###############################################################################
#
# Copyright (c) 2009 Cedric Krier.
# Copyright (c) 2007, 2008 OpenHex SPRL. (http://openhex.com) All Rights
# Reserved.
#
# 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 3 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/>.
#
###############################################################################

__metaclass__ = type

import re
try:
    # requires python 2.5+
    from hashlib import md5
except ImportError:
    from md5 import md5

import time
import urllib
import zipfile
from cStringIO import StringIO
from copy import deepcopy


import warnings
warnings.filterwarnings('always', module='relatorio.templates.opendocument')

import lxml.etree
import genshi
import genshi.output
from genshi.template import MarkupTemplate
from genshi.filters import Transformer
from genshi.filters.transform import ENTER, EXIT
from genshi.core import Stream
from genshi.template.interpolation import PREFIX


from relatorio.templates.base import RelatorioStream
from relatorio.reporting import Report, MIMETemplateLoader
try:
    from relatorio.templates.chart import Template as ChartTemplate
except ImportError:
    ChartTemplate = type(None)

GENSHI_EXPR = re.compile(r'''
        (/)?                                 # is this a closing tag?
        (for|if|choose|when|otherwise|with)  # tag directive
        \s*
        (?:\s(\w+)=["'](.*)["']|$)           # match a single attr & its value
        |
        .*                                   # or anything else
        ''', re.VERBOSE)

EXTENSIONS = {'image/png': 'png',
              'image/jpeg': 'jpg',
              'image/bmp': 'bmp',
              'image/gif': 'gif',
              'image/tiff': 'tif',
              'image/xbm': 'xbm',
             }

RELATORIO_URI = 'http://relatorio.openhex.org/'
GENSHI_URI = 'http://genshi.edgewall.org/'
MANIFEST = 'META-INF/manifest.xml'
output_encode = genshi.output.encode
EtreeElement = lxml.etree.Element

# A note regarding OpenDocument namespaces:
#
# The current code assumes the original OpenOffice document uses default
# namespace prefix ("table", "xlink", "draw", ...). We derive the actual
# namespaces URIs from their prefix, instead of the other way round. This has
# the advantage that if a new version of the format use different namespaces
# (this is not the case for ODF 1.1 but could be the case in the future since
# there is a version number in those namespaces after all), Relatorio will
# support those new formats out of the box.


# A note about attribute namespaces:
#
# Ideally, we should update the namespace map of all the nodes we add
# (Genshi) attributes to, so that the attributes use a nice "py" prefix instead
# of a generated one (eg. "ns0", which is correct but ugly) in the case no
# parent node defines it. Unfortunately, lxml doesn't support this:
# the nsmap attribute of Element objects is (currently) readonly.

def guess_type(val):
    if isinstance(val, (str, unicode)):
        return 'string'
    elif isinstance(val, (int, float, long)):
        return 'float'

class OOTemplateError(genshi.template.base.TemplateSyntaxError):
    "Error to raise when there is a SyntaxError in the genshi template"


class ImageHref:
    "A class used to add images in the odf zipfile"

    def __init__(self, zfile, manifest, context):
        self.zip = zfile
        self.manifest = manifest
        self.context = context.copy()

    def __call__(self, expr):
        bitstream, mimetype = expr[:2]
        if isinstance(bitstream, Report):
            bitstream = bitstream(**self.context).render()
        elif isinstance(bitstream, ChartTemplate):
            bitstream = bitstream.generate(**self.context).render()
        bitstream.seek(0)
        file_content = bitstream.read()
        name = md5(file_content).hexdigest()
        path = 'Pictures/%s.%s' % (name, EXTENSIONS[mimetype])
        if path not in self.zip.namelist():
            self.zip.writestr(path, file_content)
            self.manifest.add_file_entry(path, mimetype)
        return {'{http://www.w3.org/1999/xlink}href': path}


class ImageDimension:
    "A class used to set dimension in draw tags"

