using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WPF_Labyrinth_Generation
{
    /// <summary>
    /// Логика взаимодействия для MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        enum CellState { Close, Open };
        class Cell
        {
            public Cell(Point currentPosition)
            {
                Visited = false;
                Position = currentPosition;
            }

            public CellState Left { get; set; }
            public CellState Right { get; set; }
            public CellState Bottom { get; set; }
            public CellState Top { get; set; }
            public Boolean Visited { get; set; }
            public Point Position { get; set; }
        }

        private Int32 _Width, _Height, _Walls;
        private Cell[,] Cells;

        public MainWindow()
        {
            InitializeComponent();
        }

        private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            _Width = Convert.ToInt32(TextBoxWidth.Text);
        }

        private void TextBox_TextChanged2(object sender, TextChangedEventArgs e)
        {
            _Height = Convert.ToInt32(TextBoxHeight.Text);
        }

        private void TextBox_TextChanged3(object sender, TextChangedEventArgs e)
        {
            _Walls = Convert.ToInt32(TextBoxWalls.Text);
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            base.OnInitialized(e);
            Cells = new Cell[_Width, _Height];

            //заполняем начальные данные для ячеек
            for (int y = 0; y < _Height; y++)
                for (int x = 0; x < _Width; x++)
                    Cells[x, y] = new Cell(new Point(x, y));

            // Выбераем первую клеточку
            Random rand = new Random();
            Int32 startX = rand.Next(_Width);
            Int32 startY = rand.Next(_Height);

            Stack<Cell> path = new Stack<Cell>();

            Cells[startX, startY].Visited = true;
            path.Push(Cells[startX, startY]);

            while (path.Count > 0)
            {
                Cell _cell = path.Peek();

                //смотрим варианты, в какую сторону можно пойти

                List<Cell> nextStep = new List<Cell>();
                if (_cell.Position.X > 0 && !Cells[Convert.ToInt32(_cell.Position.X - 1), Convert.ToInt32(_cell.Position.Y)].Visited)
                    nextStep.Add(Cells[Convert.ToInt32(_cell.Position.X) - 1, Convert.ToInt32(_cell.Position.Y)]);
                if (_cell.Position.X < _Width - 1 && !Cells[Convert.ToInt32(_cell.Position.X) + 1, Convert.ToInt32(_cell.Position.Y)].Visited)
                    nextStep.Add(Cells[Convert.ToInt32(_cell.Position.X) + 1, Convert.ToInt32(_cell.Position.Y)]);
                if (_cell.Position.Y > 0 && !Cells[Convert.ToInt32(_cell.Position.X), Convert.ToInt32(_cell.Position.Y) - 1].Visited)
                    nextStep.Add(Cells[Convert.ToInt32(_cell.Position.X), Convert.ToInt32(_cell.Position.Y) - 1]);
                if (_cell.Position.Y < _Height - 1 && !Cells[Convert.ToInt32(_cell.Position.X), Convert.ToInt32(_cell.Position.Y) + 1].Visited)
                    nextStep.Add(Cells[Convert.ToInt32(_cell.Position.X), Convert.ToInt32(_cell.Position.Y) + 1]);

                if (nextStep.Count() > 0)
                {
                    //выбираем сторону из возможных вариантов
                    Cell next = nextStep[rand.Next(nextStep.Count())];

                    //Открываем сторону, в которую пошли на ячейках
                    if (next.Position.X != _cell.Position.X)
                    {
                        if (_cell.Position.X - next.Position.X > 0)
                        {
                            _cell.Left = CellState.Open;
                            next.Right = CellState.Open;
                        }
                        else
                        {
                            _cell.Right = CellState.Open;
                            next.Left = CellState.Open;
                        }
                    }
                    if (next.Position.Y != _cell.Position.Y)
                    {
                        if (_cell.Position.Y - next.Position.Y > 0)
                        {
                            _cell.Top = CellState.Open;
                            next.Bottom = CellState.Open;
                        }
                        else
                        {
                            _cell.Bottom = CellState.Open;
                            next.Top = CellState.Open;
                        }
                    }

                    next.Visited = true;
                    path.Push(next);
                }
                else
                {
                    //если пойти никуда нельзя, возвращаемся к предыдущему узлу
                    path.Pop();
                }
            }


            renderCells();
        }

        private void renderCells()
        {
            mCanvas.Children.Clear();
            for (int y = 0; y < _Height; y++)
            {
                for (int x = 0; x < _Width; x++)
                {
                    if (Cells[x, y].Top == CellState.Close)
                        mCanvas.Children.Add(new Line()
                        {
                            Stroke = Brushes.Black,
                            StrokeThickness = 1,
                            X1 = 20 * x,
                            Y1 = 20 * y,
                            X2 = 20 * x + 20,
                            Y2 = 20 * y
                        });

                    if (Cells[x, y].Left == CellState.Close)
                        mCanvas.Children.Add(new Line()
                        {
                            Stroke = Brushes.Black,
                            StrokeThickness = 1,
                            X1 = 20 * x,
                            Y1 = 20 * y,
                            X2 = 20 * x,
                            Y2 = 20 * y + 20
                        });

                    if (Cells[x, y].Right == CellState.Close)
                        mCanvas.Children.Add(new Line()
                        {
                            Stroke = Brushes.Black,
                            StrokeThickness = 1,
                            X1 = 20 * x + 20,
                            Y1 = 20 * y,
                            X2 = 20 * x + 20,
                            Y2 = 20 * y + 20
                        });

                    if (Cells[x, y].Bottom == CellState.Close)
                        mCanvas.Children.Add(new Line()
                        {
                            Stroke = Brushes.Black,
                            StrokeThickness = 1,
                            X1 = 20 * x,
                            Y1 = 20 * y + 20,
                            X2 = 20 * x + 20,
                            Y2 = 20 * y + 20
                        });

                }

            }
            Int32 wallsX;
            for (int k = 0; k < _Walls; k++)
            {
                for (int y = 1; y < _Height - 1; y++)
                {
                    for (int x = 1; x < _Width - 1; x++)
                    {
                        if (_Walls > 0)
                        {
                            wallsX = 0;
                            if (Cells[x, y].Top == CellState.Close || Cells[x, y].Left == CellState.Close)
                            {
                                Random randWalls = new Random();
                                wallsX = randWalls.Next(2);
                            }
                            if (wallsX % 2 == 0 && Cells[x, y].Top == CellState.Close)
                            {
                                mCanvas.Children.Add(new Line()
                                {
                                    Stroke = Brushes.Red,
                                    StrokeThickness = 1,
                                    X1 = 20 * x,
                                    Y1 = 20 * y,
                                    X2 = 20 * x + 20,
                                    Y2 = 20 * y
                                });
                                _Walls--;
                            }
                            else if (wallsX % 2 == 0 && Cells[x, y].Left == CellState.Close)
                            {
                                mCanvas.Children.Add(new Line()
                                {
                                    Stroke = Brushes.Red,
                                    StrokeThickness = 1,
                                    X1 = 20 * x,
                                    Y1 = 20 * y,
                                    X2 = 20 * x,
                                    Y2 = 20 * y + 20
                                });
                                _Walls--;
                            }
                        }
                    }
                }
            }
        }
    }
}