#ifndef RADICK_TARGET_TRACKER_H
#define RADICK_TARGET_TRACKER_H

#include "radar_protocol.h"

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

#ifdef __cplusplus
extern "C" {
#endif

#define TARGET_TRACKER_CAPACITY RD03D_MAX_TARGETS

typedef struct {
    float position_ema_alpha;
    float speed_ema_alpha;
    float motion_ema_alpha;
    float max_association_distance_mm;
    uint16_t max_missed_frames;
} target_tracker_config_t;

typedef struct {
    uint32_t id;
    float x_mm;
    float y_mm;
    float speed_cm_s;
    uint16_t resolution_mm;
    uint32_t age_frames;
    uint16_t last_seen_age_frames;
    bool visible;
    bool observed_this_frame;
} target_snapshot_t;

/* Public state keeps the module allocator-free; consumers should use snapshot. */
typedef struct {
    target_snapshot_t snapshot;
    float last_observed_x_mm;
    float last_observed_y_mm;
    float velocity_x_mm_per_frame;
    float velocity_y_mm_per_frame;
    bool active;
} target_track_state_t;

typedef struct {
    target_tracker_config_t config;
    target_track_state_t tracks[TARGET_TRACKER_CAPACITY];
    uint32_t next_id;
} target_tracker_t;

void target_tracker_default_config(target_tracker_config_t *config);

/* A NULL config selects conservative defaults suitable for the 10 Hz stream. */
void target_tracker_init(target_tracker_t *tracker,
                         const target_tracker_config_t *config);

/* Clear tracks and restart IDs at one while preserving the current config. */
void target_tracker_reset(target_tracker_t *tracker);

/*
 * Advance the tracker by exactly one radar frame. Only detections with valid
 * set participate, and at most the first three valid detections are used.
 * Returns the number of tracks retained after the update.
 */
size_t target_tracker_update(target_tracker_t *tracker,
                             const rd03d_target_t *detections,
                             size_t detection_count);

size_t target_tracker_update_frame(target_tracker_t *tracker,
                                   const rd03d_frame_t *frame);

/*
 * Copy visible tracks ordered by stable ID. Passing NULL/zero capacity is a
 * valid way to query the number of visible tracks.
 */
size_t target_tracker_snapshot(const target_tracker_t *tracker,
                               target_snapshot_t *out,
                               size_t capacity);

#ifdef __cplusplus
}
#endif

#endif /* RADICK_TARGET_TRACKER_H */