using Microsoft.VisualStudio.TestTools.UnitTesting;
using Microsoft.Xna.Framework;
using System;
using System.Collections.Generic;

namespace SemiColinGames.Tests {
  [TestClass]
  public class LineTests {
    [TestMethod]
    public void TestRasterizeSinglePoint() {
      var p1 = new Point(10, 10);
      var expected = new Point[] { p1 };
      var result = Line.Rasterize(p1, p1);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeHorizontal() {
      var p1 = new Point(10, 10);
      var p2 = new Point(15, 10);
      var expected = new Point[] {
        new Point(10, 10),
        new Point(11, 10),
        new Point(12, 10),
        new Point(13, 10),
        new Point(14, 10),
        new Point(15, 10)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeHorizontalReverse() {
      var p1 = new Point(15, 10);
      var p2 = new Point(10, 10);
      var expected = new Point[] {
        new Point(15, 10),
        new Point(14, 10),
        new Point(13, 10),
        new Point(12, 10),
        new Point(11, 10),
        new Point(10, 10)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeVertical() {
      var p1 = new Point(10, 10);
      var p2 = new Point(10, 15);
      var expected = new Point[] {
        new Point(10, 10),
        new Point(10, 11),
        new Point(10, 12),
        new Point(10, 13),
        new Point(10, 14),
        new Point(10, 15)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeVerticalReverse() {
      var p1 = new Point(10, 15);
      var p2 = new Point(10, 10);
      var expected = new Point[] {
        new Point(10, 15),
        new Point(10, 14),
        new Point(10, 13),
        new Point(10, 12),
        new Point(10, 11),
        new Point(10, 10)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeDiagonalPosPos() {
      var p1 = new Point(0, 0);
      var p2 = new Point(5, 5);
      var expected = new Point[] {
        new Point(0, 0),
        new Point(1, 1),
        new Point(2, 2),
        new Point(3, 3),
        new Point(4, 4),
        new Point(5, 5)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeDiagonalPosNeg() {
      var p1 = new Point(0, 5);
      var p2 = new Point(5, 0);
      var expected = new Point[] {
        new Point(0, 5),
        new Point(1, 4),
        new Point(2, 3),
        new Point(3, 2),
        new Point(4, 1),
        new Point(5, 0)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeDiagonalNegPos() {
      var p1 = new Point(5, 0);
      var p2 = new Point(0, 5);
      var expected = new Point[] {
        new Point(5, 0),
        new Point(4, 1),
        new Point(3, 2),
        new Point(2, 3),
        new Point(1, 4),
        new Point(0, 5)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeDiagonalNegNeg() {
      var p1 = new Point(5, 5);
      var p2 = new Point(0, 0);
      var expected = new Point[] {
        new Point(5, 5),
        new Point(4, 4),
        new Point(3, 3),
        new Point(2, 2),
        new Point(1, 1),
        new Point(0, 0)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeDoubleSlope() {
      var p1 = new Point(0, 0);
      var p2 = new Point(4, 9);
      var expected = new Point[] {
        new Point(0, 0),
        new Point(0, 1),
        new Point(1, 2),
        new Point(1, 3),
        new Point(2, 4),
        new Point(2, 5),
        new Point(3, 6),
        new Point(3, 7),
        new Point(4, 8),
        new Point(4, 9)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeDoubleSlopePlusOne() {
      var p1 = new Point(0, 0);
      var p2 = new Point(5, 10);
      var expected = new Point[] {
        new Point(0, 0),
        new Point(1, 1),
        new Point(1, 2),
        new Point(2, 3),
        new Point(2, 4),
        new Point(3, 5),
        new Point(3, 6),
        new Point(4, 7),
        new Point(4, 8),
        new Point(5, 9),
        new Point(5, 10)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeDoubleSlopePlusOneReverse() {
      var p1 = new Point(5, 10);
      var p2 = new Point(0, 0);
      var expected = new Point[] {
        new Point(5, 10),
        new Point(4, 9),
        new Point(4, 8),
        new Point(3, 7),
        new Point(3, 6),
        new Point(2, 5),
        new Point(2, 4),
        new Point(1, 3),
        new Point(1, 2),
        new Point(0, 1),
        new Point(0, 0)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeHalfSlope() {
      var p1 = new Point(0, 0);
      var p2 = new Point(9, 4);
      var expected = new Point[] {
        new Point(0, 0),
        new Point(1, 0),
        new Point(2, 1),
        new Point(3, 1),
        new Point(4, 2),
        new Point(5, 2),
        new Point(6, 3),
        new Point(7, 3),
        new Point(8, 4),
        new Point(9, 4)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeHalfSlopePlusOne() {
      var p1 = new Point(0, 0);
      var p2 = new Point(10, 5);
      var expected = new Point[] {
        new Point(0, 0),
        new Point(1, 1),
        new Point(2, 1),
        new Point(3, 2),
        new Point(4, 2),
        new Point(5, 3),
        new Point(6, 3),
        new Point(7, 4),
        new Point(8, 4),
        new Point(9, 5),
        new Point(10, 5)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }

    [TestMethod]
    public void TestRasterizeHalfSlopePlusOneReverse() {
      var p1 = new Point(10, 5);
      var p2 = new Point(0, 0);
      var expected = new Point[] {
        new Point(10, 5),
        new Point(9, 4),
        new Point(8, 4),
        new Point(7, 3),
        new Point(6, 3),
        new Point(5, 2),
        new Point(4, 2),
        new Point(3, 1),
        new Point(2, 1),
        new Point(1, 0),
        new Point(0, 0)
      };
      var result = Line.Rasterize(p1, p2);
      CollectionAssert.AreEqual(expected, result);
    }
  }
}