/*
 * client-coap.c -- RIOT client example
 *
 * Copyright (C) 2023 Jon Shallow <supjps-libcoap@jpshallow.com>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * This file is part of the CoAP library libcoap. Please see README for terms
 * of use.
 */

#include "coap_config.h"
#include <coap3/coap.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include "client-coap.h"
#include "macros/utils.h"
#include "net/utils.h"
#include <arpa/inet.h>
#include <thread.h>
#include <debug.h>

#ifdef CONFIG_LIBCOAP_CLIENT_URI
#define COAP_CLIENT_URI CONFIG_LIBCOAP_CLIENT_URI
#else /* ! CONFIG_LIBCOAP_CLIENT_URI */
#define COAP_CLIENT_URI "coap://[fe80::405:5aff:fe15:9b7f]/.well-known/core"
#endif /* ! CONFIG_LIBCOAP_CLIENT_URI */

#ifdef CONFIG_LIBCOAP_USE_PSK
#define COAP_USE_PSK CONFIG_LIBCOAP_USE_PSK
#else /* ! CONFIG_LIBCOAP_USE_PSK */
#define COAP_USE_PSK NULL
#endif /* ! CONFIG_LIBCOAP_USE_PSK */

#ifdef CONFIG_LIBCOAP_USE_PSK_ID
#define COAP_USE_PSK_ID CONFIG_LIBCOAP_USE_PSK_ID
#else /* ! CONFIG_LIBCOAP_USE_PSK_ID */
#define COAP_USE_PSK_ID NULL
#endif /* ! CONFIG_LIBCOAP_USE_PSK_ID */

static coap_context_t *main_coap_context = NULL;
static coap_optlist_t *optlist = NULL;

static int quit = 0;

static coap_response_t
message_handler(coap_session_t *session,
                const coap_pdu_t *sent,
                const coap_pdu_t *received,
                const coap_mid_t id) {
  const uint8_t *data;
  size_t len;
  size_t offset;
  size_t total;

  (void)session;
  (void)sent;
  (void)id;
  if (coap_get_data_large(received, &len, &data, &offset, &total)) {
    printf("%*.*s", (int)len, (int)len, (const char *)data);
    if (len + offset == total) {
      printf("\n");
      quit = 1;
    }
  }
  return COAP_RESPONSE_OK;
}

static void
nack_handler(coap_session_t *session COAP_UNUSED,
             const coap_pdu_t *sent COAP_UNUSED,
             const coap_nack_reason_t reason,
             const coap_mid_t id COAP_UNUSED) {

  switch (reason) {
  case COAP_NACK_TOO_MANY_RETRIES:
  case COAP_NACK_NOT_DELIVERABLE:
  case COAP_NACK_RST:
  case COAP_NACK_TLS_FAILED:
  case COAP_NACK_TLS_LAYER_FAILED:
  case COAP_NACK_WS_LAYER_FAILED:
  case COAP_NACK_WS_FAILED:
    coap_log_err("cannot send CoAP pdu\n");
    quit = 1;
    break;
  case COAP_NACK_ICMP_ISSUE:
  case COAP_NACK_BAD_RESPONSE:
  default:
    break;
  }
  return;
}

static int
resolve_address(const char *host, const char *service, coap_address_t *dst,
                int scheme_hint_bits) {
  uint16_t port = service ? atoi(service) : 0;
  int ret = 0;
  coap_str_const_t str_host;
  coap_addr_info_t *addr_info;

  str_host.s = (const uint8_t *)host;
  str_host.length = strlen(host);
  addr_info = coap_resolve_address_info(&str_host, port, port,  port, port,
                                        AF_UNSPEC, scheme_hint_bits,
                                        COAP_RESOLVE_TYPE_REMOTE);
  if (addr_info) {
    ret = 1;
    *dst = addr_info->addr;
  }

  coap_free_address_info(addr_info);
  return ret;
}

void
client_coap_init(int argc, char **argv) {
  coap_session_t *session = NULL;
  coap_pdu_t *pdu;
  coap_address_t dst;
  coap_mid_t mid;
  int len;
  coap_uri_t uri;
  char portbuf[8];
#define BUFSIZE 100
  unsigned char buf[BUFSIZE];
  int res;
  const char *coap_uri = COAP_CLIENT_URI;

  if (argc > 1) {
    coap_uri = argv[1];
  }

  /* Initialize libcoap library */
  coap_startup();

  coap_set_log_level(COAP_MAX_LOGGING_LEVEL);

