"""Sample program performing domain name lookups and showing off EasyDialogs,
Res and Dlg in the process"""

import EasyDialogs
import Res
import Dlg
import sys
import socket
import string
#
# Definitions for our resources
ID_MAIN=512

ITEM_LOOKUP_ENTRY=1
ITEM_RESULT=2
ITEM_LOOKUP_BUTTON=3
ITEM_QUIT_BUTTON=4
    
            
def main():
    """Main routine: open resource file, call dialog handler"""
    try:
        Res.OpenResFile("dnslookup-1.rsrc")
    except Res.Error:
        EasyDialogs.Message("Cannot open dnslookup-1.rsrc")
        sys.exit(1) 
    do_dialog()

def do_dialog():
    """Post dialog and handle user interaction until quit"""
    my_dlg = Dlg.GetNewDialog(ID_MAIN, -1)
    while 1:
        n = Dlg.ModalDialog(None)
        if n == ITEM_LOOKUP_BUTTON:
            tp, h, rect = my_dlg.GetDialogItem(ITEM_LOOKUP_ENTRY)
            txt = Dlg.GetDialogItemText(h)

            tp, h, rect = my_dlg.GetDialogItem(ITEM_RESULT)
            Dlg.SetDialogItemText(h, dnslookup(txt))        
        elif n == ITEM_QUIT_BUTTON:
            break

def dnslookup(str):
    """ Perform DNS lookup on str.  If first character of digit is numeric,
        assume that str contains an IP address.  Otherwise, assume that str
        contains a hostname."""
    if str == '': str = ' '
    if str[0] in string.digits:
        try:
            value = socket.gethostbyaddr(str)[0]
        except:
            value = 'Lookup failed'
    else:
        try:
            value = socket.gethostbyname(str)
        except:
            value = 'Lookup failed'
    return value

main()