using Resources;
using SmartCoalApplication.Core;
using SmartCoalApplication.Resources;
using SmartCoalApplication.SystemLayer;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SmartCoalApplication.PluginAssemblys
{
    internal sealed class PaletteCollection
    {
        /// <summary>
        /// The required number of colors for a palette.
        /// </summary>
        /// <remarks>
        /// If a palette is loaded with fewer colors than this, then it will be padded with entries
        /// that are equal to DefaultColor. If a palette is loaded with more colors than this, then
        /// the 97th through the last color will be discarded.
        /// </remarks>
        public const int PaletteColorCount = 96;
        private const char lineCommentChar = ';';
        private static readonly Encoding paletteFileEncoding = Encoding.UTF8;

        private Dictionary<string, ColorBgra[]> palettes; // maps from Name -> Palette

        public static bool ValidatePaletteName(string paletteName)
        {
            if (string.IsNullOrEmpty(paletteName))
            {
                return false;
            }

            try
            {
                string fileName = Path.ChangeExtension(paletteName, PalettesFileExtension);
                string pathName = Path.Combine(PalettesPath, fileName);
                char[] invalidFileNameChars = Path.GetInvalidFileNameChars();
                char[] invalidPathNameChars = Path.GetInvalidPathChars();

                if (pathName.IndexOfAny(invalidPathNameChars) != -1)
                {
                    return false;
                }

                if (fileName.IndexOfAny(invalidFileNameChars) != -1)
                {
                    return false;
                }

                return true;
            }

            catch (ArgumentNullException)
            {
                return false;
            }

            catch (ArgumentException)
            {
                return false;
            }
        }

        public static ColorBgra DefaultColor
        {
            get
            {
                return ColorBgra.White;
            }
        }

