#include <algorithm>

#include "Animation/RacerAnimation.h"

/********* Racer *********/

RacerAnimation::Racer::Racer(Fader *fader, int32_t pos, int32_t speed, const Fader::Color &color)
    : m_fader(fader),
      m_speed(speed),
      m_pos(pos),
      m_color(color)
{
}

void RacerAnimation::Racer::move(void)
{
    int32_t maxpos = m_fader->strips() * m_fader->modules_per_strip() * 256;

    m_pos += m_speed;

    if(m_pos >= maxpos) {
        m_pos = maxpos - (m_pos % maxpos);
        m_speed = -m_speed;
    } else if(m_pos < 0) {
        m_pos = -m_pos;
        m_speed = -m_speed;
    }
}

void RacerAnimation::Racer::render(void) const
{
    int32_t idx1 = m_pos / 256;
    int32_t idx2 = m_pos / 256 + 1;

    int32_t scale1 = (idx2 * 256) - m_pos;
    int32_t scale2 = m_pos - (idx1 * 256);

    m_fader->add_color(idx1,
        Fader::Color{
            static_cast<int16_t>(m_color.r * scale1 / 256),
            static_cast<int16_t>(m_color.g * scale1 / 256),
            static_cast<int16_t>(m_color.b * scale1 / 256),
            static_cast<int16_t>(m_color.w * scale1 / 256)
        });

    m_fader->add_color(idx2,
        Fader::Color{
            static_cast<int16_t>(m_color.r * scale2 / 256),
            static_cast<int16_t>(m_color.g * scale2 / 256),
            static_cast<int16_t>(m_color.b * scale2 / 256),
            static_cast<int16_t>(m_color.w * scale2 / 256)
        });
}

/********* RacerAnimation *********/

RacerAnimation::RacerAnimation(Fader *fader, uint32_t racer_count)
    : Animation(fader)
{
    reset();

    int32_t maxpos = m_fader->strips() * m_fader->modules_per_strip() * 256;
    std::uniform_int_distribution<int32_t> posRng(0, maxpos);
    std::uniform_int_distribution<int32_t> speedRng(-128, 128);
    std::uniform_int_distribution<int16_t> colorRng(0, 255);
    std::uniform_int_distribution<int16_t> whiteRng(0, 64);

    m_racers.reserve(racer_count);
    for(size_t i = 0; i < racer_count; i++) {
        m_racers.emplace_back(Racer{
                fader,
                posRng(m_gen),
                speedRng(m_gen),
                Fader::Color{
                    colorRng(m_gen),
                    colorRng(m_gen),
                    colorRng(m_gen),
                    whiteRng(m_gen),
                }
            });
    }
}

void RacerAnimation::loop(uint64_t frame)
{
    if(!m_stopping) {
        // clear the frame buffer
        m_fader->set_color(Fader::Color{0, 0, 0, 0});

        // move snow flakes and render
        for(auto &flake: m_racers) {
            flake.move();
            flake.render();
        }
    } else {
        m_fader->set_fadestep(4);
        m_fader->fade_color(Fader::Color{0, 0, 0, 0});
    }

    m_fader->update();

    if(m_stopping && !m_fader->something_changed()) {
        m_running = false;
    }
}

void RacerAnimation::reset(void)
{
    m_stopping = false;
    m_running = true;
}