#include "common.h"
#include <math.h>

/* Protoypes (static) */
static memcached_return server_add(memcached_st *ptr, const char *hostname, 
                                   unsigned int port,
                                   uint32_t weight,
                                   memcached_connection type);
memcached_return update_continuum(memcached_st *ptr);

static int compare_servers(const void *p1, const void *p2)
{
  int return_value;
  memcached_server_st *a= (memcached_server_st *)p1;
  memcached_server_st *b= (memcached_server_st *)p2;

  return_value= strcmp(a->hostname, b->hostname);

  if (return_value == 0)
  {
    return_value= (int) (a->port - b->port);
  }

  return return_value;
}

static void sort_hosts(memcached_st *ptr)
{
  if (ptr->number_of_hosts)
  {
    qsort(ptr->hosts, ptr->number_of_hosts, sizeof(memcached_server_st), compare_servers);
    ptr->hosts[0].count= ptr->number_of_hosts;
  }
}


memcached_return run_distribution(memcached_st *ptr)
{
  switch (ptr->distribution) 
  {
  case MEMCACHED_DISTRIBUTION_CONSISTENT:
  case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
    return update_continuum(ptr);
  case MEMCACHED_DISTRIBUTION_MODULA:
    if (ptr->flags & MEM_USE_SORT_HOSTS)
      sort_hosts(ptr);
    break;
  case MEMCACHED_DISTRIBUTION_RANDOM:
    break;
  default:
    WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
  }

  return MEMCACHED_SUCCESS;
}

void server_list_free(memcached_st *ptr, memcached_server_st *servers)
{
  unsigned int x;

  if (servers == NULL)
    return;

  for (x= 0; x < servers->count; x++)
    if (servers[x].address_info)
    {
      freeaddrinfo(servers[x].address_info);
      servers[x].address_info= NULL;
    }

  if (ptr)
    ptr->call_free(ptr, servers);
  else
    free(servers);
}

static uint32_t ketama_server_hash(const char *key, unsigned int key_length, int alignment)
{
  unsigned char results[16];
  
  md5_signature((unsigned char*)key, key_length, results);
  return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
    | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
    | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
    | (results[0 + alignment * 4] & 0xFF);
}

static int continuum_item_cmp(const void *t1, const void *t2)
{
  memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
  memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;

  /* Why 153? Hmmm... */
  WATCHPOINT_ASSERT(ct1->value != 153);
  if (ct1->value == ct2->value)
    return 0;
  else if (ct1->value > ct2->value)
    return 1;
  else
    return -1;
}

memcached_return update_continuum(memcached_st *ptr)
{
  uint32_t host_index;
  uint32_t continuum_index= 0;
  uint32_t value;
  memcached_server_st *list;
  uint32_t pointer_index;
  uint32_t pointer_counter= 0;
  uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
  uint32_t pointer_per_hash= 1;
  uint64_t total_weight= 0;
  uint32_t is_ketama_weighted= 0;
  uint32_t is_auto_ejecting= 0;
  uint32_t points_per_server= 0;
  uint32_t live_servers= 0;
  struct timeval now;

  if (gettimeofday(&now, NULL) != 0)
  {
    ptr->cached_errno = errno;
    return MEMCACHED_ERRNO;
  }

  list = ptr->hosts;

  /* count live servers (those without a retry delay set) */
  is_auto_ejecting= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS);
  if (is_auto_ejecting)
  {
    live_servers= 0;
    ptr->next_distribution_rebuild= 0;
    for (host_index= 0; host_index < ptr->number_of_hosts; ++host_index)
    {
      if (list[host_index].next_retry <= now.tv_sec)
        live_servers++;
      else
      {
        if (ptr->next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->next_distribution_rebuild)
          ptr->next_distribution_rebuild= list[host_index].next_retry;
      }
    }
  }
  else
    live_servers= ptr->number_of_hosts;

  is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
  points_per_server= is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER;

  if (live_servers == 0)
    return MEMCACHED_SUCCESS;

  if (live_servers > ptr->continuum_count)
  {
    memcached_continuum_item_st *new_ptr;

    new_ptr= ptr->call_realloc(ptr, ptr->continuum, 
                               sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);

    if (new_ptr == 0)
      return MEMCACHED_MEMORY_ALLOCATION_FAILURE;

