"""Level.py: contains the Level class"""

import DirectNotifyGlobal
import string
import LevelConstants
from PythonUtil import lineInfo, uniqueElements
import types

"""
Any data that can be edited by a level editor must be represented as
an attribute of an entity owned by the level, in order to keep the
level-editing interface simple and constant (there are at least three
places where the entire editing interface must be duplicated).

To support this, we have entities such as 'levelMgr' and 'zoneEntity' that
contain crucial level information, much of which is needed when setting
up the level object, and is needed before other entity types can be
effectively created. (If you try to create a distributed entity, but
you don't yet have the information for the zone that it's in, because
you haven't created the zone's ZoneEntity, you're hurting.)
"""

"""
ZONE TERMINOLOGY
zoneNum / modelZoneNum : the number that a modeler chooses for a zone
zoneEntId : the entity ID of the ZoneEntity that represents a zone
zoneId : the network ID of the zone
"""

class Level:
    """Level: representation of a game level, keeps track of all of the
    entities and their interrelations, and creates and destroys entities"""
    notify = DirectNotifyGlobal.directNotify.newCategory('Level')

    def __init__(self):
        self.levelSpec = None
        self.initialized = 0

    def initializeLevel(self, levelId, levelSpec, scenarioIndex):
        """ subclass should call this as soon as it has located
        its spec data """
        self.levelId = levelId
        self.levelSpec = levelSpec
        self.scenarioIndex = scenarioIndex

        self.levelSpec.setScenario(self.scenarioIndex)
        if __debug__:
            self.levelSpec.setLevel(self)

        # create some handy tables

        # entranceId to entrance entity
        self.entranceId2entity = {}

        # dict of entId -> list of callbacks to be called upon creation
        self.entId2createCallbacks = {}

        # this list contains the entIds of entities that we have actually
        # created, in order of creation
        self.createdEntIds = []

        # get an entity creator object
        self.entityCreator = self.createEntityCreator()

        # entity type -> list of entIds
        self.entType2ids = self.levelSpec.getEntType2ids(
            self.levelSpec.getAllEntIds())
        # create empty list for any entity types that are not represented
        # in the spec
        for entType in self.entityCreator.getEntityTypes():
            self.entType2ids.setdefault(entType, [])

        # create all the entities
        # TODO: maybe we should leave this to a subclass or the level user
        self.createAllEntities(priorityTypes=['levelMgr','zone','propSpinner'])

        # check on the singleton entities
        # we make our own references to them rather than expect them to
        # create the references so that the editor can create dummy
        # do-nothing entities

        # there should be one and only one levelMgr
        assert len(self.entType2ids['levelMgr']) == 1
        assert self.entType2ids['levelMgr'][0] == LevelConstants.LevelMgrEntId
        self.levelMgrEntity = self.getEntity(LevelConstants.LevelMgrEntId)

        if __debug__:
            # there should be one and only one editMgr
            assert len(self.entType2ids['editMgr']) == 1
            assert self.entType2ids['editMgr'][0] == \
                   LevelConstants.EditMgrEntId
            self.editMgrEntity = self.getEntity(LevelConstants.EditMgrEntId)

        # there should be one and only one UberZone
        assert LevelConstants.UberZoneEntId in self.entType2ids['zone']
        self.uberZoneEntity = self.getEntity(LevelConstants.UberZoneEntId)

        self.initialized = 1

    def isInitialized(self):
        return self.initialized

    def destroyLevel(self):
        self.destroyAllEntities()
        self.initialized = 0
        del self.createdEntIds
        if hasattr(self, 'entities'):
            del self.entities
        if hasattr(self, 'levelSpec'):
            del self.levelSpec

    def createEntityCreator(self):
        Level.notify.error(
            'concrete Level class must override %s' % lineInfo()[2])

    def createAllEntities(self, priorityTypes=[]):
        """creates all entities in the spec. priorityTypes is an
        optional ordered list of entity types to create first."""
        # this will be filled in as the entities are created and report in
        # this includes distributed objects on the client
        self.entities = {}

        # get list of all entity types we need to create
        entTypes = self.entityCreator.getEntityTypes()

        self.onLevelPreCreate()

        # first create the types in the priority list
        for type in priorityTypes:
            assert type in entTypes
            self.createAllEntitiesOfType(type)
            entTypes.remove(type)

