def main():
    choice = 0
    income = 4000
    global maxincome
    maxincome = 4000

    outFile = open('bh.txt', 'w')
    outFile = open('bh.txt', 'a')
    print >> outFile, '**Detailed budget history:-'
    print >> outFile
    print >> outFile, 'Starting balance: ',maxincome

    inFile = open('bh.txt', 'w')
    inFile = open('bh.txt', 'a')
    print >> inFile, '**Detailed budget history:-'
    print >> inFile
    print >> inFile, 'Starting balance: ',maxincome
    
    userInput = raw_input('Welcome to the financial planner. Press enter to continue: ')
    if userInput != "":
            choice=int(userInput)
    while choice <> 999:
        choice = menu(choice)
        if choice == 1:
            income, amt = addExp(income)

            outFile = open('bh.txt', 'a')
            print >> outFile, 'Expense Added =',amt,'Available Income:',income

        elif choice == 2:
            income, amt = removeExp(income)

            outFile = open('bh.txt', 'a')
            print >> outFile,'Expense Removed =',amt,'Available Income:',income

        elif choice == 3:
            income, amt = addIncome(income)

            outFile = open('bh.txt', 'a')
            print >> outFile,'Income Added =',amt,'Availabe Income:',income
            
        elif choice == 4:
            income, amt = removeIncome(income)

            outFile = open('bh.txt', 'a')
            print >> outFile,'Income Removed =',amt,'Availabe Income:',income
            
        elif choice == 5:
            inFile = open('bh.txt', 'r')
            displayBudgetHistory(income, inFile)

        elif choice == 999:
            print '**Thanks for using the budget utility...'

        else: print '***Invalid selection'
        
    outFile.close()
    inFile.close()

def addExp(income):
   print
   amt = input('**Enter expense to add: ')
   print

   if (amt <= income and amt > 0):
       print '**Funds before adding adding expense: ',income
       income = income-amt
       print '**Funds after adding expense: ', income
       return (income, amt)
   elif amt > income:
       print '**Insufficient funds. Cant add this expense: ',income, 'Expense: ',amt
   else: print '**Invalid entry'

def removeExp(income):
   print
   amt = input('**Enter expense amount to be removed: ')
   print
  
   global maxincome

   if (amt + income <= maxincome):
       print '**Funds before removing the expense: ',income
       income = income + amt
       print '**Funds after removing expense: ',income

   elif ((amt + income) > maxincome):
       print '**Unable to remove expense. Invalid expense: ',income,' < Expense: ',amt
          
   else: print '**Invalid Expense'

   return(income, amt)

def addIncome(income):
    print
    amt = input('**Enter income to add: ')
    print

    if (amt <= income and amt > 0):
       print '**Funds before adding income: ',income
       income = income + amt
       print '**Funds after adding income: ',income
       return (income, amt)
    

def removeIncome(income):
    print
    amt = input('**Enter income amount to be removed: ')
    print
  
    global maxincome

    if (amt - income <= maxincome):
       print '**Funds before removing the income: ',income
       income = income - amt
       print '**Funds after removing income: ',income

    elif ((amt + income) > maxincome):
       print '**Unable to remove income. Invalid income: ',income,' < Income: ',amt
          
    else: print '**Invalid income'

    return(income, amt)


def displayBudgetHistory(income, inFile):

   print
   text = inFile.read()
   print text

  
def menu(choice):
  

   print '-:MAIN MENU:-'; print;
   print '1:  <---Add Expense'
   print '2:  <---Remove Expense'
   print '3:  <---Add Income'
   print '4:  <---Remove Income'
   print '5:  <---Display Transaction History'; print;
   print '999:  <---Exit'; print;

   choice = ""
   while choice == "":
       choice = raw_input('***Enter a selection: ')

   return int(choice)
   print

main()

while True:
    user_input = raw_input("enter some value")
    try:
        data = int(user_input) #or float(...) for floats
    except ValueError:
        print "invalid input, try again"
    else:
        break
# data is an integer when the loop is left

#DONT TRY THIS AT HOME, KIDS
import os
user_input = input("crash me please")