#include "core/rendering/screen.hpp"

#include <SDL3/SDL.h>

#include <algorithm>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <ranges>

#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

auto Screen::get() -> Screen& {
    static Screen instance_;
    return instance_;
}

Screen::Screen()
    : canvas_width_(GameCanvas::WIDTH),
      canvas_height_(GameCanvas::HEIGHT),
      canvas_(static_cast<std::size_t>(GameCanvas::WIDTH) * static_cast<std::size_t>(GameCanvas::HEIGHT), 0xFF000000U) {
    if (!SDL_InitSubSystem(SDL_INIT_VIDEO)) {
        std::fprintf(stderr, "SDL_InitSubSystem(VIDEO) failed: %s\n", SDL_GetError());
        std::exit(EXIT_FAILURE);
    }
    // Els recursos SDL (finestra, renderer, textura) es creen a configure().
}

Screen::~Screen() {
    destroySdl();
    SDL_QuitSubSystem(SDL_INIT_VIDEO);
}

void Screen::configure(const Config& config) {
    destroySdl();
    config_ = config;
    createSdl();
}

void Screen::destroySdl() {
    if (game_texture_ != nullptr) {
        SDL_DestroyTexture(game_texture_);
        game_texture_ = nullptr;
    }
    if (renderer_ != nullptr) {
        SDL_DestroyRenderer(renderer_);
        renderer_ = nullptr;
    }
    if (window_ != nullptr) {
        SDL_DestroyWindow(window_);
        window_ = nullptr;
    }
}

void Screen::createSdl() {
    const int WIN_W = GameCanvas::WIDTH * config_.zoom;
    const int WIN_H = GameCanvas::HEIGHT * config_.zoom;

    Uint32 win_flags = SDL_WINDOW_RESIZABLE;
    if (config_.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_, config_.vsync ? 1 : 0);
    SDL_SetRenderLogicalPresentation(renderer_, GameCanvas::WIDTH, GameCanvas::HEIGHT, toSdlPresentation(config_.scaling_mode));

    // STREAMING: el framebuffer ARGB del joc s'actualitza per CPU cada frame
    // i s'envia a la GPU via SDL_UpdateTexture en present().
    game_texture_ = SDL_CreateTexture(renderer_, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STREAMING, 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(config_.texture_filter));
}

void Screen::clear(std::uint8_t r, std::uint8_t g, std::uint8_t b) {
    const std::uint32_t COLOR = (0xFFU << 24) | (static_cast<std::uint32_t>(r) << 16) | (static_cast<std::uint32_t>(g) << 8) | static_cast<std::uint32_t>(b);
    std::ranges::fill(canvas_, COLOR);
}

void Screen::present() {
    SDL_UpdateTexture(game_texture_, nullptr, canvas_.data(), canvas_width_ * static_cast<int>(sizeof(std::uint32_t)));

    SDL_SetRenderDrawColor(renderer_, 0x00, 0x00, 0x00, 0xFF);
    SDL_RenderClear(renderer_);
    SDL_RenderTexture(renderer_, game_texture_, nullptr, nullptr);
    SDL_RenderPresent(renderer_);
}