import sys,os
import json, requests #pip install requests

#Variable initialization
Start_Date , End_Date = sys.argv[1] , sys.argv[2]
ISSN , offset = sys.argv[3] , 0

#getting current directory and dumping data in that directory
path = os.path.join(os.getcwd(), sys.argv[4])

if not os.path.exists(path): #check if folder already exist, if it doesn't then create it
    os.makedirs(path)

#Crossref API Call
API_String = 'http://api.crossref.org/works?filter=issn:'+
ISSN+',from-pub-date:'+Start_Date+',until-pub-date:'+End_Date+'&rows=1000'
response = requests.get(API_String)
data = response.json()

# No of Records in Journal
Records = data['message']['total-results']
Req_count = Records / 1000
Rem = Records % 1000
    
if Rem == 0:
    Req_count = int(Req_count)
else:
    Req_count = int(Req_count) + 1

newpath = os.path.join(os.getcwd(), sys.argv[4],'Req_count.txt')
Request_Count_file = open(newpath , 'w')
Request_Count_file.write(str(Req_count))    
Request_Count_file.close()

# Save data in Json files
for Request in range(int(Req_count)):
		response = requests.get(API_String+'&offset='+str(offset))
		data = response.json()
		newpathforDataDump = os.path.join(os.getcwd(), sys.argv[4],'Metadata'+str(Request)+'_'+sys.argv[4]+'.json')
		with open(newpathforDataDump, 'w') as f1:
				json.dump(data , f1)
				offset = offset + 1000