/*
  SDL_image:  An example image loading library for use with SDL
  Copyright (C) 1997-2025 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.
*/

/* This is a WEBP image file loading framework */

#include "SDL_image.h"

#ifdef LOAD_WEBP

/*=============================================================================
        File: SDL_webp.c
     Purpose: A WEBP loader for the SDL library
    Revision:
  Created by: Michael Bonfils (Murlock) (26 November 2011)
              murlock42@gmail.com

=============================================================================*/

#include "SDL_endian.h"

#if !SDL_VERSION_ATLEAST(2,30,0)
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
#define SDL_PIXELFORMAT_RGBX32 SDL_PIXELFORMAT_RGBX8888
#else
#define SDL_PIXELFORMAT_RGBX32 SDL_PIXELFORMAT_XBGR8888
#endif
#endif

#ifdef macintosh
#define MACOS
#endif
#include <webp/decode.h>
#include <webp/demux.h>

static struct {
    int loaded;
    void *handle_libwebpdemux;
    void *handle_libwebp;
    VP8StatusCode (*WebPGetFeaturesInternal) (const uint8_t *data, size_t data_size, WebPBitstreamFeatures* features, int decoder_abi_version);
    uint8_t* (*WebPDecodeRGBInto) (const uint8_t* data, size_t data_size, uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
    uint8_t* (*WebPDecodeRGBAInto) (const uint8_t* data, size_t data_size, uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
    WebPDemuxer* (*WebPDemuxInternal)(const WebPData* data, int allow_partial, WebPDemuxState* state, int version);
    int (*WebPDemuxGetFrame)(const WebPDemuxer *dmux, int frame_number, WebPIterator *iter);
    int (*WebPDemuxNextFrame)(WebPIterator *iter);
    void (*WebPDemuxReleaseIterator)(WebPIterator *iter);
    uint32_t (*WebPDemuxGetI)(const WebPDemuxer* dmux, WebPFormatFeature feature);
    void (*WebPDemuxDelete)(WebPDemuxer* dmux);
} lib;

#if defined(LOAD_WEBP_DYNAMIC) && defined(LOAD_WEBPDEMUX_DYNAMIC)
#define FUNCTION_LOADER_LIBWEBP(FUNC, SIG) \
    lib.FUNC = (SIG) SDL_LoadFunction(lib.handle_libwebp, #FUNC); \
    if (lib.FUNC == NULL) { SDL_UnloadObject(lib.handle_libwebp); return -1; }
#define FUNCTION_LOADER_LIBWEBPDEMUX(FUNC, SIG) \
    lib.FUNC = (SIG) SDL_LoadFunction(lib.handle_libwebpdemux, #FUNC); \
    if (lib.FUNC == NULL) { SDL_UnloadObject(lib.handle_libwebpdemux); return -1; }
#else
#define FUNCTION_LOADER_LIBWEBP(FUNC, SIG) \
    lib.FUNC = FUNC; \
    if (lib.FUNC == NULL) { IMG_SetError("Missing webp.framework"); return -1; }
#define FUNCTION_LOADER_LIBWEBPDEMUX(FUNC, SIG) \
    lib.FUNC = FUNC; \
    if (lib.FUNC == NULL) { IMG_SetError("Missing webpdemux.framework"); return -1; }
#endif

