using NStack;
using Xunit;
using Xunit.Abstractions;

namespace Terminal.Gui.ViewTests {
	public class ScrollViewTests {
		readonly ITestOutputHelper output;

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

		[Fact]
		public void Constructors_Defaults ()
		{
			var sv = new ScrollView ();
			Assert.Equal (LayoutStyle.Computed, sv.LayoutStyle);
			Assert.True (sv.CanFocus);
			Assert.Equal (new Rect (0, 0, 0, 0), sv.Frame);
			Assert.Equal (Rect.Empty, sv.Frame);
			Assert.Null (sv.X);
			Assert.Null (sv.Y);
			Assert.Null (sv.Width);
			Assert.Null (sv.Height);
			Assert.Equal (Point.Empty, sv.ContentOffset);
			Assert.Equal (Size.Empty, sv.ContentSize);
			Assert.True (sv.AutoHideScrollBars);
			Assert.True (sv.KeepContentAlwaysInViewport);

			sv = new ScrollView (new Rect (1, 2, 20, 10));
			Assert.Equal (LayoutStyle.Absolute, sv.LayoutStyle);
			Assert.True (sv.CanFocus);
			Assert.Equal (new Rect (1, 2, 20, 10), sv.Frame);
			Assert.Null (sv.X);
			Assert.Null (sv.Y);
			Assert.Null (sv.Width);
			Assert.Null (sv.Height);
			Assert.Equal (Point.Empty, sv.ContentOffset);
			Assert.Equal (Size.Empty, sv.ContentSize);
			Assert.True (sv.AutoHideScrollBars);
			Assert.True (sv.KeepContentAlwaysInViewport);
		}

		[Fact]
		public void Adding_Views ()
		{
			var sv = new ScrollView (new Rect (0, 0, 20, 10)) {
				ContentSize = new Size (30, 20)
			};
			sv.Add (new View () { Width = 10, Height = 5 },
				new View () { X = 12, Y = 7, Width = 10, Height = 5 });

			Assert.Equal (new Size (30, 20), sv.ContentSize);
			Assert.Equal (2, sv.Subviews [0].Subviews.Count);
		}

		[Fact]
		public void KeyBindings_Command ()
		{
			var sv = new ScrollView (new Rect (0, 0, 20, 10)) {
				ContentSize = new Size (40, 20)
			};
			sv.Add (new View () { Width = 20, Height = 5 },
				new View () { X = 22, Y = 7, Width = 10, Height = 5 });

			Assert.True (sv.KeepContentAlwaysInViewport);
			Assert.True (sv.AutoHideScrollBars);
			Assert.Equal (new Point (0, 0), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.CursorUp, new KeyModifiers ())));
			Assert.Equal (new Point (0, 0), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.CursorDown, new KeyModifiers ())));
			Assert.Equal (new Point (0, -1), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.CursorUp, new KeyModifiers ())));
			Assert.Equal (new Point (0, 0), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.PageUp, new KeyModifiers ())));
			Assert.Equal (new Point (0, 0), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.PageDown, new KeyModifiers ())));
			Assert.Equal (new Point (0, -10), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.PageDown, new KeyModifiers ())));
			Assert.Equal (new Point (0, -10), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.CursorDown, new KeyModifiers ())));
			Assert.Equal (new Point (0, -10), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent ((Key)'v' | Key.AltMask, new KeyModifiers ())));
			Assert.Equal (new Point (0, 0), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.V | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (0, -10), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.CursorLeft, new KeyModifiers ())));
			Assert.Equal (new Point (0, -10), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.CursorRight, new KeyModifiers ())));
			Assert.Equal (new Point (-1, -10), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.CursorLeft, new KeyModifiers ())));
			Assert.Equal (new Point (0, -10), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.PageUp | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (0, -10), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.PageDown | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (-20, -10), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.CursorRight, new KeyModifiers ())));
			Assert.Equal (new Point (-20, -10), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.Home, new KeyModifiers ())));
			Assert.Equal (new Point (-20, 0), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.Home, new KeyModifiers ())));
			Assert.Equal (new Point (-20, 0), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.End, new KeyModifiers ())));
			Assert.Equal (new Point (-20, -10), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.End, new KeyModifiers ())));
			Assert.Equal (new Point (-20, -10), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.Home | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (0, -10), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.Home | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (0, -10), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.End | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (-20, -10), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.End | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (-20, -10), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.Home, new KeyModifiers ())));
			Assert.Equal (new Point (-20, 0), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.Home | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (0, 0), sv.ContentOffset);

