// screen_fade.cpp - Implementació de la fosa a/desde negre
// © 2026 JailDesigner

#include "core/graphics/screen_fade.hpp"

#include <algorithm>
#include <cmath>

#include "core/defaults/game.hpp"

namespace Graphics {

    ScreenFade::ScreenFade(Rendering::Renderer* renderer)
        : renderer_(renderer) {}

    void ScreenFade::start(float from, float to, float duration) {
        from_ = from;
        to_ = to;
        duration_ = duration;
        elapsed_ = 0.0F;
        active_ = true;
    }

    void ScreenFade::update(float delta_time) {
        if (!active_) {
            return;
        }
        elapsed_ += delta_time;
    }

    auto ScreenFade::alpha() const -> float {
        if (!active_) {
            return 0.0F;
        }
        if (duration_ <= 0.0F) {
            return to_;
        }
        const float T = std::clamp(elapsed_ / duration_, 0.0F, 1.0F);
        return std::lerp(from_, to_, T);
    }

    auto ScreenFade::isDone() const -> bool {
        return !active_ || elapsed_ >= duration_;
    }

    void ScreenFade::draw() const {
        const float A = alpha();
        if (A <= 0.0F) {
            return;
        }
        renderer_->pushRect(
            0.0F,
            0.0F,
            static_cast<float>(Defaults::Game::WIDTH),
            static_cast<float>(Defaults::Game::HEIGHT),
            0.0F,
            0.0F,
            0.0F,
            A);
    }

}  // namespace Graphics