/*
  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.
*/
#include <SDL3/SDL_test_common.h>
#include <SDL3/SDL_main.h>

#ifdef HAVE_OPENGL

#include <stdlib.h>

#include <SDL3/SDL_opengl.h>

typedef struct GL_Context
{
#define SDL_PROC(ret, func, params) ret (APIENTRY *func) params;
#include "../src/render/opengl/SDL_glfuncs.h"
#undef SDL_PROC
} GL_Context;

/* Undefine this if you want a flat cube instead of a rainbow cube */
#define SHADED_CUBE

static SDLTest_CommonState *state;
static SDL_GLContext context;
static GL_Context ctx;
static bool suspend_when_occluded;

static bool LoadContext(GL_Context *data)
{
#ifdef SDL_VIDEO_DRIVER_UIKIT
#define __SDL_NOGETPROCADDR__
#elif defined(SDL_VIDEO_DRIVER_ANDROID)
#define __SDL_NOGETPROCADDR__
#endif

#if defined __SDL_NOGETPROCADDR__
#define SDL_PROC(ret, func, params) data->func = func;
#else
#define SDL_PROC(ret, func, params)                                                         \
    do {                                                                                    \
        data->func = (ret (APIENTRY *) params)SDL_GL_GetProcAddress(#func);                 \
        if (!data->func) {                                                                  \
            return SDL_SetError("Couldn't load GL function %s: %s", #func, SDL_GetError()); \
        }                                                                                   \
    } while (0);
#endif /* __SDL_NOGETPROCADDR__ */

#include "../src/render/opengl/SDL_glfuncs.h"
#undef SDL_PROC
    return true;
}

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void quit(int rc)
{
    if (context) {
        /* SDL_GL_MakeCurrent(0, NULL); */ /* doesn't do anything */
        SDL_GL_DestroyContext(context);
    }
    SDLTest_CommonQuit(state);
    /* Let 'main()' return normally */
    if (rc != 0) {
        exit(rc);
    }
}

static void Render(void)
{
    static float color[8][3] = {
        { 1.0, 1.0, 0.0 },
        { 1.0, 0.0, 0.0 },
        { 0.0, 0.0, 0.0 },
        { 0.0, 1.0, 0.0 },
        { 0.0, 1.0, 1.0 },
        { 1.0, 1.0, 1.0 },
        { 1.0, 0.0, 1.0 },
        { 0.0, 0.0, 1.0 }
    };
    static float cube[8][3] = {
        { 0.5, 0.5, -0.5 },
        { 0.5, -0.5, -0.5 },
        { -0.5, -0.5, -0.5 },
        { -0.5, 0.5, -0.5 },
        { -0.5, 0.5, 0.5 },
        { 0.5, 0.5, 0.5 },
        { 0.5, -0.5, 0.5 },
        { -0.5, -0.5, 0.5 }
    };

    /* Do our drawing, too. */
    ctx.glClearColor(0.0, 0.0, 0.0, 0.0 /* used with --transparent */);
    ctx.glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    ctx.glBegin(GL_QUADS);

#ifdef SHADED_CUBE
    ctx.glColor3fv(color[0]);
    ctx.glVertex3fv(cube[0]);
    ctx.glColor3fv(color[1]);
    ctx.glVertex3fv(cube[1]);
    ctx.glColor3fv(color[2]);
    ctx.glVertex3fv(cube[2]);
    ctx.glColor3fv(color[3]);
    ctx.glVertex3fv(cube[3]);

    ctx.glColor3fv(color[3]);
    ctx.glVertex3fv(cube[3]);
    ctx.glColor3fv(color[4]);
    ctx.glVertex3fv(cube[4]);
    ctx.glColor3fv(color[7]);
    ctx.glVertex3fv(cube[7]);
    ctx.glColor3fv(color[2]);
    ctx.glVertex3fv(cube[2]);

