using System;
using System.Collections.Generic;
using System.Text;
using Terminal.Gui.Graphs;
using Xunit;
using Xunit.Abstractions;

namespace Terminal.Gui.CoreTests {
	public class LineCanvasTests {

		readonly ITestOutputHelper output;

		public LineCanvasTests (ITestOutputHelper output)
		{
			this.output = output;
		}

		[Fact, AutoInitShutdown]
		public void TestLineCanvas_Dot ()
		{
			var v = GetCanvas (out var canvas);
			canvas.AddLine (new Point (0, 0), 0, Orientation.Horizontal, BorderStyle.Single);

			v.Redraw (v.Bounds);

			string looksLike =
@"    
.";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}

		[InlineData (BorderStyle.Single)]
		[InlineData (BorderStyle.Rounded)]
		[Theory, AutoInitShutdown]
		public void TestLineCanvas_Horizontal (BorderStyle style)
		{
			var v = GetCanvas (out var canvas);
			canvas.AddLine (new Point (0, 0), 1, Orientation.Horizontal, style);

			v.Redraw (v.Bounds);

			string looksLike =
@"    
──";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}

		[Fact, AutoInitShutdown]
		public void TestLineCanvas_Horizontal_Double ()
		{
			var v = GetCanvas (out var canvas);
			canvas.AddLine (new Point (0, 0), 1, Orientation.Horizontal, BorderStyle.Double);

			v.Redraw (v.Bounds);

			string looksLike =
@" 
══";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}

		[InlineData (BorderStyle.Single)]
		[InlineData (BorderStyle.Rounded)]
		[Theory, AutoInitShutdown]
		public void TestLineCanvas_Vertical (BorderStyle style)
		{
			var v = GetCanvas (out var canvas);
			canvas.AddLine (new Point (0, 0), 1, Orientation.Vertical, style);

			v.Redraw (v.Bounds);

			string looksLike =
@"    
│
│";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}

		[Fact, AutoInitShutdown]
		public void TestLineCanvas_Vertical_Double ()
		{
			var v = GetCanvas (out var canvas);
			canvas.AddLine (new Point (0, 0), 1, Orientation.Vertical, BorderStyle.Double);

			v.Redraw (v.Bounds);

			string looksLike =
@"    
║
║";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}

		/// <summary>
		/// This test demonstrates that corners are only drawn when lines overlap.
		/// Not when they terminate adjacent to one another.
		/// </summary>
		[Fact, AutoInitShutdown]
		public void TestLineCanvas_Corner_NoOverlap ()
		{
			var v = GetCanvas (out var canvas);
			canvas.AddLine (new Point (0, 0), 1, Orientation.Horizontal, BorderStyle.Single);
			canvas.AddLine (new Point (0, 1), 1, Orientation.Vertical, BorderStyle.Single);

			v.Redraw (v.Bounds);

			string looksLike =
@"    
──
│
│";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}
		/// <summary>
		/// This test demonstrates how to correctly trigger a corner.  By
		/// overlapping the lines in the same cell
		/// </summary>
		[Fact, AutoInitShutdown]
		public void TestLineCanvas_Corner_Correct ()
		{
			var v = GetCanvas (out var canvas);
			canvas.AddLine (new Point (0, 0), 1, Orientation.Horizontal, BorderStyle.Single);
			canvas.AddLine (new Point (0, 0), 2, Orientation.Vertical, BorderStyle.Single);

			v.Redraw (v.Bounds);

			string looksLike =
@"    
┌─
│
│";
			TestHelpers.AssertDriverContentsAre (looksLike, output);

		}

		[Fact, AutoInitShutdown]
		public void TestLineCanvas_Window ()
		{
			var v = GetCanvas (out var canvas);

			// outer box
			canvas.AddLine (new Point (0, 0), 9, Orientation.Horizontal, BorderStyle.Single);
			canvas.AddLine (new Point (9, 0), 4, Orientation.Vertical, BorderStyle.Single);
			canvas.AddLine (new Point (9, 4), -9, Orientation.Horizontal, BorderStyle.Single);
			canvas.AddLine (new Point (0, 4), -4, Orientation.Vertical, BorderStyle.Single);


			canvas.AddLine (new Point (5, 0), 4, Orientation.Vertical, BorderStyle.Single);
			canvas.AddLine (new Point (0, 2), 9, Orientation.Horizontal, BorderStyle.Single);

			v.Redraw (v.Bounds);

			string looksLike =
@"    
┌────┬───┐
│    │   │
├────┼───┤
│    │   │
└────┴───┘";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}

