/*
 * Secure Network Transport Layer Library v2 implementation.
 * (sntllv2) it superseed all versions before due to the:
 * - memory consumption
 * - new features such as pulse emitting
 * - performance optimization
 *
 * This is a proprietary software. See COPYING for further details.
 *
 * (c) Askele Group 2013-2015 <http://askele.com>
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <pthread.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <fcntl.h>

#ifdef WIN32
#include <Winsock2.h>
#define EBADE 1
#define NETDB_SUCCESS 0
#else
#include <sys/select.h>
#include <netdb.h>
#include <unistd.h>
#include <uuid/uuid.h>
#endif

#include <openssl/ssl.h>
#include <openssl/err.h>

#include <tdata/usrtc.h>
#include <sexpr/sexp.h>

#include <sntl/sntllv2.h>

static int __insert_rpc_function(usrtc_t *tree, const char *name, int (*rpcf)(void *, sexp_t *))
{
  cx_rpc_t *ent = malloc(sizeof(cx_rpc_t));
  usrtc_node_t *node;

  if(!ent) return ENOMEM;
  else node = &ent->node;

  if(!(ent->name = strdup(name))) {
    free(ent);
    return ENOMEM;
  } else ent->rpcf = rpcf;

  usrtc_node_init(node, ent);
  usrtc_insert(tree, node, ent->name);

  return 0;
}

static void __destroy_rpc_list_tree(usrtc_t *tree)
{
  usrtc_node_t *node;
  cx_rpc_t *ent;

  for(node = usrtc_first(tree); node != NULL; node = usrtc_first(tree)) {
    ent = (cx_rpc_t *)usrtc_node_getdata(node);
    usrtc_delete(tree, node);
    free(ent->name);
    free(ent);
  }

  return;
}

/* negotiation functions */
/**
 * Proto: (auth-set-credentials "<login>" "<password>")
 * Return - message return; opcode as a return of this function.
 * in batch mode message with 0 index used always
 */
static int __set_credentials(void *cctx, sexp_t *sx)
{
  register int idx;
  conn_t *co = (conn_t *)cctx;
  conn_sys_t *ssys = co->ssys;
  sexp_t *isx;
  char *login = NULL;
  char *passwd = NULL;

  /* take a deal with S-exp */
  SEXP_ITERATE_LIST(sx, isx, idx) {
    if(isx->ty == SEXP_LIST) return SNE_BADPROTO;

    if(idx > 0 && isx->aty != SEXP_DQUOTE) return SNE_BADPROTO;
    if(idx == 1) login = isx->val;
    else if(idx == 2) passwd = isx->val;
    else if(idx > 2) return SNE_BADPROTO;
  }

  if(!login || !passwd) return SNE_BADPROTO;

  co->pctx->login = strdup(login);
  co->pctx->passwd = strdup(passwd);
  if(!co->pctx->login || !co->pctx->passwd) {
    if(co->pctx->login) free(co->pctx->login);
    if(co->pctx->passwd) free(co->pctx->passwd);
    return SNE_ENOMEM;
  }

  if(ssys->secure_check) return ssys->secure_check(co);
  else return SNE_SUCCESS;
}

static int __get_channels_list(void *cctx, sexp_t *sx)
{
  conn_t *co = (conn_t *)cctx;
  conn_sys_t *ssys = co->ssys;
  sxmsg_t *msg = co->messages[0];
  char *buf = msg->payload;
  usrtc_node_t *node;
  rpc_typed_list_t *list_ent;
  size_t maxlen = 65535 - sizeof(sntllv2_head_t);
  size_t ulen = 0;

  /* we will avoid S-exp scanning here */

  /* call the function */
  if(ssys->get_rpc_typed_list_tree)
    co->rpc_list = ssys->get_rpc_typed_list_tree(co);
  if(!co->rpc_list) return SNE_EPERM;

  buf += sizeof(sntllv2_head_t);
  ulen += snprintf(buf + ulen, maxlen - ulen, "(set-channels-list ");
  for(node = usrtc_first(co->rpc_list); node != NULL;
      node = usrtc_next(co->rpc_list, node)) { /* fill the list */
    list_ent = (rpc_typed_list_t *)usrtc_node_getdata(node);
    ulen += snprintf(buf + ulen, maxlen - ulen, "(:%d \"%s\")",
                     list_ent->type_id, list_ent->description);
  }
  ulen += snprintf(buf + ulen, maxlen - ulen, ")");
  msg->mhead.payload_length = ulen + sizeof(sntllv2_head_t);

