"""

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

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

# tagit imports
from tagit import config, dialogues
from tagit.utils import Frame, ns
from tagit.utils.bsfs import Namespace, ast, uuid
from tagit.widgets import Binding

# inner-module imports
from .action import Action

# constants
GROUP_PREFIX = Namespace('http://example.com/me/group')()

# exports
__all__ = []


## code ##

logger = logging.getLogger(__name__)

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

# classes
class CreateGroup(Action):
    """Create a group from selected items."""
    text = kp.StringProperty('Group items')

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

    def apply(self):
        if self.cfg('ui', 'standalone', 'grouping', 'autoname'):
            self.create_group()
        else:
            dlg = dialogues.SimpleInput()
            dlg.bind(on_ok=lambda wx: self.create_group(wx.text))
            dlg.open()

    def create_group(self, label=None):
        if len(self.root.browser.selection) > 1:
            with self.root.browser as browser, \
                 self.root.session as session:
                # create group
                grp = session.storage.node(ns.bsn.Group,
                    getattr(GROUP_PREFIX, uuid.UUID()()))
                if label is not None:
                    grp.set(ns.bsg.label, label)

                # add items to group
                ents = browser.unfold(browser.selection)
                ents.set(ns.bse.group, grp)

                # select a random representative
                rep = random.choice(list(ents))
                grp.set(ns.bsg.represented_by, rep)

                # set selection and cursor to representative
                # the representative will become valid after the search was re-applied
                browser.selection.clear()
                browser.selection.add(rep)
                browser.cursor = rep

                # notification
                logger.info(f'Grouped {len(ents)} items')

                # change event
                session.dispatch('on_predicate_modified', ns.bse.group, ents, {grp})

            # jump to cursor
            # needs to be done *after* the browser was updated
            self.root.trigger('JumpToCursor')


class DissolveGroup(Action):
    """Dissolve the selected group."""
    text = kp.StringProperty('Dissolve group')

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

    def apply(self):
        with self.root.browser as browser, \
             self.root.session as session:
            cursor = browser.cursor
            if cursor is not None and cursor in browser.folds:
                grp = browser.folds[cursor].group
                ents = session.storage.get(ns.bsn.Entity,
                        ast.filter.Any(ns.bse.group, ast.filter.Is(grp)))
                #ents.remove(ns.bse.group, grp) # FIXME: mb/port
                #grp.delete() # FIXME: mb/port

                # FIXME: fix cursor and selection
                # cursor: leave at item that was the representative
                # selection: leave as is, select all group members if the cursor was selected
                browser.frame = Frame()

                # notification
                logger.info(f'Ungrouped {len(ents)} items')

                # change event
                session.dispatch('on_predicate_modified', ns.bse.group, ents, {grp})

        self.root.trigger('JumpToCursor')


class AddToGroup(Action):
    """Add an item to a group."""
    text = kp.StringProperty('Add to group')

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

    def apply(self):
        with self.root.browser as browser, \
             self.root.session as session:
            cursor = browser.cursor
            if cursor is not None and cursor in browser.folds:
                grp = browser.folds[cursor].group
                ents = browser.unfold(browser.selection)

                for obj in ents:
                    if obj == cursor:
                        # don't add group to itself
                        continue
                    obj.set(ns.bse.group, gr)

                # all selected items will be folded, hence it becomes empty
                if cursor in browser.selection:
                    browser.selection = {cursor}
                else:
                    browser.selection.clear()

                # change event
                session.dispatch('on_predicate_modified', ns.bse.group, ents, {grp})


class OpenGroup(Action):
    """Show the items of the selected group."""
    text = kp.StringProperty('Open group')

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

    def apply(self, cursor=None):
        if cursor is None:
            cursor = self.root.browser.cursor
        elif cursor in self.root.browser.folds:
            grp = self.root.browser.folds[cursor].group
            self.root.trigger('AddToken', ast.filter.Any(
                ns.bse.group, ast.filter.Is(grp)))


class RepresentGroup(Action):
    """Make the currently selected item the representative of the current group."""
    text = kp.StringProperty('Represent')

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

    def apply(self):
        return # FIXME: mb/port
        with self.root.browser as browser, \
             self.root.filter as filter, \
             self.root.session as session:
            if browser.cursor is not None \
               and len(filter.t_head) > 0 \
               and filter.t_head[-1].predicate() == 'group':
                # we know that the cursor is part of the group, since it matches the filter.
                guid = filter.t_head[-1].condition()[0] # FIXME!
                grp = session.storage.node(guid, ns.tagit.storage.Group)
                grp.represented_by = browser.cursor
                logger.info(f'{browser.cursor} now represents {grp}')


class RemoveFromGroup(Action):
    """Remove the selected item from the group"""
    text = kp.StringProperty('Remove from group')

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

    def apply(self):
        return # FIXME: mb/port
        with self.root.browser as browser, \
             self.root.filter as filter, \
             self.root.session as session:
            if len(filter.t_head) > 0 and \
               filter.t_head[-1].predicate() == 'group':
                guid = filter.t_head[-1].condition()[0]
                grp = session.storage.group(guid)
                ents = self.root.session.storage.entities(browser.unfold(browser.selection))
                ents -= grp

                try:
                    rep = grp.represented_by
                    if grp not in rep.group:
                        # representative was removed, pick a random one
                        random.choice(list(rep.members())).represent(grp) # FIXME: member relation?
                        # grp.represented_by = random.choice(list(rep.members()))

                except ValueError:
                    # group is now empty
                    pass

                # set cursor to a non-selected (hence non-removed) item
                # clear the selection
                browser.cursor = browser.neighboring_unselected()
                browser.selection = [browser.cursor] if browser.cursor is not None else  []

                # change event
                session.dispatch('on_predicate_modified', 'group', items, {grp})

        self.root.trigger('JumpToCursor')


## config ##

config.declare(('ui', 'standalone', 'grouping', 'autoname'), config.Bool(), True,
    __name__, 'Auto-name groups', 'If enabled, group names are auto-generated (resulting in somewhat cryptical names). If disabled, a name can be specified when creating new groups.')

# keybindings

config.declare(('bindings', 'grouping', 'create'),
    config.Keybind(), Binding.simple('g', Binding.mCTRL, Binding.mREST),
    __name__, CreateGroup.text.defaultvalue, CreateGroup.__doc__)

config.declare(('bindings', 'grouping', 'ungroup'),
    config.Keybind(), Binding.simple('g', [Binding.mALT, Binding.mCTRL], Binding.mREST),
    __name__, DissolveGroup.text.defaultvalue, DissolveGroup.__doc__)

config.declare(('bindings', 'grouping', 'add'),
    config.Keybind(), Binding.simple('h', [Binding.mCTRL], Binding.mREST),
    __name__, AddToGroup.text.defaultvalue, AddToGroup.__doc__)

config.declare(('bindings', 'grouping', 'open'),
    config.Keybind(), Binding.simple('g', None, Binding.mREST),
    __name__, OpenGroup.text.defaultvalue, OpenGroup.__doc__)

config.declare(('bindings', 'grouping', 'represent'),
    config.Keybind(), Binding.simple('g', [Binding.mCTRL, Binding.mSHIFT], Binding.mREST),
    __name__, RepresentGroup.text.defaultvalue, RepresentGroup.__doc__)

config.declare(('bindings', 'grouping', 'remove'),
    config.Keybind(), Binding.simple('h', [Binding.mSHIFT, Binding.mCTRL], Binding.mREST),
    __name__, RemoveFromGroup.text.defaultvalue, RemoveFromGroup.__doc__)

## EOF ##