#   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/>.

from parpg.grease import System
from parpg.components import container

class Container(System):
    """System that controls changes to containers"""

    def __init__(self, drag_container,
                 container_component="container", 
                 containable_component="containable"
                 ):
        """Constructor"""
        self.drag_container = drag_container
        self.container_component = container_component
        self.containable_component = containable_component
        self.on_bulk_to_big = []
        
    def step(self, dt):
        """Perform changes to containers and items"""
        assert self.world is not None, "Cannot run with no world set"
        for containable in self.world.components.join(
            self.containable_component
            ):
            if containable.new_container:
                new_container = containable.new_container
                new_slot = containable.new_slot
                bulk_add = containable.bulk
                if new_slot >= 0 and new_slot < len(new_container.children):
                    bulk_add -= new_container.children[new_slot].bulk
                elif new_slot >= len(new_container.children):
                    new_slot = -1
                bulk = get_bulk(new_container) + bulk_add
                if bulk < new_container.max_bulk:
                    if new_slot >= 0:
                        new_container.children.insert(new_slot + 1, containable)
                        containable.current_container = new_container
                        old_containable = new_container.children.pop(new_slot)
                        old_containable.current_container = drag_container
                        drag_container.children = [old_containable]
                else:
                    for listener in self.on_bulk_to_big:
                        listener(bulk, new_container.max_bulk)