/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_internal.h"

#ifdef SDL_VIDEO_DRIVER_RISCOS

#include "../SDL_sysvideo.h"
#include "SDL_riscosframebuffer_c.h"
#include "SDL_riscosvideo.h"
#include "SDL_riscoswindow.h"

#include <kernel.h>
#include <swis.h>

bool RISCOS_CreateWindowFramebuffer(SDL_VideoDevice *_this, SDL_Window *window, SDL_PixelFormat *format, void **pixels, int *pitch)
{
    SDL_WindowData *internal = window->internal;
    const char *sprite_name = "display";
    unsigned int sprite_mode;
    _kernel_oserror *error;
    _kernel_swi_regs regs;
    const SDL_DisplayMode *mode;
    int size;
    int w, h;

    SDL_GetWindowSizeInPixels(window, &w, &h);

    // Free the old framebuffer surface
    RISCOS_DestroyWindowFramebuffer(_this, window);

    // Create a new one
    mode = SDL_GetCurrentDisplayMode(SDL_GetDisplayForWindow(window));
    if ((SDL_ISPIXELFORMAT_PACKED(mode->format) || SDL_ISPIXELFORMAT_ARRAY(mode->format))) {
        *format = mode->format;
        sprite_mode = (unsigned int)mode->internal;
    } else {
        *format = SDL_PIXELFORMAT_XBGR8888;
        sprite_mode = (1 | (90 << 1) | (90 << 14) | (6 << 27));
    }

    // Calculate pitch
    *pitch = (((w * SDL_BYTESPERPIXEL(*format)) + 3) & ~3);

    // Allocate the sprite area
    size = sizeof(sprite_area) + sizeof(sprite_header) + ((*pitch) * h);
    internal->fb_area = SDL_malloc(size);
    if (!internal->fb_area) {
        return false;
    }

    internal->fb_area->size = size;
    internal->fb_area->count = 0;
    internal->fb_area->start = 16;
    internal->fb_area->end = 16;

    // Create the actual image
    regs.r[0] = 256 + 15;
    regs.r[1] = (int)internal->fb_area;
    regs.r[2] = (int)sprite_name;
    regs.r[3] = 0;
    regs.r[4] = w;
    regs.r[5] = h;
    regs.r[6] = sprite_mode;
    error = _kernel_swi(OS_SpriteOp, &regs, &regs);
    if (error) {
        SDL_free(internal->fb_area);
        return SDL_SetError("Unable to create sprite: %s (%i)", error->errmess, error->errnum);
    }

    internal->fb_sprite = (sprite_header *)(((Uint8 *)internal->fb_area) + internal->fb_area->start);
    *pixels = ((Uint8 *)internal->fb_sprite) + internal->fb_sprite->image_offset;

    return true;
}

bool RISCOS_UpdateWindowFramebuffer(SDL_VideoDevice *_this, SDL_Window *window, const SDL_Rect *rects, int numrects)
{
    SDL_WindowData *internal = window->internal;
    _kernel_swi_regs regs;
    _kernel_oserror *error;

    regs.r[0] = 512 + 52;
    regs.r[1] = (int)internal->fb_area;
    regs.r[2] = (int)internal->fb_sprite;
    regs.r[3] = 0; // window->x << 1;
    regs.r[4] = 0; // window->y << 1;
    regs.r[5] = 0x50;
    regs.r[6] = 0;
    regs.r[7] = 0;
    error = _kernel_swi(OS_SpriteOp, &regs, &regs);
    if (error) {
        return SDL_SetError("OS_SpriteOp 52 failed: %s (%i)", error->errmess, error->errnum);
    }

    return true;
}

void RISCOS_DestroyWindowFramebuffer(SDL_VideoDevice *_this, SDL_Window *window)
{
    SDL_WindowData *internal = window->internal;

    if (internal->fb_area) {
        SDL_free(internal->fb_area);
        internal->fb_area = NULL;
    }
    internal->fb_sprite = NULL;
}

#endif // SDL_VIDEO_DRIVER_RISCOS