#ifdef __APPLE__
    /* Need to turn off optimizations so weak framework load check works */
    __attribute__ ((optnone))
#endif
int IMG_InitWEBP()
{
    if (lib.loaded == 0) {
#if defined(LOAD_WEBP_DYNAMIC) && defined(LOAD_WEBPDEMUX_DYNAMIC)
        lib.handle_libwebpdemux = SDL_LoadObject(LOAD_WEBPDEMUX_DYNAMIC);
        if (lib.handle_libwebpdemux == NULL) {
            return -1;
        }
        lib.handle_libwebp = SDL_LoadObject(LOAD_WEBP_DYNAMIC);
        if (lib.handle_libwebp == NULL) {
            return -1;
        }
#endif
        FUNCTION_LOADER_LIBWEBP(WebPGetFeaturesInternal, VP8StatusCode (*) (const uint8_t *data, size_t data_size, WebPBitstreamFeatures* features, int decoder_abi_version))
        FUNCTION_LOADER_LIBWEBP(WebPDecodeRGBInto, uint8_t * (*) (const uint8_t* data, size_t data_size, uint8_t* output_buffer, size_t output_buffer_size, int output_stride))
        FUNCTION_LOADER_LIBWEBP(WebPDecodeRGBAInto, uint8_t * (*) (const uint8_t* data, size_t data_size, uint8_t* output_buffer, size_t output_buffer_size, int output_stride))
        FUNCTION_LOADER_LIBWEBPDEMUX(WebPDemuxInternal, WebPDemuxer* (*)(const WebPData*, int, WebPDemuxState*, int))
        FUNCTION_LOADER_LIBWEBPDEMUX(WebPDemuxGetFrame, int (*)(const WebPDemuxer *dmux, int frame_number, WebPIterator *iter))
        FUNCTION_LOADER_LIBWEBPDEMUX(WebPDemuxNextFrame, int (*)(WebPIterator *iter))
        FUNCTION_LOADER_LIBWEBPDEMUX(WebPDemuxReleaseIterator, void (*)(WebPIterator *iter))
        FUNCTION_LOADER_LIBWEBPDEMUX(WebPDemuxGetI, uint32_t (*)(const WebPDemuxer* dmux, WebPFormatFeature feature))
        FUNCTION_LOADER_LIBWEBPDEMUX(WebPDemuxDelete, void (*)(WebPDemuxer* dmux))
    }
    ++lib.loaded;

    return 0;
}
void IMG_QuitWEBP()
{
    if (lib.loaded == 0) {
        return;
    }
    if (lib.loaded == 1) {
#if defined(LOAD_WEBP_DYNAMIC) && defined(LOAD_WEBPDEMUX_DYNAMIC)
        SDL_UnloadObject(lib.handle_libwebp);
        SDL_UnloadObject(lib.handle_libwebpdemux);
#endif
    }
    --lib.loaded;
}

static int webp_getinfo (SDL_RWops *src, int *datasize) {
    Sint64 start;
    int is_WEBP;
    Uint8 magic[20];

    if (!src) {
        return 0;
    }
    start = SDL_RWtell(src);
    is_WEBP = 0;
    if (SDL_RWread(src, magic, 1, sizeof(magic)) == sizeof(magic)) {
        if (magic[ 0] == 'R' &&
            magic[ 1] == 'I' &&
            magic[ 2] == 'F' &&
            magic[ 3] == 'F' &&
            magic[ 8] == 'W' &&
            magic[ 9] == 'E' &&
            magic[10] == 'B' &&
            magic[11] == 'P' &&
            magic[12] == 'V' &&
            magic[13] == 'P' &&
            magic[14] == '8' &&
           (magic[15] == ' ' || magic[15] == 'X' || magic[15] == 'L')) {
            is_WEBP = 1;
            if (datasize) {
                *datasize = (int)(SDL_RWseek(src, 0, RW_SEEK_END) - start);
            }
        }
    }
    SDL_RWseek(src, start, RW_SEEK_SET);
    return(is_WEBP);
}

/* See if an image is contained in a data source */
int IMG_isWEBP(SDL_RWops *src)
{
    return webp_getinfo(src, NULL);
}

SDL_Surface *IMG_LoadWEBP_RW(SDL_RWops *src)
{
    Sint64 start;
    const char *error = NULL;
    SDL_Surface *surface = NULL;
    Uint32 format;
    WebPBitstreamFeatures features;
    int raw_data_size;
    uint8_t *raw_data = NULL;
    int r;
    uint8_t *ret;

    if (!src) {
        /* The error message has been set in SDL_RWFromFile */
        return NULL;
    }

    start = SDL_RWtell(src);

    if ((IMG_Init(IMG_INIT_WEBP) & IMG_INIT_WEBP) == 0) {
        goto error;
    }

    raw_data_size = -1;
    if (!webp_getinfo(src, &raw_data_size)) {
        error = "Invalid WEBP";
        goto error;
    }

    raw_data = (uint8_t*) SDL_malloc(raw_data_size);
    if (raw_data == NULL) {
        error = "Failed to allocate enough buffer for WEBP";
        goto error;
    }

    r = (int)SDL_RWread(src, raw_data, 1, raw_data_size);
    if (r != raw_data_size) {
        error = "Failed to read WEBP";
        goto error;
    }