  /* we're ready for messaging mode */
  co->flags |= SNSX_MESSAGINGMODE;

  return SNE_SUCCESS;
}

static int __set_channels_list(void *cctx, sexp_t *sx)
{
  register int idx;
  conn_t *co = (conn_t *)cctx;
  conn_sys_t *ssys = co->ssys;
  sexp_t *isx, *iisx;
  int id, r;

  SEXP_ITERATE_LIST(sx, isx, idx) {
    if(!idx) continue;

    if(isx->ty != SEXP_LIST) return SNE_BADPROTO;
    if(sexp_list_length(isx) != 2) return SNE_BADPROTO;

    /* get id */
    sexp_list_car(isx, &iisx);
    if(iisx->ty == SEXP_LIST) return SNE_BADPROTO;
    if(iisx->aty != SEXP_BASIC) return SNE_BADPROTO;
    if(iisx->val[0] != ':') return SNE_BADPROTO;
    id = atoi(iisx->val + sizeof(char));

    /* get short description */
    sexp_list_cdr(isx, &iisx);
    if(iisx->ty == SEXP_LIST) return SNE_BADPROTO;
    if(iisx->aty != SEXP_DQUOTE) return SNE_BADPROTO;

    /* ok, here we go */
    if(ssys->set_typed_list_callback) {
      r = ssys->set_typed_list_callback(co, id, iisx->val);
      if(r != SNE_SUCCESS) return r;
    }
  }

  /* we're ready for messaging mode */
  co->flags |= SNSX_MESSAGINGMODE;

  return SNE_SUCCESS;
}

static int __init_systemrpc_tree(usrtc_t *rtree)
{
  /* batch mode negotiation context functions */
  if(__insert_rpc_function(rtree, "auth-set-credentials", __set_credentials)) goto __fail;
  if(__insert_rpc_function(rtree, "get-channels-list", __get_channels_list)) goto __fail;
  if(__insert_rpc_function(rtree, "set-channels-list", __set_channels_list)) goto __fail;

  return 0;

 __fail:
  __destroy_rpc_list_tree(rtree);
  return ENOMEM;
}

static long __cmp_cstr(const void *a, const void *b)
{
  return (long)strcmp((const char *)a, (const char *)b);
}

int connections_init(conn_sys_t *ssys)
{
  int r = 0;

  if(!ssys) return EINVAL;
  else memset(ssys, 0, sizeof(conn_sys_t));

  if(!(ssys->connections = malloc(sizeof(usrtc_t)))) return ENOMEM;

  /* init connections list */
  usrtc_init(ssys->connections, USRTC_REDBLACK, MAX_CONNECTIONS,
             __cmp_cstr);
  if((r = pthread_rwlock_init(&(ssys->rwlock), NULL)))
    goto __fini;

  /* init RPC list related functions */
  if(!(ssys->system_rpc = malloc(sizeof(cx_rpc_list_t)))) {
    r = ENOMEM;
    goto __lfini;
  } else {
    if(!(ssys->system_rpc->rpc_tree = malloc(sizeof(usrtc_t)))) {
      r = ENOMEM;
      goto __lfini;
    }
    usrtc_init(ssys->system_rpc->rpc_tree, USRTC_SPLAY, 256, __cmp_cstr);
    r = __init_systemrpc_tree(ssys->system_rpc->rpc_tree);
    if(r) {
      free(ssys->system_rpc->rpc_tree);
      goto __lfini;
    }
  }

  return 0;

 __lfini:
  if(ssys->system_rpc) free(ssys->system_rpc);
  pthread_rwlock_destroy(&(ssys->rwlock));
 __fini:
  if(ssys->connections) free(ssys->connections);

  return r;
}

conn_sys_t *connections_create(void)
{
  int r = 0;
  conn_sys_t *nsys = malloc(sizeof(conn_sys_t));

  if(!nsys) {
    errno = ENOMEM;
    return NULL;
  }

  r = connections_init(nsys);
  if(r) {
    errno = r;
    free(nsys);
    return NULL;
  }

  return nsys;
}