#
# program to prettyprint an XML tree
#
import xml.etree.ElementTree as ET
import sys
#
# by how many spaces should a child be indented from its parent?
#
factor = 4

#
# put the attributes into a string
# make sure there is no trailing space
#
def print_node_attributes(node):
    strout = ''
    # now add on the attributes
    for key in node.attrib:
        strout += '%s="%s" ' % (key, node.attrib[key])
    # return this, less any trailing spaces
    strout2 = " " + strout.strip()
    return strout2
        
#
# go through the XML tree; we do this recursively
#
def find_kids(node, depth):
    global factor
    # build the indent; factor spaces for each level
    indent = ''
    for i in range(factor * depth):
        indent += ' '
    # print the opening tag + attributes
    print(indent + "<" + node.tag, end='')
    if node.attrib:
        attrstr = print_node_attributes(node)
    else:
        attrstr = ''
    if node.text:
    	nodetxt = node.text
    else:
    	nodetxt = ''
    # see if there are any kids
    # assume no children initially
    anykids = False
    for child in node:
        # at least one -- drop out
        anykids = True;
        break;
    if not anykids:
        # no -- close the tag and element
        if node.text:
        	print(attrstr + ">" + nodetxt + "</" + node.tag + ">")
        else:
        	print(attrstr + "/>")
    else:
        # yes -- close tag, leave element open
        # check that nodetext is not a newline
        if nodetxt == '\n':
            print(attrstr + ">")
        else:
            print(attrstr + ">" + nodetxt)
        # now print the kids
        for child in node:
            find_kids(child, depth + 1)
        # and close the element
        print(indent + "</" + node.tag + ">")
    
        
# load the XML into memory
#
fptr = open("books.xml", "r")
tree = fptr.read()
xmltreeroot = ET.fromstring(tree)
#
# print the tree
#
find_kids(xmltreeroot, 0)