#if 0
    {/* extract size of picture, not interesting since we don't know about alpha channel */
      int width = -1, height = -1;
      if (!WebPGetInfo(raw_data, raw_data_size, &width, &height)) {
          printf("WebPGetInfo has failed\n");
          return NULL;
    } }
#endif

    if (lib.WebPGetFeaturesInternal(raw_data, raw_data_size, &features, WEBP_DECODER_ABI_VERSION) != VP8_STATUS_OK) {
        error = "WebPGetFeatures has failed";
        goto error;
    }

    if (features.has_alpha) {
       format = SDL_PIXELFORMAT_RGBA32;
    } else {
       format = SDL_PIXELFORMAT_RGB24;
    }

    surface = SDL_CreateRGBSurfaceWithFormat(0, features.width, features.height, 0, format);
    if (surface == NULL) {
        error = "Failed to allocate SDL_Surface";
        goto error;
    }

    if (features.has_alpha) {
        ret = lib.WebPDecodeRGBAInto(raw_data, raw_data_size, (uint8_t *)surface->pixels, surface->pitch * surface->h,  surface->pitch);
    } else {
        ret = lib.WebPDecodeRGBInto(raw_data, raw_data_size, (uint8_t *)surface->pixels, surface->pitch * surface->h,  surface->pitch);
    }

    if (!ret) {
        error = "Failed to decode WEBP";
        goto error;
    }

    if (raw_data) {
        SDL_free(raw_data);
    }

    return surface;


error:
    if (raw_data) {
        SDL_free(raw_data);
    }

    if (surface) {
        SDL_FreeSurface(surface);
    }

    if (error) {
        IMG_SetError("%s", error);
    }

    SDL_RWseek(src, start, RW_SEEK_SET);
    return NULL;
}

IMG_Animation *IMG_LoadWEBPAnimation_RW(SDL_RWops *src)
{
    Sint64 start;
    const char *error = NULL;
    WebPBitstreamFeatures features;
    struct WebPDemuxer *demuxer = NULL;
    WebPIterator iter;
    IMG_Animation *anim = NULL;
    int raw_data_size;
    uint8_t *raw_data = NULL;
    WebPData wd;
    uint32_t bgcolor;
    SDL_Surface *canvas = NULL;

    // State machine variables for correct disposal handling
    int prev_dispose = WEBP_MUX_DISPOSE_NONE;
    SDL_Rect prev_rect;
    uint32_t clear_color;

    if (!src) {
        /* The error message has been set in SDL_RWFromFile */
        return NULL;
    }

    start = SDL_RWtell(src);

    if ((IMG_Init(IMG_INIT_WEBP) & IMG_INIT_WEBP) == 0) {
        goto error;
    }

    raw_data_size = -1;
    if (!webp_getinfo(src, &raw_data_size)) {
        error = "Invalid WEBP Animation";
        goto error;
    }

    raw_data = (uint8_t*) SDL_malloc(raw_data_size);
    if (raw_data == NULL) {
        goto error;
    }

    if ((int)SDL_RWread(src, raw_data, 1, raw_data_size) != raw_data_size) {
        goto error;
    }

    if (lib.WebPGetFeaturesInternal(raw_data, raw_data_size, &features, WEBP_DECODER_ABI_VERSION) != VP8_STATUS_OK) {
        error = "WebPGetFeatures() failed";
        goto error;
    }

    wd.size = raw_data_size;
    wd.bytes = raw_data;
    demuxer = lib.WebPDemuxInternal(&wd, 0, NULL, WEBP_DEMUX_ABI_VERSION);
    if (!demuxer) {
        error = "WebPDemux() failed";
        goto error;
    }

    anim = (IMG_Animation *)SDL_calloc(1, sizeof(*anim));
    if (!anim) {
        goto error;
    }
    anim->w = features.width;
    anim->h = features.height;
    anim->count = lib.WebPDemuxGetI(demuxer, WEBP_FF_FRAME_COUNT);
    anim->frames = (SDL_Surface **)SDL_calloc(anim->count, sizeof(*anim->frames));
    anim->delays = (int *)SDL_calloc(anim->count, sizeof(*anim->delays));
    if (!anim->frames || !anim->delays) {
        goto error;
    }

    canvas = SDL_CreateRGBSurfaceWithFormat(0, anim->w, anim->h, 0, features.has_alpha ? SDL_PIXELFORMAT_RGBA32 : SDL_PIXELFORMAT_RGBX32);
    if (!canvas) {
        goto error;
    }

