"""

Part of the tagit module.
A copy of the license is provided with the project.
Author: Matthias Baumgartner, 2022
"""
# standard imports
from functools import partial
import os

# kivy imports
from kivy.cache import Cache
from kivy.lang import Builder
import kivy.properties as kp

# tagit imports
from tagit import config, dialogues
from tagit.external.kivy_garden.contextmenu import ContextMenu
from tagit.utils import clamp, errors
from tagit.utils import ns
from tagit.utils.bsfs import ast
from tagit.widgets import Binding
from tagit.widgets.filter import FilterAwareMixin
from tagit.widgets.session import StorageAwareMixin, ConfigAwareMixin
#from tagit.ai.features.content import ContentFeature, FeatureBuilder # FIXME: mb/port
#from tagit.parsing.search import sortkeys # FIXME: mb/port


# inner-module imports
from .action import Action

# exports
__all__ = []


## code ##

# load kv
Builder.load_file(os.path.join(os.path.dirname(__file__), 'search.kv'))

# classes
class Search(Action, StorageAwareMixin, ConfigAwareMixin):
    """Apply the current search filter and update the browser."""
    text = kp.StringProperty('Search')

    # internal category for the cache
    _CACHE_CATEGORY = 'tagit.search'

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'search', 'search'))

    def on_root(self, wx, root):
        Action.on_root(self, wx, root)
        ConfigAwareMixin.on_root(self, wx, root)
        StorageAwareMixin.on_root(self, wx, root)

    def on_config_changed(self, session, key, value):
        """Update cache settings."""
        if self._CACHE_CATEGORY not in Cache._categories:
            pass
        elif key == ('ui', 'standalone', 'search', 'cache_items'):
            value = None if value <= 0 else value
            Cache._categories[self._CACHE_CATEGORY]['limit'] = value
        elif key == ('ui', 'standalone', 'search', 'cache_timeout'):
            value = None if value <= 0 else value
            Cache._categories[self._CACHE_CATEGORY]['timeout'] = value

    def on_cfg(self, wx, cfg):
        """Initialize the cache."""
        if self._CACHE_CATEGORY not in Cache._categories:
            n_items = self.cfg('ui', 'standalone', 'search', 'cache_items')
            n_items = None if n_items <= 0 else n_items
            timeout = self.cfg('ui', 'standalone', 'search', 'cache_timeout')
            timeout = None if timeout <= 0 else timeout
            Cache.register(self._CACHE_CATEGORY, n_items, timeout)

    def on_storage_modified(self, sender):
        # clear the whole cache
        Cache.remove(self._CACHE_CATEGORY, None)

    def on_predicate_modified(self, sender, predicate, objects, diff):
        Cache.remove(self._CACHE_CATEGORY, None) # clears the whole cache
        self.apply()
        return # FIXME: mb/port
        tbd = set()
        # walk through cache
        for ast, sort in Cache._objects[self._CACHE_CATEGORY]:
            # check ast
            if ast is not None:
                for token in ast:
                    if token.predicate() == predicate:
                        if predicate in ('tag', 'group') and \
                           len(set(diff) & set(token.condition())) == 0:
                               # tag predicate but the tag in question was not changed; skip
                               continue
                        tbd.add((ast, sort))
                        break # no need to search further

            # check sort
            if sort is not None:
                if sort.predicate() == predicate:
                    tbd.add((ast, sort))

        for key in tbd:
            Cache.remove(self._CACHE_CATEGORY, key)

        # re-apply searches
        self.apply()

    def apply(self):
        browser = self.root.browser
        filter = self.root.filter
        session = self.root.session

        with browser:
            # get query
            query, sort = filter.get_query()
            # log search
            # FIXME: mb/port/log
            #session.log.log_search(
            #    'filter',
            #    session.storage.lib.meta,
            #    (filter.t_head, filter.t_tail),
            #    (filter.f_head + [browser.frame], filter.f_tail),
            #    )

