#include "clock.h"

#include <assert.h>

#include "util/log.h"

#define SC_CLOCK_NDEBUG // comment to debug

#define SC_CLOCK_RANGE 32

void
sc_clock_init(struct sc_clock *clock) {
    clock->range = 0;
    clock->offset = 0;
}

void
sc_clock_update(struct sc_clock *clock, sc_tick system, sc_tick stream) {
    if (clock->range < SC_CLOCK_RANGE) {
        ++clock->range;
    }

    sc_tick offset = system - stream;
    clock->offset = ((clock->range - 1) * clock->offset + offset)
                  / clock->range;

#ifndef SC_CLOCK_NDEBUG
    LOGD("Clock estimation: pts + %" PRItick, clock->offset);
#endif
}

sc_tick
sc_clock_to_system_time(struct sc_clock *clock, sc_tick stream) {
    assert(clock->range); // sc_clock_update() must have been called
    return stream + clock->offset;
}