    ptr->continuum= new_ptr;
    ptr->continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
  }

  if (is_ketama_weighted) 
  {
    for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index) 
    {
      if (list[host_index].weight == 0)
      {
        list[host_index].weight = 1;
      }
      if (!is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
        total_weight += list[host_index].weight;
    }
  }

  for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index) 
  {
    if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
      continue;

    if (is_ketama_weighted) 
    {
        float pct = (float)list[host_index].weight / (float)total_weight;
        pointer_per_server= floorf(pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001) * 4;
        pointer_per_hash= 4;
#ifdef DEBUG
        printf("ketama_weighted:%s|%d|%llu|%u\n", 
               list[host_index].hostname, 
               list[host_index].port,  
               (unsigned long long)list[host_index].weight, 
               pointer_per_server);
#endif
    }
    for (pointer_index= 1;
         pointer_index <= pointer_per_server / pointer_per_hash;
         ++pointer_index) 
    {
      char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
      size_t sort_host_length;

      if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
      {
        sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
                                   "%s-%d",
                                   list[host_index].hostname,
                                   pointer_index - 1);

      }
      else
      {
        sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
                                   "%s:%d-%d", 
                                   list[host_index].hostname,
                                   list[host_index].port, pointer_index - 1);
      }
      WATCHPOINT_ASSERT(sort_host_length);

      if (is_ketama_weighted)
      {
        unsigned int i;
        for (i = 0; i < pointer_per_hash; i++)
        {
          value= ketama_server_hash(sort_host, sort_host_length, i);
          ptr->continuum[continuum_index].index= host_index;
          ptr->continuum[continuum_index++].value= value;
        }
      }
      else
      {
        value= memcached_generate_hash_value(sort_host, sort_host_length, ptr->hash_continuum);
        ptr->continuum[continuum_index].index= host_index;
        ptr->continuum[continuum_index++].value= value;
      }
    }
    pointer_counter+= pointer_per_server;
  }

  WATCHPOINT_ASSERT(ptr);
  WATCHPOINT_ASSERT(ptr->continuum);
  WATCHPOINT_ASSERT(ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
  ptr->continuum_points_counter= pointer_counter;
  qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);

#ifdef DEBUG
  for (pointer_index= 0; ptr->number_of_hosts && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++) 
  {
    WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
  }
#endif

  return MEMCACHED_SUCCESS;
}


memcached_return memcached_server_push(memcached_st *ptr, memcached_server_st *list)
{
  unsigned int x;
  uint16_t count;
  memcached_server_st *new_host_list;

  if (!list)
    return MEMCACHED_SUCCESS;

  count= list[0].count;
  new_host_list= ptr->call_realloc(ptr, ptr->hosts, 
                                   sizeof(memcached_server_st) * (count + ptr->number_of_hosts));

  if (!new_host_list)
    return MEMCACHED_MEMORY_ALLOCATION_FAILURE;

  ptr->hosts= new_host_list;

  for (x= 0; x < count; x++)
  {
    if ((ptr->flags & MEM_USE_UDP && list[x].type != MEMCACHED_CONNECTION_UDP)
            || ((list[x].type == MEMCACHED_CONNECTION_UDP)
            && ! (ptr->flags & MEM_USE_UDP)) )
      return MEMCACHED_INVALID_HOST_PROTOCOL;

    WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
    memcached_server_create(ptr, &ptr->hosts[ptr->number_of_hosts]);
    /* TODO check return type */
    (void)memcached_server_create_with(ptr, &ptr->hosts[ptr->number_of_hosts], list[x].hostname, 
                                       list[x].port, list[x].weight, list[x].type);
    ptr->number_of_hosts++;
  }
  ptr->hosts[0].count= ptr->number_of_hosts;

  return run_distribution(ptr);
}

memcached_return memcached_server_add_unix_socket(memcached_st *ptr, 
                                                  const char *filename)
{
  return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
}

memcached_return memcached_server_add_unix_socket_with_weight(memcached_st *ptr, 
                                                              const char *filename, 
                                                              uint32_t weight)
{
  if (!filename)
    return MEMCACHED_FAILURE;

  return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
}

memcached_return memcached_server_add_udp(memcached_st *ptr, 
                                          const char *hostname,
                                          unsigned int port)
{
  return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
}

