// firmware/src/hmac.h
#pragma once
#include <stdint.h>

#ifdef NATIVE_TEST
#include <string>
using HString = std::string;
#else
#include <Arduino.h>
using HString = String;
#endif

// Returns lowercase hex-encoded HMAC-SHA256 signature.
// Message signed: method + "\n" + path + "\n" + timestamp_str + "\n" + hex(sha256(body))
// Matches server verify_device_hmac format: POST\n{path}\n{timestamp}\n{sha256(body)}
HString hmac_sign(const HString& secret_hex,
                  const HString& method,
                  const HString& path,
                  uint32_t timestamp,
                  const HString& body);