/*
 * The SDL 1.2 calls Fish Fillets NG uses, on top of SDL2 (see compat/SDL.h).
 * Copyright (C) 2026 FredyGames. GNU GPL version 2 or later, like Fish Fillets NG.
 */
#include <SDL2/SDL.h>
#undef SDL_SetColorKey
#undef SDL_PollEvent
#undef SDL_GetKeyName
#include <string.h>

extern "C" {

static SDL_Window *window = NULL;
static SDL_Renderer *renderer = NULL;
static SDL_Texture *texture = NULL;
static SDL_Surface *screen = NULL;
static Uint8 keystate[1024];

static int fold(SDL_Keycode sym)
{
    if (sym & SDLK_SCANCODE_MASK) {
        return 256 + (sym & ~SDLK_SCANCODE_MASK);
    }
    return sym < 256 ? sym : 0;
}

static SDL_Keycode unfold(int sym)
{
    if (sym >= 256) {
        return (SDL_Keycode)((sym - 256) | SDLK_SCANCODE_MASK);
    }
    return sym;
}

SDL_Surface *fy_SetVideoMode(int width, int height, int bpp, Uint32 flags)
{
    (void)bpp;
    (void)flags;
    if (window == NULL) {
        window = SDL_CreateWindow("", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height, 0);
        if (window == NULL) {
            return NULL;
        }
        renderer = SDL_CreateRenderer(window, -1, 0);
        if (renderer == NULL) {
            return NULL;
        }
    }
    else {
        SDL_SetWindowSize(window, width, height);
    }
    if (texture) {
        SDL_DestroyTexture(texture);
    }
    if (screen) {
        SDL_FreeSurface(screen);
    }
    screen = SDL_CreateRGBSurfaceWithFormat(0, width, height, 32, SDL_PIXELFORMAT_RGB888);
    texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGB888, SDL_TEXTUREACCESS_STREAMING, width, height);
    if (screen == NULL || texture == NULL) {
        return NULL;
    }
    return screen;
}

SDL_Surface *fy_GetVideoSurface(void)
{
    return screen;
}

int fy_Flip(SDL_Surface *s)
{
    if (s == NULL || texture == NULL) {
        return -1;
    }
    SDL_UpdateTexture(texture, NULL, s->pixels, s->pitch);
    SDL_RenderClear(renderer);
    SDL_RenderCopy(renderer, texture, NULL, NULL);
    SDL_RenderPresent(renderer);
    return 0;
}

void fy_WM_SetCaption(const char *title, const char *icon)
{
    (void)icon;
    if (window) {
        SDL_SetWindowTitle(window, title);
    }
}

Uint16 fy_Unicode(int sym, Uint16 mod)
{
    if (sym < 32 || sym > 126) {
        return sym == '\b' || sym == '\r' || sym == '\t' ? sym : 0;
    }
    bool shift = (mod & KMOD_SHIFT) != 0;
    if (sym >= 'a' && sym <= 'z') {
        bool caps = (mod & KMOD_CAPS) != 0;
        return (shift != caps) ? sym - 32 : sym;
    }
    if (shift) {
        static const char from[] = "1234567890-=[];'`\\,./";
        static const char to[] = "!@#$%^&*()_+{}:\"~|<>?";
        const char *p = strchr(from, sym);
        if (p && *p) {
            return to[p - from];
        }
    }
    return sym;
}

int fy_PollEvent(SDL_Event *event)
{
    while (SDL_PollEvent(event)) {
        if (event->type == SDL_KEYDOWN || event->type == SDL_KEYUP) {
            int sym = fold(event->key.keysym.sym);
            if (sym == 0) {
                continue;
            }
            keystate[sym] = event->type == SDL_KEYDOWN ? 1 : 0;
            event->key.keysym.sym = sym;
            return 1;
        }
        if (event->type == SDL_MOUSEBUTTONDOWN || event->type == SDL_MOUSEBUTTONUP
                || event->type == SDL_QUIT)
        {
            return 1;
        }
    }
    return 0;
}

Uint8 *fy_GetKeyState(int *numkeys)
{
    if (numkeys) {
        *numkeys = 1024;
    }
    return keystate;
}

const char *fy_GetKeyName(int sym)
{
    return SDL_GetKeyName(unfold(sym));
}

SDL_Surface *fy_DisplayFormat(SDL_Surface *surface)
{
    return SDL_ConvertSurface(surface, screen->format, 0);
}

SDL_Surface *fy_DisplayFormatAlpha(SDL_Surface *surface)
{
    return SDL_ConvertSurfaceFormat(surface, SDL_PIXELFORMAT_ARGB8888, 0);
}

int fy_SetColorKey(SDL_Surface *surface, Uint32 flag, Uint32 key)
{
    return SDL_SetColorKey(surface, (flag & 0x1000) ? SDL_TRUE : SDL_FALSE, key);
}

Uint32 fy_GetColorKey(SDL_Surface *surface)
{
    Uint32 key = 0;
    SDL_GetColorKey(surface, &key);
    return key;
}

int fy_SetAlpha(SDL_Surface *surface, Uint32 flag, Uint8 alpha)
{
    if (flag & 0x10000) {
        SDL_SetSurfaceBlendMode(surface, SDL_BLENDMODE_BLEND);
        return SDL_SetSurfaceAlphaMod(surface, alpha);
    }
    SDL_SetSurfaceAlphaMod(surface, 255);
    return SDL_SetSurfaceBlendMode(surface, SDL_BLENDMODE_NONE);
}

void fy_WarpMouse(Uint16 x, Uint16 y)
{
    if (window) {
        SDL_WarpMouseInWindow(window, x, y);
    }
}

}