		/// <summary>
		/// Demonstrates when <see cref="BorderStyle.Rounded"/> corners are used. Notice how
		/// not all lines declare rounded.  If there are 1+ lines intersecting and a corner is
		/// to be used then if any of them are rounded a rounded corner is used.
		/// </summary>
		[Fact, AutoInitShutdown]
		public void TestLineCanvas_Window_Rounded ()
		{
			var v = GetCanvas (out var canvas);

			// outer box
			canvas.AddLine (new Point (0, 0), 9, Orientation.Horizontal, BorderStyle.Rounded);

			// BorderStyle.Single is ignored because corner overlaps with the above line which is Rounded
			// this results in a rounded corner being used.
			canvas.AddLine (new Point (9, 0), 4, Orientation.Vertical, BorderStyle.Single);
			canvas.AddLine (new Point (9, 4), -9, Orientation.Horizontal, BorderStyle.Rounded);
			canvas.AddLine (new Point (0, 4), -4, Orientation.Vertical, BorderStyle.Single);

			// These lines say rounded but they will result in the T sections which are never rounded.
			canvas.AddLine (new Point (5, 0), 4, Orientation.Vertical, BorderStyle.Rounded);
			canvas.AddLine (new Point (0, 2), 9, Orientation.Horizontal, BorderStyle.Rounded);

			v.Redraw (v.Bounds);

			string looksLike =
@"    
╭────┬───╮
│    │   │
├────┼───┤
│    │   │
╰────┴───╯";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}

		[Fact, AutoInitShutdown]
		public void TestLineCanvas_Window_Double ()
		{
			var v = GetCanvas (out var canvas);

			// outer box
			canvas.AddLine (new Point (0, 0), 9, Orientation.Horizontal, BorderStyle.Double);
			canvas.AddLine (new Point (9, 0), 4, Orientation.Vertical, BorderStyle.Double);
			canvas.AddLine (new Point (9, 4), -9, Orientation.Horizontal, BorderStyle.Double);
			canvas.AddLine (new Point (0, 4), -4, Orientation.Vertical, BorderStyle.Double);


			canvas.AddLine (new Point (5, 0), 4, Orientation.Vertical, BorderStyle.Double);
			canvas.AddLine (new Point (0, 2), 9, Orientation.Horizontal, BorderStyle.Double);

			v.Redraw (v.Bounds);

			string looksLike =
@"    
╔════╦═══╗
║    ║   ║
╠════╬═══╣
║    ║   ║
╚════╩═══╝";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}


		[Theory, AutoInitShutdown]
		[InlineData (BorderStyle.Single)]
		[InlineData (BorderStyle.Rounded)]
		public void TestLineCanvas_Window_DoubleTop_SingleSides (BorderStyle thinStyle)
		{
			var v = GetCanvas (out var canvas);

			// outer box
			canvas.AddLine (new Point (0, 0), 9, Orientation.Horizontal, BorderStyle.Double);
			canvas.AddLine (new Point (9, 0), 4, Orientation.Vertical, thinStyle);
			canvas.AddLine (new Point (9, 4), -9, Orientation.Horizontal, BorderStyle.Double);
			canvas.AddLine (new Point (0, 4), -4, Orientation.Vertical, thinStyle);


			canvas.AddLine (new Point (5, 0), 4, Orientation.Vertical, thinStyle);
			canvas.AddLine (new Point (0, 2), 9, Orientation.Horizontal, BorderStyle.Double);

			v.Redraw (v.Bounds);

			string looksLike =
@"    
╒════╤═══╕
│    │   │
╞════╪═══╡
│    │   │
╘════╧═══╛
";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}

		[Theory, AutoInitShutdown]
		[InlineData (BorderStyle.Single)]
		[InlineData (BorderStyle.Rounded)]
		public void TestLineCanvas_Window_SingleTop_DoubleSides (BorderStyle thinStyle)
		{
			var v = GetCanvas (out var canvas);

