketHeight,
      ),
      racketPaint,
    );
  }

  @override
  bool shouldRepaint(covariant PongGamePainter oldDelegate) {
    // Repaint only if the ball or racket position changes
    return ballX != oldDelegate.ballX ||
        ballY != oldDelegate.ballY ||
        racketX != oldDelegate.racketX;
  }
}