using System;
using System.Linq;
using System.Globalization;

namespace Xamarin.Forms
{
	[Xaml.ProvideCompiled("Xamarin.Forms.Core.XamlC.ColorTypeConverter")]
	public class ColorTypeConverter : TypeConverter
	{
		// Supported inputs
		// HEX		#rgb, #argb, #rrggbb, #aarrggbb
		// RGB		rgb(255,0,0), rgb(100%,0%,0%)					values in range 0-255 or 0%-100%
		// RGBA		rgba(255, 0, 0, 0.8), rgba(100%, 0%, 0%, 0.8)	opacity is 0.0-1.0
		// HSL		hsl(120, 100%, 50%)								h is 0-360, s and l are 0%-100%
		// HSLA		hsla(120, 100%, 50%, .8)						opacity is 0.0-1.0
		// Predefined color											case insensitive
		public override object ConvertFromInvariantString(string value)
		{
			if (value != null)
			{
				value = value.Trim();
				if (value.StartsWith("#", StringComparison.Ordinal))
					return Color.FromHex(value);

				if (value.StartsWith("rgba", StringComparison.OrdinalIgnoreCase)) {
					var op = value.IndexOf('(');
					var cp = value.LastIndexOf(')');
					if (op < 0 || cp < 0 || cp < op)
						throw new InvalidOperationException($"Cannot convert \"{value}\" into {typeof(Color)}");
					var quad = value.Substring(op + 1, cp - op - 1).Split(',');
					if (quad.Length != 4)
						throw new InvalidOperationException($"Cannot convert \"{value}\" into {typeof(Color)}");
					var r = ParseColorValue(quad[0], 255, acceptPercent: true);
					var g = ParseColorValue(quad[1], 255, acceptPercent: true);
					var b = ParseColorValue(quad[2], 255, acceptPercent: true);
					var a = ParseOpacity(quad[3]);
					return new Color(r, g, b, a);
				}

				if (value.StartsWith("rgb", StringComparison.OrdinalIgnoreCase)) {
					var op = value.IndexOf('(');
					var cp = value.LastIndexOf(')');
					if (op < 0 || cp < 0 || cp < op)
						throw new InvalidOperationException($"Cannot convert \"{value}\" into {typeof(Color)}");
					var triplet = value.Substring(op + 1, cp - op - 1).Split(',');
					if (triplet.Length != 3)
						throw new InvalidOperationException($"Cannot convert \"{value}\" into {typeof(Color)}");
					var r = ParseColorValue(triplet[0], 255, acceptPercent: true);
					var g = ParseColorValue(triplet[1], 255, acceptPercent: true);
					var b = ParseColorValue(triplet[2], 255, acceptPercent: true);
					return new Color(r, g, b);
				}

				if (value.StartsWith("hsla", StringComparison.OrdinalIgnoreCase)) {
					var op = value.IndexOf('(');
					var cp = value.LastIndexOf(')');
					if (op < 0 || cp < 0 || cp < op)
						throw new InvalidOperationException($"Cannot convert \"{value}\" into {typeof(Color)}");
					var quad = value.Substring(op + 1, cp - op - 1).Split(',');
					if (quad.Length != 4)
						throw new InvalidOperationException($"Cannot convert \"{value}\" into {typeof(Color)}");
					var h = ParseColorValue(quad[0], 360, acceptPercent: false);
					var s = ParseColorValue(quad[1], 100, acceptPercent: true);
					var l = ParseColorValue(quad[2], 100, acceptPercent: true);
					var a = ParseOpacity(quad[3]);
					return Color.FromHsla(h, s, l, a);
				}

				if (value.StartsWith("hsl", StringComparison.OrdinalIgnoreCase)) {
					var op = value.IndexOf('(');
					var cp = value.LastIndexOf(')');
					if (op < 0 || cp < 0 || cp < op)
						throw new InvalidOperationException($"Cannot convert \"{value}\" into {typeof(Color)}");
					var triplet = value.Substring(op + 1, cp - op - 1).Split(',');
					if (triplet.Length != 3)
						throw new InvalidOperationException($"Cannot convert \"{value}\" into {typeof(Color)}");
					var h = ParseColorValue(triplet[0], 360, acceptPercent: false);
					var s = ParseColorValue(triplet[1], 100, acceptPercent: true);
					var l = ParseColorValue(triplet[2], 100, acceptPercent: true);
					return Color.FromHsla(h, s, l);
				}

