#!/usr/bin/env python
"""
Usage: {prog} [OPTION] FILE1 FILE2 xPath

Compare two XML files, ignoring element and attribute order.

xPath a valid path should be defined or wildcard "*" should be used.
example:
    ./{{urn:ietf:params:xml:ns:yang:ietf-interfaces}}interfaces/
    {{urn:ietf:params:xml:ns:yang:ietf-interfaces}}interface[
    {{urn:ietf:params:xml:ns:yang:ietf-interfaces}}name='loop0']

Any extra options are passed to the `diff' command.

Copyright (c) 2017, Johannes H. Jensen.
License: BSD, see LICENSE for more details.
"""
from __future__ import print_function, unicode_literals

import os
import subprocess
import sys
import xml.etree.ElementTree as ET
from tempfile import NamedTemporaryFile


def attr_str(k, v):
    return "{}=\"{}\"".format(k, v)


def node_str(n):
    attrs = sorted(n.attrib.items())
    astr = " ".join(attr_str(k, v) for k, v in attrs)
    s = n.tag
    if astr:
        s += " " + astr
    return s


def node_key(n):
    return node_str(n)


def indent(s, level):
    return "  " * level + s


def write_sorted(stream, node, level=0):
    if node is None:
        return
    children = node.getchildren()
    text = (node.text or "").strip()
    tail = (node.tail or "").strip()

    if children or text:
        children.sort(key=node_key)

        stream.write(indent("<" + node_str(node) + ">\n", level))

        if text:
            stream.write(indent(text + "\n", level))

        for child in children:
            write_sorted(stream, child, level + 1)

        stream.write(indent("</" + node.tag + ">\n", level))
    else:
        stream.write(indent("<" + node_str(node) + "/>\n", level))

    if tail:
        stream.write(indent(tail + "\n", level))


if sys.version_info < (3, 0):
    # Python 2
    import codecs

    def unicode_writer(fp):
        return codecs.getwriter('utf-8')(fp)
else:
    # Python 3
    def unicode_writer(fp):
        return fp


def xmldiffs(file1, file2, xpath="*", diffargs=["-u"]):
    tree = ET.parse(file1)
    tmp1 = unicode_writer(NamedTemporaryFile('w'))
    if xpath == "*":
        write_sorted(tmp1, tree.getroot())
    else:
        write_sorted(tmp1, tree.getroot().find(xpath))

    tmp1.flush()

    tree = ET.parse(file2)
    tmp2 = unicode_writer(NamedTemporaryFile('w'))
    if xpath == "*":
        write_sorted(tmp2, tree.getroot())
    else:
        write_sorted(tmp2, tree.getroot().find(xpath))
    tmp2.flush()

    args = ["diff"]
    args += diffargs
    args += ["--label", file1, "--label", file2]
    args += [tmp1.name, tmp2.name]

    return subprocess.call(args)


def print_usage(prog):
    print(__doc__.format(prog=prog).strip())


if __name__ == '__main__':
    args = sys.argv
    prog = os.path.basename(args.pop(0))

    if '-h' in args or '--help' in args:
        print_usage(prog)
        exit(0)

    if len(args) < 3:
        print_usage(prog)
        exit(1)

    xPath = args.pop(-1)
    file2 = args.pop(-1)
    file1 = args.pop(-1)

    xPath = xPath if xPath else "*"

    diffargs = args if args else ["-u", "-s"]

    exit(xmldiffs(file1, file2, xPath, diffargs))