        public static ColorBgra[] DefaultPalette
        {
            get
            {
                return
                    new ColorBgra[PaletteColorCount]
                    {
                        ColorBgra.FromUInt32(0xff000000),
                        ColorBgra.FromUInt32(0xff404040),
                        ColorBgra.FromUInt32(0xffff0000),
                        ColorBgra.FromUInt32(0xffff6a00),
                        ColorBgra.FromUInt32(0xffffd800),
                        ColorBgra.FromUInt32(0xffb6ff00),
                        ColorBgra.FromUInt32(0xff4cff00),
                        ColorBgra.FromUInt32(0xff00ff21),
                        ColorBgra.FromUInt32(0xff00ff90),
                        ColorBgra.FromUInt32(0xff00ffff),
                        ColorBgra.FromUInt32(0xff0094ff),
                        ColorBgra.FromUInt32(0xff0026ff),
                        ColorBgra.FromUInt32(0xff4800ff),
                        ColorBgra.FromUInt32(0xffb200ff),
                        ColorBgra.FromUInt32(0xffff00dc),
                        ColorBgra.FromUInt32(0xffff006e),
                        ColorBgra.FromUInt32(0xffffffff),
                        ColorBgra.FromUInt32(0xff808080),
                        ColorBgra.FromUInt32(0xff7f0000),
                        ColorBgra.FromUInt32(0xff7f3300),
                        ColorBgra.FromUInt32(0xff7f6a00),
                        ColorBgra.FromUInt32(0xff5b7f00),
                        ColorBgra.FromUInt32(0xff267f00),
                        ColorBgra.FromUInt32(0xff007f0e),
                        ColorBgra.FromUInt32(0xff007f46),
                        ColorBgra.FromUInt32(0xff007f7f),
                        ColorBgra.FromUInt32(0xff004a7f),
                        ColorBgra.FromUInt32(0xff00137f),
                        ColorBgra.FromUInt32(0xff21007f),
                        ColorBgra.FromUInt32(0xff57007f),
                        ColorBgra.FromUInt32(0xff7f006e),
                        ColorBgra.FromUInt32(0xff7f0037),
                        ColorBgra.FromUInt32(0xffa0a0a0),
                        ColorBgra.FromUInt32(0xff303030),
                        ColorBgra.FromUInt32(0xffff7f7f),
                        ColorBgra.FromUInt32(0xffffb27f),
                        ColorBgra.FromUInt32(0xffffe97f),
                        ColorBgra.FromUInt32(0xffdaff7f),
                        ColorBgra.FromUInt32(0xffa5ff7f),
                        ColorBgra.FromUInt32(0xff7fff8e),
                        ColorBgra.FromUInt32(0xff7fffc5),
                        ColorBgra.FromUInt32(0xff7fffff),
                        ColorBgra.FromUInt32(0xff7fc9ff),
                        ColorBgra.FromUInt32(0xff7f92ff),
                        ColorBgra.FromUInt32(0xffa17fff),
                        ColorBgra.FromUInt32(0xffd67fff),
                        ColorBgra.FromUInt32(0xffff7fed),
                        ColorBgra.FromUInt32(0xffff7fb6),
                        ColorBgra.FromUInt32(0xffc0c0c0),
                        ColorBgra.FromUInt32(0xff606060),
                        ColorBgra.FromUInt32(0xff7f3f3f),
                        ColorBgra.FromUInt32(0xff7f593f),
                        ColorBgra.FromUInt32(0xff7f743f),
                        ColorBgra.FromUInt32(0xff6d7f3f),
                        ColorBgra.FromUInt32(0xff527f3f),
                        ColorBgra.FromUInt32(0xff3f7f47),
                        ColorBgra.FromUInt32(0xff3f7f62),
                        ColorBgra.FromUInt32(0xff3f7f7f),
                        ColorBgra.FromUInt32(0xff3f647f),
                        ColorBgra.FromUInt32(0xff3f497f),
                        ColorBgra.FromUInt32(0xff503f7f),
                        ColorBgra.FromUInt32(0xff6b3f7f),
                        ColorBgra.FromUInt32(0xff7f3f76),
                        ColorBgra.FromUInt32(0xff7f3f5b),
                        ColorBgra.FromUInt32(0x80000000),
                        ColorBgra.FromUInt32(0x80404040),
                        ColorBgra.FromUInt32(0x80ff0000),
                        ColorBgra.FromUInt32(0x80ff6a00),
                        ColorBgra.FromUInt32(0x80ffd800),
                        ColorBgra.FromUInt32(0x80b6ff00),
                        ColorBgra.FromUInt32(0x804cff00),
                        ColorBgra.FromUInt32(0x8000ff21),
                        ColorBgra.FromUInt32(0x8000ff90),
                        ColorBgra.FromUInt32(0x8000ffff),
                        ColorBgra.FromUInt32(0x800094ff),
                        ColorBgra.FromUInt32(0x800026ff),
                        ColorBgra.FromUInt32(0x804800ff),
                        ColorBgra.FromUInt32(0x80b200ff),
                        ColorBgra.FromUInt32(0x80ff00dc),
                        ColorBgra.FromUInt32(0x80ff006e),
                        ColorBgra.FromUInt32(0x80ffffff),
                        ColorBgra.FromUInt32(0x80808080),
                        ColorBgra.FromUInt32(0x807f0000),
                        ColorBgra.FromUInt32(0x807f3300),
                        ColorBgra.FromUInt32(0x807f6a00),
                        ColorBgra.FromUInt32(0x805b7f00),
                        ColorBgra.FromUInt32(0x80267f00),
                        ColorBgra.FromUInt32(0x80007f0e),
                        ColorBgra.FromUInt32(0x80007f46),
                        ColorBgra.FromUInt32(0x80007f7f),
                        ColorBgra.FromUInt32(0x80004a7f),
                        ColorBgra.FromUInt32(0x8000137f),
                        ColorBgra.FromUInt32(0x8021007f),
                        ColorBgra.FromUInt32(0x8057007f),
                        ColorBgra.FromUInt32(0x807f006e),
                        ColorBgra.FromUInt32(0x807f0037)
                    };
            }
        }

        public string[] PaletteNames
        {
            get
            {
                Dictionary<string, ColorBgra[]>.KeyCollection keyCollection = this.palettes.Keys;
                string[] keys = new string[keyCollection.Count];
                int index = 0;

                foreach (string key in keyCollection)
                {
                    keys[index] = key;
                    ++index;
                }

                return keys;
            }
        }

        public PaletteCollection()
        {
            this.palettes = new Dictionary<string, ColorBgra[]>();
        }

        public static string PalettesFileExtension
        {
            get
            {
                // seems like using .txt is just simpler: makes it obvious that it is human readable/writable, and not xml (which has high perf costs @ startup)
                return ".txt";
            }
        }

        public static string PalettesPath
        {
            get
            {
                string userDataPath = PdnInfo.UserDataPath;
                string palettesDirName = PdnResources.GetString("ColorPalettes.UserDataSubDirName");
                string palettesPath = Path.Combine(userDataPath, palettesDirName);
                return palettesPath;
            }
        }

        private static bool ParseColor(string colorString, out ColorBgra color)
        {
            bool returnVal;
            if (string.IsNullOrEmpty(colorString))
            {
                color = DefaultColor;
                returnVal = false;
                return returnVal;
            }