    def __init__(self, namespaces):
        self.namespaces = namespaces

    def __call__(self, expr, width, height):
        # expr could be (bitstream, mimetype)
        # or (bitstreamm mimetype, width, height)
        if len(expr) == 4:
            width, height = expr[2:]
        attrs = {}
        if width:
            attrs['{%s}width' % self.namespaces['svg']] = width
        if height:
            attrs['{%s}height' % self.namespaces['svg']] = height
        return attrs


class ColumnCounter:
    """A class used to count the actual maximum number of cells (and thus
    columns) a table contains accross its rows.
    """
    def __init__(self):
        self.temp_counters = {}
        self.counters = {}

    def reset(self, loop_id):
        self.temp_counters[loop_id] = 0

    def inc(self, loop_id):
        self.temp_counters[loop_id] += 1

    def store(self, loop_id, table_name):
        self.counters[table_name] = max(self.temp_counters.pop(loop_id),
                                        self.counters.get(table_name, 0))


def wrap_nodes_between(first, last, new_parent):
    """An helper function to move all nodes between two nodes to a new node
    and add that new node to their former parent. The boundary nodes are
    removed in the process.
    """
    old_parent = first.getparent()

    # Any text after the opening tag (and not within a tag) need to be handled
    # explicitly. For example in <if>xxx<span>yyy</span>zzz</if>, zzz is
    # copied along the span tag, but not xxx, which corresponds to the tail
    # attribute of the opening tag.
    if first.tail:
        new_parent.text = first.tail
    for node in first.itersiblings():
        if node is last:
            break
        # appending a node to a new parent also
        # remove it from its previous parent
        new_parent.append(node)
    old_parent.replace(first, new_parent)
    old_parent.remove(last)


def update_py_attrs(node, value):
    """An helper function to update py_attrs of a node.
    """
    if not value:
        return
    py_attrs_attr = '{%s}attrs' % GENSHI_URI
    if not py_attrs_attr in node.attrib:
        node.attrib[py_attrs_attr] = value
    else:
        node.attrib[py_attrs_attr] = \
                "(lambda x, y: x.update(y) or x)(%s or {}, %s or {})" % \
                (node.attrib[py_attrs_attr], value)


class Template(MarkupTemplate):

    def __init__(self, source, filepath=None, filename=None, loader=None,
                 encoding=None, lookup='strict', allow_exec=True):
        self.namespaces = {}
        self.inner_docs = []
        self.has_col_loop = False
        super(Template, self).__init__(source, filepath, filename, loader,
                                       encoding, lookup, allow_exec)

    def _parse(self, source, encoding):
        """parses the odf file.

        It adds genshi directives and finds the inner docs.
        """
        zf = zipfile.ZipFile(self.filepath)
        content = zf.read('content.xml')
        styles = zf.read('styles.xml')

        template = super(Template, self)
        content = template._parse(self.insert_directives(content), encoding)
        styles = template._parse(self.insert_directives(styles), encoding)
        content_files = [('content.xml', content)]
        styles_files = [('styles.xml', styles)]

        while self.inner_docs:
            doc = self.inner_docs.pop()
            c_path, s_path = doc + '/content.xml', doc + '/styles.xml'
            content = zf.read(c_path)
            styles = zf.read(s_path)

            c_parsed = template._parse(self.insert_directives(content),
                                       encoding)
            s_parsed = template._parse(self.insert_directives(styles),
                                       encoding)
            content_files.append((c_path, c_parsed))
            styles_files.append((s_path, s_parsed))

        zf.close()
        parsed = []
        for fpath, fparsed in content_files + styles_files:
            parsed.append((genshi.core.PI, ('relatorio', fpath), None))
            parsed += fparsed

        return parsed

    def insert_directives(self, content):
        """adds the genshi directives, handle the images and the innerdocs.
        """
        tree = lxml.etree.parse(StringIO(content))
        root = tree.getroot()