            # apply search or fetch it from the cache
            items = Cache.get(self._CACHE_CATEGORY, (query, sort), None)
            if items is None:
                # FIXME: mb/port: consider sort
                items = list(session.storage.sorted(ns.bsn.Entity, query))
                Cache.append(self._CACHE_CATEGORY, (query, sort), items)

            # apply search order because it's cheaper to do it here rather
            # than in the backend (also see uix.kivy.filter.get_query).
            items = list(reversed(items[:])) if filter.sortdir else items[:]
            # update browser
            browser.set_items(items)


class ShowSelected(Action):
    """Show only selected items."""
    text = kp.StringProperty('Selected only')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'search', 'exclusive'))

    def apply(self):
        with self.root.browser as browser:
            if len(browser.selection) == 0:
                # silently ignore if no images selected
                pass
            elif len(browser.selection) == 1 and list(browser.selection)[0] in browser.folds:
                # selection is a group
                self.root.trigger('OpenGroup', list(browser.selection)[0])
            else:
                token = ast.filter.IsIn(browser.unfold(browser.selection))
                self.root.trigger('AddToken', token)


class RemoveSelected(Action):
    """Exclude selected items."""
    text = kp.StringProperty('Exclude selection')

    def ktrigger(self, evt):
        return Binding.check(evt, self.cfg('bindings', 'search', 'remove'))

    def apply(self):
        with self.root.browser as browser:
            if len(browser.selection) == 0:
                # silently ignore if no images selected
                pass
            else:
                new_cursor = browser.neighboring_unselected()
                token = ast.filter.IsNotIn(browser.unfold(browser.selection))
                self.root.trigger('AddToken', token)
                # fix frame
                browser.cursor = new_cursor
                browser.selection = {browser.cursor} if browser.cursor is not None else  set()
                self.root.trigger('JumpToCursor')


class SortKey(Action):
    """Select by which property items are ordered."""
    text = kp.StringProperty('Sort by')

    def apply(self, predicate=None):
        if predicate is None:
            x = self.pos[0] + self.width
            y = self.pos[1] + self.height
            self.menu.show(x, y)
        else:
            self.set_sortkey(predicate)

    def on_root(self, wx, root):
        super(SortKey, self).on_root(wx, root)

        # Order is essential here:
        # 1. the menu has to be created
        # 2. the menu has to be attached to a parent
        # 3. the menu has to be populated
        # The visibility has to be triggered after (2) or (3)
        self.menu = ContextMenu(
            bounding_box_widget = self.root,
            cancel_handler_widget = self.root)
        self.root.add_widget(self.menu)
        self.menu._on_visible(False)

        # TODO: The whole sortkeys setup is rather brittle
        # e.g. what happens if new features become available at runtime?

        # default sortkeys
        return # FIXME: mb/port

        options = sortkeys.scope.library | sortkeys.typedef.anchored # FIXME: mb/port
        # apply whitelist and blacklist config
        options -= set(self.cfg('ui', 'standalone', 'search', 'sort_blacklist'))
        whitelist = set(self.cfg('ui', 'standalone', 'search', 'sort_whitelist'))
        whitelist = whitelist if len(whitelist) else options
        options &= whitelist
        # TODO: If there are several versions of the same feature class, keep only the most frequent
        # * get feature predicates and their feature class (i.e. name)
        # * if needed, get their frequencies via Features.Entities(ctrl.stor.num, fid)
        # For now, all known features are used.

