import threading
import time
import MySQLdb
import traceback
import sys
import datetime

class DBCursor:
    def __init__(self,lock,cursor,db):
        self.lock=lock
        self.cursor=cursor
        self.db=db
        lock.acquire()
        
    def close(self):
        self.lock.release()

    def execute(self,format,*arg):
        try:
            #print "format:",format
            #print "args:",arg
            return self.cursor.execute(format,*arg)
        except (MySQLdb.InterfaceError,MySQLdb.OperationalError):
            print>>sys.stderr, datetime.datetime.now()
            traceback.print_exc()
            self.cursor=self.db.reconnect()
            print "format:",format
            print "args", arg
            return self.cursor.execute(format,*arg)
        except:
            print>>sys.stderr, datetime.datetime.now()
            traceback.print_exc()
            print "format:",format
            print "args", arg

    def fetchone(self):
        try:
            return self.cursor.fetchone()
        except (MySQLdb.InterfaceError,MySQLdb.OperationalError):
            print>>sys.stderr, datetime.datetime.now()
            traceback.print_exc()
            self.cursor=self.db.reconnect()
            return self.cursor.fetchone()
        except:
            print>>sys.stderr, datetime.datetime.now()
            traceback.print_exc()

    def fetchall(self):
        try:
            return self.cursor.fetchall()
        except (MySQLdb.InterfaceError,MySQLdb.OperationalError):
            print>>sys.stderr, datetime.datetime.now()
            traceback.print_exc()
            self.cursor=self.db.reconnect()
            return self.cursor.fetchall()
        except:
            print>>sys.stderr, datetime.datetime.now()
            traceback.print_exc()

    def insert_id(self):
        try:
            return self.cursor.lastrowid()
        except (MySQLdb.InterfaceError,MySQLdb.OperationalError):
            print>>sys.stderr, datetime.datetime.now()
            traceback.print_exc()
            self.cursor=self.db.reconnect()
            return self.cursor.lastrowid()
        except:
            print>>sys.stderr, datetime.datetime.now()
            traceback.print_exc()

class DBLayer:
    def __init__(self):
        self.db=None
        self.maxTries=30
        self.cursorLock=threading.RLock()
        
    def connect(self,**arg):
        self.dbArgs=arg
        self.db=MySQLdb.connect(**arg)
    
    def reconnect(self):
        count=0

        db=None
        while count<self.maxTries:
            try:
                db=MySQLdb.connect(**self.dbArgs)
            except MySQLdb.OperationalError:
                count=count+1
                print>>sys.stderr, "database reconnect try: ",count,"of",self.maxTries
                time.sleep(2*count)
            except:
                print>>sys.stderr, datetime.datetime.now()
                traceback.print_exc()
            else:
                self.db=db
                return self.db.cursor()

        raise IOError, "could not reconnect to database"
    
    def cursor(self):
        return DBCursor(self.cursorLock,self.db.cursor(),self)

    def commit(self):
        try:
            return self.db.commit()
        except:
            print>>sys.stderr, datetime.datetime.now()
            traceback.print_exc()

    def rollback(self):
        try:
            return self.db.rollback()
        except:
            print>>sys.stderr, datetime.datetime.now()
            traceback.print_exc()