#
# Copyright 2008-2014 Zuza Software Foundation
#
# This file is part of the Translate Toolkit.
#
# 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/>.

from contextlib import contextmanager

from lxml import etree

from translate.misc.xml_helpers import get_safe_xml_parser
from translate.storage.placeables import StringElem, xliff
from translate.storage.xliff import xliffunit
from translate.storage.xml_extract import misc, xpath_breadcrumb


class Translatable:
    """
    A node corresponds to a translatable element. A node may have children,
    which correspond to placeables.
    """

    def __init__(
        self, placeable_name, xpath, dom_node, source, is_inline=False
    ) -> None:
        self.placeable_name = placeable_name
        self.source = source
        self.xpath = xpath
        self.is_inline = is_inline
        self.dom_node = dom_node

    @property
    def placeables(self):
        return [
            placeable
            for placeable in self.source
            if isinstance(placeable, Translatable)
        ]

    @property
    def has_translatable_text(self):
        """
        Check if it contains any chunk of text with more than whitespace.

        If not, then there's nothing to translate.
        """
        return any(isinstance(chunk, str) and chunk.strip() for chunk in self.source)


def reduce_unit_tree(f, unit_node, *state):
    return misc.reduce_tree(
        f, unit_node, unit_node, lambda unit_node: unit_node.placeables, *state
    )


class ParseState:
    """
    Maintain constants and variables used during the walking of a DOM tree
    (via the function apply).
    """

    def __init__(
        self, no_translate_content_elements, inline_elements={}, nsmap={}
    ) -> None:
        self.no_translate_content_elements = no_translate_content_elements
        self.inline_elements = inline_elements
        self.is_inline = False
        self.xpath_breadcrumb = xpath_breadcrumb.XPathBreadcrumb()
        self.placeable_name = "<top-level>"
        self.nsmap = nsmap


def _process_placeable(dom_node, state):
    """
    Process current placeable.

    This returns all nested translatable content for this placeable as a single
    Translatable object, or just returns an empty Translatable object for this
    placeable if there is no nested translatable content.
    """
    placeable = find_translatable_dom_nodes(dom_node, state, process_translatable)

    if len(placeable) == 0:
        # There are no recognized child tags and thus no Translatable object is
        # returned. So create a Translatable with the name "placeable".
        return Translatable("placeable", state.xpath_breadcrumb.xpath, dom_node, [])
    if len(placeable) == 1:
        # The ideal situation: we got exactly one Translatable back when
        # processing this tree.
        return placeable[0]
    raise ValueError(
        "BUG: find_translatable_dom_nodes should never return "
        "more than a single Translatable object"
    )


def process_translatable(dom_node, state):
    """
    Process a translatable DOM node.

    Any translatable content present in a child node is treated as a placeable.
    """
    source = [str(dom_node.text or "")]

    # Append Translatable objects and unicode strings for the translatable
    # content for all the children.
    for child in dom_node:
        source.extend((_process_placeable(child, state), str(child.tail or "")))

    translatable = Translatable(
        state.placeable_name,
        state.xpath_breadcrumb.xpath,
        dom_node,
        source,
        state.is_inline,
    )
    return [translatable]


def _has_idml_translatable_content(dom_node):
    has_translatable_content = True
    if dom_node.tag == "ParagraphStyleRange":
        has_translatable_content = False

        for content_node in dom_node.findall(".//Content"):
            # Iterate over all the Content tags in this ParagraphStyleRange tag.
            if content_node.text is not None and content_node.text.strip():
                return True

            for child in content_node.iterdescendants():
                # The Content node can just have a child before any nested
                # text, and therefore its text is None, so we have to check if
                # it has children, and if any of its children has text.
                if (
                    not isinstance(child, etree._ProcessingInstruction)
                    and child.text is not None
                    and child.text.strip()
                ):
                    return True

                if child.tail is not None and child.tail.strip():
                    return True

    return has_translatable_content


def _retrieve_idml_placeables(dom_node, state):
    source = []
    for child in dom_node:
        if not isinstance(child, etree._Element):
            continue