			sv.KeepContentAlwaysInViewport = false;
			Assert.False (sv.KeepContentAlwaysInViewport);
			Assert.True (sv.AutoHideScrollBars);
			Assert.Equal (new Point (0, 0), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.CursorUp, new KeyModifiers ())));
			Assert.Equal (new Point (0, 0), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.CursorDown, new KeyModifiers ())));
			Assert.Equal (new Point (0, -1), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.CursorUp, new KeyModifiers ())));
			Assert.Equal (new Point (0, 0), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.PageUp, new KeyModifiers ())));
			Assert.Equal (new Point (0, 0), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.PageDown, new KeyModifiers ())));
			Assert.Equal (new Point (0, -10), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.PageDown, new KeyModifiers ())));
			Assert.Equal (new Point (0, -19), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.PageDown, new KeyModifiers ())));
			Assert.Equal (new Point (0, -19), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.CursorDown, new KeyModifiers ())));
			Assert.Equal (new Point (0, -19), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent ((Key)'v' | Key.AltMask, new KeyModifiers ())));
			Assert.Equal (new Point (0, -9), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.V | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (0, -19), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.CursorLeft, new KeyModifiers ())));
			Assert.Equal (new Point (0, -19), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.CursorRight, new KeyModifiers ())));
			Assert.Equal (new Point (-1, -19), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.CursorLeft, new KeyModifiers ())));
			Assert.Equal (new Point (0, -19), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.PageUp | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (0, -19), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.PageDown | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (-20, -19), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.PageDown | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (-39, -19), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.PageDown | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (-39, -19), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.CursorRight, new KeyModifiers ())));
			Assert.Equal (new Point (-39, -19), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.PageUp | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (-19, -19), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.Home, new KeyModifiers ())));
			Assert.Equal (new Point (-19, 0), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.Home, new KeyModifiers ())));
			Assert.Equal (new Point (-19, 0), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.End, new KeyModifiers ())));
			Assert.Equal (new Point (-19, -19), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.End, new KeyModifiers ())));
			Assert.Equal (new Point (-19, -19), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.Home | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (0, -19), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.Home | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (0, -19), sv.ContentOffset);
			Assert.True (sv.ProcessKey (new KeyEvent (Key.End | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (-39, -19), sv.ContentOffset);
			Assert.False (sv.ProcessKey (new KeyEvent (Key.End | Key.CtrlMask, new KeyModifiers ())));
			Assert.Equal (new Point (-39, -19), sv.ContentOffset);
		}

		[Fact, AutoInitShutdown]
		public void AutoHideScrollBars_ShowHorizontalScrollIndicator_ShowVerticalScrollIndicator ()
		{
			var sv = new ScrollView {
				Width = 10,
				Height = 10
			};

			Application.Top.Add (sv);
			Application.Begin (Application.Top);

			Assert.True (sv.AutoHideScrollBars);
			Assert.False (sv.ShowHorizontalScrollIndicator);
			Assert.False (sv.ShowVerticalScrollIndicator);
			TestHelpers.AssertDriverContentsWithFrameAre ("", output);

			sv.AutoHideScrollBars = false;
			sv.ShowHorizontalScrollIndicator = true;
			sv.ShowVerticalScrollIndicator = true;
			sv.Redraw (sv.Bounds);
			TestHelpers.AssertDriverContentsWithFrameAre (@"
         ▲
         ┬
         │
         │
         │
         │
         │
         ┴
         ▼
◄├─────┤► 
", output);
		}

		[Fact, AutoInitShutdown]
		public void ContentSize_AutoHideScrollBars_ShowHorizontalScrollIndicator_ShowVerticalScrollIndicator ()
		{
			var sv = new ScrollView {
				Width = 10,
				Height = 10,
				ContentSize = new Size (50, 50)
			};

			Application.Top.Add (sv);
			Application.Begin (Application.Top);

			Assert.Equal (50, sv.ContentSize.Width);
			Assert.Equal (50, sv.ContentSize.Height);
			Assert.True (sv.AutoHideScrollBars);
			Assert.True (sv.ShowHorizontalScrollIndicator);
			Assert.True (sv.ShowVerticalScrollIndicator);
			TestHelpers.AssertDriverContentsWithFrameAre (@"
         ▲
         ┬
         ┴
         ░
         ░
         ░
         ░
         ░
         ▼
◄├┤░░░░░► 
", output);
		}

		[Fact, AutoInitShutdown]
		public void ContentOffset_ContentSize_AutoHideScrollBars_ShowHorizontalScrollIndicator_ShowVerticalScrollIndicator ()
		{
			var sv = new ScrollView {
				Width = 10,
				Height = 10,
				ContentSize = new Size (50, 50),
				ContentOffset = new Point (25, 25)
			};

			Application.Top.Add (sv);
			Application.Begin (Application.Top);

			Assert.Equal (-25, sv.ContentOffset.X);
			Assert.Equal (-25, sv.ContentOffset.Y);
			Assert.Equal (50, sv.ContentSize.Width);
			Assert.Equal (50, sv.ContentSize.Height);
			Assert.True (sv.AutoHideScrollBars);
			Assert.True (sv.ShowHorizontalScrollIndicator);
			Assert.True (sv.ShowVerticalScrollIndicator);
			TestHelpers.AssertDriverContentsWithFrameAre (@"
         ▲
         ░
         ░
         ░
         ┬
         │
         ┴
         ░
         ▼
◄░░░├─┤░► 
", output);
		}

