# coding=utf-8

import threading
import _mysql
from settings import Settings

database_lock = threading.Lock()

try:
  # Although SQLAlchemy is optional, it is highly recommended
  import sqlalchemy.pool as pool  
  _mysql = pool.manage( module = _mysql,
                        pool_size = Settings.DATABASE_POOL_SIZE,
                        max_overflow = Settings.DATABASE_POOL_OVERFLOW)
  Settings._.USING_SQLALCHEMY = True
except ImportError:
  pass

def OpenDb():
  if Settings._.CONN is None:
    Settings._.CONN = _mysql.connect(host = Settings.DATABASE_HOST,
                                     user = Settings.DATABASE_USERNAME,
                                     passwd = Settings.DATABASE_PASSWORD,
                                     db = Settings.DATABASE_DB)

def FetchAll(query, method=1):
  """
  Query and fetch all results as a list
  """
  db = Settings._.CONN
  
  db.query(query)
  r = db.use_result()
  return r.fetch_row(0, method)

def FetchOne(query, method=1):
  """
  Query and fetch only the first result
  """
  db = Settings._.CONN
  
  db.query(query)
  r = db.use_result()
  try:
    return r.fetch_row(1, method)[0]
  except:
    return None

def UpdateDb(query):
  """
  Update the DB (UPDATE/DELETE) and return # of affected rows
  """
  db = Settings._.CONN
  
  db.query(query)
  return db.affected_rows()
    
def InsertDb(query):
  """
  Insert into the DB and return the primary key of new row
  """
  db = Settings._.CONN
  
  db.query(query)
  return db.insert_id()

def CloseDb():
  if Settings._.CONN is not None:
    Settings._.CONN.close()