mohan-bee/compact-pir

firmware/main/motion_logic.h

#pragma once

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

typedef struct {
    uint64_t boot_ms;
    uint64_t last_motion_ms;
    bool settled;
    bool seen_motion;
} motion_state_t;

static inline bool motion_update(motion_state_t *state, uint64_t now_ms,
                                 bool pir_high, uint64_t settle_ms,
                                 uint64_t hold_ms)
{
    // Unsigned elapsed times remain correct across the millisecond counter wrap.
    if (!state->settled) {
        if ((uint64_t)(now_ms - state->boot_ms) < settle_ms) {
            return false;
        }
        state->settled = true;
    }
    if (pir_high) {
        state->last_motion_ms = now_ms;
        state->seen_motion = true;
    }
    if (state->seen_motion &&
        (uint64_t)(now_ms - state->last_motion_ms) < hold_ms) {
        return true;
    }
    state->seen_motion = false;
    return false;
}