#! /usr/bin/env python
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>.

# This script unites Mallard pages into a single hierarchical page, to
# be processed to create a PDF document.

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

xrefs = []

class Page:
    id = None
    filepath = None
    xml_node = None
    xref = None
    done = False

    def __init__(self, node):
        self.id = node.attrib.get('id')
        self.filepath = node.attrib.get('{http://projectmallard.org/cache/1.0/}href')
        self.xml_node = ET.parse(self.filepath[7:])
        self.load_xrefs()

    def load_xrefs(self):
        global xrefs
        for node in self.xml_node.findall(".//{http://projectmallard.org/1.0/}link[@type='guide']"):
            self.xref = node.attrib.get('xref')
            break
        if self.xref:
            sort_title = self.xml_node.findall(".//{http://projectmallard.org/1.0/}title")[0].text
            for node in self.xml_node.findall(".//{http://projectmallard.org/1.0/}title[@type='sort']"):
                sort_title = node.text
                break
            xrefs.append((self.xref, self, sort_title))

    def complete(self):
        for xref, page, sort_title in xrefs:
            if xref == self.id:
                new_parent_element = self.xml_node.getroot()
            elif xref.startswith(self.id + '#'):
                section_id = xref.split('#')[1]
                section = self.xml_node.findall(".//*[@id='%s']" % section_id)
                try:
                    new_parent_element = section[0]
                except IndexError:
                    print >> sys.stderr, 'W: missing section:', section_id
                    continue
            else:
                continue

            new_section = ET.SubElement(new_parent_element, '{http://projectmallard.org/1.0/}section')
            new_section.attrib['id'] = 'auto-' + page.id
            new_section.extend(page.xml_node.getroot().getchildren())
            page.done = True


def create_mallard_cache(directory):
    page_files = [os.path.join(directory, x) for x in os.listdir(directory) \
            if x.endswith('.page') and x != '_united.page']
    cmd = ['yelp-build', 'cache', '-o', '-']
    cmd.extend(page_files)
    p = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
    stdout, stderr = p.communicate()
    if p.returncode != 0:
        raise Exception('failed to create initial mallard cache')
    return stdout

def create_united_page(mallard_cache, directory):
    global xrefs

    pages = {}

    index_cache = ET.fromstring(mallard_cache)

    # load pages
    for page_node in index_cache.findall(".//{http://projectmallard.org/1.0/}page"):
        page = Page(page_node)
        pages[page.id] = page

    xrefs.sort(lambda x, y: cmp(x[2], y[2]))

    for page in pages.values():
        page.complete()

    leftovers = []
    for page in pages.values():
        if page.done:
            continue
        if page.id == 'index':
            continue
        leftovers.append(page)

    if leftovers:
        index_page = pages.get('index')
        appendix = ET.SubElement(index_page.xml_node.getroot(), '{http://projectmallard.org/1.0/}section')
        appendix.attrib['id'] = 'appendix'
        ET.SubElement(appendix, '{http://projectmallard.org/1.0/}title').text = 'Annexes'
        for page in leftovers:
            new_section = ET.SubElement(appendix, '{http://projectmallard.org/1.0/}section')
            new_section.extend(page.xml_node.getroot().getchildren())

    pages['index'].xml_node.write(os.path.join(directory, '_united.page'))

def create_united_mallard_cache(directory):
    cmd = ['yelp-build', 'cache', '-o', os.path.join(directory, '_united.cache'),
            os.path.join(directory, '_united.page')]
    if subprocess.call(cmd) != 0:
        raise Exception('failed to create united mallard cache')

def create_latex(directory, latex_filename):
    xsl_path = os.path.abspath(os.path.dirname(__file__))
    cmd = ['xsltproc', os.path.join(xsl_path, 'mal2latex.xsl'),
            os.path.join(directory, '_united.cache')]
    p = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
    stdout, stderr = p.communicate()
    if p.returncode != 0:
        raise Exception('failed to create united LaTeX file')
    file(latex_filename, 'w').write(stdout)


if __name__ == '__main__':
    parser = OptionParser()
    parser.add_option('-d', '--directory', dest='directory',
            metavar='DIRECTORY', default='.')
    parser.add_option('-l', '--latex', dest='latex', metavar='FILEANAME')

    options, args = parser.parse_args()
    directory = options.directory
    mallard_cache = create_mallard_cache(directory)
    create_united_page(mallard_cache, directory)
    create_united_mallard_cache(directory)
    create_latex(directory, options.latex)