iot_skeleton/esp32/main/protocol.cpp

#include "protocol.h"
#include "ws.h"
#include <stdio.h>
#include <stdarg.h>
#include <inttypes.h>

#define PROTOCOL_VERSION 1

static uint32_t msg_id = 1;

static inline int append(char* buf, size_t size, int pos, const char* fmt, ...)
{
    if ((size_t)pos >= size) return -1;

    va_list args;
    va_start(args, fmt);
    int written = vsnprintf(buf + pos, size - pos, fmt, args);
    va_end(args);

    if (written < 0 || (size_t)(pos + written) >= size)
    {
        return -1;
    }

    return pos + written;
}

int build_telemetry(
    char* buf,
    size_t buf_size,
    int64_t ts,
    uint32_t device_id,
    const char* metric,
    const char* source,
    const char* unit,
    const int* values,
    size_t count
)
{
    int pos = 0;

    // --- header ---
    pos = append(buf, buf_size, pos,
                 "{\"v\":1,\"t\":\"t\",\"id\":%lu,\"ts\":%lld,\"d\":%lu,\"p\":{",
                 (unsigned long)protocol_next_id(),
                 (long long)ts,
                 (unsigned long)device_id
    );
    if (pos < 0) return -1;

    // --- payload meta ---
    pos = append(buf, buf_size, pos,
                 "\"m\":\"%s\",\"s\":\"%s\",\"u\":\"%s\",\"v\":[",
                 metric,
                 source,
                 unit
    );
    if (pos < 0) return -1;

    // --- values ---
    for (size_t i = 0; i < count ; i ++)
    {
        pos = append(buf, buf_size, pos,
                     "[%u,%d]%s",
                     values[i*2 + 0], // delta time
                     values[i*2 + 1],
                     (i < count - 1) ? "," : ""
        );
        if (pos < 0) return -1;
    }

    // --- close ---
    pos = append(buf, buf_size, pos, "]}}");
    if (pos < 0) return -1;

    return pos;
}

__attribute__((deprecated))
// --- TELEMETRY (single measurement) ---
int build_telemetry_single(
    char* buf,
    size_t buf_size,
    const char* id,
    const char* device_id,
    int64_t ts_ms,
    const char* metric,
    double value,
    const char* unit,
    const char* source,
    int64_t m_ts_ms
)
{
    int pos = 0;

    // header
    pos = append(buf, buf_size, pos,
                 "{\"v\":%d,\"id\":\"%s\",\"type\":\"telemetry\",\"ts\":%lld,"
                 "\"deviceId\":\"%s\",\"payload\":{\"measurements\":[",
                 PROTOCOL_VERSION,
                 id,
                 (long long)ts_ms,
                 device_id
    );
    if (pos < 0) return -1;

    // measurement start
    pos = append(buf, buf_size, pos,
                 "{\"metric\":\"%s\",\"value\":%.3f",
                 metric,
                 value
    );
    if (pos < 0) return -1;

    // optional
    if (unit)
    {
        pos = append(buf, buf_size, pos, ",\"unit\":\"%s\"", unit);
        if (pos < 0) return -1;
    }

    if (source)
    {
        pos = append(buf, buf_size, pos, ",\"source\":\"%s\"", source);
        if (pos < 0) return -1;
    }

    if (m_ts_ms > 0)
    {
        pos = append(buf, buf_size, pos, ",\"ts\":%lld", (long long)m_ts_ms);
        if (pos < 0) return -1;
    }

    // close measurement + payload
    pos = append(buf, buf_size, pos, "}]}}");
    if (pos < 0) return -1;

    return pos;
}

__attribute__((deprecated))
// --- EVENT ---
int build_event(
    char* buf,
    size_t buf_size,
    const char* id,
    const char* device_id,
    int64_t ts_ms,
    const char* name,
    const char* severity,
    const char* message
)
{
    int pos = 0;

    // header
    pos = append(buf, buf_size, pos,
                 "{\"v\":%d,\"id\":\"%s\",\"type\":\"event\",\"ts\":%lld,"
                 "\"deviceId\":\"%s\",\"payload\":{",
                 PROTOCOL_VERSION,
                 id,
                 (long long)ts_ms,
                 device_id
    );
    if (pos < 0) return -1;

    // required
    pos = append(buf, buf_size, pos, "\"name\":\"%s\"", name);
    if (pos < 0) return -1;

    // optional
    if (severity)
    {
        pos = append(buf, buf_size, pos, ",\"severity\":\"%s\"", severity);
        if (pos < 0) return -1;
    }

    if (message)
    {
        pos = append(buf, buf_size, pos, ",\"message\":\"%s\"", message);
        if (pos < 0) return -1;
    }

    // close
    pos = append(buf, buf_size, pos, "}}");
    if (pos < 0) return -1;

    return pos;
}

uint32_t protocol_next_id()
{
    return msg_id++;
};

void protocol_send_event_hb(int64_t ts)
{
    // формируешь JSON строго по контракту

    // пример:
    char buf[128];

    uint32_t id = protocol_next_id();

    snprintf(buf, sizeof(buf),
        "{\"v\":1,\"id\":%" PRIu32 ",\"t\":\"e\",\"ts\":%" PRIu64 ",\"d\":%u,\"p\":{\"type\":\"hb\"}}",
        id, ts, CONFIG_DEVICE_ID);

    ws_send(buf);
}

bool protocol_is_connected()
{
    return ws_is_connected();
}