				string[] parts = value.Split('.');
				if (parts.Length == 1 || (parts.Length == 2 && parts[0] == "Color"))
				{
					string color = parts[parts.Length - 1];
					switch (color.ToLowerInvariant()) {
					case "default": return Color.Default;
					case "accent": return Color.Accent;
					case "aliceblue": return Color.AliceBlue;
					case "antiquewhite": return Color.AntiqueWhite;
					case "aqua": return Color.Aqua;
					case "aquamarine": return Color.Aquamarine;
					case "azure": return Color.Azure;
					case "beige": return Color.Beige;
					case "bisque": return Color.Bisque;
					case "black": return Color.Black;
					case "blanchedalmond": return Color.BlanchedAlmond;
					case "blue": return Color.Blue;
					case "blueViolet": return Color.BlueViolet;
					case "brown": return Color.Brown;
					case "burlywood": return Color.BurlyWood;
					case "cadetblue": return Color.CadetBlue;
					case "chartreuse": return Color.Chartreuse;
					case "chocolate": return Color.Chocolate;
					case "coral": return Color.Coral;
					case "cornflowerblue": return Color.CornflowerBlue;
					case "cornsilk": return Color.Cornsilk;
					case "crimson": return Color.Crimson;
					case "cyan": return Color.Cyan;
					case "darkblue": return Color.DarkBlue;
					case "darkcyan": return Color.DarkCyan;
					case "darkgoldenrod": return Color.DarkGoldenrod;
					case "darkgray": return Color.DarkGray;
					case "darkgreen": return Color.DarkGreen;
					case "darkkhaki": return Color.DarkKhaki;
					case "darkmagenta": return Color.DarkMagenta;
					case "darkolivegreen": return Color.DarkOliveGreen;
					case "darkorange": return Color.DarkOrange;
					case "darkorchid": return Color.DarkOrchid;
					case "darkred": return Color.DarkRed;
					case "darksalmon": return Color.DarkSalmon;
					case "darkseagreen": return Color.DarkSeaGreen;
					case "darkslateblue": return Color.DarkSlateBlue;
					case "darkslategray": return Color.DarkSlateGray;
					case "darkturquoise": return Color.DarkTurquoise;
					case "darkviolet": return Color.DarkViolet;
					case "deeppink": return Color.DeepPink;
					case "deepskyblue": return Color.DeepSkyBlue;
					case "dimgray": return Color.DimGray;
					case "dodgerblue": return Color.DodgerBlue;
					case "firebrick": return Color.Firebrick;
					case "floralwhite": return Color.FloralWhite;
					case "forestgreen": return Color.ForestGreen;
					case "fuchsia": return Color.Fuchsia;
					case "gainsboro": return Color.Gainsboro;
					case "ghostwhite": return Color.GhostWhite;
					case "gold": return Color.Gold;
					case "goldenrod": return Color.Goldenrod;
					case "gray": return Color.Gray;
					case "green": return Color.Green;
					case "greenyellow": return Color.GreenYellow;
					case "honeydew": return Color.Honeydew;
					case "hotpink": return Color.HotPink;
					case "indianred": return Color.IndianRed;
					case "indigo": return Color.Indigo;
					case "ivory": return Color.Ivory;
					case "khaki": return Color.Khaki;
					case "lavender": return Color.Lavender;
					case "lavenderblush": return Color.LavenderBlush;
					case "lawngreen": return Color.LawnGreen;
					case "lemonchiffon": return Color.LemonChiffon;
					case "lightblue": return Color.LightBlue;
					case "lightcoral": return Color.LightCoral;
					case "lightcyan": return Color.LightCyan;
					case "lightgoldenrodyellow": return Color.LightGoldenrodYellow;
					case "lightgray": return Color.LightGray;
					case "lightgreen": return Color.LightGreen;
					case "lightpink": return Color.LightPink;
					case "lightsalmon": return Color.LightSalmon;
					case "lightseagreen": return Color.LightSeaGreen;
					case "lightskyblue": return Color.LightSkyBlue;
					case "lightslategray": return Color.LightSlateGray;
					case "lightsteelblue": return Color.LightSteelBlue;
					case "lightyellow": return Color.LightYellow;
					case "lime": return Color.Lime;
					case "limegreen": return Color.LimeGreen;