        # assign default/fake namespaces so that documents do not need to
        # define them if they don't use them
        self.namespaces = {
            "text": "urn:text",
            "draw": "urn:draw",
            "table": "urn:table",
            "office": "urn:office",
            "xlink": "urn:xlink",
            "svg": "urn:svg",
        }
        # but override them with the real namespaces
        self.namespaces.update(root.nsmap)

        # remove any "root" namespace as lxml.xpath do not support them
        self.namespaces.pop(None, None)

        self.namespaces['py'] = GENSHI_URI
        self.namespaces['relatorio'] = RELATORIO_URI

        self._invert_style(tree)
        self._handle_relatorio_tags(tree)
        self._handle_images(tree)
        self._handle_innerdocs(tree)
        self._escape_values(tree)
        return StringIO(lxml.etree.tostring(tree))

    def _invert_style(self, tree):
        "inverts the text:a and text:span"
        xpath_expr = "//text:a[starts-with(@xlink:href, 'relatorio://')]" \
                     "/text:span"
        for span in tree.xpath(xpath_expr, namespaces=self.namespaces):
            text_a = span.getparent()
            outer = text_a.getparent()
            text_a.text = span.text
            span.text = ''
            text_a.remove(span)
            outer.replace(text_a, span)
            span.append(text_a)

    def _relatorio_statements(self, tree):
        "finds the relatorio statements (text:a/text:placeholder)"
        # If this node href matches the relatorio URL it is kept.
        # If this node href matches a genshi directive it is kept for further
        # processing.
        xlink_href_attrib = '{%s}href' % self.namespaces['xlink']
        text_a = '{%s}a' % self.namespaces['text']
        placeholder = '{%s}placeholder' % self.namespaces['text']
        s_xpath = "//text:a[starts-with(@xlink:href, 'relatorio://')]" \
                  "| //text:placeholder"

        r_statements = []
        opened_tags = []
        # We map each opening tag with its closing tag
        closing_tags = {}
        for statement in tree.xpath(s_xpath, namespaces=self.namespaces):
            if statement.tag == placeholder:
                expr = statement.text[1:-1]
            elif statement.tag == text_a:
                expr = urllib.unquote(statement.attrib[xlink_href_attrib][12:])

            if not expr:
                raise OOTemplateError("No expression in the tag",
                                      self.filepath)
            closing, directive, attr, attr_val = \
                    GENSHI_EXPR.match(expr).groups()
            is_opening = closing != '/'

            warn_msg = None
            if not statement.text:
                warn_msg = "No statement text in '%s' for '%s'" \
                           % (self.filepath, expr)
            elif expr != statement.text and statement.tag == text_a:
                warn_msg = "url and text do not match in %s: %s != %s" \
                           % (self.filepath, expr,
                              statement.text.encode('utf-8'))
            if warn_msg:
                if directive is not None and not is_opening:
                    warn_msg += " corresponding to opening tag '%s'" \
                                % opened_tags[-1].text
                warnings.warn(warn_msg)

            if directive is not None:
                # map closing tags with their opening tag
                if is_opening:
                    opened_tags.append(statement)
                else:
                    closing_tags[id(opened_tags.pop())] = statement
            # - we only need to return opening statements
            if is_opening:
                r_statements.append((statement,
                                     (expr, directive, attr, attr_val))
                                   )
        assert not opened_tags
        return r_statements, closing_tags

    def _handle_relatorio_tags(self, tree):
        """
        Will treat all relatorio tag (py:if/for/choose/when/otherwise)
        tags
        """
        # Some tag/attribute name constants
        table_namespace = self.namespaces['table']
        table_row_tag = '{%s}table-row' % table_namespace
        table_cell_tag = '{%s}table-cell' % table_namespace

        office_name = '{%s}value' % self.namespaces['office']
        office_valuetype = '{%s}value-type' % self.namespaces['office']

        py_attrs_attr = '{%s}attrs' % GENSHI_URI
        py_replace = '{%s}replace' % GENSHI_URI

        r_statements, closing_tags = self._relatorio_statements(tree)

        for r_node, parsed in r_statements:
            expr, directive, attr, a_val = parsed

