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

namespace MultiTerm.Protocols.Model;

/// <summary>
/// A class that represents a single <see cref="byte"/> and contains some additional information and methods.
/// A time can be stored in combination with this <see cref="byte"/> using the <see cref="Time"/> property. E.g. to represent arrived or sent time.
/// Several methods to display the <see cref="byte"/> in other formats are provided.
/// </summary>
public partial class ExtendedByte
{
    /// <summary>
    /// Data in the form of a byte.
    /// </summary>
    public byte Byte { get; set; }

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

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

    /// <summary>
    /// Creates an instance of <see cref="ExtendedByte"/> with a given <paramref name="dataByte"/> and <paramref name="time"/>.
    /// </summary>
    /// <param name="dataByte">data</param>
    /// <param name="time">time</param>
    public ExtendedByte(byte dataByte, TimeOnly time)
    {
        this.Byte = dataByte;
        this.Time = time;
    }

    /// <summary>
    /// Returns this <see cref="Byte"/> as ASCII encoded String.
    /// </summary>
    /// <returns></returns>
    public override string ToString()
    {
        return Encoding.ASCII.GetString(new byte[] { this.Byte });
    }

    /// <summary>
    /// Returns displayable character as string.
    /// ASCII control sequences are replaced with unicode control pictures.
    /// </summary>
    /// <returns>string with single character</returns>
    public string ToCharacterString()
    {
        char character = (char)this.Byte;
        string characterString;

        // character is ASCII encoded and is a control sequence
        if (char.IsAscii(character) && character <= '\x001F')
        {
            // conver to unicode Control Picture (see https://en.wikipedia.org/wiki/Control_Pictures)
            characterString = ((char)('\u2400' + character)).ToString();
        }
        // else just convert using ASCII code
        else if(char.IsAscii(character))
        {
            characterString = Encoding.ASCII.GetString(new byte[] { this.Byte });
        }
        else
        {
            characterString = "?";
        }

        return characterString;
    }

    /// <summary>
    /// Returns displayable hex string.
    /// </summary>
    /// <returns></returns>
    public string ToHexString()
    {
        // hexadecimal converter for byte to string
        static string hexConverter(byte ch) => Convert.ToHexString(new byte[] { ch });

        // extract bytes from character and convert to correct format
        return ConvertToString(new byte[] { this.Byte }, hexConverter, 2);
    }

    /// <summary>
    /// Returns displayable binary string.
    /// </summary>
    /// <returns></returns>
    public string ToBinaryString()
    {
        // binary converter for byte to string
        static string binaryConverter(byte ch) => Convert.ToString(ch, 2);

        // extract bytes from character and convert to correct format
        return ConvertToString(new byte[] { this.Byte }, binaryConverter, 8);
    }

    /// <summary>
    /// Converts a <paramref name="byteArray"/> to a string, using the given <paramref name="conversionFunction"/> to convert a single byte to a character.
    /// <paramref name="oneByteWidth"/> defines how many characters the result string should contain (the left side will be padded with zeroes).
    /// </summary>
    /// <returns>converte string</returns>
    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;
    }
}