					case "linen": return Color.Linen;
					case "magenta": return Color.Magenta;
					case "maroon": return Color.Maroon;
					case "mediumaquamarine": return Color.MediumAquamarine;
					case "mediumblue": return Color.MediumBlue;
					case "mediumorchid": return Color.MediumOrchid;
					case "mediumpurple": return Color.MediumPurple;
					case "mediumseagreen": return Color.MediumSeaGreen;
					case "mediumslateblue": return Color.MediumSlateBlue;
					case "mediumspringgreen": return Color.MediumSpringGreen;
					case "mediumturquoise": return Color.MediumTurquoise;
					case "mediumvioletred": return Color.MediumVioletRed;
					case "midnightblue": return Color.MidnightBlue;
					case "mintcream": return Color.MintCream;
					case "mistyrose": return Color.MistyRose;
					case "moccasin": return Color.Moccasin;
					case "navajowhite": return Color.NavajoWhite;
					case "navy": return Color.Navy;
					case "oldlace": return Color.OldLace;
					case "olive": return Color.Olive;
					case "olivedrab": return Color.OliveDrab;
					case "orange": return Color.Orange;
					case "orangered": return Color.OrangeRed;
					case "orchid": return Color.Orchid;
					case "palegoldenrod": return Color.PaleGoldenrod;
					case "palegreen": return Color.PaleGreen;
					case "paleturquoise": return Color.PaleTurquoise;
					case "palevioletred": return Color.PaleVioletRed;
					case "papayawhip": return Color.PapayaWhip;
					case "peachpuff": return Color.PeachPuff;
					case "peru": return Color.Peru;
					case "pink": return Color.Pink;
					case "plum": return Color.Plum;
					case "powderblue": return Color.PowderBlue;
					case "purple": return Color.Purple;
					case "red": return Color.Red;
					case "rosybrown": return Color.RosyBrown;
					case "royalblue": return Color.RoyalBlue;
					case "saddlebrown": return Color.SaddleBrown;
					case "salmon": return Color.Salmon;
					case "sandybrown": return Color.SandyBrown;
					case "seagreen": return Color.SeaGreen;
					case "seashell": return Color.SeaShell;
					case "sienna": return Color.Sienna;
					case "silver": return Color.Silver;
					case "skyblue": return Color.SkyBlue;
					case "slateblue": return Color.SlateBlue;
					case "slategray": return Color.SlateGray;
					case "snow": return Color.Snow;
					case "springgreen": return Color.SpringGreen;
					case "steelblue": return Color.SteelBlue;
					case "tan": return Color.Tan;
					case "teal": return Color.Teal;
					case "thistle": return Color.Thistle;
					case "tomato": return Color.Tomato;
					case "transparent": return Color.Transparent;
					case "turquoise": return Color.Turquoise;
					case "violet": return Color.Violet;
					case "wheat": return Color.Wheat;
					case "white": return Color.White;
					case "whitesmoke": return Color.WhiteSmoke;
					case "yellow": return Color.Yellow;
					case "yellowgreen": return Color.YellowGreen;
					}
					var field = typeof(Color).GetFields().FirstOrDefault(fi => fi.IsStatic && string.Equals(fi.Name, color, StringComparison.OrdinalIgnoreCase));
					if (field != null)
						return (Color)field.GetValue(null);
					var property = typeof(Color).GetProperties().FirstOrDefault(pi => string.Equals(pi.Name, color, StringComparison.OrdinalIgnoreCase) && pi.CanRead && pi.GetMethod.IsStatic);
					if (property != null)
						return (Color)property.GetValue(null, null);
				}
			}

			throw new InvalidOperationException($"Cannot convert \"{value}\" into {typeof(Color)}");
		}

		static double ParseColorValue(string elem, int maxValue, bool acceptPercent)
		{
			elem = elem.Trim();
			if (elem.EndsWith("%", StringComparison.Ordinal) && acceptPercent) {
				maxValue = 100;
				elem = elem.Substring(0, elem.Length - 1);
			}
			return (double)(int.Parse(elem, NumberStyles.Number, CultureInfo.InvariantCulture).Clamp(0, maxValue)) / maxValue;
		}

		static double ParseOpacity(string elem)
		{
			return double.Parse(elem, NumberStyles.Number, CultureInfo.InvariantCulture).Clamp(0, 1);
		}
	}
}