using System;
using System.Collections.Generic;
using System.Globalization;

namespace FF8.Encoding
{
    public sealed class FF8TextEncodingCodepage
    {
        private readonly Char[] _chars;
        private readonly Dictionary<Char, Byte> _bytes;
        /// <summary>
        /// Characters not in the codepage but have alternative characters that can be used.
        /// </summary>
        private readonly Dictionary<Char, Char> _alts;
        
        public FF8TextEncodingCodepage(Char[] chars, Dictionary<Char, Byte> bytes)
        {
            _chars = chars ?? throw new ArgumentNullException(nameof(chars));
            _bytes = bytes ?? throw new ArgumentNullException(nameof(bytes));
            _alts = GetAlts();
        }

        public Char this[Byte b]
        {
            get
            {
                Char c = _chars[b];
                if (c == '\0')
                    return '�';
                    //throw new ArgumentOutOfRangeException("b", b, $"Cannot find maping for the encoded character: {b}.");
                return c;
            }
        }

        public Byte this[Char c]
        {
            get {
                if (_bytes.ContainsKey(c))
                    return _bytes[c];
                else if(_alts.ContainsKey(c))
                    return _bytes[_alts[c]];
                else
                    throw new KeyNotFoundException(String.Format(@"Character 0x{0:x4} '{1}' is unsupported. please add to alts or codepage", (ushort)c,c));
            }
        }

        public Char? TryGetChar(Byte b)
        {
            Char c = _chars[b];
            if (c == '\0')
                return null;
            return c;
        }

        public Byte? TryGetByte(Char c)
        {
            Byte b;
            if (_bytes.TryGetValue(c, out b))
                return b;
            else if (_alts.ContainsKey(c) && _bytes.TryGetValue(_alts[c], out b))
                    return b;
            return null;
        }

        public void GetParameters(out Char[] chars, out HashSet<Char>[] bytes)
        {
            chars = (Char[])_chars.Clone();

            bytes = new HashSet<Char>[256];
            for (Int32 i = 0; i < 256; i++)
                bytes[i] = new HashSet<Char>();

            foreach (KeyValuePair<Char, Byte> pair in _bytes)
                bytes[pair.Value].Add(pair.Key);
        }

        public static FF8TextEncodingCodepage Create()
        {
            var chars = CreateDefaultEncoding();

            Dictionary<Char, Byte> bytes = new Dictionary<Char, Byte>(chars.Length);
            for (Int32 i = chars.Length - 1; i >= 0; i--)
            {
                Char ch = chars[i];
                switch (ch)
                {
                    case '¥':
                    case '☻':
                    case 'ⱷ':
                        chars[i] = '\0';
                        continue;
                    case '\0':
                        continue;
                }

                bytes[chars[i]] = (Byte)i;
            }
            return new FF8TextEncodingCodepage(chars, bytes);
        }
        private static Dictionary<Char, Char> GetAlts()
        {
            switch (CultureInfo.CurrentCulture.TwoLetterISOLanguageName)
            {
                case "jp":
                    return new Dictionary<char, char>
                    {
                        { '\'','・' },
                        { '{','「' },
                        { '}','」' },
                    }; 
                case "ru":
                    return new Dictionary<char, char>
                    {
                        { '\'','‘' },
                        { '{','「' },
                        { '}','」' },
                    };
                default:
                    return new Dictionary<char, char>
                    {
                        { '\'','‘' },
                        { '{','「' },
                        { '}','」' },
                    };
            }
        }
        private static Char[] CreateDefaultEncoding()
        {
            switch (CultureInfo.CurrentCulture.TwoLetterISOLanguageName)
            {
                case "jp":
                    return CreateJapaneseCodepage();
                case "ru":
                    return CreateRussianCodepage();
                default:
                    return CreateEuropeanCodepage();
            }
        }

        private static Char[] CreateEuropeanCodepage()
        {
            Char[] chars = new Char[256]
            {
                '\0', '\0', '\n', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
                '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '®', '®', '®', '®', '\0', '\0', '\0',
                ' ', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '%', '/', ':', '!', '?',
                '…', '+', '-', '=', '*', '&', '「', '」', '(', ')', '·', '.', ',', '~', '“', '”',
                '‘', '#', '$', '"', '_', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K',
                'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a',
                'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q',
                'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'À', 'Á', 'Â', 'Ä', 'Ç', 'È', 'É',
                'Ê', 'Ë', 'Ì', 'Í', 'Î', 'Ï', 'Ñ', 'Ò', 'Ó', 'Ô', 'Ö', 'Ù', 'Ú', 'Û', 'Ü', 'Œ',
                'ß', 'à', 'á', 'â', 'ä', 'ç', 'è', 'é', 'ê', 'ë', 'ì', 'í', 'î', 'ï', 'ñ', 'ò',
                'ó', 'ô', 'ö', 'ù', 'ú', 'û', 'ü', 'œ',
                'Ⅷ', '[', ']', '■', '◎', '♦', '〖', '〗',
                '□', '★', '『', '』', '▽', ';', '▼', '‾', '⨯', '☆', '¥', '↓', '°', '¡', '¿', '─',
                '«', '»', '±', '♬', '¥', '↑', '¥', '¥', '¥', '™', '<', '>', '¥', '¥', '¥', '¥',
                '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '\0', '\0',
                '¥', '¥', '¥', '☻', '☻', '☻', '☻', '☻', '☻', '☻', '☻', '\0', '\0', '☻', '☻', '☻',
                '☻', '☻', '☻', '☻', '☻', '☻', '☻', '☻', '☻', '\0', '☻', '\0', '☻', 'ⱷ', 'ⱷ', 'ⱷ'
            };
            return chars;
        }

