using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Numerics;
using System.Text;

namespace Masuit.Tools.Strings;

/// <summary>
/// 数制格式化器
/// </summary>
public class UnicodeFormater
{
    /// <summary>
    /// 数制表示字符集
    /// </summary>
    private List<string> Characters { get; }

    /// <summary>
    /// 进制长度
    /// </summary>
    public int Length => Characters.Count;

    /// <summary>
    /// 起始值偏移
    /// </summary>
    private readonly byte _offset;

    /// <summary>
    /// 数制格式化器
    /// </summary>
    public UnicodeFormater()
    {
        Characters = new List<string>() { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };
    }

    /// <summary>
    /// 数制格式化器
    /// </summary>
    /// <param name="characters">符号集</param>
    /// <param name="offset">起始值偏移</param>
    public UnicodeFormater(string characters, byte offset = 0)
    {
        if (string.IsNullOrEmpty(characters))
        {
            throw new ArgumentException("符号集不能为空");
        }

        var enumerator = StringInfo.GetTextElementEnumerator(characters);
        Characters = new List<string>();
        while (enumerator.MoveNext())
        {
            Characters.Add(enumerator.GetTextElement());
        }

        _offset = offset;
    }

    /// <summary>
    /// 数制格式化器
    /// </summary>
    /// <param name="characters">符号集</param>
    /// <param name="offset">起始值偏移</param>
    public UnicodeFormater(List<string> characters, byte offset = 0)
    {
        if (characters.IsNullOrEmpty())
        {
            throw new ArgumentException("符号集不能为空");
        }

        Characters = characters;
        _offset = offset;
    }

#if NET5_0_OR_GREATER

        /// <summary>
        /// 数制格式化器
        /// </summary>
        /// <param name="characters">符号集</param>
        /// <param name="offset">起始值偏移</param>
        public UnicodeFormater(ReadOnlySpan<byte> characters, byte offset = 0)
        {
            if (characters == null || characters.Length == 0)
            {
                throw new ArgumentException("符号集不能为空");
            }

            Characters = Encoding.UTF8.GetString(characters).Select(c => c.ToString()).ToList();
            _offset = offset;
        }

        /// <summary>
        /// 数制格式化器
        /// </summary>
        /// <param name="characters">符号集</param>
        /// <param name="offset">起始值偏移</param>
        public UnicodeFormater(ReadOnlySpan<char> characters, byte offset = 0)
        {
            if (characters == null || characters.Length == 0)
            {
                throw new ArgumentException("符号集不能为空");
            }

            Characters = characters.ToString().Select(c => c.ToString()).ToList();
            _offset = offset;
        }

#endif

    /// <summary>
    /// 数制格式化器
    /// </summary>
    /// <param name="characters">符号集</param>
    /// <param name="offset">起始值偏移</param>
    public UnicodeFormater(byte[] characters, byte offset = 0)
    {
        if (characters == null || characters.Length == 0)
        {
            throw new ArgumentException("符号集不能为空");
        }

        Characters = Encoding.UTF8.GetString(characters).Select(c => c.ToString()).ToList();
        _offset = offset;
    }

    /// <summary>
    /// 数制格式化器
    /// </summary>
    /// <param name="characters">符号集</param>
    /// <param name="offset">起始值偏移</param>
    public UnicodeFormater(char[] characters, byte offset = 0)
    {
        if (characters == null || characters.Length == 0)
        {
            throw new ArgumentException("符号集不能为空");
        }

        Characters = characters.Select(c => c.ToString()).ToList();
        _offset = offset;
    }

    /// <summary>
    /// 数制格式化器
    /// </summary>
    /// <param name="base">进制</param>
    /// <param name="offset">起始值偏移</param>
    public UnicodeFormater(byte @base, byte offset = 0)
    {
        Characters = @base switch
        {
            <= 2 => new List<string>() { "0", "1" },
            > 2 and < 65 => "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+/".Substring(0, @base).Select(c => c.ToString()).ToList(),
            >= 65 and <= 91 => "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!#$%&()*+,-.:;<=>?@[]^_`{|}~\"".Substring(0, @base).Select(c => c.ToString()).ToList(),
            _ => throw new ArgumentException("默认进制最大支持91进制")
        };

        if (offset >= @base)
        {
            throw new ArgumentException("偏移量不能超过进制基数" + @base);
        }

        _offset = offset;
    }

    /// <summary>
    /// 数字转换为指定的进制形式字符串
    /// </summary>
    /// <param name="number"></param>
    /// <returns></returns>
    public string ToString(long number)
    {
        int start = 0;
        int resultOffset = 0;
        if (_offset > 0)
        {
            start = 1;
            resultOffset = _offset - 1;
        }

        number -= resultOffset;
        List<string> result = [];
        long t = Math.Abs(number);
        while (t != 0)
        {
            var mod = t % Length;
            t = Math.Abs(t / Length);
            var character = Characters[Convert.ToInt32(mod) - start];
            result.Insert(0, character);
        }

        if (number < 0)
        {
            result.Insert(0, "-");
        }

        return string.Join("", result);
    }

    /// <summary>
    /// 数字转换为指定的进制形式字符串
    /// </summary>
    /// <param name="number"></param>
    /// <returns></returns>
    public string ToString(BigInteger number)
    {
        int start = 0;
        int resultOffset = 0;
        if (_offset > 0)
        {
            start = 1;
            resultOffset = _offset - 1;
        }

        number -= resultOffset;
        List<string> result = [];
        if (number < 0)
        {
            number = -number;
            result.Add("0");
        }

        BigInteger t = number;

        while (t != 0)
        {
            var mod = t % Length;
            t = BigInteger.Abs(BigInteger.Divide(t, Length));
            var character = Characters[(int)mod - start];
            result.Insert(0, character);
        }

        return string.Join("", result);
    }

    /// <summary>
    /// 指定字符串转换为指定进制的数字形式
    /// </summary>
    /// <param name="str"></param>
    /// <returns></returns>
    public long FromString(string str)
    {
        byte start = 0;
        int resultOffset = 0;
        if (_offset > 0)
        {
            start = 1;
            resultOffset = _offset - 1;
        }

        int j = 0;
        var emoji = new List<string>();
        var enumerator = StringInfo.GetTextElementEnumerator(str);
        while (enumerator.MoveNext())
        {
            emoji.Add(enumerator.GetTextElement());
        }

        emoji.Reverse();
        return emoji.Where(Characters.Contains).Sum(ch => (Characters.IndexOf(ch) + start) * (long)Math.Pow(Length, j++)) + resultOffset;
    }

    /// <summary>
    /// 指定字符串转换为指定进制的大数形式
    /// </summary>
    /// <param name="str"></param>
    /// <returns></returns>
    public BigInteger FromStringBig(string str)
    {
        byte start = 0;
        int resultOffset = 0;
        if (_offset > 0)
        {
            start = 1;
            resultOffset = _offset - 1;
        }
        int j = 0;
        var emoji = new List<string>();
        var enumerator = StringInfo.GetTextElementEnumerator(str);
        while (enumerator.MoveNext())
        {
            emoji.Add(enumerator.GetTextElement());
        }
        emoji.Reverse();
        return emoji.Where(Characters.Contains).Aggregate(BigInteger.Zero, (current, c) => current + (Characters.IndexOf(c) + start) * BigInteger.Pow(Length, j++)) + resultOffset;
    }

    /// <summary>Returns a string that represents the current object.</summary>
    /// <returns>A string that represents the current object.</returns>
    public override string ToString()
    {
        return Length + "进制模式，进制符：" + Characters.Join("");
    }
}