using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using UnitTestSharp;

namespace Glass.UnitTests
{
    public class SpriteFontDefinitionTests : TestFixture
    {
        static SpriteFontDefinition MakeFont(char glyph, int xAdvance)
        {
            var font = new SpriteFontDefinition();
            font.GlyphDefinitions[glyph] = new SpriteFontDefinition.GlyphDefinition
            {
                XAdvance = xAdvance
            };
            return font;
        }

        public class GlyphWidthTests : TestFixture
        {
            public void GlyphWidthReturnsXAdvance()
            {
                var font = MakeFont('A', xAdvance: 7);
                CheckEqual(7, font.GlyphWidth('A'));
            }

            public void GlyphWidthIsZeroForMissingGlyph()
            {
                var font = MakeFont('B', xAdvance: 7);
                CheckEqual(0, font.GlyphWidth('A'));
            }

            public void GlyphWidthIsNotSizeX()
            {
                var font = new SpriteFontDefinition();
                font.GlyphDefinitions['A'] = new SpriteFontDefinition.GlyphDefinition
                {
                    XAdvance = 7,
                    Size = new Point(99, 99)
                };
                CheckEqual(7, font.GlyphWidth('A'));
            }
        }

        public class SpaceBetweenGlyphsTests : TestFixture
        {
            public void SpaceBetweenGlyphsReturnsKerning()
            {
                var font = new SpriteFontDefinition();
                font.Kernings[((short)'A', (short)'V')] = -2;
                CheckEqual(-2, font.SpaceBetweenGlyphs('A', 'V'));
            }

            public void SpaceBetweenGlyphsIsZeroWithNoKerningEntry()
            {
                var font = new SpriteFontDefinition();
                CheckEqual(0, font.SpaceBetweenGlyphs('A', 'V'));
            }

            public void SpaceBetweenGlyphsIsZeroWhenLeftGlyphIsNull()
            {
                var font = new SpriteFontDefinition();
                font.Kernings[((short)'A', (short)'V')] = -2;
                CheckEqual(0, font.SpaceBetweenGlyphs(null, 'V'));
            }

            public void SpaceBetweenGlyphsIsZeroWhenRightGlyphIsNull()
            {
                var font = new SpriteFontDefinition();
                font.Kernings[((short)'A', (short)'V')] = -2;
                CheckEqual(0, font.SpaceBetweenGlyphs('A', null));
            }

            public void SpaceBetweenGlyphsIsZeroWhenBothGlyphsAreNull()
            {
                var font = new SpriteFontDefinition();
                CheckEqual(0, font.SpaceBetweenGlyphs(null, null));
            }

            public void SpaceBetweenGlyphsIsDirectional()
            {
                var font = new SpriteFontDefinition();
                font.Kernings[((short)'A', (short)'V')] = -2;
                // No entry for (V, A), so only one direction has kerning.
                CheckEqual(-2, font.SpaceBetweenGlyphs('A', 'V'));
                CheckEqual(0, font.SpaceBetweenGlyphs('V', 'A'));
            }
        }
    }
}