#!/usr/pkg/bin/python3.13
"""
Syncthing-GTK - tools

Wrapper around GTKBuilder. Allows using conditional (<IF>) tags in
glade files.

Usage:
    - Crete instance
    - Enable conditions (enable_condition call)
    - Call add_from_file or add_from_string method
    - Continue as usual
"""


import logging
from xml.dom import minidom

from gi.repository import Gtk

from syncthing_gtk.tools import _  # gettext function
from syncthing_gtk.tools import get_locale_dir

from .tools import GETTEXT_DOMAIN, IS_WINDOWS

log = logging.getLogger("UIBuilder")


class UIBuilder(Gtk.Builder):
    def __init__(self):
        Gtk.Builder.__init__(self)
        self.set_translation_domain(GETTEXT_DOMAIN)
        self.conditions = set([])
        self.icon_paths = []
        self.xml = None

    def add_from_file(self, filename):
        """Builds UI from file"""
        log.debug("Loading glade file %s", filename)
        if len(self.conditions) == 0 and not IS_WINDOWS and get_locale_dir() is None:
            # There is no need to do any magic in this case; Just use
            # Gtk.Builder directly
            Gtk.Builder.add_from_file(self, filename)
        else:
            with open(filename, "r") as f:
                self.add_from_string(f.read())

    def add_from_string(self, string):
        """Builds UI from string"""
        self.xml = minidom.parseString(string)
        self._build()

    def add_from_resource(self, *a):
        raise RuntimeError("add_from_resource is not supported")

    def enable_condition(self, *conds):
        """Enables condition. Conditions are case-insensitive"""
        for c in conds:
            log.debug("Enabled: %s", c)
            self.conditions.add(c)

    def disable_condition(self, *conds):
        """Disables condition. Conditions are case-insensitive"""
        for c in conds:
            log.debug("Disabled: %s", c)
            self.conditions.remove(c)

    def condition_met(self, cond):
        """
        Returns True if condition is met. Empty condition is True.
        Spaces at beginning or end of expressions are stripped.

        Supports simple |, & and !
        operators, but no parenthesis.
        (I just hope I'd never have to use them)
        """
        if "|" in cond:
            for sub in cond.split("|", 1):
                if self.condition_met(sub):
                    return True
            return False
        if "&" in cond:
            for sub in cond.split("&", 1):
                if not self.condition_met(sub):
                    return False
            return True
        if cond.strip().startswith("!"):
            return not self.condition_met(cond.strip()[1:])
        return cond.strip() in self.conditions

    def replace_icon_path(self, prefix, replace_with):
        """
        All path replaceaments defined using this method are applied
        by _build method on anything that remotely resembles icon path.
        """
        if not prefix.endswith("/"):
            prefix = "%s/" % (prefix,)
        if not replace_with.endswith("/"):
            replace_with = "%s/" % (replace_with,)
        self.icon_paths.append((prefix, replace_with))

    def _build(self):
        """
        Fun part starts here. Recursively walks through entire DOM tree,
        removes all <IF> tags replacing them with child nodes if when
        condition is met and fixes icon paths, if required.
        """
        log.debug("Enabled conditions: %s", self.conditions)
        self._replace_icon_paths(self.xml.documentElement)
        self._find_conditions(self.xml.documentElement)
        if IS_WINDOWS or get_locale_dir() is not None:
            self._find_translatables()
        # Now this will convert parsed DOM tree back to XML and fed it
        # to Gtk.Builder XML parser.
        # God probably kills kitten every time when method is called...
        Gtk.Builder.add_from_string(self, self.xml.toxml())

    def _find_translatables(self, node=None):
        """
        Fuck GTK devs.
        With cacti.
        https://bugzilla.gnome.org/show_bug.cgi?id=574520
        """
        if node is None:
            node = self.xml.documentElement
        for child in node.childNodes:
            if child.nodeType == child.ELEMENT_NODE:
                if child.tagName.lower() in ("property", "col"):
                    if child.getAttribute("translatable") == "yes":
                        self._translate(child)
                else:
                    self._find_translatables(child)

    def _translate(self, node):
        for child in node.childNodes:
            if child.nodeType == child.TEXT_NODE:
                child.nodeValue = _(child.nodeValue)

    def _replace_icon_paths(self, node):
        """Recursive part for _build - icon paths"""
        for child in node.childNodes:
            if child.nodeType == child.ELEMENT_NODE:
                self._replace_icon_paths(child)
                if child.tagName.lower() == "property":
                    if child.getAttribute("name") == "pixbuf":
                        # GtkImage, pixbuf path
                        self._check_icon_path(child)
                    elif child.getAttribute("name") == "icon":
                        # window or dialog, icon path
                        self._check_icon_path(child)

    def _find_conditions(self, node):
        """Recursive part for _build - <IF> tags"""
        for child in node.childNodes:
            if child.nodeType == child.ELEMENT_NODE:
                self._find_conditions(child)
                if child.tagName.lower() == "if":
                    self._solve_if_element(child)
                elif child.getAttribute("if") != "":
                    condition = child.getAttribute("if")
                    if not self.condition_met(condition):
                        log.debug("Removed '%s' by attribute: %s", child.tagName, condition)
                        node.removeChild(child)
                    else:
                        child.removeAttribute("if")

    def _solve_if_element(self, element):
        """
        Reads "condition" attribute and decides if condition is met
        Conditions are case-insensitive
        """
        condition = element.getAttribute("condition").lower().strip()
        if self.condition_met(condition):
            # Merge child nodes in place of this IF element
            # Remove ELSE elements, if any
            log.debug("Allowed node %s", condition)
            for elseem in getElementsByTagNameCI(element, "else"):
                element.removeChild(elseem)
            merge_with_parent(element, element)
        else:
            # Remove this element, but merge ELSE elements, if any
            log.debug("Removed node %s", condition)
            for elseem in getElementsByTagNameCI(element, "else"):
                merge_with_parent(elseem, element)
            element.parentNode.removeChild(element)

    def _check_icon_path(self, element):
        def replace(path):
            """
            If specified path begins with one of replaceament prefixes,
            returns path with modified prefix.
            """
            for prefix, replace_with in self.icon_paths:
                if path.startswith(prefix):
                    return "%s%s" % (replace_with, path[len(prefix) :])
            return path

        for n in element.childNodes:
            if n.nodeType == n.TEXT_NODE:
                n.data = replace(n.data)
        return


def getElementsByTagNameCI(node, tagname):
    """
    Returns all elements with matching tag; Compares in
    case-insensitive way.
    """
    tagname = tagname.lower()
    return [
        child
        for child in node.childNodes
        if (child.nodeType == child.ELEMENT_NODE and child.tagName.lower() == tagname)
    ]


def merge_with_parent(element, insert_before):
    """Merges child nodes with parent node"""
    for child in element.childNodes:
        if child.nodeType == child.ELEMENT_NODE:
            element.removeChild(child)
            insert_before.parentNode.appendChild(child)
            insert_before.parentNode.insertBefore(child, insert_before)
    element.parentNode.removeChild(element)
