// Copyright 2015 by Artem Prilutskiy

#include "UserDataStore.h"

#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <syslog.h>

#define GET_ID_FOR_CALL         0
#define GET_CREDENTIALS_FOR_ID  1

UserDataStore::UserDataStore(const char* file) :
  connection(NULL)
{
  const char* queries[] =
  {
    // GET_ID_FOR_CALL
    "SELECT `ID`"
    " FROM Users"
    " WHERE `Call` = ?"
    " ORDER BY `Priority`"
    " LIMIT 1",
    // GET_CREDENTIALS_FOR_ID
    "SELECT `Call`, `Text`"
    " FROM Users"
    " WHERE `ID` = ?",
  };

  connection = mysql_init(NULL);

  mysql_options(connection, MYSQL_READ_DEFAULT_FILE, realpath(file, NULL));
  mysql_real_connect(connection, NULL, NULL, NULL, NULL, 0, NULL, CLIENT_REMEMBER_OPTIONS);

  my_bool active = true;
  mysql_options(connection, MYSQL_OPT_RECONNECT, &active);

  for (size_t index = 0; index < PREPARED_STATEMENT_COUNT; index ++)
  {
    const char* query = queries[index];
    statements[index] = mysql_stmt_init(connection);
    mysql_stmt_prepare(statements[index], query, strlen(query));
  }

  const char* error = mysql_error(connection);
  if ((error != NULL) && (*error != '\0'))
    syslog(LOG_CRIT, "MySQL error: %s\n", error);
}

UserDataStore::~UserDataStore()
{
  for (size_t index = 0; index < PREPARED_STATEMENT_COUNT; index ++)
    mysql_stmt_close(statements[index]);

  mysql_close(connection);
}

// Public methods

uint32_t UserDataStore::getPrivateIDForCall(const char* call)
{
  uint32_t number;
  size_t length = strlen(call);

  return
    execute(GET_ID_FOR_CALL, 1, 1,
      MYSQL_TYPE_STRING, call, length,
      MYSQL_TYPE_LONG, &number) *
    number;
}


bool UserDataStore::getCredentialsForID(uint32_t number, char* call, char* text)
{
  return
    execute(GET_CREDENTIALS_FOR_ID, 1, 2,
      MYSQL_TYPE_LONG, &number,
      MYSQL_TYPE_STRING, call, LONG_CALLSIGN_LENGTH + 1,
      MYSQL_TYPE_STRING, text, SLOW_DATA_TEXT_LENGTH + 1);
}

// Internals

MYSQL_BIND* UserDataStore::bind(int count, va_list* arguments)
{
  MYSQL_BIND* bindings = NULL;
  if (count > 0)
  {
    bindings = (MYSQL_BIND*)calloc(count, sizeof(MYSQL_BIND));
    for (int index = 0; index < count; index ++)
    {
      int type = va_arg(*arguments, int);
      bindings[index].buffer_type = (enum_field_types)type;
      bindings[index].buffer = va_arg(*arguments, void*);
      if ((type == MYSQL_TYPE_STRING) ||
          (type == MYSQL_TYPE_DATETIME))
      {
        bindings[index].buffer_length = va_arg(*arguments, int);
        bindings[index].length = &bindings[index].buffer_length;
      }
    }
  }
  return bindings;
}

bool UserDataStore::execute(int index, int count1, int count2, ...)
{
  bool result = true;
  MYSQL_STMT* statement = statements[index];
  
  va_list arguments;
  va_start(arguments, count2);
  MYSQL_BIND* parameters = bind(count1, &arguments);
  MYSQL_BIND* columns = bind(count2, &arguments);
  va_end(arguments);
  
  if ((parameters && mysql_stmt_bind_param(statement, parameters)) ||
      (columns    && mysql_stmt_bind_result(statement, columns))   ||
                     mysql_stmt_execute(statement)                 ||
      (columns    && mysql_stmt_store_result(statement)))
  {
    const char* error = mysql_stmt_error(statement);
    syslog(LOG_CRIT, "MySQL error while processing statement %d: %s\n", index, error);
    result = false;
  }
  
  if (result && columns)
  {
    result = !mysql_stmt_fetch(statement);
    mysql_stmt_free_result(statement);
  }
  
  free(columns);
  free(parameters);
  return result;
}