        if isinstance(child, etree._ProcessingInstruction):
            # TODO this probably won't be using the right xpath.
            source.append(
                Translatable(
                    "placeable", state.xpath_breadcrumb.xpath, child, [], False
                )
            )

            if child.tail is not None and child.tail.strip():
                source.append(str(child.tail))

            continue

        namespace, tag = misc.parse_tag(child.tag)

        with parse_status_set(namespace, tag, state):
            # Ensure we extract all the tags below ParagraphStyleRange as
            # placeables, independently of them being translatable or not.
            # state.is_inline = True

            nested_stuff = []

            if child.text is not None and child.text.strip():
                nested_stuff = [str(child.text)]

            nested_stuff.extend(_retrieve_idml_placeables(child, state))

            source.append(
                Translatable(
                    "placeable",
                    state.xpath_breadcrumb.xpath,
                    child,
                    nested_stuff,
                    state.is_inline,
                )
            )

            if child.tail is not None and child.tail.strip():
                source.append(str(child.tail))

    return source


def process_idml_translatable(dom_node, state):
    if _has_idml_translatable_content(dom_node):
        source = _retrieve_idml_placeables(dom_node, state)

        translatable = Translatable(
            state.placeable_name,
            state.xpath_breadcrumb.xpath,
            dom_node,
            source,
            state.is_inline,
        )
        return [translatable]

    return []


def _process_children(dom_node, state, process_func):
    """
    Process an untranslatable DOM node.

    Since the node is untranslatable it just returns any translatable content
    present in its child nodes.
    """
    children = [
        find_translatable_dom_nodes(child, state, process_func) for child in dom_node
    ]

    # Flatten a list of lists into a list of elements
    children = [child for child_list in children for child in child_list]

    if len(children) > 1:
        _namespace, tag = misc.parse_tag(dom_node.tag)
        intermediate_translatable = Translatable(
            tag, state.xpath_breadcrumb.xpath, dom_node, children
        )
        return [intermediate_translatable]
    return children


def compact_tag(nsmap, namespace, tag) -> str:
    if namespace in nsmap:
        return f"{nsmap[namespace]}:{tag}"
    return f"{{{namespace}}}{tag}"


@contextmanager
def parse_status_set(namespace, tag, state):
    # Set XPath breadcrumb item for the current node.
    xpath_item = compact_tag(state.nsmap, namespace, tag)
    state.xpath_breadcrumb.start_tag(xpath_item)

    # Set the placeable name for the current node.
    old_placeable_name = state.placeable_name
    state.placeable_name = tag

    # Set the inline status for the current node.
    old_inline = state.is_inline
    state.is_inline = (namespace, tag) in state.inline_elements

    yield state

    # Reset inline status, placeable name and XPath breadcrumb to the
    # previous values.
    state.is_inline = old_inline
    state.placeable_name = old_placeable_name
    state.xpath_breadcrumb.end_tag()


def find_translatable_dom_nodes(dom_node, state, process_func=process_translatable):
    # For now, we only want to deal with XML elements.
    # And we want to avoid processing instructions, which
    # are XML elements (in the inheritance hierarchy).
    if not isinstance(dom_node, etree._Element) or isinstance(
        dom_node, etree._ProcessingInstruction
    ):
        return []

    namespace, tag = misc.parse_tag(dom_node.tag)

    with parse_status_set(namespace, tag, state):
        if (namespace, tag) not in state.no_translate_content_elements:
            return process_func(dom_node, state)
        return _process_children(dom_node, state, process_func)


class IdMaker:
    def __init__(self) -> None:
        self._max_id = 0
        self._obj_id_map = {}

    def get_id(self, obj):
        if not self.has_id(obj):
            self._obj_id_map[obj] = self._max_id
            self._max_id += 1
        return self._obj_id_map[obj]

    def has_id(self, obj):
        return obj in self._obj_id_map


def _to_placeables(parent_translatable, translatable, id_maker):
    """
    Convert the translatable object to a list of strings and XLIFF
    placeables.
    """
    result = []
    for chunk in translatable.source:
        if isinstance(chunk, str):
            result.append(chunk)
        else:
            id = str(id_maker.get_id(chunk))
            if chunk.is_inline:
                sub = _to_placeables(parent_translatable, chunk, id_maker)
                result.append(xliff.G(id=id, sub=sub))
            else:
                result.append(xliff.X(id=id, xid=chunk.xpath))
    return result