            /*int v = 0;
            if (!int.TryParse(colorString, out v))
            {
                color = DefaultColor;
                returnVal = false;
                return returnVal;
            }*/

            try
            {
                color = ColorBgra.ParseHexString(colorString);
                returnVal = true;
            }

            catch (Exception ex)
            {
                Tracing.Ping("Exception while parsing color string '" + colorString + "' :" + ex.ToString());
                color = DefaultColor;
                returnVal = false;
            }

            return returnVal;
        }

        public static string RemoveComments(string line)
        {
            int commentIndex = line.IndexOf(lineCommentChar);

            if (commentIndex != -1)
            {
                return line.Substring(0, commentIndex);
            }
            else
            {
                return line;
            }
        }

        public static bool ParsePaletteLine(string line, out ColorBgra color)
        {
            color = DefaultColor;

            if (line == null)
            {
                return false;
            }

            string trimmed1 = RemoveComments(line);
            string trimmed = trimmed1.Trim();

            if (trimmed.Length < 4)
            {
                return false;
            }

            bool gotColor = ParseColor(trimmed, out color);
            return gotColor;
        }

        public static ColorBgra[] ParsePaletteString(string paletteString)
        {
            List<ColorBgra> palette = new List<ColorBgra>();
            StringReader sr = new StringReader(paletteString);

            while (true)
            {
                string line = sr.ReadLine();

                if (line == null)
                {
                    break;
                }

                ColorBgra color;
                bool gotColor = ParsePaletteLine(line, out color);

                if (gotColor && palette.Count < PaletteColorCount)
                {
                    palette.Add(color);
                }
            }

            return palette.ToArray();
        }

        public static ColorBgra[] LoadPalette(string palettePath)
        {
            ColorBgra[] palette = null;
            FileStream paletteFile = new FileStream(palettePath, FileMode.Open, FileAccess.Read, FileShare.Read);

            try
            {
                StreamReader sr = new StreamReader(paletteFile, paletteFileEncoding);

                try
                {
                    string paletteString = sr.ReadToEnd();
                    palette = ParsePaletteString(paletteString);
                }

                finally
                {
                    sr.Close(); // as per docs, this also closes paletteFile
                    sr = null;
                    paletteFile = null;
                }
            }

            finally
            {
                if (paletteFile != null)
                {
                    paletteFile.Close();
                    paletteFile = null;
                }
            }

            if (palette == null)
            {
                return new ColorBgra[0];
            }
            else
            {
                return palette;
            }
        }

        private static string FormatColor(ColorBgra color)
        {
            return color.ToHexString();
        }

        public static string GetPaletteSaveString(ColorBgra[] palette)
        {
            StringWriter sw = new StringWriter();

            string header = PdnResources.GetString("ColorPalette.SaveHeader");
            sw.WriteLine(header);

            foreach (ColorBgra color in palette)
            {
                string colorString = FormatColor(color);
                sw.WriteLine(colorString);
            }

            return sw.ToString();
        }

        public static void SavePalette(string palettePath, ColorBgra[] palette)
        {
            FileStream paletteFile = new FileStream(palettePath, FileMode.Create, FileAccess.Write, FileShare.Read);

            try
            {
                StreamWriter sw = new StreamWriter(paletteFile, paletteFileEncoding);

                try
                {
                    string paletteString = GetPaletteSaveString(palette);
                    sw.WriteLine(paletteString);
                }

                finally
                {
                    sw.Close(); // as per documentation, this closes paletteFile as well
                    sw = null;
                    paletteFile = null;
                }
            }

            finally
            {
                if (paletteFile != null)
                {
                    paletteFile.Close();
                    paletteFile = null;
                }
            }
        }

