/// <summary>
  /// 連連看幫助類
  /// </summary>
  public class LinkHelper
  {
    /// <summary>
    /// 連連看，看板
    /// </summary>
    public int[,] LinkBoard { get; set; }
    /// <summary>
    /// 連線成功事件
    /// </summary>
    public event EventHandler SucClick;
    /// <summary>
    /// 連接失敗事件
    /// </summary>
    public event EventHandler FailClick;
    private int col = 10;
    public int Col
    {
      get
      {
        return col;
      }
      set
      {
        col = value;
      }
    }
    private int row = 10;
    public int Row
    {
      get
      {
        return row;
      }
      set
      {
        row = value;
      }
    }
    /// <summary>
    /// 嘗試連線
    /// </summary>
    public void LinkLine(Point first, Point second)
    {
      EventArgs e = new EventArgs();
      if (checkLink(first, second))
      {
        //連線成功
        this.LinkBoard[first.X, first.Y] = 0;
        this.LinkBoard[second.X, second.Y] = 0;
        if (this.SucClick != null)
        {
          SucClick(this, e);
        }
      }
      else {
        //連線失敗
        if (this.FailClick != null)
        {
          FailClick(this, e);
        }
      }
    }
    /// <summary>
    /// 是否賦值
    /// </summary>
    /// <param name="p"></param>
    /// <returns></returns>
    public bool IsChecked(Point p)
    {
      bool flag = false;
      if (p.X != -1 && p.Y != -1)
      {
        flag = true;
      }
      return flag;
    }
    #region 核心算法
    /// <summary>
    /// 判斷是否連線成功
    /// </summary>
    /// <param name="a">第一個(gè)點(diǎn)擊對象</param>
    /// <param name="b">第二個(gè)點(diǎn)擊對象</param>
    /// <returns></returns>
    private bool checkLink(Point a, Point b)
    {
      if (!Point.Equals(a, b))
      {
        if (this.LinkBoard[a.X, a.Y] == this.LinkBoard[b.X, b.Y])
        {
          if (a.X == b.X && horizon(a, b))
          {
            return true;
          }
          if (a.Y == b.Y && vertical(a, b))
          {
            return true;
          }
          if (oneCorner(a, b))
          {
            return true;
          }
          else
          {
            return twoCorner(a, b);
          }
        }
        else {
          //如果點(diǎn)擊的不是同一個(gè)圖案，直接返回false
          return false;
        }
      }
      else {
        //如果點(diǎn)擊的是同一個(gè)位置的圖案，直接返回false;
        return false;
      }
    }
    /// <summary>
    /// 水平連線
    /// </summary>
    /// <param name="a"></param>
    /// <param name="b"></param>
    /// <returns></returns>
    private bool horizon(Point a, Point b)
    {
      int col_start = a.Y < b.Y ? a.Y : b.Y;    //獲取a,b中較小的y值
      int col_end = a.Y < b.Y ? b.Y : a.Y;     //獲取a,b中較大的值
      //遍歷a,b之間是否通路，如果一個(gè)不是就返回false;
      for (int i = col_start + 1; i < col_end; i++)
      {
        if (this.LinkBoard[a.X, i] != 0)
        {
          return false;
        }
      }
      return true;
    }
    /// <summary>
    /// 垂直連線
    /// </summary>
    /// <param name="a"></param>
    /// <param name="b"></param>
    /// <returns></returns>
    private bool vertical(Point a, Point b)
    {
      int row_start = a.X < b.X ? a.X : b.X;
      int row_end = a.X < b.X ? b.X : a.X;
      for (int i = row_start + 1; i < row_end; i++)
      {
        if (this.LinkBoard[i, a.Y] != 0)
        {
          return false;
        }
      }
      return true;
    }
    /// <summary>
    /// 一個(gè)拐角
    /// </summary>
    /// <param name="a"></param>
    /// <param name="b"></param>
    /// <returns></returns>
    private bool oneCorner(Point a, Point b)
    {
      Point c = new Point(b.X, a.Y);
      Point d = new Point(a.X, b.Y);
      //判斷C點(diǎn)是否有元素        
      if (this.LinkBoard[c.X, c.Y] == 0)
      {
        bool path1 = horizon(b, c) && vertical(a, c);
        return path1;
      }
      //判斷D點(diǎn)是否有元素
      if (this.LinkBoard[d.X, d.Y] == 0)
      {
        bool path2 = horizon(a, d) && vertical(b, d);
        return path2;
      }
      else
      {
        return false;
      }
    }
    /// <summary>
    /// 兩個(gè)拐角
    /// </summary>
    /// <param name="a"></param>
    /// <param name="b"></param>
    /// <returns></returns>
    private bool twoCorner(Point a, Point b)
    {
      List<Line> ll = scan(a, b);
      if (ll.Count == 0)
      {
        return false;
      }
      for (int i = 0; i < ll.Count; i++)
      {
        Line tmpLine = ll[i];
        if (tmpLine.direct == 1)
        {
          if (vertical(a, tmpLine.a) && vertical(b, tmpLine.b))
          {
            return true;
          }
        }
        else if (tmpLine.direct == 0)
        {
          if (horizon(a, tmpLine.a) && horizon(b, tmpLine.b))
          {
            return true;
          }
        }
      }
      return false;
    }
    /// <summary>
    /// 掃描A與B之間的連接點(diǎn)組成的線
    /// </summary>
    /// <param name="a"></param>
    /// <param name="b"></param>
    /// <returns></returns>
    private List<Line> scan(Point a, Point b)
    {
      List<Line> linkList = new List<Line>();
      //檢測a點(diǎn),b點(diǎn)的左側(cè)是否能夠垂直直連
      for (int i = a.Y; i >= 0; i--)
      {
        if (this.LinkBoard[a.X, i] == 0 && this.LinkBoard[b.X, i] == 0 && vertical(new Point(a.X, i), new Point(b.X, i)))
        {
          linkList.Add(new Line(new Point(a.X, i), new Point(b.X, i), 0));
        }
      }
      //檢測a點(diǎn),b點(diǎn)的右側(cè)是否能夠垂直直連
      for (int i = a.Y; i < Col; i++)
      {
        if (this.LinkBoard[a.X, i] == 0 && this.LinkBoard[b.X, i] == 0 && vertical(new Point(a.X, i), new Point(b.X, i)))
        {
          linkList.Add(new Line(new Point(a.X, i), new Point(b.X, i), 0));
        }
      }
      //檢測a點(diǎn),b點(diǎn)的上側(cè)是否能夠水平直連
      for (int j = a.X; j >= 0; j--)
      {
        if (this.LinkBoard[j, a.Y] == 0 && this.LinkBoard[j, b.Y] == 0 && horizon(new Point(j, a.Y), new Point(j, b.Y)))
        {
          linkList.Add(new Line(new Point(j, a.Y), new Point(j, b.Y), 1));
        }
      }
      //檢測a點(diǎn),b點(diǎn)的下側(cè)是否能夠水平直連
      for (int j = a.X; j < Row; j++)
      {
        if (this.LinkBoard[j, a.Y] == 0 && this.LinkBoard[j, b.Y] == 0 && horizon(new Point(j, a.Y), new Point(j, b.Y)))
        {
          linkList.Add(new Line(new Point(j, a.Y), new Point(j, b.Y), 1));
        }
      }
      return linkList;
    }
    #endregion
  }