        # populate menu
        for sortkey in sorted(options):
            text = sortkey
            if ContentFeature.is_feature_id(sortkey):
                text = FeatureBuilder.class_from_guid(sortkey).friendly_guid(sortkey)

            self.menu.add_text_item(
                text=text,
                on_release=partial(self.release_wrapper, sortkey)
            )

    def release_wrapper(self, sortkey, *args):
        # hide
        self.menu.hide()
        # trigger event
        self.set_sortkey(sortkey)

    def set_sortkey(self, predicate):
        return # FIXME: mb/port
        with self.root.filter as filter:
            try:
                # TODO: What if a predicate accepts several types (e.g. num and anchored)
                if predicate in sortkeys.typedef.anchored:
                    cursor = self.root.browser.cursor
                    if cursor is None:
                        raise errors.UserError('an image needs to be selected for similarity sort.')
                    # TODO: We normally want the anchored search to be sorted most similar
                    # to least similar (sortdir=False). We could adjust the sortdir automatically.
                    # Note that VFilterAction_SortOrder would *not* get notified automatically.
                    filter.sortkey = partial(ast.AnchoredSort, predicate, cursor.guid)
                elif predicate in sortkeys.typedef.numerical:
                    filter.sortkey = partial(ast.NumericalSort, predicate)
                elif predicate in sortkeys.typedef.alphabetical:
                    filter.sortkey = partial(ast.AlphabeticalSort, predicate)
                else:
                    raise errors.UserError('invalid sort key selected')

            except Exception as e:
                dialogues.Error(text=str(e)).open()

        # stick to cursor
        self.root.trigger('JumpToCursor')


class SortOrder(Action, FilterAwareMixin):
    """Switch between ascending and descending order."""
    text = kp.StringProperty('Toggle sort order')

    def on_root(self, wx, root):
        Action.on_root(self, wx, root)
        FilterAwareMixin.on_root(self, wx, root)

    def on_sortdir(self, wx, sortdir):
        if self._image is not None:
            self._image.source = self.source_down if sortdir else self.source_up

    def on_filter(self, wx, filter):
        # remove old binding
        if self.filter is not None:
            self.filter.unbind(sortdir=self.on_sortdir)
        # add new binding
        self.filter = filter
        if self.filter is not None:
            self.filter.bind(sortdir=self.on_sortdir)
            self.on_sortdir(self.filter, self.filter.sortdir)

    def __del__(self):
        # remove old binding
        if self.filter is not None:
            self.filter.unbind(sortdir=self.on_sortdir)
            self.filter = None

    def apply(self):
        with self.root.filter as filter, \
             self.root.browser as browser:
            filter.sortdir = not filter.sortdir
            # keep the same field of view as before
            browser.offset = clamp(browser.n_items - (browser.offset + browser.page_size),
                                   browser.max_offset)


## config ##

config.declare(('ui', 'standalone', 'search', 'sort_blacklist'), config.List(config.String()), [],
    __name__, 'Blacklisted sortkeys', 'Sort keys that will not be shown in the sort selection. This does not affect whitelisted keys.')

config.declare(('ui', 'standalone', 'search', 'sort_whitelist'), config.List(config.String()), [],
    __name__, 'Whitelisted sortkeys', 'Sort keys that will always be shown in the sort selection. Overrules blacklisted keys.')

config.declare(('ui', 'standalone', 'search', 'cache_items'), config.Unsigned(), 0,
    __name__, 'Search cache size', 'Number of searches that are held in cache. Zero means no limit.')

config.declare(('ui', 'standalone', 'search', 'cache_timeout'), config.Unsigned(), 0,
    __name__, 'Search cache timeout', 'Number of seconds until searches are discarded from the search cache. Zero means no limit.')

# keybindings

config.declare(('bindings', 'search', 'search'),
    config.Keybind(), Binding.simple(Binding.F5),
    __name__, Search.text.defaultvalue, Search.__doc__)

config.declare(('bindings', 'search', 'exclusive'),
    config.Keybind(), Binding.simple(Binding.ENTER, Binding.mCTRL, Binding.mREST),
    __name__, ShowSelected.text.defaultvalue, ShowSelected.__doc__)

config.declare(('bindings', 'search', 'remove'),
    config.Keybind(), Binding.simple(Binding.DEL, None, Binding.mALL),
    __name__, RemoveSelected.text.defaultvalue, RemoveSelected.__doc__)

## EOF ##