using System;
using System.Runtime.InteropServices;

internal static class Nova64
{
    private const string LibName = "nova64_core";

    /* ========================================================================== */
    /* Enums                                                                      */
    /* ========================================================================== */

    [Flags]
    public enum Nova64Transform : uint
    {
        None = 0,
        FlipH = 1 << 0,
        FlipV = 1 << 1,
        Rot90 = 1 << 2,
        Rot180 = 1 << 3,
        Rot270 = 1 << 4
    }

    /* ========================================================================== */
    /* PPU Delegates                                                              */
    /* ========================================================================== */

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate void PpuFillRectDelegate(IntPtr dst, uint dstStride, int x, int y, int w, int h, ushort color);

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate void PpuBlitDelegate(IntPtr src, uint srcStride, IntPtr dst, uint dstStride, int srcX, int srcY, int dstX, int dstY, int w, int h);

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate void PpuBlitColorKeyDelegate(IntPtr src, uint srcStride, IntPtr dst, uint dstStride, int srcX, int srcY, int dstX, int dstY, int w, int h, ushort keyColor);

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate void PpuBlendDelegate(IntPtr src, uint srcStride, IntPtr dst, uint dstStride, int srcX, int srcY, int dstX, int dstY, int w, int h, byte globalAlpha);

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate void PpuBlitTransformDelegate(IntPtr src, uint srcStride, IntPtr dst, uint dstStride, int srcX, int srcY, int dstX, int dstY, int w, int h, Nova64Transform transform);

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate void PpuBlitScaleDelegate(IntPtr src, uint srcStride, int srcW, int srcH, IntPtr dst, uint dstStride, int dstX, int dstY, int dstW, int dstH);

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate void PpuWaitIdleDelegate();

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    [return: MarshalAs(UnmanagedType.I1)]
    public delegate bool PpuIsBusyDelegate();

    /* ========================================================================== */
    /* PPU Interface Struct                                                       */
    /* ========================================================================== */

    [StructLayout(LayoutKind.Sequential)]
    public struct Nova64PpuInterface
    {
        public IntPtr fill_rect;
        public IntPtr blit;
        public IntPtr blit_colorkey;
        public IntPtr blend;
        public IntPtr blit_transform;
        public IntPtr blit_scale;
        public IntPtr wait_idle;
        public IntPtr is_busy;
    }

    /* ========================================================================== */
    /* I/O Delegates                                                              */
    /* ========================================================================== */

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate void DisplayFlushDelegate(IntPtr buffer, ushort width, ushort height);

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate void AudioOutputDelegate(IntPtr samples, uint count);

    [UnmanagedFunctionPointer(CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
    public delegate int SdReadFileDelegate(uint slotIdx, string filePath, IntPtr destinationBuffer, uint destinationLength);

    [UnmanagedFunctionPointer(CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
    public delegate int SdGetFileSizeDelegate(uint slotIdx, string filePath);

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate void CartridgeStatusDelegate(uint slotIdx, [MarshalAs(UnmanagedType.I1)] bool isInserted);

    [UnmanagedFunctionPointer(CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
    public delegate void LogMessageDelegate([MarshalAs(UnmanagedType.LPStr)] string message);

    /* ========================================================================== */
    /* I/O Interface Struct                                                       */
    /* ========================================================================== */

    [StructLayout(LayoutKind.Sequential)]
    public struct Nova64IoInterface
    {
        public IntPtr audio_output;
        public IntPtr sd_read_file;
        public IntPtr sd_get_file_size;
        public IntPtr cartridge_status;
        public IntPtr log_message;
    }

    /* ========================================================================== */
    /* Native Imports                                                             */
    /* ========================================================================== */

    [DllImport(LibName, CallingConvention = CallingConvention.Cdecl)]
    [return: MarshalAs(UnmanagedType.I1)]
    public static extern bool nova64_init(IntPtr io_interface, IntPtr ppu_interface);

    [DllImport(LibName, CallingConvention = CallingConvention.Cdecl)]
    public static extern int nova64_main();

    [DllImport(LibName, CallingConvention = CallingConvention.Cdecl)]
    [return: MarshalAs(UnmanagedType.I1)]
    public static extern bool nova64_shutdown();

    [DllImport(LibName, CallingConvention = CallingConvention.Cdecl)]
    [return: MarshalAs(UnmanagedType.I1)]
    public static extern bool nova64_is_finalized();

    [DllImport(LibName, CallingConvention = CallingConvention.Cdecl)]
    public static extern uint nova64_get_version();
}