// HTTP client for POSTing sensor readings to the Quantumancy backend's
// `POST /api/device/telemetry` endpoint (see the design spec's "Contract"
// section: docs/superpowers/specs/2026-07-23-esp32-sensor-node-design.md).
//
// UNVERIFIED AGAINST REAL HARDWARE — see README.md.

#pragma once

#include <stddef.h>
#include "esp_err.h"
#include "sensor_driver.h"

#ifdef __cplusplus
extern "C" {
#endif

// Builds the request body:
//   {"readings": [{"sensor_type": str, "value": number, "unit": str,
//                  "metadata": {}}, ...]}
// and POSTs it to "<DEVICE_BACKEND_BASE_URL>/api/device/telemetry" with
// `Authorization: Bearer <DEVICE_PAIRING_TOKEN>` and
// `Content-Type: application/json`. Takes ownership of any non-NULL
// `metadata` cJSON pointers in `readings` — they are freed as part of
// building/serializing the body regardless of whether the POST succeeds.
// No-ops (returns ESP_OK) if `count` is 0.
esp_err_t telemetry_client_post_readings(const sensor_reading_t *readings, size_t count);

// Starts the FreeRTOS task that, on a DEVICE_REPORT_INTERVAL_SEC cadence,
// collects a fresh batch of readings from the sensor registry and POSTs
// them via telemetry_client_post_readings(). Call once from app_main()
// after wifi_manager_start() and sensor_registry_init_all().
void telemetry_client_start_task(void);

#ifdef __cplusplus
}
#endif