/* SPDX-License-Identifier: Unlicense
 */

#include "graphics.hpp"
#include "vdp.hpp"

#include <cstdlib>
#include <cassert>

static size_t kIntegerScaling = 2;

Graphics::Graphics()
{
#if HAS_GRAPHICS == 1
    SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);

    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
        return;
    }
    _window = SDL_CreateWindow("Gut (SEGA MD/G emulator)",
                              SDL_WINDOWPOS_UNDEFINED,
                              SDL_WINDOWPOS_UNDEFINED,
                              VDP(0).kRenderWidth * kIntegerScaling,
                              VDP(0).kRenderHeight * kIntegerScaling,
                              SDL_WINDOW_RESIZABLE);
    if (!_window) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create window: %s\n", SDL_GetError());
        SDL_Quit();
        return;
    }
    _renderer = SDL_CreateRenderer(_window, -1, 0);
    if (!_renderer) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create renderer: %s\n", SDL_GetError());
        SDL_Quit();
        return;
    }
    _render_texture = SDL_CreateTexture(
            _renderer,
            SDL_PIXELFORMAT_ARGB8888,
            SDL_TEXTUREACCESS_STREAMING,
            VDP(0).kRenderWidth,
            VDP(0).kRenderHeight);
    if (!_render_texture) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create texture: %s\n", SDL_GetError());
        SDL_Quit();
        return;
    }
    if (SDL_GL_SetSwapInterval(-1)) {
        printf("Couldn't set adaptive VSync: falling back to hard VSync\n");
        if (SDL_GL_SetSwapInterval(1)) {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't set up VSync: %s\n", SDL_GetError());
            SDL_Quit();
            return;
        }
    }
#endif
    _initialized_ok = true;
}

Graphics::~Graphics()
{
#if HAS_GRAPHICS == 1
    if (_window) {
        if (_renderer) {
            if (_render_texture) {
                SDL_DestroyTexture(_render_texture);
            }
            SDL_DestroyRenderer(_renderer);
        }
        SDL_DestroyWindow(_window);
    }
    SDL_Quit();
#endif
}

void Graphics::Render(const VDP& vdp)
{
    const uint32_t* buffer = vdp.GetRenderedBuffer();
#if HAS_GRAPHICS == 1
    void* pixels;
    int pitch;
    if (SDL_LockTexture(_render_texture, NULL, &pixels, &pitch) < 0) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't lock texture: %s\n", SDL_GetError());
        // TODO probably should return and propagate error
        abort();
    }
    assert(pitch == VDP(0).kRenderWidth * sizeof(*buffer));
    (void) pitch;
    memcpy(pixels, buffer, VDP(0).kRenderWidth * VDP(0).kRenderHeight * sizeof(*buffer));
    SDL_UnlockTexture(_render_texture);
    SDL_RenderClear(_renderer);
    SDL_RenderCopy(_renderer, _render_texture, NULL, NULL);
    SDL_RenderPresent(_renderer);
#else
    (void) buffer;
#endif
}

void Graphics::ReRender()
{
#if HAS_GRAPHICS == 1
    SDL_RenderClear(_renderer);
    SDL_RenderCopy(_renderer, _render_texture, NULL, NULL);
    SDL_RenderPresent(_renderer);
#endif
}