        private bool DoesPalettesPathExist()
        {
            string palettesPath = PalettesPath;
            bool returnVal;

            try
            {
                returnVal = Directory.Exists(palettesPath);
            }

            catch (Exception ex)
            {
                Tracing.Ping("Exception while querying whether palettes path, '" + palettesPath + "' exists: " + ex.ToString());
                returnVal = false;
            }

            return returnVal;
        }

        public static void EnsurePalettesPathExists()
        {
            string palettesPath = PalettesPath;

            try
            {
                if (!Directory.Exists(palettesPath))
                {
                    Directory.CreateDirectory(palettesPath);
                }
            }

            catch (Exception ex)
            {
                // Fail silently
                Tracing.Ping("Exception while ensuring that " + palettesPath + " exists: " + ex.ToString());
            }
        }

        public void Load()
        {
            if (!DoesPalettesPathExist())
            {
                // can't load anything! no custom palettes exist.
                // we really don't want to create this directory unless they've
                // saved anything in to it. this is especially important if they
                // install and then set their language. the path name is localized
                // so we only want the final name to be there.
                this.palettes = new Dictionary<string, ColorBgra[]>();
                return;
            }

            string[] pathNames = new string[0];

            try
            {
                pathNames = Directory.GetFiles(PalettesPath, "*" + PalettesFileExtension);
            }

            catch (Exception ex)
            {
                // Trace the error, but otherwise fail silently
                Tracing.Ping("Exception while retrieving list of palette filenames: " + ex.ToString());
            }

            // Now, load the palettes
            Dictionary<string, ColorBgra[]> newPalettes = new Dictionary<string, ColorBgra[]>();

            foreach (string pathName in pathNames)
            {
                ColorBgra[] palette = LoadPalette(pathName);
                ColorBgra[] goodPalette = EnsureValidPaletteSize(palette);
                string fileName = Path.GetFileName(pathName);
                string paletteName = Path.ChangeExtension(fileName, null);
                newPalettes.Add(paletteName, goodPalette);
            }

            this.palettes = newPalettes;
        }

        public void Save()
        {
            EnsurePalettesPathExists();

            string palettesPath = PalettesPath;

            foreach (string paletteName in this.palettes.Keys)
            {
                ColorBgra[] palette = this.palettes[paletteName];
                ColorBgra[] goodPalette = EnsureValidPaletteSize(palette);
                string fileName = Path.ChangeExtension(paletteName, PalettesFileExtension);
                string pathName = Path.Combine(palettesPath, fileName);
                SavePalette(pathName, goodPalette);
            }
        }

        public static ColorBgra[] EnsureValidPaletteSize(ColorBgra[] colors)
        {
            ColorBgra[] validPalette = new ColorBgra[PaletteColorCount];

            for (int i = 0; i < PaletteColorCount; ++i)
            {
                if (i >= colors.Length)
                {
                    validPalette[i] = DefaultColor;
                }
                else
                {
                    validPalette[i] = colors[i];
                }
            }

            return validPalette;
        }

        public ColorBgra[] Get(string name)
        {
            string existingKeyName;
            bool contains = Contains(name, out existingKeyName);

            if (contains)
            {
                ColorBgra[] colors = this.palettes[existingKeyName];
                return (ColorBgra[])colors.Clone();
            }
            else
            {
                return null;
            }
        }

        public bool Contains(string name, out string existingKeyName)
        {
            foreach (string key in this.palettes.Keys)
            {
                if (string.Compare(key, name, StringComparison.InvariantCultureIgnoreCase) == 0)
                {
                    existingKeyName = key;
                    return true;
                }
            }

            existingKeyName = null;
            return false;
        }

        public void AddOrUpdate(string name, ColorBgra[] colors)
        {
            if (colors.Length != PaletteColorCount)
            {
                throw new ArgumentException("palette must have exactly " + PaletteColorCount.ToString() + " colors (actual: " + colors.Length.ToString() + ")");
            }

            Delete(name);
            this.palettes.Add(name, colors);
        }

        public bool Delete(string name)
        {
            string existingKeyName;
            bool contains = Contains(name, out existingKeyName);

            if (contains)
            {
                this.palettes.Remove(existingKeyName);
                return true;
            }

            return false;
        }
    }
}