			// outer box
			canvas.AddLine (new Point (0, 0), 9, Orientation.Horizontal, thinStyle);
			canvas.AddLine (new Point (9, 0), 4, Orientation.Vertical, BorderStyle.Double);
			canvas.AddLine (new Point (9, 4), -9, Orientation.Horizontal, thinStyle);
			canvas.AddLine (new Point (0, 4), -4, Orientation.Vertical, BorderStyle.Double);


			canvas.AddLine (new Point (5, 0), 4, Orientation.Vertical, BorderStyle.Double);
			canvas.AddLine (new Point (0, 2), 9, Orientation.Horizontal, thinStyle);

			v.Redraw (v.Bounds);

			string looksLike =
@"    
╓────╥───╖
║    ║   ║
╟────╫───╢
║    ║   ║
╙────╨───╜

";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}

		[Fact, AutoInitShutdown]
		public void TestLineCanvas_PositiveLocation ()
		{
			var x = 1;
			var y = 1;
			var v = GetCanvas (out var canvas, x, y);

			// outer box
			canvas.AddLine (new Point (x, y), 9, Orientation.Horizontal, BorderStyle.Single);
			canvas.AddLine (new Point (x + 9, y + 0), 4, Orientation.Vertical, BorderStyle.Single);
			canvas.AddLine (new Point (x + 9, y + 4), -9, Orientation.Horizontal, BorderStyle.Single);
			canvas.AddLine (new Point (x + 0, y + 4), -4, Orientation.Vertical, BorderStyle.Single);


			canvas.AddLine (new Point (x + 5, y + 0), 4, Orientation.Vertical, BorderStyle.Single);
			canvas.AddLine (new Point (x + 0, y + 2), 9, Orientation.Horizontal, BorderStyle.Single);

			v.Redraw (v.Bounds);

			string looksLike =
@"    

 ┌────┬───┐
 │    │   │
 ├────┼───┤
 │    │   │
 └────┴───┘";
			TestHelpers.AssertDriverContentsAre (looksLike, output);
		}

		[Theory, AutoInitShutdown]
		[InlineData (0, 0, @"
═══
══
═══")]
		[InlineData (1, 0, @"
══
═
══")]
		[InlineData (2, 0, @"
═

═")]
		[InlineData (0, 1, @"
══
═══")]
		[InlineData (0, 2, @"
═══")]
		public void TestLineCanvasRenderOffset_NoOffset (int xOffset, int yOffset, string expect)
		{
			var canvas = new LineCanvas ();
			canvas.AddLine (new Point (0, 0), 2, Orientation.Horizontal, BorderStyle.Double);
			canvas.AddLine (new Point (0, 1), 1, Orientation.Horizontal, BorderStyle.Double);
			canvas.AddLine (new Point (0, 2), 2, Orientation.Horizontal, BorderStyle.Double);

			var bmp = canvas.GenerateImage (new Rect (xOffset, yOffset, 3, 3));
			var actual = BmpToString (bmp);
			Assert.Equal (expect.TrimStart (), actual);

		}

		private string BmpToString (System.Rune? [,] bmp)
		{
			var sb = new StringBuilder ();
			for (int y = 0; y < bmp.GetLength (1); y++) {
				for (int x = 0; x < bmp.GetLength (0); x++) {
					sb.Append (bmp [y, x]);
				}
				sb.AppendLine ();
			}

			return sb.ToString ().TrimEnd ();
		}


		/// <summary>
		/// Creates a new <see cref="View"/> into which a <see cref="LineCanvas"/> is rendered
		/// at <see cref="View.DrawContentComplete"/> time.
		/// </summary>
		/// <param name="canvas">The <see cref="LineCanvas"/> you can draw into.</param>
		/// <param name="offsetX">How far to offset the <see cref="View.Bounds"/> in X</param>
		/// <param name="offsetX">How far to offset the <see cref="View.Bounds"/> in Y</param>
		/// <returns></returns>
		private View GetCanvas (out LineCanvas canvas, int offsetX = 0, int offsetY = 0)
		{
			var v = new View {
				Width = 10,
				Height = 5,
				Bounds = new Rect (offsetX, offsetY, 10, 5)
			};

			var canvasCopy = canvas = new LineCanvas ();
			v.DrawContentComplete += (r) => canvasCopy.Draw (v, v.Bounds);

			return v;
		}
	}
}