    /* Background color is BGRA byte order according to the spec */
    bgcolor = lib.WebPDemuxGetI(demuxer, WEBP_FF_BACKGROUND_COLOR);
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
    bgcolor = SDL_MapRGBA(canvas->format,
                          (bgcolor >> 8) & 0xFF,
                          (bgcolor >> 16) & 0xFF,
                          (bgcolor >> 24) & 0xFF,
                          (bgcolor >> 0) & 0xFF);
#else
    bgcolor = SDL_MapRGBA(canvas->format,
                          (bgcolor >> 16) & 0xFF,
                          (bgcolor >> 8) & 0xFF,
                          (bgcolor >> 0) & 0xFF,
                          (bgcolor >> 24) & 0xFF);
#endif

    /* Initialize canvas - use bgcolor for non-alpha format, transparency for alpha */
    if (features.has_alpha) {
        clear_color = SDL_MapRGBA(canvas->format, 0, 0, 0, 0);
    } else {
        clear_color = bgcolor;
    }

    SDL_FillRect(canvas, NULL, clear_color);
    SDL_zero(prev_rect);

    SDL_zero(iter);
    if (lib.WebPDemuxGetFrame(demuxer, 1, &iter)) {
        do {
            SDL_Surface* curr;
            SDL_Rect dst;
            int frame_idx = (iter.frame_num - 1);
            if (frame_idx < 0 || frame_idx >= anim->count) {
                continue;
            }

            /* Set up destination rect for current frame */
            dst.x = iter.x_offset;
            dst.y = iter.y_offset;
            dst.w = iter.width;
            dst.h = iter.height;

            /* Handle disposal of the PREVIOUS frame before drawing the current one */
            if (prev_dispose == WEBP_MUX_DISPOSE_BACKGROUND) {
                SDL_FillRect(canvas, &prev_rect, clear_color);
            }

            curr = SDL_CreateRGBSurfaceWithFormat(0, iter.width, iter.height, 0, SDL_PIXELFORMAT_RGBA32);
            if (!curr) {
                goto error;
            }

            if (!lib.WebPDecodeRGBAInto(iter.fragment.bytes,
                                        iter.fragment.size,
                                        (uint8_t *)curr->pixels,
                                        curr->pitch * curr->h,
                                        curr->pitch)) {
                error = "WebPDecodeRGBAInto() failed";
                SDL_FreeSurface(curr);
                goto error;
            }

            /* Set blend mode. WEBP_MUX_NO_BLEND overwrites pixels, avoiding the need to manual clear */
            if (iter.blend_method == WEBP_MUX_BLEND) {
                SDL_SetSurfaceBlendMode(curr, SDL_BLENDMODE_BLEND);
            } else {
                SDL_SetSurfaceBlendMode(curr, SDL_BLENDMODE_NONE);
            }

            SDL_BlitSurface(curr, NULL, canvas, &dst);
            SDL_FreeSurface(curr);

            /* Store complete frame state */
            anim->frames[frame_idx] = SDL_DuplicateSurface(canvas);
            anim->delays[frame_idx] = iter.duration;

            /* Update state for the next frame's disposal logic */
            prev_dispose = iter.dispose_method;
            prev_rect = dst;

        } while (lib.WebPDemuxNextFrame(&iter));

        lib.WebPDemuxReleaseIterator(&iter);
    }

    SDL_FreeSurface(canvas);

    lib.WebPDemuxDelete(demuxer);

    SDL_free(raw_data);

    return anim;

error:
    if (canvas) {
        SDL_FreeSurface(canvas);
    }
    if (anim) {
        IMG_FreeAnimation(anim);
    }
    if (demuxer) {
        lib.WebPDemuxDelete(demuxer);
    }
    if (raw_data) {
        SDL_free(raw_data);
    }

    if (error) {
        IMG_SetError("%s", error);
    }
    SDL_RWseek(src, start, RW_SEEK_SET);
    return NULL;
}

#else
#if _MSC_VER >= 1300
#pragma warning(disable : 4100) /* warning C4100: 'op' : unreferenced formal parameter */
#endif

int IMG_InitWEBP()
{
    IMG_SetError("WEBP images are not supported");
    return -1;
}

void IMG_QuitWEBP()
{
}

/* See if an image is contained in a data source */
int IMG_isWEBP(SDL_RWops *src)
{
    return 0;
}

/* Load a WEBP type image from an SDL datasource */
SDL_Surface *IMG_LoadWEBP_RW(SDL_RWops *src)
{
    return NULL;
}

IMG_Animation *IMG_LoadWEBPAnimation_RW(SDL_RWops *src) {
    return NULL;
}

#endif /* LOAD_WEBP */
