#!/usr/bin/env python3
from __future__ import print_function
from math import *
from ROOT import TFile, TObject, TTree
from array import array
from ROOT import gDirectory
import sys
import os

DQMfile = sys.argv[1]
RunNumber = sys.argv[2]
globalTagVar = sys.argv[3]

if not os.path.isfile(DQMfile):
#    print "Error: file", DQMfile, "not found, exit" 
    sys.exit(0)



thefile = TFile( DQMfile )
globalTagDir = 'DQMData/Run ' + RunNumber + '/Info/Run summary/CMSSWInfo'

if not gDirectory.GetDirectory( globalTagDir ):
#    print "Warning: globalTag not found in DQM file"
    sys.exit(0)    

keys = gDirectory.GetDirectory( globalTagDir ).GetListOfKeys()

key = keys[0]
globalTag = ''
while key:
    obj = key.ReadObj()
    if globalTagVar in obj.GetName():
        globalTag = obj.GetName()[len("<"+globalTagVar+">s="):-len("</"+globalTagVar+">")]
        break
    key = keys.After(key)
if len(globalTag) > 1:
    if globalTag.find('::') >= 0: 
        print(globalTag[0:globalTag.find('::')])
    else:
        print(globalTag)


