using System;
using System.Collections.Generic;
using WasmBox.Pixie.Markup;

namespace WasmBox.Pixie.Terminal.Devices {
    /// <summary>
    /// A style manager that applies styles by setting the color
    /// properties of the 'System.Console' class.
    /// </summary>
    public sealed class ConsoleStyleManager /*: StyleManager*/ {
        /// <summary>
        /// Creates a console style manager.
        /// </summary>
        // public ConsoleStyleManager()
        //     : this(
        //         ConsoleStyle.ToPixieColor(Console.ForegroundColor, Colors.White),
        //         ConsoleStyle.ToPixieColor(Console.BackgroundColor, Colors.Black))
        // { }

        // /// <summary>
        // /// Creates a console style manager from a default foreground
        // /// and background color.
        // /// </summary>
        // /// <param name="defaultForegroundColor">The default foreground color.</param>
        // /// <param name="defaultBackgroundColor">The default background color.</param>
        // public ConsoleStyleManager(
        //     Color defaultForegroundColor,
        //     Color defaultBackgroundColor)
        // {
        //     this.styleStack = new Stack<ConsoleStyle>();
        //     this.styleStack.Push(
        //         new ConsoleStyle(
        //             defaultForegroundColor,
        //             defaultBackgroundColor,
        //             true));
        // }

        // private Stack<ConsoleStyle> styleStack;

        // private ConsoleStyle CurrentStyle => styleStack.Peek();

        // /// <inheritdoc/>
        // public override void PushForegroundColor(Color color)
        // {
        //     var curStyle = CurrentStyle;
        //     PushStyle(
        //         new ConsoleStyle(
        //             color.Over(curStyle.ForegroundColor),
        //             curStyle.BackgroundColor));
        // }

        // /// <inheritdoc/>
        // public override void PushBackgroundColor(Color color)
        // {
        //     var curStyle = CurrentStyle;
        //     PushStyle(
        //         new ConsoleStyle(
        //             curStyle.ForegroundColor,
        //             color.Over(curStyle.BackgroundColor)));
        // }

        // /// <inheritdoc/>
        // public override void PushDecoration(
        //     TextDecoration decoration,
        //     Func<TextDecoration, TextDecoration, TextDecoration> updateDecoration)
        // {
        //     // 'System.Console' doesn't support text decorations. Just push
        //     // the current style.
        //     PushStyle(CurrentStyle);
        // }

        // private void PushStyle(ConsoleStyle style)
        // {
        //     style.Apply(CurrentStyle);
        //     styleStack.Push(style);
        // }

        // /// <inheritdoc/>
        // public override void PopStyle()
        // {
        //     var popped = styleStack.Pop();
        //     CurrentStyle.Apply(popped);
        // }
    }

    internal sealed class ConsoleStyle {
        public ConsoleStyle(
            Color foregroundColor,
            Color backgroundColor)
            : this(foregroundColor, backgroundColor, false) { }

        public ConsoleStyle(
            Color foregroundColor,
            Color backgroundColor,
            bool isRootStyle) {
            this.ForegroundColor = foregroundColor;
            this.BackgroundColor = backgroundColor;
            this.IsRootStyle = isRootStyle;
        }

        public Color ForegroundColor { get; private set; }

        public Color BackgroundColor { get; private set; }

        public bool IsRootStyle { get; private set; }

        /// <summary>
        /// Applies this style, given a previous style.
        /// </summary>
        // public void Apply( ConsoleStyle style )
        // {
            // var newFg = ToConsoleColor(ForegroundColor);
            // var newBg = ToConsoleColor(BackgroundColor);

            // if (IsRootStyle)
            // {
            //     Console.ResetColor();
            //     return;
            // }

            // if (Console.ForegroundColor != newFg)
            // {
            //     Console.ForegroundColor = newFg;
            // }

            // if (Console.BackgroundColor != newBg)
            // {
            //     Console.BackgroundColor = newBg;
            // }
        // }

        static ConsoleStyle() {
            // colorMap = new Dictionary<ConsoleColor, Color>()
            // {
            //     { ConsoleColor.Black, Colors.Black },
            //     { ConsoleColor.Blue, Colors.Blue },
            //     { ConsoleColor.Cyan, Colors.Cyan },
            //     { ConsoleColor.Gray, Colors.Gray },
            //     { ConsoleColor.Green, Colors.Green },
            //     { ConsoleColor.Magenta, Colors.Magenta },
            //     { ConsoleColor.Red, Colors.Red },
            //     { ConsoleColor.White, Colors.White },
            //     { ConsoleColor.Yellow, Colors.Yellow },
            //     { ConsoleColor.DarkBlue, MakeDark(Colors.Blue) },
            //     { ConsoleColor.DarkCyan, MakeDark(Colors.Cyan) },
            //     { ConsoleColor.DarkGray, MakeDark(Colors.Gray) },
            //     { ConsoleColor.DarkGreen, MakeDark(Colors.Green) },
            //     { ConsoleColor.DarkMagenta, MakeDark(Colors.Magenta) },
            //     { ConsoleColor.DarkRed, MakeDark(Colors.Red) },
            //     { ConsoleColor.DarkYellow, MakeDark(Colors.Yellow) }
            // };

            colorMap = new Dictionary<int, Color>() { { 0, Colors.Black }, { 9, Colors.Blue }, { 11, Colors.Cyan }, { 7, Colors.Gray }, { 10, Colors.Green }, { 13, Colors.Magenta }, { 12, Colors.Red }, { 15, Colors.White }, { 14, Colors.Yellow }, { 1, MakeDark(Colors.Blue) }, { 3, MakeDark(Colors.Cyan) }, { 8, MakeDark(Colors.Gray) }, { 2, MakeDark(Colors.Green) }, { 5, MakeDark(Colors.Magenta) }, { 4, MakeDark(Colors.Red) }, { 6, MakeDark(Colors.Yellow) }
            };
        }

        private static Dictionary<int, Color> colorMap;

        private static Color MakeDark(Color color) {
            double factor = 0.5;
            return new Color(
                factor * color.Red,
                factor * color.Green,
                factor * color.Blue,
                color.Alpha);
        }

        public static Color ToPixieColor(int color, Color fallbackResult) {
            Color result;
            if (colorMap.TryGetValue(color, out result)) {
                return result;
            }
            else {
                return fallbackResult;
            }
        }

        public static int ToConsoleColor(Color color) {
            var nearestColor = 7;
            var nearestColorDistSqr = 3.0;
            foreach (var pair in colorMap) {
                var otherColor = pair.Value;
                var distR = otherColor.Red - color.Red;
                var distG = otherColor.Green - color.Green;
                var distB = otherColor.Blue - color.Blue;
                var distSqr = distR * distR + distG * distG + distB * distB;
                if (distSqr < nearestColorDistSqr) {
                    nearestColorDistSqr = distSqr;
                    nearestColor = pair.Key;
                }
            }
            return nearestColor;
        }
    }
}