#pragma once

#include <stdint.h>
#include <deque>
#include <mbedtls/config.h>
#include <mbedtls/entropy.h>
#include <mbedtls/ctr_drbg.h>
#include <mbedtls/certs.h>
#include <mbedtls/x509.h>
#include <mbedtls/ssl.h>
#include <mbedtls/ssl_cookie.h>
#include <mbedtls/error.h>
#include <mbedtls/debug.h>
#include <mbedtls/timing.h>

/* ----------------------------------------- */

class DTLSSRTPHandshake {
public:
  DTLSSRTPHandshake();
  int init(mbedtls_x509_crt* certificate, mbedtls_pk_context* privateKey, int(*writeCallback)(const uint8_t* data, int* nbytes)); // writeCallback should return 0 on succes < 0 on error. nbytes holds the number of bytes to be sent and needs to be set to the number of bytes actually sent. 
  int shutdown();
  int parse(const uint8_t* data, size_t nbytes);
  bool hasKeyingMaterial();
                 
private:
  int extractKeyingMaterial();
  int resetSession();
    
private:
  mbedtls_x509_crt* cert;                                  /* Certificate, we do not own the key. Make sure it's kept alive during the livetime of this class instance. */
  mbedtls_pk_context* key;                                 /* Private key, we do not own the key. Make sure it's kept alive during the livetime of this class instance. */
  mbedtls_entropy_context entropy_ctx; 
  mbedtls_ctr_drbg_context rand_ctx;
  mbedtls_ssl_context ssl_ctx;
  mbedtls_ssl_config ssl_conf;
  mbedtls_ssl_cookie_ctx cookie_ctx;
  mbedtls_timing_delay_context timer_ctx;

public:
  int (*write_callback)(const uint8_t* data, int* nbytes); 
  std::deque<uint8_t> buffer;                              /* Accessed from BIO callbback. We copy the bytes you pass into `parse()` into this temporary buffer which is read by a trigger to `mbedlts_ssl_handshake()`. */
  std::string cipher;                                      /* selected SRTP cipher. */
  std::string remote_key;
  std::string remote_salt;
  std::string local_key;
  std::string local_salt;
};

/* ----------------------------------------- */
  
inline bool DTLSSRTPHandshake::hasKeyingMaterial() {
  return (0 != remote_key.size()
          && 0 != remote_salt.size()
          && 0 != local_key.size()
          && 0 != local_salt.size());
}

/* ----------------------------------------- */