diff_file_generator

#!/usr/bin/python


import os
import sys
import os.path
from diff_file_data import *

#Check if file exists


def check_file(file_path):
	if os.path.exists(file_path) == True:
		pass
	else:
		print 'invalid input'
		pass

#display the options to select the required drivers
# /option_name[]: array containing name of the files
# /list_length: length of array option_name


def disp(list_length):
	print 'Select the driver'
	for num in range(0,list_length):
		print '%s' % option_name[num]


#Reading input from the user
# /user_input: input by user


def inp(list_length):
	user_input = int(input("Enter a choice: "))
	if user_input >=1 and user_input<=list_length: 
		return user_input-1
	else:
		print 'invalid input'
		return	inp(list_length)

		
#depending on the user choice the elements from the list are selected
# /file_path[]: array of paths of the selected drivers
# /list_length: number of pair of files that can be compared
# /diff_name: the name of the generated diff file


def select(user_input, list_length,temp):
	diff_name=option_name[user_input]
	delete_file(diff_name)
	file_path=fil[user_input]
	ln=len(file_path)
	for num in range(0,ln):
		files=file_path[num]
		first_file=files[0]
		check_file(first_file)
		second_file=files[1]
		check_file(second_file)
		return_statement=command_line_statement(first_file,second_file,temp)
		call(return_statement)
		con_catenate(diff_name)
		num=num+1
		delete_file(temp)


#function to get the string to be used as shell commmand  
# /first_file: input file 1
# /second_file: input file 2
# /required_file: output diff file 
# /returns: return value of diff


def command_line_statement(first_file,second_file,required_file):
	return ('diff %s %s > %s.txt') % (first_file,second_file,required_file)


#to run the command in shell we use os.system
# /return_statement: return command for shell execution


def call(return_statement):
	os.system(return_statement)


#concatanate multiple diff_files generated
# /file_name: name of the final diff file


def con_catenate(file_name):
	statement=('cat temp.txt >> %s.txt') % file_name
	os.system(statement) 

#function to delete the unwanted files


def delete_file(file_name):
	statement=('rm %s.txt') % file_name
	os.system(statement)


#function_to_display_the_generated_diff_file
# /req_file: the required driver files which have been compared
# /shell_command: return command for shell execution


def file_display(req_file):
	file_name=option_name[req_file]
	shell_command= 'gvim %s.txt' %file_name
	os.system(shell_command)
	

#set variables to zero
# /usip: user input to select the file
# /ret: return statement generated
# /req: required file name 
# /ret: return value of diff
# /name: length of array option_name
# /path: length of array file_path


usip=0

ret=0

t='temp'

req=0

name=len(option_name)

path=len(fil)


disp(name)

usip=inp(name)

select(usip,path,t)

file_display(usip)