#
# Example of XML functions and methods in Python
#
# Matt Bishop, MHI 289I, Fall 2019
#
import xml.etree.ElementTree as ET
import sys

#
# function to pause output
#
def pauseoutput():
    try:
        toss = input(">> ")
    except Exception:
        sys.exit(0)

#
# load the XML into memory
#
fptr = open("sample1.xml", "r")
xmltree = ET.parse(fptr)
xmltreeroot = xmltree.getroot()
#
# print the tree as an object
#
print(xmltree)
pauseoutput()
#
# now print the whole tree
#
print("Here's the actual XML tree itself")
for node in xmltree.iter():
    print(node.tag, node.attrib)
pauseoutput()
#
# Now let's see what the main headers are
# these are the outline nodes under the root
#
print("Now the main headers:")
for child in xmltreeroot:
    if child.tag == "outline":
        name = child.attrib.get("text")
        print(name)
pauseoutput()
#
# now we want to print the name and the URL only
# they are the text and xmlUrl attributes of outline nodes
# all outline nodes have the name attribute,
# but the ones without URLs are headers so we print them
# against the left margin, and the others indented
#
print("Now here are the names and URLs of the podcasts")
for node in xmltree.iter("outline"):
    # get them
    name = node.attrib.get("text")
    URL = node.attrib.get("xmlUrl")
    # now print them out
    if name and not URL:
        print(name)
    else:
        print("\t%s -- %s" % (name, URL))
pauseoutput()
#
# okay, we just want the URLs and not the names
# two ways to do this:
#
print("Now, just the URLs: method 1, look for outline nodes ")
print("and print the xmlUrl attribute value ... './/outline' + if:")
for node in xmltree.findall(".//outline"):
    URL = node.attrib.get("xmlUrl")
    if URL:
        print(URL)
pauseoutput()
print("Method 2, we know they are all 2 outlines deep, so ")
print("just grab the xmlURL attribute value; thi assumes all ")
print("such nodes have that attribute ... './/outline/outline':")
for node in xmltree.findall(".//outline/outline"):
    URL = node.attrib.get("xmlUrl")
    print(URL)
pauseoutput()
print("Method 3, we select all elements with attribute xmlUrl ... './/*[@xmlUrl]':")
for node in xmltree.findall(".//*[@xmlUrl]"):
    URL = node.attrib.get("xmlUrl")
    print(URL)
pauseoutput()
#
# Now we want to edit the tree
# first, we want to get rid of the "Books and Fiction" part
#
print("Now delete the Books and Fiction subtree and print the main headers:")
for child in xmltreeroot:
    if child.tag == "outline":
        name = child.attrib.get("text")
        if name == "Books and Fiction":
            xmltreeroot.remove(child)
for child in xmltreeroot:
    if child.tag == "outline":
        name = child.attrib.get("text")
        print(name)
pauseoutput()
#
# now write it out
#
xmltree.write("sample1-output1.xml")
pauseoutput()
#
# now we want to change an attribute, the "MacBreak Weekly" to "MacWeek Breakly"
#
print("Now we change 'MacBreak Weekly' to 'MacWeek Breakly':")
# find the element and change it
for node in xmltreeroot.findall('.//outline'):
    if node.attrib.get("text") == "MacBreak Weekly":
#        print node.attrib.get("xmlUrl")
        node.set("text", "MacWeek Breakly")
for node in xmltree.iter():
    print(node.tag, node.attrib)
pauseoutput()
#
# Let's add back something on fiction, but make it about computer science
#
print("Adding Computer Science Fiction and 2 books:")
newelem = ET.SubElement(xmltreeroot, "outline")
newelem.set('text', "Computer Scence Fiction")
x1 = ET.SubElement(newelem, "outline")
x1.set('text', "Shockwave Rider")
x1.set('author', "John Brunner")
x2 = ET.SubElement(newelem, "outline")
x2.set('text', "Snow Crash")
x2.set('author', "Neal Stephenson")
for node in xmltree.iter():
    print(node.tag, node.attrib)
pauseoutput()
#
# now write it out
#
xmltree.write("sample1-output2.xml")