		[Fact, AutoInitShutdown]
		public void Frame_And_Labels_Does_Not_Overspill_ScrollView ()
		{
			var sv = new ScrollView {
				X = 3,
				Y = 3,
				Width = 10,
				Height = 10,
				ContentSize = new Size (50, 50)
			};
			for (int i = 0; i < 8; i++) {
				sv.Add (new CustomButton ("█", $"Button {i}", 20, 3) { Y = i * 3 });
			}
			Application.Top.Add (sv);
			Application.Begin (Application.Top);

			TestHelpers.AssertDriverContentsWithFrameAre (@"
   █████████▲
   ██████But┬
   █████████┴
   ┌────────░
   │     But░
   └────────░
   ┌────────░
   │     But░
   └────────▼
   ◄├┤░░░░░► ", output);

			sv.ContentOffset = new Point (5, 5);
			Application.Refresh ();
			TestHelpers.AssertDriverContentsWithFrameAre (@"
   ─────────▲
   ─────────┬
    Button 2│
   ─────────┴
   ─────────░
    Button 3░
   ─────────░
   ─────────░
    Button 4▼
   ◄├─┤░░░░► ", output);
		}

		private class CustomButton : FrameView {
			private Label labelFill;
			private Label labelText;

			public CustomButton (string fill, ustring text, int width, int height)
			{
				Width = width;
				Height = height;
				labelFill = new Label () { AutoSize = false, Width = Dim.Fill (), Height = Dim.Fill (), Visible = false };
				var fillText = new System.Text.StringBuilder ();
				for (int i = 0; i < Bounds.Height; i++) {
					if (i > 0) {
						fillText.AppendLine ("");
					}
					for (int j = 0; j < Bounds.Width; j++) {
						fillText.Append (fill);
					}
				}
				labelFill.Text = fillText.ToString ();
				labelText = new Label (text) { X = Pos.Center (), Y = Pos.Center () };
				Add (labelFill, labelText);
				CanFocus = true;
			}

			public override bool OnEnter (View view)
			{
				Border.BorderStyle = BorderStyle.None;
				Border.DrawMarginFrame = false;
				labelFill.Visible = true;
				view = this;
				return base.OnEnter (view);
			}

			public override bool OnLeave (View view)
			{
				Border.BorderStyle = BorderStyle.Single;
				Border.DrawMarginFrame = true;
				labelFill.Visible = false;
				if (view == null)
					view = this;
				return base.OnLeave (view);
			}
		}

		[Fact, AutoInitShutdown]
		public void Clear_Window_Inside_ScrollView ()
		{
			var topLabel = new Label ("At 15,0") { X = 15 };
			var sv = new ScrollView {
				X = 3,
				Y = 3,
				Width = 10,
				Height = 10,
				ContentSize = new Size (23, 23),
				KeepContentAlwaysInViewport = false
			};
			var bottomLabel = new Label ("At 15,15") { X = 15, Y = 15 };
			Application.Top.Add (topLabel, sv, bottomLabel);
			Application.Begin (Application.Top);

			TestHelpers.AssertDriverContentsWithFrameAre (@"
               At 15,0 
                       
                       
            ▲          
            ┬          
            ┴          
            ░          
            ░          
            ░          
            ░          
            ░          
            ▼          
   ◄├┤░░░░░►           
                       
                       
               At 15,15", output);

			var attributes = new Attribute [] {
				Colors.TopLevel.Normal,
				Colors.TopLevel.Focus,
				Colors.Base.Normal
			};

			TestHelpers.AssertDriverColorsAre (@"
00000000000000000000000
00000000000000000000000
00000000000000000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00011111111110000000000
00000000000000000000000
00000000000000000000000
00000000000000000000000", attributes);

			sv.Add (new Window ("1") { X = 3, Y = 3, Width = 20, Height = 20 });
			Application.Refresh ();
			TestHelpers.AssertDriverContentsWithFrameAre (@"
               At 15,0 
                       
                       
            ▲          
            ┬          
            ┴          
      ┌ 1 ──░          
      │     ░          
      │     ░          
      │     ░          
      │     ░          
      │     ▼          
   ◄├┤░░░░░►           
                       
                       
               At 15,15", output);

			TestHelpers.AssertDriverColorsAre (@"
00000000000000000000000
00000000000000000000000
00000000000000000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00000022222210000000000
00000022222210000000000
00000022222210000000000
00000022222210000000000
00000022222210000000000
00000022222210000000000
00011111111110000000000
00000000000000000000000
00000000000000000000000
00000000000000000000000", attributes);

			sv.ContentOffset = new Point (20, 20);
			Application.Refresh ();
			TestHelpers.AssertDriverContentsWithFrameAre (@"
               At 15,0 
                       
                       
     │      ▲          
     │      ░          
   ──┘      ░          
            ░          
            ░          
            ┬          
            │          
            ┴          
            ▼          
   ◄░░░░├─┤►           
                       
                       
               At 15,15", output);

			TestHelpers.AssertDriverColorsAre (@"
00000000000000000000000
00000000000000000000000
00000000000000000000000
00022200000010000000000
00022200000010000000000
00022200000010000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00000000000010000000000
00011111111110000000000
00000000000000000000000
00000000000000000000000
00000000000000000000000", attributes);
		}
	}
}
