using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.Text.RegularExpressions;

namespace TriangleTest
{
  public partial class Form1 : Form
  {
    public Form1()
    {
      InitializeComponent();
    }
    private void Test_Click(object sender, EventArgs e)
    {
      //等腰，等邊，直角，鈍角，銳角。
      Dictionary<String, int> result = new Dictionary<String, int>();
      result.Add("等腰", 0);
      result.Add("等邊", 0);
      result.Add("直角", 0);
      result.Add("鈍角", 0);
      result.Add("銳角", 0);
      var t1 = edge1.Text;
      var t2 = edge2.Text;
      var t3 = edge3.Text;
      if (CheckInput(t1, t2, t3))
      {
        var e1 = double.Parse(edge1.Text);
        var e2 = double.Parse(edge2.Text);
        var e3 = double.Parse(edge3.Text);
        double[] Numbers = new double[] { e1, e2, e3 };
        double powSum = Math.Pow(e1, 2) + Math.Pow(e2, 2) + Math.Pow(e3, 2);
        double max = Numbers.Max();
        if (CheckTriangle(e1, e2, e3))
        {
          //三角形。
          result["等腰"] = CheckEquicrural(e1, e2, e3) ? 1 : 0;
          result["等邊"] = CheckEquilateral(e1, e2, e3) ? 1 : 0;
          result["直角"] = CheckRightAngle(powSum, max) ? 1 : 0;
          result["鈍角"] = CheckObtuseAngle(powSum, max) ? 1 : 0;
          result["銳角"] = CheckAcuteAngle(powSum, max) ? 1 : 0;
          string resultTip = result["等腰"] == 1 ? "等腰" : "";
          resultTip += result["等邊"] == 1 ? "等邊" : "";
          resultTip += result["直角"] == 1 ? "直角" : "";
          resultTip += result["鈍角"] == 1 ? "鈍角" : "";
          resultTip += result["銳角"] == 1 ? "銳角" : "";
          resultTip += "三角形";
          MessageBox.Show(resultTip);
        }
        else
        {
          //不是三角形。
          MessageBox.Show("您輸入的三邊構(gòu)不成三角形！");
        }
      }
      else
      {
        //輸入非法。
        MessageBox.Show("您輸入的信息有問題！");
      }
    }

    private bool CheckAcuteAngle(double powSum, double max)
    {
      return (Math.Pow(max, 2) < powSum - Math.Pow(max, 2)) ? true : false;
    }

    private bool CheckObtuseAngle(double powSum, double max)
    {
      return (Math.Pow(max, 2) > powSum - Math.Pow(max, 2)) ? true : false;
    }

    private bool CheckRightAngle(double powSum, double max)
    {
      return (Math.Pow(max, 2) == powSum - Math.Pow(max, 2)) ? true : false;
    }

    private bool CheckEquicrural(double e1, double e2, double e3)
    {
      return (e1 == e2 && e2 == e3) ? true : false;
    }

    private bool CheckEquilateral(double e1, double e2, double e3)
    {
      return (e1 == e2 || e2 == e3 || e3 == e1) ? true : false;
    }

    private bool CheckTriangle(double edge1, double edge2, double edge3)
    {
      double[] edges = new double[] { edge1, edge2, edge3 };
      double sum = edges[0] + edges[1] + edges[2];
      int succFlag = 0;
      for (int i = 0; i < edges.Count(); i++)
      {
        if (edges[i] < sum - edges[i])
        {
          succFlag++;
        }
      }
      if (succFlag == 3)
      {
        return true;
      }
      else
      {
        return false;
      }
    }

    private bool CheckInput(string edge1, string edge2, string edge3)
    {
      bool result = false;
      Regex reg = new Regex("^[0-9]*$");
      if (reg.IsMatch(edge1) && reg.IsMatch(edge2) && reg.IsMatch(edge3))
      {
        if (Int32.Parse(edge1) > 0 && Int32.Parse(edge2) > 0 && Int32.Parse(edge3) > 0)
        {
          result = true;
        }
      }
      return result;
    }
  }
}