using System.Runtime.InteropServices;
using FFXIVClientStructs.FFXIV.Client.Graphics;

namespace XivCommon.Functions.NamePlates; 

[StructLayout(LayoutKind.Explicit, Size = 0x28)]
internal unsafe struct NumberArrayData {
    [FieldOffset(0x0)]
    public AtkArrayData AtkArrayData;

    [FieldOffset(0x20)]
    public int* IntArray;

    public void SetValue(int index, int value) {
        if (index >= this.AtkArrayData.Size) {
            return;
        }

        if (this.IntArray[index] == value) {
            return;
        }

        this.IntArray[index] = value;
        this.AtkArrayData.HasModifiedData = 1;
    }
}

[StructLayout(LayoutKind.Explicit, Size = 0x20)]
internal unsafe struct AtkArrayData {
    [FieldOffset(0x0)]
    public void* vtbl;

    [FieldOffset(0x8)]
    public int Size;

    [FieldOffset(0x1C)]
    public byte Unk1C;

    [FieldOffset(0x1D)]
    public byte Unk1D;

    [FieldOffset(0x1E)]
    public byte HasModifiedData;

    [FieldOffset(0x1F)]
    public byte Unk1F; // initialized to -1
}

[StructLayout(LayoutKind.Explicit, Size = 0x30)]
internal unsafe struct StringArrayData {
    [FieldOffset(0x0)]
    public AtkArrayData AtkArrayData;

    [FieldOffset(0x20)]
    public byte** StringArray; // char * *

    [FieldOffset(0x28)]
    public byte* UnkString; // char *
}

/// <summary>
/// The various different name plate types
/// </summary>
public enum PlateType {
    /// <summary>
    /// A normal player name plate
    /// </summary>
    Player = 0,

    /// <summary>
    /// A name plate with the icon and FC tag removed
    /// </summary>
    NoIconOrFc = 1, // 2, 5

    /// <summary>
    /// A name plate with a level string visible, title always below the name, and FC tag removed
    /// </summary>
    LevelNoFc = 3, // 4

    /// <summary>
    /// A name plate with only the name visible
    /// </summary>
    NameOnly = 6,

    /// <summary>
    /// A name plate with only the level string and name visible
    /// </summary>
    LevelAndName = 7,

    /// <summary>
    /// A name plate where the title always appears below the name and the FC tag is removed
    /// </summary>
    LowTitleNoFc = 8,
}

/// <summary>
/// A colour, represented in the RGBA format.
/// </summary>
public class RgbaColour {
    /// <summary>
    /// The red component of the colour.
    /// </summary>
    public byte R { get; set; }

    /// <summary>
    /// The green component of the colour.
    /// </summary>
    public byte G { get; set; }

    /// <summary>
    /// The blue component of the colour.
    /// </summary>
    public byte B { get; set; }

    /// <summary>
    /// The alpha component of the colour.
    /// </summary>
    public byte A { get; set; } = byte.MaxValue;

    /// <summary>
    /// Converts an unsigned integer into an RgbaColour.
    /// </summary>
    /// <param name="rgba">32-bit integer representing an RGBA colour</param>
    /// <returns>an RgbaColour equivalent to the integer representation</returns>
    public static implicit operator RgbaColour(uint rgba) {
        var r = (byte) ((rgba >> 24) & 0xFF);
        var g = (byte) ((rgba >> 16) & 0xFF);
        var b = (byte) ((rgba >> 8) & 0xFF);
        var a = (byte) (rgba & 0xFF);

        return new RgbaColour {
            R = r,
            G = g,
            B = b,
            A = a,
        };
    }

    /// <summary>
    /// Converts an RgbaColour into an unsigned integer representation.
    /// </summary>
    /// <param name="rgba">an RgbaColour to convert</param>
    /// <returns>32-bit integer representing an RGBA colour</returns>
    public static implicit operator uint(RgbaColour rgba) {
        return (uint) ((rgba.R << 24)
                       | (rgba.G << 16)
                       | (rgba.B << 8)
                       | rgba.A);
    }

    /// <summary>
    /// Converts a ByteColor into an RgbaColour.
    /// </summary>
    /// <param name="rgba">ByteColor</param>
    /// <returns>equivalent RgbaColour</returns>
    public static implicit operator RgbaColour(ByteColor rgba) {
        return (uint) ((rgba.R << 24)
                       | (rgba.G << 16)
                       | (rgba.B << 8)
                       | rgba.A);
    }

    /// <summary>
    /// Converts an RgbaColour into a ByteColor.
    /// </summary>
    /// <param name="rgba">RgbaColour</param>
    /// <returns>equivalent ByteColour</returns>
    public static implicit operator ByteColor(RgbaColour rgba) {
        return new() {
            R = rgba.R,
            G = rgba.G,
            B = rgba.B,
            A = rgba.A,
        };
    }
}