        # create the other entities in any old order
        for type in entTypes:
            self.createAllEntitiesOfType(type)

        self.onLevelPostCreate()

    def destroyAllEntities(self):
        assert uniqueElements(self.createdEntIds)
        # destroy the entities in reverse order
        while len(self.createdEntIds) > 0:
            entId = self.createdEntIds.pop()
            entity = self.getEntity(entId)
            if entity is not None:
                Level.notify.debug('destroying %s %s' % (
                    self.getEntityType(entId), entId))
                entity.destroy()
                assert not entId in self.entities
            else:
                Level.notify.error('trying to destroy entity %s, but '
                                   'it is already gone' % entId)

    def createAllEntitiesOfType(self, entType):
        """creates all entities of a given type"""
        assert entType in self.entityCreator.getEntityTypes()

        self.onEntityTypePreCreate(entType)

        for entId in self.entType2ids[entType]:
            self.createEntity(entId)

        self.onEntityTypePostCreate(entType)

    def createEntity(self, entId):
        assert not entId in self.createdEntIds
        spec = self.levelSpec.getEntitySpec(entId)
        Level.notify.debug('creating %s %s' % (spec['type'], entId))
        entity = self.entityCreator.createEntity(entId)
        # NOTE: the entity is not considered to really be created until
        # it has all of its initial spec data; see 'initializeEntity'
        # below.
        if entity is not 'nothing':
            assert uniqueElements(self.createdEntIds)
            assert entId not in self.createdEntIds
            self.createdEntIds.append(entId)

        # call the create handler
        # we used to do this in initializeEntity, but that did not
        # allow for additional initialization to be performed in
        # derived entity __init__ funcs before their presence was announced
        # Note that now DistributedEntity's are responsible for calling
        # this for themselves
        self.onEntityCreate(entId)

        return entity

    def initializeEntity(self, entity):
        """populate an entity with its spec data. This is not done
        in createEntity in order to allow other pieces of code to create
        entities; this is called directly by Entity.
        """
        entId = entity.entId
        spec = self.levelSpec.getEntitySpec(entId)
        # on initialization, set items directly on entity
        for key,value in spec.items():
            if key in ('type', 'name', 'comment',):
                continue
            entity.setAttribInit(key, value)

        # entity is initialized, add it to the list of entities
        # if this assert fails, check distributed entities to make sure
        # they're calling down to Entity.destroy
        if __debug__:
            if entId in self.entities:
                self.notify.warning(
                    'entity %s already in entity table... '
                    'make sure distributedEntity is calling down to '
                    'Entity.destroy!')
        self.entities[entId] = entity

    def getEntity(self, entId):
        return self.entities.get(entId)

    def getEntityType(self, entId):
        return self.levelSpec.getEntityType(entId)

    def getEntityZoneEntId(self, entId):
        """return entId of zone that contains the entity"""
        return self.levelSpec.getEntityZoneEntId(entId)

    def getEntityZoneNum(self, entId):
        """return the model zoneNum of zone that contains the entity"""
        return self.levelSpec.getEntityZoneNum(entId)

    def getEntityZoneId(self, entId):
        """return network zoneId of zone that contains the entity"""
        # this is called during entity creation on the AI; we have to
        # handle this carefully, since the information required to
        # produce a zoneId is not available until the level's zone
        # entities have been instantiated.
        zoneEntId = self.getEntityZoneEntId(entId)
        # fundamental entities (levelMgr) are responsible for creating
        # tables like 'zoneEntId2zoneId'; if those tables haven't been
        # created yet, just return None
        if not hasattr(self, 'zoneNum2zoneId'):
            return None
        # this might return None if all of our zone entities haven't
        # been created yet. this could be a problem if zone entities
        # are ever distributed. it also means that no distributed entities
        # should be created before the zone entities.
        return self.zoneEntId2zoneId.get(zoneEntId)

    def getZoneId(self, dummy=None, zoneNum=None, entId=None):
        """look up network zoneId by zoneNum or entId"""
        assert (zoneNum is not None) or (entId is not None)
        assert not ((zoneNum is not None) and (entId is not None))
        if zoneNum is not None:
            assert zoneNum in self.zoneNum2zoneId
            return self.zoneNum2zoneId[zoneNum]
        else:
            assert entId in self.zoneEntId2zoneId
            return self.zoneEntId2zoneId[entId]