        private static Char[] CreateJapaneseCodepage()
        {
            Char[] chars = new Char[256]
            {
                '\0', '\0', '\n', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
                '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '®', '®', '®', '®', '\0', '\0', '\0',
                'バ','ば','ビ','び','ブ','ぶ','ベ','べ','ボ','ぼ','ガ','が','ギ','ぎ','グ','ぐ',
                'ゲ','げ','ゴ','ご','ザ','ざ','ジ','じ','ズ','ず','ゼ','ぜ','ゾ','ぞ','ダ','だ',
                'ヂ','ぢ','ヅ','づ','デ','で','ド','ど','ヴ','パ','ぱ','ピ','ぴ','プ','ぷ','ペ',
                'ぺ','ポ','ぽ','０','１','２','３','４','５','６','７','８','９','、','。','　',
                'ハ','は','ヒ','ひ','フ','ふ','ヘ','へ','ホ','ほ','カ','か','キ','き','ク','く',
                'ケ','け','コ','こ','サ','さ','シ','し','ス','す','セ','せ','ソ','そ','タ','た',
                'チ','ち','ツ','つ','テ','て','ト','と','ウ','う','ア','あ','イ','い','エ','え',
                'オ','お','ナ','な','ニ','に','ヌ','ぬ','ネ','ね','ノ','の','マ','ま','ミ','み',
                'ム','む','メ','め','モ','も','ラ','ら','リ','り','ル','る','レ','れ','ロ','ろ',
                'ヤ','や','ユ','ゆ','ヨ','よ','ワ','わ','ン','ん','ヲ','を','ッ','っ','ャ','ゃ',
                'ュ','ゅ','ョ','ょ','ァ','ぁ','ィ','ぃ','ゥ','ぅ','ェ','ぇ','ォ','ぉ','Ａ','Ｂ','Ｃ',
                'Ｄ','Ｅ','Ｆ','Ｇ','Ｈ','Ｉ','Ｊ','Ｋ','Ｌ','Ｍ','Ｎ','Ｏ','Ｐ','Ｑ','Ｒ',
                'Ｓ','Ｔ','Ｕ','Ｖ','Ｗ','Ｘ','Ｙ','Ｚ','！','？','…','＋','－','＝','＊','／',
                '％','＆','「','」','（','）','収','容','所','駅','・','．','，','：','～','ー'
            };
            return chars;
        }

        private static Char[] CreateRussianCodepage()
        {
            Char[] chars = new Char[256]
            {
                '\0', '\0', '\n', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
                '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '®', '®', '®', '®', '\0', '\0', '\0',
                ' ', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '%', '/', ':', '!', '?',
                '…', '+', '-', '=', '*', '&', '「', '」', '(', ')', '∙', '.', ',', '~', '”', '“',
                '‘', '#', '$', '’', '_', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K',
                'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a',
                'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q',
                'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'Б', 'Г', 'Д', 'Ё', 'Ж', 'З', 'И',
                'Й', 'Л', 'П', 'У', 'Ф', 'Ц', 'Ч', 'Ш', 'Щ', 'Ъ', 'Ы', 'Ь', 'Э', 'Ю', 'Я', 'б',
                'в', 'г', 'д', 'ж', 'з', 'й', 'к', 'л', 'м', 'н', 'п', 'т', 'ф', 'ц', 'ч', 'ш',
                'щ', 'ъ', 'ы', 'ь', 'э', 'ю', 'я', 'ё',
                'Ⅷ', '[', ']', '■', '◎', '♦', '〖', '〗',
                '□', '★', '『', '』', '▽', ';', '▼', '‾', '⨯', '☆', '¥', '↓', '°', '¡', '¿', '─',
                '«', '»', '±', '♬', '¥', '↑', '¥', '¥', '¥', '™', '<', '>', '¥', '¥', '¥', '¥',
                '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '¥', '\0', '\0',
                '¥', '¥', '¥', '☻', '☻', '☻', '☻', '☻', '☻', '☻', '☻', '\0', '\0', '☻', '☻', '☻',
                '☻', '☻', '☻', '☻', '☻', '☻', '☻', '☻', '☻', '\0', '☻', '\0', '☻', 'ⱷ', 'ⱷ', 'ⱷ'
            };
            return chars;
        }
    }
}