def _make_store_adder(store):
    """
    Return a function which, when called with a Translatable will add
    a unit to 'store'. The placeables will be represented as strings according
    to 'placeable_quoter'.
    """
    id_maker = IdMaker()

    def add_translatable_to_store(parent_translatable, translatable) -> None:
        """
        Construct a new translation unit, set its source and location
        information and add it to 'store'.
        """
        unit = store.UnitClass("")
        unit.rich_source = [
            StringElem(_to_placeables(parent_translatable, translatable, id_maker))
        ]
        if isinstance(unit, xliffunit):
            unit.setid(translatable.xpath)
        else:
            unit.addlocation(translatable.xpath)
        store.addunit(unit)

    return add_translatable_to_store


def make_postore_adder(store, id_maker, filename):
    """
    Return a function which, when called with a Translatable will add
    a unit to 'store'. The placeables will be represented as strings according
    to 'placeable_quoter'.
    """

    def add_translatable_to_store(parent_translatable, translatable) -> None:
        """
        Construct a new translation unit, set its source and location
        information and add it to 'store'.
        """
        xliff_unit = xliffunit("")
        placeables = _to_placeables(parent_translatable, translatable, id_maker)
        xliff_unit.rich_source = [StringElem(placeables)]

        # Get the plain text for the unit source. The output is enclosed within
        # XLIFF source tags we don't want, so strip them.
        unit_source = etree.tostring(xliff_unit.source_dom, encoding="unicode")
        unit_source = unit_source[unit_source.find(">", 1) + 1 :]
        unit_source = unit_source[: unit_source.rfind("<", 1)]

        # Create the PO unit and add it to the PO store.
        po_unit = store.UnitClass(unit_source)
        po_unit.addlocation(translatable.xpath)
        po_unit.addlocation(filename)
        store.addunit(po_unit)

    return add_translatable_to_store


def _walk_idml_translatable_tree(
    translatables, store_adder, parent_translatable
) -> None:
    """
    Traverse all the found IDML translatables and add them to the Store.

    Inline translatables are not added to the Store.
    """
    for translatable in translatables:
        if translatable.dom_node.tag == "ParagraphStyleRange":
            store_adder(parent_translatable, translatable)
            continue

        new_parent_translatable = parent_translatable
        _walk_idml_translatable_tree(
            translatable.placeables, store_adder, new_parent_translatable
        )


def _walk_translatable_tree(
    translatables, store_adder, parent_translatable, stored_by_parent=False
) -> None:
    """
    Traverse all the found translatables and add them to the Store.

    Inline translatables are not added to the Store.
    """
    for translatable in translatables:
        store_here = translatable.has_translatable_text and (
            not translatable.is_inline or not stored_by_parent
        )
        if store_here:
            store_adder(parent_translatable, translatable)
        new_parent_translatable = parent_translatable
        _walk_translatable_tree(
            translatable.placeables,
            store_adder,
            new_parent_translatable,
            store_here or stored_by_parent,
        )


def reverse_map(a_map):
    return {value: key for key, value in a_map.items()}


def build_idml_store(odf_file, store, parse_state, store_adder=None):
    """Build a store for the given IDML file."""
    store_adder = store_adder or _make_store_adder(store)
    tree = etree.parse(odf_file, get_safe_xml_parser())
    root = tree.getroot()
    parse_state.nsmap = reverse_map(root.nsmap)
    translatables = find_translatable_dom_nodes(
        root, parse_state, process_idml_translatable
    )
    _walk_idml_translatable_tree(translatables, store_adder, None)
    return tree


def build_store(odf_file, store, parse_state, store_adder=None):
    """Build a store for the given XML file."""
    store_adder = store_adder or _make_store_adder(store)
    tree = etree.parse(odf_file, get_safe_xml_parser())
    root = tree.getroot()
    parse_state.nsmap = reverse_map(root.nsmap)
    translatables = find_translatable_dom_nodes(root, parse_state)
    _walk_translatable_tree(translatables, store_adder, None)
    return tree