    # these events are thrown as the level initializes itself
    # LEVEL
    def getLevelPreCreateEvent(self):
        """This is the event that is thrown immediately before the level
        creates its entities."""
        return 'levelPreCreate-%s' % (self.levelId)
    def getLevelPostCreateEvent(self):
        """This is the event that is thrown immediately after the level
        creates its entities."""
        return 'levelPostCreate-%s' % (self.levelId)
    # ENTITY TYPE
    def getEntityTypePreCreateEvent(self, entType):
        """This is the event that is thrown immediately before the level
        creates the entities of the given type."""
        return 'entityTypePreCreate-%s-%s' % (self.levelId, entType)
    def getEntityTypePostCreateEvent(self, entType):
        """This is the event that is thrown immediately after the level
        creates the entities of the given type."""
        return 'entityTypePostCreate-%s-%s' % (self.levelId, entType)
    # ENTITY
    def getEntityCreateEvent(self, entId):
        """This is the event that is thrown immediately after a
        particular entity is initialized"""
        return 'entityCreate-%s-%s' % (self.levelId, entId)
    def getEntityOfTypeCreateEvent(self, entType):
        """This event is thrown immediately after each instance of the
        given entity type is created; handlers must accept an entId"""
        return 'entityOfTypeCreate-%s-%s' % (self.levelId, entType)

    # these handlers are called as the level initializes itself
    # LEVEL
    def onLevelPreCreate(self):
        """Level is about to create its entities"""
        messenger.send(self.getLevelPreCreateEvent())
    def onLevelPostCreate(self):
        """Level is done creating its entities"""
        messenger.send(self.getLevelPostCreateEvent())
    # ENTITY TYPE
    def onEntityTypePreCreate(self, entType):
        """Level is about to create these entities"""
        messenger.send(self.getEntityTypePreCreateEvent(entType))
    def onEntityTypePostCreate(self, entType):
        """Level has just created these entities"""
        messenger.send(self.getEntityTypePostCreateEvent(entType))
    # ENTITY
    def onEntityCreate(self, entId):
        """Level has just created this entity"""
        # send the entity-create event
        messenger.send(self.getEntityCreateEvent(entId))
        # send the entity-of-type create event
        messenger.send(
            self.getEntityOfTypeCreateEvent(self.getEntityType(entId)),
            [entId])
        # call any callbacks
        if entId in self.entId2createCallbacks:
            for callback in self.entId2createCallbacks[entId]:
                callback()
            del self.entId2createCallbacks[entId]

    # Use to set a callback to be called when entity is created.
    # If entity already exists, callback will be called immediately.
    def setEntityCreateCallback(self, entId, callback):
        ent = self.getEntity(entId)
        if ent is not None:
            callback()
            return
        self.entId2createCallbacks.setdefault(entId, [])
        self.entId2createCallbacks[entId].append(callback)

    # these are events and handlers that are invoked as entities are destroyed
    def getEntityDestroyEvent(self, entId):
        """This is the event that is thrown immediately before an
        entity is destroyed"""
        return 'entityDestroy-%s-%s' % (self.levelId, entId)
    def onEntityDestroy(self, entId):
        """Level is about to destroy this entity"""
        assert entId in self.entities
        # send the entity-destroy event
        messenger.send(self.getEntityDestroyEvent(entId))

        del self.entities[entId]
        # if we created this entity, remove its entId from the
        # createdEntIds list
        if entId in self.createdEntIds:
            # this should only happen if someone deleted an entity
            # with an editor
            self.createdEntIds.remove(entId)

    if __debug__:
        # the level generates these events when the spec changes
        def getAttribChangeEventName(self):
            return 'attribChange-%s' % self.levelId
        def getInsertEntityEventName(self):
            return 'insertEntity-%s' % self.levelId
        def getRemoveEntityEventName(self):
            return 'removeEntity-%s' % self.levelId
        
        # these handlers are called directly by our levelSpec
        def handleAttribChange(self, entId, attrib, value, username=None):
            entity = self.getEntity(entId)
            # the entity might be AI- or client-only
            if entity is not None:
                entity.handleAttribChange(attrib, value)
            messenger.send(self.getAttribChangeEventName(),
                           [entId, attrib, value, username])

        def setEntityCreatorUsername(self, entId, editUsername):
            # this is called just before an entity is inserted, with the
            # entId of the new entity and the username of the editor
            # that requested its creation.
            pass

        def handleEntityInsert(self, entId):
            # update our local type->entId table
            self.entType2ids[self.getEntityType(entId)].append(entId)
            self.createEntity(entId)
            messenger.send(self.getInsertEntityEventName(), [entId])

        def handleEntityRemove(self, entId):
            messenger.send(self.getRemoveEntityEventName(), [entId])
            # if we didn't create it, don't destroy it (probably a distributed
            # entity on the client; wait for AI to destroy it)
            if entId in self.createdEntIds:
                entity = self.getEntity(entId)
                entity.destroy()
            # update our local type->entId table
            self.entType2ids[self.getEntityType(entId)].remove(entId)

        def handleVisChange(self):
            """the zone visibility lists have changed"""
            pass