#include "kernels.h"
#include <math.h>

double native_signal(double t, double start, int stages, int cyclic, const double *data) {
    if (t < start) return data[0];
    double elapsed = t-start, duration = 0, offset = 0;
    for (int i=0;i<stages;i++) duration += data[16+i];
    if (cyclic && duration > 0) elapsed = fmod(elapsed,duration);
    else if (elapsed >= duration) return data[8+stages-1];
    for (int i=0;i<stages;i++) {
        double d = data[16+i];
        if (elapsed < offset+d || i == stages-1)
            return d <= 0 ? data[8+i] : data[i] + (elapsed-offset)/d*(data[8+i]-data[i]);
        offset += d;
    }
    return data[8+stages-1];
}

double native_signal_break(double t, double end, double start, int stages,
                           int cyclic, const double *data) {
    double duration=0, offset=0, result=end;
    for (int i=0;i<stages;i++) duration += data[16+i];
    /* A cyclic endpoint is already the next cycle's start. Listing both can
       create two nearly equal floating-point break times for one event. */
    for (int i=0;i<stages+(cyclic?0:1);i++) {
        double event=start+offset;
        if (cyclic && duration > 0 && event <= t) {
            double cycle=fmax(0,floor((t-event)/duration)+1);
            event += cycle*duration;
            if (event <= t) event += duration;
        }
        if (event > t) result=fmin(result,event);
        if (i < stages) offset += data[16+i];
    }
    return result;
}