#include <glib.h>
#include <stdbool.h>

#include "animate.h"
#include "state.h"
#include "log.h"

double quadratic_bezier(double x, double a, double b, double c)
{
	g_assert(x >= 0 && x <= 1);
	g_assert(a >= 0 && a <= 1);
	g_assert(b >= 0 && b <= 1);
	g_assert(c >= 0 && c <= 1);

	const double t = 1 - x;
	return a * t * t + 2 * b * t * x + c * x * x;
}

double cubic_bezier(double x, double a, double b, double c, double d)
{
	g_assert(x >= 0 && x <= 1);
	g_assert(a >= 0 && a <= 1);
	g_assert(b >= 0 && b <= 1);
	g_assert(c >= 0 && c <= 1);
	g_assert(d >= 0 && d <= 1);

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

typedef struct {
    Animation anim;
    gint64 start;
    gint64 duration;
    double x;
} AnimationShine;

bool shine_paint(AnimationShine *anim, cairo_t *cr, const Layout *layout)
{
    gint64 now = g_get_monotonic_time();
    if (anim->start == 0)
        anim->start = now;

    gint64 end = anim->start + anim->duration;
    anim->x = 1.0;

    if (now <= end) {
        double t = (double)(now - anim->start) / (end - anim->start);
        anim->x = cubic_bezier(t, 0.19, 1.0, 0.22, 1.0);
    }

    // Draw at x on the surface...
    return false;
}

Animation *animation_shine_create(gint64 duration)
{
    // Note the 0 initialization
    AnimationShine *anim = g_malloc0(sizeof(AnimationShine));
    anim->anim.type = ANIM_SHINE;
    anim->anim.paint = (DrawFunc)shine_paint;
    anim->duration = duration;
    return (gpointer)anim;
}

void animation_destroy(Animation *anim)
{
    //XXX
    g_free(anim);
}

// vim: ts=4 sw=4 et