            # If the node is a genshi directive statement:
            if directive is not None:
                opening = r_node
                closing = closing_tags[id(r_node)]

                # - we find the nearest common ancestor of the closing and
                #   opening statements
                o_ancestors = [opening]
                c_ancestors = [closing] + list(closing.iterancestors())
                ancestor = None
                for node in opening.iterancestors():
                    try:
                        idx = c_ancestors.index(node)
                        assert c_ancestors[idx] == node
                        # we only need ancestors up to the common one
                        del c_ancestors[idx:]
                        ancestor = node
                        break
                    except ValueError:
                        # c_ancestors.index(node) raise ValueError if node is
                        # not a child of c_ancestors
                        pass
                    o_ancestors.append(node)
                assert ancestor is not None, \
                       "No common ancestor found for opening and closing tag"

                outermost_o_ancestor = o_ancestors[-1]
                outermost_c_ancestor = c_ancestors[-1]

                # handle horizontal repetitions (over columns)
                if directive == "for" and ancestor.tag == table_row_tag:
                    a_val = self._handle_column_loops(parsed, ancestor,
                                                      opening,
                                                      outermost_o_ancestor,
                                                      outermost_c_ancestor)

                # - we create a <py:xxx> node
                if attr is not None:
                    attribs = {attr: a_val}
                else:
                    attribs = {}
                genshi_node = EtreeElement('{%s}%s' % (GENSHI_URI,
                                                       directive),
                                           attrib=attribs,
                                           nsmap={'py': GENSHI_URI})

                # - we move all the nodes between the opening and closing
                #   statements to this new node (append also removes from old
                #   parent)
                # - we replace the opening statement by the <py:xxx> node
                # - we delete the closing statement (and its ancestors)
                wrap_nodes_between(outermost_o_ancestor, outermost_c_ancestor,
                                   genshi_node)
            else:
                # It's not a genshi statement it's a python expression
                r_node.attrib[py_replace] = expr
                parent = r_node.getparent().getparent()
                if parent is None or parent.tag != table_cell_tag:
                    continue

                # The grand-parent tag is a table cell we should set the
                # correct value and type for this cell.
                dico = "{'%s': %s, '%s': __relatorio_guess_type(%s)}"
                update_py_attrs(parent, dico %
                        (office_name, expr, office_valuetype, expr))
                parent.attrib.pop(office_valuetype, None)
                parent.attrib.pop(office_name, None)

    def _handle_column_loops(self, statement, ancestor, opening,
                             outer_o_node, outer_c_node):
        _, directive, attr, a_val = statement

        self.has_col_loop = True

        table_namespace = self.namespaces['table']
        table_col_tag = '{%s}table-column' % table_namespace
        table_num_col_attr = '{%s}number-columns-repeated' % table_namespace

        py_attrs_attr = '{%s}attrs' % GENSHI_URI
        repeat_tag = '{%s}repeat' % RELATORIO_URI

        # table node (it is not necessarily the direct parent of ancestor)
        table_node = ancestor.iterancestors('{%s}table' % table_namespace) \
                             .next()
        table_name = table_node.attrib['{%s}name' % table_namespace]

        # add counting instructions
        loop_id = id(opening)

        # 1) add reset counter code on the row opening tag
        #    (through a py:attrs attribute).
        # Note that table_name is not needed in the first two
        # operations, but a unique id within the table is required
        # to support nested column repetition
        update_py_attrs(ancestor, "__relatorio_reset_col_count(%d)" % loop_id)

        # 2) add increment code (through a py:attrs attribute) on
        #    the first cell node after the opening (cell node)
        #    ancestor
        enclosed_cell = outer_o_node.getnext()
        assert enclosed_cell.tag == '{%s}table-cell' % table_namespace
        update_py_attrs(enclosed_cell, "__relatorio_inc_col_count(%d)" %
                loop_id)

