sensor_stream.h

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/*******************************************************************************
 * File Name: sensor_stream.h
 *
 * Description: Periodic sensor sampler for the Bento Desktop Buddy bridge.
 *              Emits `bento.sensor.data` NUS events at a caller-specified
 *              interval. v1 supports a single active stream at a time; the
 *              ring-of-active-streams described in SPEC §5.3.2 is deferred
 *              until multi-sensor dashboards are needed.
 *
 *              Reference: TESAIoT_PLAN/2026-4/Bento_Buddy/SPEC.md §5.3.2–§5.3.3.
 *
 ******************************************************************************/
 
#ifndef SENSOR_STREAM_H
#define SENSOR_STREAM_H
 
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
/* One-time FreeRTOS task spawn. Safe to call multiple times — subsequent
 * calls are no-ops. Invoked lazily the first time a stream is started. */
int sensor_stream_init(void);
 
/* Start streaming sensor id at the given interval (clamped to [10, 5000] ms).
 * Replaces any in-progress stream (v1 single-stream). Returns 0 on success,
 * -1 if id is not recognised. */
int sensor_stream_start(const char *id, uint32_t interval_ms);
 
/* Stop the active stream. Idempotent. */
void sensor_stream_stop(const char *id);
 
/* Number of samples dropped because the NUS TX queue refused to accept
 * them (link disconnected or buffer full). Exposed for bento.info.board. */
uint32_t sensor_stream_dropped_count(void);
 
/* True iff a stream is currently active. Used by the firmware-update handler
 * to return {"ok":false,"error":"busy"} when a flash attempt races a running
 * stream. */
bool sensor_stream_is_active(void);
 
/* Stop any active stream unconditionally. Idempotent. Called by the firmware-
 * update flow on Y-approve so the flasher operates on a quiescent device. */
void sensor_stream_stop_all(void);
 
#ifdef __cplusplus
}
#endif
 
#endif /* SENSOR_STREAM_H */