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() {
  runApp(const PongGame());
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Pong Game',
      theme:
          ThemeData(scaffoldBackgroundColor: Color.fromARGB(255, 41, 38, 38)),
      home: const StartScreen(),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: GestureDetector(
        onTap: () {
          Navigator.of(context).push(MaterialPageRoute(
            builder: (context) {
              return const GameScreen();
            },
          ));
        },
        child: const Center(
          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();
}

@visibleForTesting
class _GameScreenState extends State<GameScreen> {
  final ballSize = 20.0;
  final racketWidth = 240.0;
  final racketHeight = 25.0;
  final racketBottomOffset = 100.0;

  final initialBallSpeed = 2.0;

  double ballX = 0;
  double ballY = 0;
  double ballSpeedX = 0;
  double ballSpeedY = 0;
  double racketX = 20;
  int score = 0;

  late Ticker ticker;
  final double ballSpeedMultiplier = 2;

  @override
  void initState() {
    super.initState();
    startGame();
  }

  @override
  void dispose() {
    super.dispose();
    stopGame();
  }

  void startGame() {
    final random = Random();
    ballX = 0;
    ballY = 0;
    ballSpeedX = initialBallSpeed;
    ballSpeedY = initialBallSpeed;
    racketX = 200;
    score = 0;

    if (random.nextBool()) ballSpeedX = -ballSpeedX;
    if (random.nextBool()) ballSpeedY = -ballSpeedY;

    Future.delayed(const Duration(seconds: 1), () {
      ticker = Ticker((elapsed) {
        setState(() {
          moveBall(ballSpeedMultiplier);
        });
      });
      ticker.start();
    });
  }

  void stopGame() {
    ticker.dispose();
  }

  void moveBall(double ballSPeedMultiplier) {
    ballX += ballSpeedX * ballSpeedMultiplier;
    ballY += ballSpeedY * ballSpeedMultiplier;
    final Size size = MediaQuery.of(context).size;

    if (ballX < 0 || ballX > size.width - ballSize) {
      ballSpeedX = -ballSpeedX;
    }

    if (ballY < 0) {
      ballSpeedY = -ballSpeedY;
    }

    // Was prüft diese if-Anweisung?
    if (ballY > size.height - ballSize - racketHeight - racketBottomOffset &&
        ballX >= racketX &&
        ballX <= racketX + racketWidth) {
      ballSpeedY = -ballSpeedY;
    } else if (ballY > size.height - ballSize) {
      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();
              },
            ),
          );
        },
      );
    }
  }

  moveRacket(double x) {
    setState(() {
      racketX = x - racketWidth / 2;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: [
          GestureDetector(
            onHorizontalDragUpdate: (details) {
              moveRacket(details.globalPosition.dx);
            },
            child: CustomPaint(
              painter: PongGamePainter(
                racketHeight: racketHeight,
                racketWidth: racketWidth,
                racketX: racketX,
                racketBottomOffset: racketBottomOffset,
                ballSize: ballSize,
                ballX: ballX,
                ballY: ballY,
              ),
              size: Size.infinite,
            ),
          ),
          Center(
            child: Text(
              'Punkte: $score',
              style: const TextStyle(
                fontSize: 30,
                fontWeight: FontWeight.bold,
              ),
            ),
          ),
          Positioned(
            top: 20,
            right: 20,
            child: IconButton(
              icon: const Icon(
                CupertinoIcons.pause,
                size: 30,
              ),
              onPressed: () {
                stopGame();
                showDialog(
                    context: context,
                    builder: (context) {
                      return PongMenu(
                        title: 'Pause',
                        subTitle: 'Deine Punkte: $score',
                        child: CupertinoButton(
                          onPressed: () {},
                          child: const Text('Weiter'),
                        ),
                      );
                    });
              },
            ),
          )
        ],
      ),
    );
  }
}

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;

  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) {
    final racketPaint = Paint()..color = Colors.white;
    final ballPaint = Paint()..color = Colors.white;

    canvas.drawOval(
      Rect.fromLTWH(ballX, ballY, ballSize, ballSize),
      ballPaint,
    );

    canvas.drawRect(
      Rect.fromLTWH(
        racketX,
        size.height - racketHeight - racketBottomOffset,
        racketWidth,
        racketHeight,
      ),
      racketPaint,
    );
  }

  @override
  bool shouldRepaint(covariant PongGamePainter oldDelegate) {
    return ballX != oldDelegate.ballX ||
        ballY != oldDelegate.ballY ||
        racketX != oldDelegate.racketX;
  }
}