#include <math.h>

#include "layout.h"
#include "effect.h"
#include "any_log.h"

double cubic_bezier(double x, double a, double b, double c, double d)
{
	const double t = 1 - x;
	return a * (t * t * t) + 3 * b * (t * t * x) + 3 * c * (t * x * x) + d * (x * x * x);
}

static void effect_pulse_pre(effect_t *effect, layout_t *layout, cairo_t *cr)
{
    struct timespec now;
    timespec_get(&now, TIME_UTC);

    // After half the duration we invert direction
    struct timespec midpoint = timespec_div(effect->duration, 2);
    struct timespec diff = timespec_diff(now, effect->start);

    double t = timespec_greater(midpoint, diff)
             ? (double)timespec_to_ms(diff) / timespec_to_ms(midpoint)
             : 1.0 - (double)timespec_to_ms(timespec_diff(diff, midpoint)) / timespec_to_ms(midpoint);

    // Make it customizable
    double s = cubic_bezier(t, 0.19, 1.0, 0.22, 1.0);

    // Make it a parameter
    const double amplitude = 0.12;

    // FIXME: The intent was to scale the animation for long blocks, but it needs more love
    //
    int x_max = amplitude * (layout->height + (layout->width / (double)layout->height) - 1);
    int y_max = amplitude * layout->height;

    layout->x_padding = layout->block->x_padding + x_max * s;
    layout->y_padding = layout->block->y_padding + y_max * s;
}

effect_t *effect_pulse(struct timespec duration)
{
    effect_t *effect = calloc(1, sizeof(effect_t));
    effect->type = EFFECT_PULSE;
    effect->duration = duration;
    effect->pre = effect_pulse_pre;
    return effect;
}

void effect_free(effect_t *effect)
{
    free(effect);
}