#ifndef GPS_TIME_ANCHOR_H_INCLUDED
#define GPS_TIME_ANCHOR_H_INCLUDED

#include <stdbool.h>
#include <stdint.h>

#define GPS_TIME_WEEK_SECONDS      604800.0
#define GPS_TIME_HALF_WEEK_SECONDS 302400.0

/* Resolve the week of a newly received HOW against the previous HOW anchor.
 * The HOW contains seconds-of-week; the signed half-week rule makes the
 * Saturday/Sunday rollover explicit without depending on a NAV timer. */
int gps_time_resolve_how_week(bool previous_valid,
                              int previous_week,
                              double previous_tow_sec,
                              int fallback_week,
                              double how_tow_sec);

/* Convert a receiver-sample timestamp to GPS time from a HOW/sample anchor.
 * raw counters are modulo 2^32.  max_age_sec must keep the signed difference
 * unambiguous (and also rejects a stale HOW anchor). */
bool gps_time_from_sample_anchor(int anchor_week,
                                 double anchor_tow_sec,
                                 uint32_t anchor_raw_sample,
                                 double anchor_corrected_sample,
                                 uint32_t event_raw_sample,
                                 double event_corrected_sample,
                                 double samples_per_second,
                                 double max_age_sec,
                                 int* event_week_out,
                                 double* event_tow_sec_out,
                                 double* elapsed_sec_out);

#endif