#############################################################################
#
# Copyright (c) 2010 by Casey Duncan and contributors
# All Rights Reserved.
#
# This software is subject to the provisions of the MIT License
# A copy of the license should accompany this distribution.
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
#
#############################################################################

__version__ = '$Id$'

import operator
from bGrease.geometry import Vec2d, Vec2dArray, Rect
from bGrease import color

# Allowed field types -> default values
types = {int:lambda: 0, 
         float:lambda: 0.0, 
         bool:lambda: False,
         str:lambda:"", 
         object:lambda:None,
         Vec2d:lambda: Vec2d(0,0), 
         Vec2dArray:lambda: Vec2dArray(),
         color.RGBA: lambda: color.RGBA(0.0, 0.0, 0.0, 0.0),
         Rect: lambda: Rect(0.0, 0.0, 0.0, 0.0),
         list: lambda: list(),
         dict: lambda: dict(),
         }

class Schema(dict):
        """Field schema definition for custom components"""

        def __init__(self, **fields):
                for ftype in fields.values():
                        assert ftype in types, fname + " has an illegal field type"
                self.update(fields)


class FieldAccessor(object):
        """Facade for manipulating a field for a set of entities"""

        __field = None
        __entities = None
        __attrs = None
        __getter = None
        __parent_getters = ()

        def __init__(self, field, entities, attrs=()):
                self.__field = field
                self.__entities = entities
                field_getter = operator.attrgetter(field.name)
                self.__attrs = attrs
                if attrs:
                        getters = [field_getter] + [operator.attrgetter(attr) for attr in attrs]
                        def get(entity):
                                value = entity
                                for getter in getters:
                                        value = getter(value)
                                return value
                        self.__getter = get
                        self.__parent_getters = getters[:-1]
                else:
                        self.__getter = field_getter

        def __getattr__(self, name):
                """Return a FieldAccessor for the child attribute"""
                return self.__class__(self.__field, self.__entities, self.__attrs + (name,))

        def __setattr__(self, name, value):
                if value is self:
                        return # returned by mutators
                if hasattr(self.__class__, name):
                        # Set local attr
                        self.__dict__[name] = value
                elif not name.startswith('_'):
                        getattr(self, name).__set__(value)
                else:
                        raise AttributeError("Cannot set field attribute: %s" % name)

        @property
        def __setter(self):
                """Return the proper setter function for setting the field value"""
                if not self.__attrs:
                        return setattr
                else:
                        parent_getters = self.__parent_getters
                        def setter(data, name, value):
                                for getter in parent_getters:
                                        data = getter(data)
                                setattr(data, name, value)
                        self.__setter = setter
                        return setter

        def __set__(self, value):
                """Set field values en masse"""
                # Mass set field attr
                setter = self.__setter
                component = self.__field.component
                if self.__attrs:
                        name = self.__attrs[-1]
                else:
                        name = self.__field.name
                if isinstance(value, FieldAccessor):
                        # Join set between two entity sets
                        if not self.__attrs:
                                cast = self.__field.cast
                        else: 
                                cast = lambda x: x
                        for entity in self.__entities:
                                try:
                                        setter(component[entity], name, cast(value[entity]))
                                except KeyError:
                                        pass
                else:
                        if not self.__attrs:
                                value = self.__field.cast(value)
                        for entity in self.__entities:
                                try:
                                        setter(component[entity], name, value)
                                except KeyError:
                                        pass

        def __getitem__(self, entity):
                """Return the field value for a single entity (used for joins)"""
                if entity in self.__entities:
                        return self.__getter(self.__field.component[entity])
                raise KeyError(entity)

        def __contains__(self, entity):
                return entity in self.__entities

        def __repr__(self):
                return '<%s %s @ %x>' % (
                        self.__class__.__name__, 
                        '.'.join((self.__field.name,) + self.__attrs), id(self))

        def __nonzero__(self):
                return bool(self.__entities)

        def __iter__(self):
                """Return an iterator of all field values in the set"""
                component = self.__field.component
                getter = self.__getter
                for entity in self.__entities:
                        try:
                                data = component[entity]
                        except KeyError:
                                continue
                        yield getter(data)