        # 3) add "store count" code as a py:replace node, as the
        #    last child of the row
        attr_value = "__relatorio_store_col_count(%d, %r)" \
                     % (loop_id, table_name)
        replace_node = EtreeElement('{%s}replace' % GENSHI_URI,
                                    attrib={'value': attr_value},
                                    nsmap={'py': GENSHI_URI})
        ancestor.append(replace_node)

        # find the position in the row of the cells holding the
        # <for> and </for> instructions
        # We use "*" so as to count both normal cells and covered/hidden cells
        position_xpath_expr = 'count(preceding-sibling::*)'
        opening_pos = \
            int(outer_o_node.xpath(position_xpath_expr,
                                   namespaces=self.namespaces))
        closing_pos = \
            int(outer_c_node.xpath(position_xpath_expr,
                                   namespaces=self.namespaces))

        # check whether or not the opening tag spans several rows
        a_val = self._handle_row_spanned_column_loops(
                    statement, outer_o_node, opening_pos, closing_pos)

        # check if this table's headers were already processed
        repeat_node = table_node.find(repeat_tag)
        if repeat_node is not None:
            prev_pos = (int(repeat_node.attrib['opening']),
                        int(repeat_node.attrib['closing']))
            if (opening_pos, closing_pos) != prev_pos:
                raise Exception(
                    'Incoherent column repetition found! '
                    'If a table has several lines with repeated '
                    'columns, the repetition need to be on the '
                    'same columns across all lines.')
        else:
            # compute splits: oo collapses the headers of adjacent
            # columns which use the same style. We need to split
            # any column header which is repeated so many times
            # that it encompasses any of the column headers that
            # we need to repeat
            to_split = []
            idx = 0
            childs = list(table_node.iterchildren(table_col_tag))
            for tag in childs:
                inc = int(tag.attrib.get(table_num_col_attr, 1))
                oldidx = idx
                idx += inc
                if oldidx < opening_pos < idx or \
                   oldidx < closing_pos < idx:
                    to_split.append(tag)

            # split tags
            for tag in to_split:
                tag_pos = table_node.index(tag)
                num = int(tag.attrib.pop(table_num_col_attr))
                new_tags = [deepcopy(tag) for _ in range(num)]
                table_node[tag_pos:tag_pos+1] = new_tags

            # recompute the list of column headers as it could
            # have changed.
            coldefs = list(table_node.iterchildren(table_col_tag))

            # compute the column header nodes corresponding to
            # the opening and closing tags.
            first = table_node[opening_pos]
            last = table_node[closing_pos]

            # add a <relatorio:repeat> node around the column
            # definitions nodes
            attribs = {
               "opening": str(opening_pos),
               "closing": str(closing_pos),
               "table": table_name
            }
            repeat_node = EtreeElement(repeat_tag, attrib=attribs,
                                       nsmap={'relatorio': RELATORIO_URI})
            wrap_nodes_between(first, last, repeat_node)
        return a_val

    def _handle_row_spanned_column_loops(self, statement, outer_o_node,
                                         opening_pos, closing_pos):
        """handles column repetitions which span several rows, by duplicating
        the py:for node for each row, and make the loops work on a copy of the
        original iterable as to not exhaust generators."""

        _, directive, attr, a_val = statement
        table_namespace = self.namespaces['table']
        table_rowspan_attr = '{%s}number-rows-spanned' % table_namespace

        # checks wether there is a (meaningful) rowspan
        rows_spanned = int(outer_o_node.attrib.get(table_rowspan_attr, 1))
        if rows_spanned == 1:
            return a_val

        table_row_tag = '{%s}table-row' % table_namespace
        table_cov_cell_tag = '{%s}covered-table-cell' % table_namespace

