import 'dart:math';

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

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

  final int gridSize = 12;

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Bubble-Twist',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // TRY THIS: Try running your application with "flutter run". You'll see
        // the application has a purple toolbar. Then, without quitting the app,
        // try changing the seedColor in the colorScheme below to Colors.green
        // and then invoke "hot reload" (save your changes or press the "hot
        // reload" button in a Flutter-supported IDE, or press "r" if you used
        // the command line to start the app).
        //
        // Notice that the counter didn't reset back to zero; the application
        // state is not lost during the reload. To reset the state, use hot
        // restart instead.
        //
        // This works for code too, not just values: Most code changes can be
        // tested with just a hot reload.
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page', gridSize: 12),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title, required this.gridSize});

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;
  final int gridSize;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  late List<List<int>> _grid;
  int _selectedRow = -1;
  int _selectedCol = -1;

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

  void _initializeGrid() {
    _grid = List.generate(widget.gridSize,
        (_) => List.generate(widget.gridSize, (_) => Random().nextInt(5)));
    _removeInitialMatches();
  }

  void _removeInitialMatches() {
    bool hasMatches;
    do {
      hasMatches = _removeMatches();
      _applyGravity();
    } while (hasMatches);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Candy Crush'),
      ),
      body: Center(
        child: Expanded(
          child: GridView.builder(
            shrinkWrap: true,
            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
              crossAxisCount: widget.gridSize,
            ),
            itemCount: widget.gridSize * widget.gridSize,
            itemBuilder: (BuildContext context, int index) {
              int row = index ~/ widget.gridSize;
              int col = index % widget.gridSize;
              return GestureDetector(
                onTap: () => _onTileTap(row, col),
                child: Container(
                  margin: const EdgeInsets.all(2),
                  decoration: BoxDecoration(
                    color: _getColor(_grid[row][col]),
                    borderRadius: BorderRadius.circular(8),
                  ),
                ),
              );
            },
          ),
        ),
      ),
    );
  }

  Color _getColor(int value) {
    switch (value) {
      case 0:
        return Colors.red;
      case 1:
        return Colors.blue;
      case 2:
        return Colors.green;
      case 3:
        return Colors.yellow;
      case 4:
        return Colors.orange;
      default:
        return Colors.white;
    }
  }

  void _onTileTap(int row, int col) {
    setState(() {
      if (_selectedRow == -1 && _selectedCol == -1) {
        _selectedRow = row;
        _selectedCol = col;
      } else {
        if (_isValidMove(_selectedRow, _selectedCol, row, col)) {
          _swapTiles(_selectedRow, _selectedCol, row, col);
          while (_removeMatches()) {
            _applyGravity();
          }
        }
        _selectedRow = -1;
        _selectedCol = -1;
      }
    });
  }

  bool _isValidMove(int row1, int col1, int row2, int col2) {
    if ((row1 == row2 && (col1 - col2).abs() == 1) ||
        (col1 == col2 && (row1 - row2).abs() == 1)) {
      int temp = _grid[row1][col1];
      _grid[row1][col1] = _grid[row2][col2];
      _grid[row2][col2] = temp;

      bool isValid = _findMatches(row1, col1).isNotEmpty ||
          _findMatches(row2, col2).isNotEmpty;

      _grid[row2][col2] = _grid[row1][col1];
      _grid[row1][col1] = temp;

      return isValid;
    }
    return false;
  }

  List<List<int>> _findMatches(int row, int col) {
    int color = _grid[row][col];
    List<List<int>> matches = [];

    // Check horizontally
    List<int> horizontalMatch = [];
    for (int c = col; c >= 0 && _grid[row][c] == color; c--) {
      horizontalMatch.add(c);
    }
    for (int c = col + 1; c < widget.gridSize && _grid[row][c] == color; c++) {
      horizontalMatch.add(c);
    }
    if (horizontalMatch.length >= 3) {
      for (int c in horizontalMatch) {
        matches.add([row, c]);
      }
    }

    // Check vertically
    List<int> verticalMatch = [];
    for (int r = row; r >= 0 && _grid[r][col] == color; r--) {
      verticalMatch.add(r);
    }
    for (int r = row + 1; r < widget.gridSize && _grid[r][col] == color; r++) {
      verticalMatch.add(r);
    }
    if (verticalMatch.length >= 3) {
      for (int r in verticalMatch) {
        matches.add([r, col]);
      }
    }

    return matches;
  }

  bool _removeMatches() {
    List<List<int>> allMatches = [];

    for (int row = 0; row < widget.gridSize; row++) {
      for (int col = 0; col < widget.gridSize; col++) {
        List<List<int>> matches = _findMatches(row, col);
        if (matches.isNotEmpty) {
          allMatches.addAll(matches);
        }
      }
    }

    for (var match in allMatches) {
      _grid[match[0]][match[1]] = -1; // Mark the tile as removed
    }

    return allMatches.isNotEmpty;
  }

  void _applyGravity() {
    for (int col = 0; col < widget.gridSize; col++) {
      int emptyRow = widget.gridSize - 1;
      for (int row = widget.gridSize - 1; row >= 0; row--) {
        if (_grid[row][col] != -1) {
          _grid[emptyRow][col] = _grid[row][col];
          if (emptyRow != row) {
            _grid[row][col] = -1;
          }
          emptyRow--;
        }
      }

      for (int row = emptyRow; row >= 0; row--) {
        _grid[row][col] = Random().nextInt(5);
      }
    }
  }

  void _swapTiles(int row1, int col1, int row2, int col2) {
    int temp = _grid[row1][col1];
    _grid[row1][col1] = _grid[row2][col2];
    _grid[row2][col2] = temp;
  }
}