memcached_return memcached_server_add_udp_with_weight(memcached_st *ptr, 
                                                      const char *hostname,
                                                      unsigned int port,
                                                      uint32_t weight)
{
  if (!port)
    port= MEMCACHED_DEFAULT_PORT; 

  if (!hostname)
    hostname= "localhost"; 

  return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
}

memcached_return memcached_server_add(memcached_st *ptr, 
                                      const char *hostname, 
                                      unsigned int port)
{
  return memcached_server_add_with_weight(ptr, hostname, port, 0);
}

memcached_return memcached_server_add_with_weight(memcached_st *ptr, 
                                                  const char *hostname, 
                                                  unsigned int port,
                                                  uint32_t weight)
{
  if (!port)
    port= MEMCACHED_DEFAULT_PORT; 

  if (!hostname)
    hostname= "localhost";

  return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
}

static memcached_return server_add(memcached_st *ptr, const char *hostname, 
                                   unsigned int port,
                                   uint32_t weight,
                                   memcached_connection type)
{
  memcached_server_st *new_host_list;

  if ( (ptr->flags & MEM_USE_UDP && type != MEMCACHED_CONNECTION_UDP)
      || ( (type == MEMCACHED_CONNECTION_UDP) && !(ptr->flags & MEM_USE_UDP) ) )
    return MEMCACHED_INVALID_HOST_PROTOCOL;
  
  new_host_list= ptr->call_realloc(ptr, ptr->hosts, 
                                   sizeof(memcached_server_st) * (ptr->number_of_hosts+1));

  if (new_host_list == NULL)
    return MEMCACHED_MEMORY_ALLOCATION_FAILURE;

  ptr->hosts= new_host_list;

  /* TODO: Check return type */
  (void)memcached_server_create_with(ptr, &ptr->hosts[ptr->number_of_hosts], hostname, port, weight, type);
  ptr->number_of_hosts++;
  ptr->hosts[0].count= ptr->number_of_hosts;

  return run_distribution(ptr);
}

memcached_return memcached_server_remove(memcached_server_st *st_ptr)
{
  uint32_t x, host_index;
  memcached_st *ptr= st_ptr->root;
  memcached_server_st *list= ptr->hosts;

  for (x= 0, host_index= 0; x < ptr->number_of_hosts; x++) 
  {
    if (strncmp(list[x].hostname, st_ptr->hostname, MEMCACHED_MAX_HOST_LENGTH) != 0 || list[x].port != st_ptr->port) 
    {
      if (host_index != x)
        memcpy(list+host_index, list+x, sizeof(memcached_server_st));
      host_index++;
    } 
  }
  ptr->number_of_hosts= host_index;

  if (st_ptr->address_info) 
  {
    freeaddrinfo(st_ptr->address_info);
    st_ptr->address_info= NULL;
  }
  run_distribution(ptr);

  return MEMCACHED_SUCCESS;
}

memcached_server_st *memcached_server_list_append(memcached_server_st *ptr, 
                                                  const char *hostname, unsigned int port,
                                                  memcached_return *error)
{
  return memcached_server_list_append_with_weight(ptr, hostname, port, 0, error);
}

memcached_server_st *memcached_server_list_append_with_weight(memcached_server_st *ptr, 
                                                              const char *hostname, unsigned int port,
                                                              uint32_t weight, 
                                                              memcached_return *error)
{
  unsigned int count;
  memcached_server_st *new_host_list;

  if (hostname == NULL || error == NULL)
    return NULL;

  if (!port)
    port= MEMCACHED_DEFAULT_PORT; 

  /* Increment count for hosts */
  count= 1;
  if (ptr != NULL)
  {
    count+= ptr[0].count;
  } 

  new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
  if (!new_host_list)
  {
    *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
    return NULL;
  }

  /* TODO: Check return type */
  memcached_server_create_with(NULL, &new_host_list[count-1], hostname, port, weight, MEMCACHED_CONNECTION_TCP);

  /* Backwards compatibility hack */
  new_host_list[0].count= count;

  *error= MEMCACHED_SUCCESS;
  return new_host_list;
}

unsigned int memcached_server_list_count(memcached_server_st *ptr)
{
  if (ptr == NULL)
    return 0;

  return ptr[0].count;
}

void memcached_server_list_free(memcached_server_st *ptr)
{
  server_list_free(NULL, ptr);
}