        # if so, we need to:

        # 1) create a with node to define a temporary variable
        temp_var = "__relatorio_temp%d" % id(outer_o_node)
        # a_val == "target in iterable"
        target, iterable = a_val.split(' in ', 1)
        vars = "%s = list(%s)" % (temp_var, iterable.strip())
        with_node = EtreeElement('{%s}with' % GENSHI_URI,
                                 attrib={"vars": vars},
                                 nsmap={'py': GENSHI_URI})

        # 2) transform a_val to use that temporary variable
        a_val = "%s in %s" % (target, temp_var)

        # 3) wrap the corresponding cells on the next row(s)
        #    (those should be covered-table-cell) inside a
        #    duplicate py:for node (looping on the temporary
        #    variable).
        row_node = outer_o_node.getparent()
        row_node.addprevious(with_node)
        rows_to_wrap = [row_node]
        assert row_node.tag == table_row_tag
        next_rows = row_node.itersiblings(table_row_tag)
        for row_idx in range(rows_spanned-1):
            next_row_node = next_rows.next()
            rows_to_wrap.append(next_row_node)
            # compute the start and end nodes
            first = next_row_node[opening_pos]
            last = next_row_node[closing_pos]
            assert first.tag == table_cov_cell_tag
            assert last.tag == table_cov_cell_tag
            # wrap them
            tag = '{%s}%s' % (GENSHI_URI, directive)
            for_node = EtreeElement(tag,
                                    attrib={attr: a_val},
                                    nsmap={'py': GENSHI_URI})
            wrap_nodes_between(first, last, for_node)

        # 4) wrap all the corresponding rows indide the "with"
        #    node
        for node in rows_to_wrap:
            with_node.append(node)
        return a_val

    def _handle_images(self, tree):
        "replaces all draw:frame named 'image: ...' by draw:image nodes"
        draw_namespace = self.namespaces['draw']
        draw_name = '{%s}name' % draw_namespace
        draw_image = '{%s}image' % draw_namespace
        py_attrs = '{%s}attrs' % self.namespaces['py']
        svg_namespace = self.namespaces['svg']
        svg_width = '{%s}width' % svg_namespace
        svg_height = '{%s}height' % svg_namespace
        xpath_expr = "//draw:frame[starts-with(@draw:name, 'image:')]"
        for draw in tree.xpath(xpath_expr, namespaces=self.namespaces):
            d_name = draw.attrib[draw_name][6:].strip()
            attr_expr = "__relatorio_make_href(%s)" % d_name
            image_node = EtreeElement(draw_image,
                                      attrib={py_attrs: attr_expr},
                                      nsmap={'draw': draw_namespace,
                                             'py': GENSHI_URI})
            draw.replace(draw[0], image_node)
            width = draw.attrib.pop(svg_width, None)
            height = draw.attrib.pop(svg_height, None)
            attr_expr = "__relatorio_make_dimension(%s, '%s', '%s')" % \
                    (d_name, width, height)
            draw.attrib[py_attrs] = attr_expr

    def _handle_innerdocs(self, tree):
        "finds inner_docs and adds them to the processing stack."
        href_attrib = '{%s}href' % self.namespaces['xlink']
        xpath_expr = "//draw:object[starts-with(@xlink:href, './')" \
                     "and @xlink:show='embed']"
        for draw in tree.xpath(xpath_expr, namespaces=self.namespaces):
            self.inner_docs.append(draw.attrib[href_attrib][2:])

    def _escape_values(self, tree):
        "escapes element values"
        for element in tree.iter():
            for attrs in element.keys():
                if not attrs.startswith('{%s}' % GENSHI_URI):
                    element.attrib[attrs] = element.attrib[attrs]\
                            .replace(PREFIX, PREFIX * 2)
            if element.text:
                element.text = element.text.replace(PREFIX, PREFIX * 2)

    def generate(self, *args, **kwargs):
        "creates the RelatorioStream."
        serializer = OOSerializer(self.filepath)
        kwargs['__relatorio_make_href'] = ImageHref(serializer.outzip,
                                                    serializer.manifest,
                                                    kwargs)
        kwargs['__relatorio_make_dimension'] = ImageDimension(self.namespaces)
        kwargs['__relatorio_guess_type'] = guess_type