    ctx.glColor3fv(color[0]);
    ctx.glVertex3fv(cube[0]);
    ctx.glColor3fv(color[5]);
    ctx.glVertex3fv(cube[5]);
    ctx.glColor3fv(color[6]);
    ctx.glVertex3fv(cube[6]);
    ctx.glColor3fv(color[1]);
    ctx.glVertex3fv(cube[1]);

    ctx.glColor3fv(color[5]);
    ctx.glVertex3fv(cube[5]);
    ctx.glColor3fv(color[4]);
    ctx.glVertex3fv(cube[4]);
    ctx.glColor3fv(color[7]);
    ctx.glVertex3fv(cube[7]);
    ctx.glColor3fv(color[6]);
    ctx.glVertex3fv(cube[6]);

    ctx.glColor3fv(color[5]);
    ctx.glVertex3fv(cube[5]);
    ctx.glColor3fv(color[0]);
    ctx.glVertex3fv(cube[0]);
    ctx.glColor3fv(color[3]);
    ctx.glVertex3fv(cube[3]);
    ctx.glColor3fv(color[4]);
    ctx.glVertex3fv(cube[4]);

    ctx.glColor3fv(color[6]);
    ctx.glVertex3fv(cube[6]);
    ctx.glColor3fv(color[1]);
    ctx.glVertex3fv(cube[1]);
    ctx.glColor3fv(color[2]);
    ctx.glVertex3fv(cube[2]);
    ctx.glColor3fv(color[7]);
    ctx.glVertex3fv(cube[7]);
#else  /* flat cube */
    ctx.glColor3f(1.0, 0.0, 0.0);
    ctx.glVertex3fv(cube[0]);
    ctx.glVertex3fv(cube[1]);
    ctx.glVertex3fv(cube[2]);
    ctx.glVertex3fv(cube[3]);

    ctx.glColor3f(0.0, 1.0, 0.0);
    ctx.glVertex3fv(cube[3]);
    ctx.glVertex3fv(cube[4]);
    ctx.glVertex3fv(cube[7]);
    ctx.glVertex3fv(cube[2]);

    ctx.glColor3f(0.0, 0.0, 1.0);
    ctx.glVertex3fv(cube[0]);
    ctx.glVertex3fv(cube[5]);
    ctx.glVertex3fv(cube[6]);
    ctx.glVertex3fv(cube[1]);

    ctx.glColor3f(0.0, 1.0, 1.0);
    ctx.glVertex3fv(cube[5]);
    ctx.glVertex3fv(cube[4]);
    ctx.glVertex3fv(cube[7]);
    ctx.glVertex3fv(cube[6]);

    ctx.glColor3f(1.0, 1.0, 0.0);
    ctx.glVertex3fv(cube[5]);
    ctx.glVertex3fv(cube[0]);
    ctx.glVertex3fv(cube[3]);
    ctx.glVertex3fv(cube[4]);

    ctx.glColor3f(1.0, 0.0, 1.0);
    ctx.glVertex3fv(cube[6]);
    ctx.glVertex3fv(cube[1]);
    ctx.glVertex3fv(cube[2]);
    ctx.glVertex3fv(cube[7]);
#endif /* SHADED_CUBE */

    ctx.glEnd();

    ctx.glMatrixMode(GL_MODELVIEW);
    ctx.glRotatef(5.0, 1.0, 1.0, 1.0);
}

static void LogSwapInterval(void)
{
    int interval = 0;
    if (SDL_GL_GetSwapInterval(&interval)) {
       SDL_Log("Swap Interval : %d\n", interval);
    } else {
       SDL_Log("Swap Interval : %d error: %s\n", interval, SDL_GetError());
    }
}

int main(int argc, char *argv[])
{
    int fsaa, accel;
    int value;
    int i, done;
    const SDL_DisplayMode *mode;
    SDL_Event event;
    Uint64 then, now;
    Uint32 frames;
    int dw, dh;
    int swap_interval = 0;

    /* Initialize parameters */
    fsaa = 0;
    accel = -1;