  /* Parse the URI */
  len = coap_split_uri((const unsigned char *)coap_uri, strlen(coap_uri), &uri);
  if (len != 0) {
    coap_log_warn("Failed to parse uri %s\n", coap_uri);
    goto fail;
  }

  snprintf(portbuf, sizeof(portbuf), "%d", uri.port);
  snprintf((char *)buf, sizeof(buf), "%*.*s", (int)uri.host.length,
           (int)uri.host.length, (const char *)uri.host.s);
  /* resolve destination address where packet should be sent */
  len = resolve_address((const char *)buf, portbuf, &dst, 1 << uri.scheme);
  if (len <= 0) {
    coap_log_warn("Failed to resolve address %*.*s\n", (int)uri.host.length,
                  (int)uri.host.length, (const char *)uri.host.s);
    goto fail;
  }

  main_coap_context = coap_new_context(NULL);
  if (!main_coap_context) {
    coap_log_warn("Failed to initialize context\n");
    goto fail;
  }

  coap_context_set_block_mode(main_coap_context, COAP_BLOCK_USE_LIBCOAP);

  if (uri.scheme == COAP_URI_SCHEME_COAP) {
    session = coap_new_client_session(main_coap_context, NULL, &dst,
                                      COAP_PROTO_UDP);
  } else if (uri.scheme == COAP_URI_SCHEME_COAP_TCP) {
    session = coap_new_client_session(main_coap_context, NULL, &dst,
                                      COAP_PROTO_TCP);
#if defined (COAP_USE_PSK) && defined(COAP_USE_PSK_ID)
  } else {
    static coap_dtls_cpsk_t dtls_psk;
    static char client_sni[256];

    memset(client_sni, 0, sizeof(client_sni));
    memset(&dtls_psk, 0, sizeof(dtls_psk));
    dtls_psk.version = COAP_DTLS_CPSK_SETUP_VERSION;
    if (uri.host.length) {
      memcpy(client_sni, uri.host.s,
             MIN(uri.host.length, sizeof(client_sni) - 1));
    }
    else {
      memcpy(client_sni, "localhost", 9);
    }
    dtls_psk.client_sni = client_sni;
    dtls_psk.psk_info.identity.s = (const uint8_t *)COAP_USE_PSK_ID;
    dtls_psk.psk_info.identity.length = strlen(COAP_USE_PSK_ID);
    dtls_psk.psk_info.key.s = (const uint8_t *)COAP_USE_PSK;
    dtls_psk.psk_info.key.length = strlen(COAP_USE_PSK);

    session = coap_new_client_session_psk2(main_coap_context, NULL, &dst,
                                           COAP_PROTO_DTLS, &dtls_psk);
#else /* ! COAP_USE_PSK && ! COAP_USE_PSK_ID */
    coap_log_err("CONFIG_LIBCOAP_USE_PSK and CONFIG_LIBCOAP_USE_PSK_ID not defined\n");
    goto fail;
#endif /* ! COAP_USE_PSK && ! COAP_USE_PSK_ID */
  }

  if (!session) {
    coap_log_warn("Failed to create session\n");
    goto fail;
  }

  coap_register_response_handler(main_coap_context, message_handler);
  coap_register_nack_handler(main_coap_context, nack_handler);

  /* construct CoAP message */
  pdu = coap_pdu_init(COAP_MESSAGE_CON,
                      COAP_REQUEST_CODE_GET,
                      coap_new_message_id(session),
                      coap_session_max_pdu_size(session));
  if (!pdu) {
    coap_log_warn("Failed to create PDU\n");
    goto fail;
  }

  len = coap_uri_into_options(&uri, &dst, &optlist, 1, buf, sizeof(buf));
  if (len) {
    coap_log_warn("Failed to create options\n");
    goto fail;
  }

  /* Add option list (which will be sorted) to the PDU */
  if (optlist) {
    res = coap_add_optlist_pdu(pdu, &optlist);
    if (res != 1) {
      coap_log_warn("Failed to add options to PDU\n");
      goto fail;
    }
  }

  /* and send the PDU */
  mid = coap_send(session, pdu);
  if (mid == COAP_INVALID_MID) {
    coap_log_warn("Failed to send PDU\n");
    goto fail;
  }
  while (!quit) {
    coap_io_process(main_coap_context, 1000);
  }
fail:
  /* Clean up library usage so client can be run again */
  quit = 0;
  coap_delete_optlist(optlist);
  optlist = NULL;
  coap_session_release(session);
  session = NULL;
  coap_free_context(main_coap_context);
  main_coap_context = NULL;
  coap_cleanup();
}