#include "core/rendering/screen.hpp"

#include <SDL3/SDL.h>

#include <cstdio>
#include <cstdlib>

#include "utils/defaults.hpp"
#include "utils/defines.hpp"

namespace {

    auto toSdlPresentation(Defaults::ScalingMode mode) -> SDL_RendererLogicalPresentation {
        switch (mode) {
            case Defaults::ScalingMode::DISABLED:
                return SDL_LOGICAL_PRESENTATION_DISABLED;
            case Defaults::ScalingMode::STRETCH:
                return SDL_LOGICAL_PRESENTATION_STRETCH;
            case Defaults::ScalingMode::LETTERBOX:
                return SDL_LOGICAL_PRESENTATION_LETTERBOX;
            case Defaults::ScalingMode::OVERSCAN:
                return SDL_LOGICAL_PRESENTATION_OVERSCAN;
            case Defaults::ScalingMode::INTEGER:
                return SDL_LOGICAL_PRESENTATION_INTEGER_SCALE;
        }
        return SDL_LOGICAL_PRESENTATION_LETTERBOX;
    }

    auto toSdlScaleMode(Defaults::TextureFilter filter) -> SDL_ScaleMode {
        return filter == Defaults::TextureFilter::LINEAR ? SDL_SCALEMODE_LINEAR : SDL_SCALEMODE_NEAREST;
    }

}  // namespace

Screen* Screen::instance = nullptr;

void Screen::init() {
    if (instance == nullptr) {
        instance = new Screen();
    }
}

void Screen::destroy() {
    delete instance;
    instance = nullptr;
}

auto Screen::get() -> Screen* {
    return instance;
}

Screen::Screen() {
    if (!SDL_InitSubSystem(SDL_INIT_VIDEO)) {
        std::fprintf(stderr, "SDL_InitSubSystem(VIDEO) failed: %s\n", SDL_GetError());
        std::exit(EXIT_FAILURE);
    }

    const int WIN_W = GameCanvas::WIDTH * Defaults::Window::ZOOM;
    const int WIN_H = GameCanvas::HEIGHT * Defaults::Window::ZOOM;

    Uint32 win_flags = SDL_WINDOW_RESIZABLE;
    if (Defaults::Window::FULLSCREEN) { win_flags |= SDL_WINDOW_FULLSCREEN; }

    window_ = SDL_CreateWindow(Texts::WINDOW_TITLE, WIN_W, WIN_H, win_flags);
    if (window_ == nullptr) {
        std::fprintf(stderr, "SDL_CreateWindow failed: %s\n", SDL_GetError());
        std::exit(EXIT_FAILURE);
    }

    renderer_ = SDL_CreateRenderer(window_, nullptr);
    if (renderer_ == nullptr) {
        std::fprintf(stderr, "SDL_CreateRenderer failed: %s\n", SDL_GetError());
        std::exit(EXIT_FAILURE);
    }

    SDL_SetRenderVSync(renderer_, Defaults::Video::VSYNC ? 1 : 0);
    SDL_SetRenderLogicalPresentation(renderer_, GameCanvas::WIDTH, GameCanvas::HEIGHT, toSdlPresentation(Defaults::Video::SCALING_MODE));

    // Destination ARGB texture: paletted surfaces will be blitted onto this
    // (each surface contributes its own palette, so the final image is full ARGB).
    game_texture_ = SDL_CreateTexture(renderer_, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_TARGET, GameCanvas::WIDTH, GameCanvas::HEIGHT);
    if (game_texture_ == nullptr) {
        std::fprintf(stderr, "SDL_CreateTexture failed: %s\n", SDL_GetError());
        std::exit(EXIT_FAILURE);
    }
    SDL_SetTextureScaleMode(game_texture_, toSdlScaleMode(Defaults::Video::TEXTURE_FILTER));
}

Screen::~Screen() {
    if (game_texture_ != nullptr) { SDL_DestroyTexture(game_texture_); }
    if (renderer_ != nullptr) { SDL_DestroyRenderer(renderer_); }
    if (window_ != nullptr) { SDL_DestroyWindow(window_); }
    SDL_QuitSubSystem(SDL_INIT_VIDEO);
}

void Screen::clear(std::uint8_t r, std::uint8_t g, std::uint8_t b) {
    SDL_SetRenderTarget(renderer_, game_texture_);
    SDL_SetRenderDrawColor(renderer_, r, g, b, 0xFF);
    SDL_RenderClear(renderer_);
    SDL_SetRenderTarget(renderer_, nullptr);
}

void Screen::present() {
    SDL_SetRenderDrawColor(renderer_, 0x00, 0x00, 0x00, 0xFF);
    SDL_RenderClear(renderer_);
    SDL_RenderTexture(renderer_, game_texture_, nullptr, nullptr);
    SDL_RenderPresent(renderer_);
}