using CommunityToolkit.Mvvm.ComponentModel;
using System.Text;

namespace MultiTerm.Protocols.Model;

/// <summary>
/// A class that represents a Character and contains some additional information and methods.
/// A time can be stored in combination with this Character using the <see cref="Time"/> property. E.g. to represent arrived or sent time.
/// Several methods to display the Character in other formats than Unicode are provided.
/// </summary>
public partial class ExtendedChar
{
    /// <summary>
    /// Data in the form of a character. UTF-16 code unit.
    /// </summary>
    public char Character { get; set; }

    /// <summary>
    /// Time that is associated with the <see cref="Character"/>.
    /// E.g. to represent arrived or sent time.
    /// </summary>
    public TimeOnly Time { get; private set; }

    /// <summary>
    /// Creates an instance of ExtendedChar with a given <paramref name="character"/>.
    /// Sets <see cref="Time"/> to now.
    /// </summary>
    /// <param name="character">data</param>
    public ExtendedChar(char character) : this(character, TimeOnly.FromDateTime(DateTime.Now)) { }

    /// <summary>
    /// Creates an instance of ExtendedChar with a given <paramref name="character"/> and <paramref name="time"/>.
    /// Initializes string properties <see cref="StringUtf16"/>, <see cref="StringHex"/> and <see cref="StringBin"/>.
    /// </summary>
    /// <param name="character">data</param>
    /// <param name="time">time</param>
    public ExtendedChar(char character, TimeOnly time)
    {
        this.Character = character;
        this.Time = time;
    }

    public override string ToString()
    {
        return this.Character.ToString();
    }

    public string ToUtf16String()
    {
        string characterString;

        // character is ASCII encoded and is a control sequence
        if (char.IsAscii(this.Character) && this.Character <= '\x001F')
        {
            // conver to unicode Control Picture (see https://en.wikipedia.org/wiki/Control_Pictures)
            characterString = ((char)('\u2400' + this.Character)).ToString();

            // TODO Remove
            //characterString = this.Character switch
            //{
            //    '\t' => "\\t",
            //    ' '  => " ",
            //    '\n' => "\u240A",
            //    '\r' => "\u240D",
            //    '\v' => "\\v",
            //    '\f' => "\\f",
            //    _ => this.Character.ToString()
            //};
        }
        // TODO Remove
        //else if (char.IsControl(this.Character))
        //{
        //    characterString = "<CTRL>";
        //}
        else
        {
            characterString = this.Character.ToString();
        }

        return characterString;
    }

    public string ToHexString()
    {
        // hexadecimal converter for byte to string
        Converter<byte, string> hexConverter = (ch) => Convert.ToHexString(new byte[] { ch });

        // extract bytes from character and convert to correct format
        return ConvertToString(GetCharacterByteArray(this.Character), hexConverter, 2);

        //// foreach byte convert to hex and add to string
        //string hexString = String.Empty;
        //for (int i = 0; i < byteArray.Length; i++)
        //{
        //    // add byte to string in binary format, padding left with zeros up to 8
        //    hexString += $"{Convert.ToString(byteArray[i], 2).PadLeft(8, '0')}";
        //    // if not last byte add space separator
        //    if (i < byteArray.Length - 1)
        //    {
        //        hexString += " ";
        //    }
        //}
        //return hexString;


        //// get byte array from character and convert to hexadecimal
        //return Convert.ToHexString(GetCharacterByteArray(this.Character)).PadLeft(2); 
    }

    public string ToBinaryString()
    {
        // binary converter for byte to string
        Converter<byte, string> binaryConverter = (ch) => Convert.ToString(ch, 2);

        // extract bytes from character and convert to correct format
        return ConvertToString(GetCharacterByteArray(this.Character), binaryConverter, 8);
    }

    private static string ConvertToString(byte[] byteArray, Converter<byte, string> conversionFunction, int oneByteWidth)
    {
        // foreach byte convert to binary and add to string
        string resultString = String.Empty;

        // go through whole array
        for (int i = 0; i < byteArray.Length; i++)
        {
            // add byte to string in correct format, padding left with zeros up to width of one byte
            resultString += $"{conversionFunction(byteArray[i]).PadLeft(oneByteWidth, '0')}";

            // if not last byte add space separator
            if (i < byteArray.Length - 1)
            {
                resultString += " ";
            }
        }

        return resultString;
    }

    private static byte[] GetCharacterByteArray(char character)
    {
        byte[] byteArray = Array.Empty<byte>();

        if (char.IsAscii(character))
        {
            byteArray = Encoding.ASCII.GetBytes(character.ToString());
        }
        else
        {
            // extract bytes from utf16 character
            byteArray = Encoding.Unicode.GetBytes(character.ToString());
        }

        return byteArray;
    }
}