    /* Initialize test framework */
    state = SDLTest_CommonCreateState(argv, SDL_INIT_VIDEO);
    if (!state) {
        return 1;
    }

    for (i = 1; i < argc;) {
        int consumed;

        consumed = SDLTest_CommonArg(state, i);
        if (consumed == 0) {
            if (SDL_strcasecmp(argv[i], "--fsaa") == 0 && i + 1 < argc) {
                fsaa = SDL_atoi(argv[i + 1]);
                consumed = 2;
            } else if (SDL_strcasecmp(argv[i], "--accel") == 0 && i + 1 < argc) {
                accel = SDL_atoi(argv[i + 1]);
                consumed = 2;
            } else if(SDL_strcasecmp(argv[i], "--suspend-when-occluded") == 0) {
                suspend_when_occluded = true;
                consumed = 1;
            } else {
                consumed = -1;
            }
        }
        if (consumed < 0) {
            static const char *options[] = { "[--fsaa n]", "[--accel n]", "[--suspend-when-occluded]", NULL };
            SDLTest_CommonLogUsage(state, argv[0], options);
            quit(1);
        }
        i += consumed;
    }

    /* Set OpenGL parameters */
    state->window_flags |= SDL_WINDOW_OPENGL;
    state->gl_red_size = 5;
    state->gl_green_size = 5;
    state->gl_blue_size = 5;
    state->gl_depth_size = 16;
    state->gl_double_buffer = 1;
    if (fsaa) {
        state->gl_multisamplebuffers = 1;
        state->gl_multisamplesamples = fsaa;
    }
    if (accel >= 0) {
        state->gl_accelerated = accel;
    }

    if (!SDLTest_CommonInit(state)) {
        quit(2);
    }

    /* Create OpenGL context */
    context = SDL_GL_CreateContext(state->windows[0]);
    if (!context) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "SDL_GL_CreateContext(): %s\n", SDL_GetError());
        quit(2);
    }

    /* Important: call this *after* creating the context */
    if (!LoadContext(&ctx)) {
        SDL_Log("Could not load GL functions\n");
        quit(2);
        return 0;
    }

    SDL_GL_SetSwapInterval(state->render_vsync);
    swap_interval = state->render_vsync;

    mode = SDL_GetCurrentDisplayMode(SDL_GetPrimaryDisplay());
    if (mode) {
        SDL_Log("Screen BPP    : %d\n", SDL_BITSPERPIXEL(mode->format));
    }

    LogSwapInterval();

    SDL_GetWindowSize(state->windows[0], &dw, &dh);
    SDL_Log("Window Size   : %d,%d\n", dw, dh);
    SDL_GetWindowSizeInPixels(state->windows[0], &dw, &dh);
    SDL_Log("Draw Size     : %d,%d\n", dw, dh);
    SDL_Log("\n");
    SDL_Log("Vendor        : %s\n", ctx.glGetString(GL_VENDOR));
    SDL_Log("Renderer      : %s\n", ctx.glGetString(GL_RENDERER));
    SDL_Log("Version       : %s\n", ctx.glGetString(GL_VERSION));
    SDL_Log("Extensions    : %s\n", ctx.glGetString(GL_EXTENSIONS));
    SDL_Log("\n");

