#!/usr/bin/env python3
#
# Modified from the htmldiff script developed by Dominique Hazael-Massieux
# for the http://services.w3.org/htmldiff website.
# License information found at https://github.com/w3c/htmldiff-ui/blob/master/LICENSE
# for "htmldiffy.py".
#
# Copyright (c) 2008-2020 w3c
# Copyright (c) 2016-2021, The Khronos Group Inc.
# SPDX-License-Identifier: MIT
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import atexit
import os
import re
import sys
import tempfile
import tidy

from subprocess import Popen, PIPE

def tidyFile(filename):
    ifp = open(filename, 'r')

    # option for tidy
    options = dict(tidy_mark=0,show_warnings=0,quiet=1,char_encoding='utf8')
    html5 = re.search(r"<!doctype\s+html\s*>", ifp.read(4096),
                      re.IGNORECASE)
    ifp.seek(0)
    html5_options = {'add_xml_space': 'no',
                     'output_xhtml': 'no',
                     'tidy_mark': 'no',
                     'new_blocklevel_tags': 'article,aside,canvas,dialog,details,figcaption,figure,footer,header,hgroup,menu,nav,section,main,summary,math,semantics,mrow,mfenced,mtable,mtr,mtd,mi,mn,msub,mo,mfrac,munderover,mtext,svg,g,image,rect,text,desc,line,path,polygon,ellipse,tspan,defs,feoffset,fecolormatrix,filter,fegaussianblur,feblend,marker,circle',
                     'new_inline_tags': 'video,audio,canvas,ruby,rt,rp,time,meter,progress,track,source,emu-val,emu-nt,emu-t,mark',
                     'break_before_br': 'no',
                     'vertical_space': 'no',
                     'enclose_text': 'no',
                     'numeric_entities': 'yes',
                     'wrap': '1000',
                     'wrap_attributes': 'no',
                     'drop_empty_paras': 'no'
                     }
    if html5:
        options.update(html5_options)
    newtidy = tidy.parseString(ifp.read(), **options)
    if len(newtidy.errors) > 0:
        if not html5:
            ifp.seek(0)
            options.update(html5_options)
            newtidy = tidy.parseString(ifp.read(), **options)
    ifp.close()

    fp = tempfile.NamedTemporaryFile(
           mode='w+', prefix='htmldiff-', suffix='.html')
    atexit.register(fp.close)
    fp.write(str(newtidy))
    fp.flush()
    fp.seek(0)

    # sys.stderr.write('tidyFile: tempfile name %s\n' % fp.name)

    if (newtidy.errors):
        sys.stderr.write('tidyFile: tidy.parseString error: %s\n' % str(newtidy.errors))
    return fp

def call_perl(args):

    scriptdir = os.path.abspath(os.path.dirname(sys.argv[0]))
    perlscript = os.path.join(scriptdir, 'htmldiff.pl')
    cmd = [perlscript]
    cmd.extend(args)
    p = Popen(cmd,
              text=True,
              stdin=PIPE, stdout=PIPE, stderr=PIPE)
    sys.stdout.flush()
    sys.stderr.flush()
    (out, err) = p.communicate()
    p.stdin.close()
    if err:
        print(out)
        sys.stderr.write('htmldiff: An error occurred when running htmldiff.pl on the documents: %s\n'% str(err))
        exit(1)
    else:
        print(out)
        exit(0)

def usage():
    # didn't investigate fully what -c does - something about mhtml comments?
    sys.stderr.write("""htmldiff: need two filename args file1 file2

May also pass arguments:
    -l  Make diff highlights links that jump to the following diff
    -t  Add a script to optionally hide old text via button
    -o  Complete omit old text
    -h  show this text
""")
    sys.exit(1)

if __name__ == '__main__':

    docs = []
    passthru_args = []
    for arg in sys.argv[1:]:
        if arg in ('-c', '-l', '-t', '-o'):
            passthru_args.append(arg)
        elif arg == '-h':
            usage()
        else:
            docs.append(arg)

    if (len(docs) != 2):
        usage()
    refdoc = tidyFile(docs[0])

    newdoc = tidyFile(docs[1])
    passthru_args.append(refdoc.name)
    passthru_args.append(newdoc.name)
    call_perl(passthru_args)