        counter = ColumnCounter()
        kwargs['__relatorio_reset_col_count'] = counter.reset
        kwargs['__relatorio_inc_col_count'] = counter.inc
        kwargs['__relatorio_store_col_count'] = counter.store

        stream = super(Template, self).generate(*args, **kwargs)
        if self.has_col_loop:
            # Note that we can't simply add a "number-columns-repeated"
            # attribute and then fill it with the correct number of columns
            # because that wouldn't work if more than one column is repeated.
            transformation = DuplicateColumnHeaders(counter)
            col_filter = Transformer('//repeat[namespace-uri()="%s"]'
                                     % RELATORIO_URI)
            col_filter = col_filter.apply(transformation)
            stream = Stream(list(stream), self.serializer) | col_filter
        return RelatorioStream(stream, serializer)


class DuplicateColumnHeaders(object):
    def __init__(self, counter):
        self.counter = counter

    def __call__(self, stream):
        for mark, (kind, data, pos) in stream:
            # for each repeat tag found
            if mark is ENTER:
                # get the number of columns for that table
                attrs = data[1]
                table = attrs.get('table')
                col_count = self.counter.counters[table]

                # collect events (column header tags) to repeat
                events = []
                for submark, event in stream:
                    if submark is EXIT:
                        break
                    events.append(event)

                # repeat them
                for _ in range(col_count):
                    for event in events:
                        yield None, event
            else:
                yield mark, (kind, data, pos)


class Manifest(object):

    def __init__(self, content):
        self.tree = lxml.etree.parse(StringIO(content))
        self.root = self.tree.getroot()
        self.namespaces = self.root.nsmap

    def __str__(self):
        return lxml.etree.tostring(self.tree, encoding='UTF-8',
                                   xml_declaration=True)

    def add_file_entry(self, path, mimetype=None):
        manifest_namespace = self.namespaces['manifest']
        attribs = {'{%s}media-type' % manifest_namespace: mimetype or '',
                   '{%s}full-path' % manifest_namespace: path}
        entry_node = EtreeElement('{%s}%s' % (manifest_namespace,
                                              'file-entry'),
                                  attrib=attribs,
                                  nsmap={'manifest': manifest_namespace})
        self.root.append(entry_node)


class OOSerializer:

    def __init__(self, oo_path):
        self.inzip = zipfile.ZipFile(oo_path)
        self.manifest = Manifest(self.inzip.read(MANIFEST))
        self.new_oo = StringIO()
        self.outzip = zipfile.ZipFile(self.new_oo, 'w')
        self.xml_serializer = genshi.output.XMLSerializer()

    def __call__(self, stream):
        files = {}
        for kind, data, pos in stream:
            if kind == genshi.core.PI and data[0] == 'relatorio':
                stream_for = data[1]
                continue
            files.setdefault(stream_for, []).append((kind, data, pos))

        now = time.localtime()[:6]
        for f_info in self.inzip.infolist():
            if f_info.filename.startswith('ObjectReplacements'):
                continue
            elif f_info.filename in files:
                stream = files[f_info.filename]
                # create a new file descriptor, copying some attributes from
                # the original file
                new_info = zipfile.ZipInfo(f_info.filename, now)
                for attr in ('compress_type', 'flag_bits', 'create_system'):
                    setattr(new_info, attr, getattr(f_info, attr))
                serialized_stream = output_encode(self.xml_serializer(stream))
                self.outzip.writestr(new_info, serialized_stream)
            elif f_info.filename == MANIFEST:
                self.outzip.writestr(f_info, str(self.manifest))
            else:
                self.outzip.writestr(f_info, self.inzip.read(f_info.filename))
        self.inzip.close()
        self.outzip.close()

        return self.new_oo

MIMETemplateLoader.add_factory('oo.org', Template)