    if (SDL_GL_GetAttribute(SDL_GL_RED_SIZE, &value)) {
        SDL_Log("SDL_GL_RED_SIZE: requested %d, got %d\n", 5, value);
    } else {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to get SDL_GL_RED_SIZE: %s\n", SDL_GetError());
    }
    if (SDL_GL_GetAttribute(SDL_GL_GREEN_SIZE, &value)) {
        SDL_Log("SDL_GL_GREEN_SIZE: requested %d, got %d\n", 5, value);
    } else {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to get SDL_GL_GREEN_SIZE: %s\n", SDL_GetError());
    }
    if (SDL_GL_GetAttribute(SDL_GL_BLUE_SIZE, &value)) {
        SDL_Log("SDL_GL_BLUE_SIZE: requested %d, got %d\n", 5, value);
    } else {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to get SDL_GL_BLUE_SIZE: %s\n", SDL_GetError());
    }
    if (SDL_GL_GetAttribute(SDL_GL_DEPTH_SIZE, &value)) {
        SDL_Log("SDL_GL_DEPTH_SIZE: requested %d, got %d\n", 16, value);
    } else {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to get SDL_GL_DEPTH_SIZE: %s\n", SDL_GetError());
    }
    if (fsaa) {
        if (SDL_GL_GetAttribute(SDL_GL_MULTISAMPLEBUFFERS, &value)) {
            SDL_Log("SDL_GL_MULTISAMPLEBUFFERS: requested 1, got %d\n", value);
        } else {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to get SDL_GL_MULTISAMPLEBUFFERS: %s\n",
                         SDL_GetError());
        }
        if (SDL_GL_GetAttribute(SDL_GL_MULTISAMPLESAMPLES, &value)) {
            SDL_Log("SDL_GL_MULTISAMPLESAMPLES: requested %d, got %d\n", fsaa,
                    value);
        } else {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to get SDL_GL_MULTISAMPLESAMPLES: %s\n",
                         SDL_GetError());
        }
    }
    if (accel >= 0) {
        if (SDL_GL_GetAttribute(SDL_GL_ACCELERATED_VISUAL, &value)) {
            SDL_Log("SDL_GL_ACCELERATED_VISUAL: requested %d, got %d\n", accel,
                    value);
        } else {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to get SDL_GL_ACCELERATED_VISUAL: %s\n",
                         SDL_GetError());
        }
    }

    /* Set rendering settings */
    ctx.glMatrixMode(GL_PROJECTION);
    ctx.glLoadIdentity();
    ctx.glOrtho(-2.0, 2.0, -2.0, 2.0, -20.0, 20.0);
    ctx.glMatrixMode(GL_MODELVIEW);
    ctx.glLoadIdentity();
    ctx.glEnable(GL_DEPTH_TEST);
    ctx.glDepthFunc(GL_LESS);
    ctx.glShadeModel(GL_SMOOTH);

    /* Main render loop */
    frames = 0;
    then = SDL_GetTicks();
    done = 0;
    while (!done) {
        bool update_swap_interval = false;
        int active_windows = 0;

        /* Check for events */
        ++frames;
        while (SDL_PollEvent(&event)) {
            SDLTest_CommonEvent(state, &event, &done);
            if (event.type == SDL_EVENT_KEY_DOWN) {
                if (event.key.key == SDLK_O) {
                    swap_interval--;
                    update_swap_interval = true;
                } else if (event.key.key == SDLK_P) {
                    swap_interval++;
                    update_swap_interval = true;
                }
            }
        }

        if (update_swap_interval) {
            SDL_Log("Swap interval to be set to %d\n", swap_interval);
        }

        for (i = 0; i < state->num_windows; ++i) {
            int w, h;
            if (state->windows[i] == NULL ||
                (suspend_when_occluded && (SDL_GetWindowFlags(state->windows[i]) & SDL_WINDOW_OCCLUDED))) {
                continue;
            }
            ++active_windows;
            SDL_GL_MakeCurrent(state->windows[i], context);
            if (update_swap_interval) {
                SDL_GL_SetSwapInterval(swap_interval);
                LogSwapInterval();
            }
            SDL_GetWindowSizeInPixels(state->windows[i], &w, &h);
            ctx.glViewport(0, 0, w, h);
            Render();
            SDL_GL_SwapWindow(state->windows[i]);
        }

        /* If all windows are occluded, throttle event polling to 15hz. */
        if (!active_windows) {
            SDL_DelayNS(SDL_NS_PER_SECOND / 15);
        }
    }

    /* Print out some timing information */
    now = SDL_GetTicks();
    if (now > then) {
        SDL_Log("%2.2f frames per second\n",
                ((double)frames * 1000) / (now - then));
    }
    quit(0);
    return 0;
}

#else /* HAVE_OPENGL */

int main(int argc, char *argv[])
{
    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "No OpenGL support on this system\n");
    return 1;
}

#endif /* HAVE_OPENGL */