#include <string.h>
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>

#include "scheme.h"

#include "../any_log.h"

typedef struct {
    effect_t effect;
    double amplitude;
} effect_pulse_t;

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->info->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);

    const double amplitude = ((effect_pulse_t *)effect)->amplitude;

    // 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;
}

static effect_t *effect_pulse_allocate(const effect_info_t *info)
{
    effect_pulse_t *effect = malloc(sizeof(effect_pulse_t));
    effect_init((effect_t *)effect, info);
    effect->amplitude = *(unsigned int *)info->state / 100.0;
    return (effect_t *)effect;
}

static void effect_pulse_finalize(effect_t *effect)
{
    free(effect);
}

static bool effect_pulse_validate(effect_info_t *info, const effect_scheme_t *scheme)
{
    unsigned int amplitude = *(unsigned int *)info->state;
    if (amplitude > 100) {
        log_error("Effect '%s' pulse amplitude must not exceed 100", info->label);
        return false;
    }

    return true;
}

static const config_entry_t effect_pulse_entries[] = {
    { "amplitude", CONFIG_UINT, NULL, 0 },
    { 0 },
};

const effect_scheme_t effect_pulse_scheme = {
    .name = "pulse",
    .info = {
        .duration = {
            .tv_sec = 0,
            .tv_nsec = 200000000,
        },
        .allocate = effect_pulse_allocate,
        .finalize = effect_pulse_finalize,
        .pre = effect_pulse_pre,
    },
    .size = sizeof(unsigned int),
    .entries = effect_pulse_entries,
    .validate = effect_pulse_validate,
};