        ## batch comparison operators ##

        def __match(self, value, op):
                component = self.__field.component
                getter = self.__getter
                matches = set()
                add = matches.add
                if isinstance(value, FieldAccessor):
                        # Join match between entity sets
                        for entity in self.__entities:
                                try:
                                        data = component[entity]
                                        other = value[entity]
                                except KeyError:
                                        continue
                                if op(getter(data), other):
                                        add(entity)
                else:
                        for entity in self.__entities:
                                try:
                                        data = component[entity]
                                except KeyError:
                                        continue
                                if op(getter(data), value):
                                        add(entity)
                return matches

        def __eq__(self, value):
                """Return an entity set of all entities with a matching field value"""
                return self.__match(value, operator.eq)

        def __ne__(self, value):
                """Return an entity set of all entities not matching field value"""
                return self.__match(value, operator.ne)

        def __gt__(self, value):
                """Return an entity set of all entities with a greater field value"""
                return self.__match(value, operator.gt)

        def __ge__(self, value):
                """Return an entity set of all entities with a greater or equal field value"""
                return self.__match(value, operator.ge)

        def __lt__(self, value):
                """Return an entity set of all entities with a lesser field value"""
                return self.__match(value, operator.lt)

        def __le__(self, value):
                """Return an entity set of all entities with a lesser or equal field value"""
                return self.__match(value, operator.le)

        def _contains(self, values):
                """Return an entity set of all entities with a field value contained in values"""
                return self.__match(values, operator.contains)

        ## Batch in-place mutator methods

        def __mutate(self, value, op):
                component = self.__field.component
                if self.__attrs:
                        name = self.__attrs[-1]
                else:
                        name = self.__field.name
                getter = self.__getter
                setter = self.__setter
                if isinstance(value, FieldAccessor):
                        # Join between entity sets
                        for entity in self.__entities:
                                try:
                                        data = component[entity]
                                        other = value[entity]
                                except KeyError:
                                        continue
                                setter(data, name, op(getter(data), other))
                else:
                        for entity in self.__entities:
                                try:
                                        data = component[entity]
                                except KeyError:
                                        continue
                                setter(data, name, op(getter(data), value))
                return self

        def __iadd__(self, value):
                return self.__mutate(value, operator.iadd)

        def __isub__(self, value):
                return self.__mutate(value, operator.isub)

        def __imul__(self, value):
                return self.__mutate(value, operator.imul)

        def __idiv__(self, value):
                return self.__mutate(value, operator.idiv)

        def __itruediv__(self, value):
                return self.__mutate(value, operator.itruediv)

        def __ifloordiv__(self, value):
                return self.__mutate(value, operator.ifloordiv)

        def __imod__(self, value):
                return self.__mutate(value, operator.imod)

        def __ipow__(self, value):
                return self.__mutate(value, operator.ipow)

        def __ilshift__(self, value):
                return self.__mutate(value, operator.ilshift)

        def __irshift__(self, value):
                return self.__mutate(value, operator.irshift)

        def __iand__(self, value):
                return self.__mutate(value, operator.iand)

        def __ior__(self, value):
                return self.__mutate(value, operator.ior)

        def __ixor__(self, value):
                return self.__mutate(value, operator.ixor)


class Field(object):
        """Component field metadata and accessor interface"""

        def __init__(self, component, name, type, accessor_factory=FieldAccessor):
                self.component = component
                self.name = name
                self.type = type
                self.default = types.get(type)
                self.accessor_factory = accessor_factory

        def cast(self, value):
                """Cast value to the appropriate type for thi field"""
                if self.type is not object:
                        return self.type(value)
                else:
                        return value

        def accessor(self, entities=None):
                """Return the field accessor for the entities in the component,
                or all entities in the set specified that are also in the component
                """
                if entities is None or entities is self.component.entities:
                        entities = self.component.entities
                else:
                        entities = entities & self.component.entities
                return self.accessor_factory(self, entities)