lodel2_mirror/EditorialModel/components.py

# -*- coding: utf-8 -*-

## @package EditorialModel.components
# @brief Base objects for all EditorialModel components
#
# Defines the EditorialModel::components::EmComponent class

import datetime
import hashlib
import EditorialModel
from Lodel.utils.mlstring import MlString


## @brief This class is the mother class of all editorial model objects
#
# It gather all the properties and mechanism that are common to every editorial model objects
# @see EditorialModel::classes::EmClass, EditorialModel::types::EmType, EditorialModel::fieldgroups::EmFieldGroup, EditorialModel::fields::EmField
class EmComponent(object):

    ## Used by EmComponent::modify_rank
    ranked_in = None

    def __init__(self, model, uid, name, string=None, help_text=None, date_update=None, date_create=None, rank=None):
        if type(self) == EmComponent:
            raise NotImplementedError('Abstract class')
        if model.__class__.__name__ != 'Model':
            raise TypeError("Excepted type for 'model' arg is <class 'Model'> but got {} instead".format(type(model)))

        self.model = model

        self.uid = uid
        self.check_type('uid', int)
        self.name = name
        self.check_type('name', str)
        self.string = MlString() if string is None else string
        self.check_type('string', MlString)
        self.help_text = MlString() if help_text is None else help_text
        self.check_type('help_text', MlString)
        self.date_update = datetime.datetime.now() if date_update is None else date_update  # WARNING timezone !
        self.check_type('date_update', datetime.datetime)
        self.date_create = datetime.datetime.now() if date_create is None else date_create  # WARNING timezone !
        self.check_type('date_create', datetime.datetime)
        self._inited = False

        #Handling specials ranks for component creation
        self.rank = rank

    ## @brief Return a dict with attributes name as key and attributes value as value
    # @note Used at creation and deletion to call the migration handler
    def attr_dump(self):
        return {fname: fval for fname, fval in self.__dict__.items() if not (fname.startswith('_') or (fname == 'uid') or (fname == 'model'))}

    ## @brief Return a dict with attributes name as key and attributes value flattened
    def attr_flat(self):
        attributes_dump = self.attr_dump()
        for attr_name in list(attributes_dump.keys()):
            if isinstance(attributes_dump[attr_name], EmComponent):
                attributes_dump[attr_name] = attributes_dump[attr_name].uid
            elif isinstance(attributes_dump[attr_name], MlString):
                attributes_dump[attr_name] = attributes_dump[attr_name].__str__()
        attributes_dump['component'] = self.__class__.__name__

        return attributes_dump

    @property
    ## @brief Provide a uniq name
    #
    # Identify a component with his type and name
    def uniq_name(self):
        uname = self.__class__.__name__
        if not isinstance(self, EditorialModel.fields.EmField):  # WARNING this could crash with fieldtypes
            try:
                uname += '_' + self.em_class.name  # TODO Ajouter la propriété
            except AttributeError:
                pass
        uname += '_' + self.name
        return uname

    ## @brief This function has to be called after the instanciation, checks, and init manipulations are done
    # @note Create a new attribute _inited that allow __setattr__ to know if it has or not to call the migration handler
    def init_ended(self):
        self._inited = True

    ## @brief Reimplementation for calling the migration handler to register the change
    def __setattr__(self, attr_name, value):
        inited = '_inited' in self.__dict__ and self.__dict__['_inited']
        if inited:
            # if fails raise MigrationHandlerChangeError
            self.model.migration_handler.register_change(self.model, self.uid, {attr_name: getattr(self, attr_name)}, {attr_name: value})
        super(EmComponent, self).__setattr__(attr_name, value)
        if inited:
            self.model.migration_handler.register_model_state(self.model, hash(self.model))

    ## Check the type of attribute named var_name
    # @param var_name str : the attribute name
    # @param excepted_type tuple|type : Tuple of type or a type
    # @throw AttributeError if wrong type detected
    def check_type(self, var_name, excepted_type):
        var = getattr(self, var_name)

        if not isinstance(var, excepted_type):
            raise AttributeError("Excepted %s to be an %s but got %s instead" % (var_name, str(excepted_type), str(type(var))))

    ## @brief Hash function that allows to compare two EmComponent
    # @return EmComponent+ClassName+uid
    def __hash__(self):
        # flatten list of attributes of the component to an ordered list
        # so every time we have the same string representation
        attributes_flat = self.attr_flat()
        ordered_attributes = sorted(list(attributes_flat.keys()))

        component_dump = []
        for attr_name in ordered_attributes:
            if isinstance(attributes_flat[attr_name], datetime.datetime):  # drop date values
                continue
            component_dump.append((attr_name, attributes_flat[attr_name]))

        return int(hashlib.md5(str(component_dump).encode('utf-8')).hexdigest(), 16)

    ## @brief Test if two EmComponent are "equals"
    # @return True or False
    def __eq__(self, other):
        return hash(self) == hash(other)

    ## Check if the EmComponent is valid
    # This function has to check that rank are correct and continuous other checks are made in childs classes
    # @warning Hardcoded minimum rank
    # @warning Rank modified by _fields['rank'].value
    # @throw EmComponentCheckError if fails
    def check(self):
        self.model.sort_components(self.__class__)
        if self.get_max_rank() != len(self.same_rank_group()) or self.rank <= 0:
            #Non continuous ranks
            for i, component in enumerate(self.same_rank_group()):
                component.rank = i + 1
        # No need to sort again here

    ## @brief Delete predicate. Indicates if a component can be deleted
    # @return True if deletion OK else return False
    def delete_check(self):
        raise NotImplementedError("Virtual method")

    ## @brief Get the maximum rank given an EmComponent child class and a ranked_in filter
    # @return The max rank is the rank group or 0 if no components in that group
    def get_max_rank(self):
        same_rgroup = self.same_rank_group()
        return max([comp.rank for comp in same_rgroup]) if len(same_rgroup) > 0 else 0

    ## Return an array of instances that are concerned by the same rank
    # @return An array of instances that are concerned by the same rank
    def same_rank_group(self):
        components = self.model.components(self.__class__)
        ranked_in = self.__class__.ranked_in
        return [c for c in components if getattr(c, ranked_in) == getattr(self, ranked_in)]

    ## Set a new rank for this component
    # @note This function assume that ranks are properly set from 1 to x with no gap
    #
    # @warning Hardcoded minimum rank
    # @warning Rank modified by _fields['rank'].value
    #
    # @param new_rank int: The new rank
    #
    # @throw TypeError If bad argument type
    # @throw ValueError if out of bound value
    def set_rank(self, new_rank):
        if not isinstance(new_rank, int):
            raise TypeError("Excepted <class int> but got " + str(type(new_rank)))
        if new_rank <= 0 or (new_rank > 1 and new_rank > self.get_max_rank()):
            raise ValueError("Invalid new rank : " + str(new_rank))

        mod = new_rank - self.rank  # Indicates the "direction" of the "move"

        if mod == 0:
            return True

        limits = [self.rank + (1 if mod > 0 else -1), new_rank]  # The range of modified ranks
        limits.sort()

        for component in [c for c in self.same_rank_group() if c.rank >= limits[0] and c.rank <= limits[1]]:
            component.rank = component.rank + (-1 if mod > 0 else 1)

        self.rank = new_rank

        self.model.sort_components(self.__class__)

    ## Modify a rank given an integer modifier
    # @note this method always tries to make the modification : if modifier is too big put
    # the component in last position, if modifier is to small put the component
    # in first position
    # @param rank_mod int : can be a negative positive or zero integer
    # @return True if the modification was made as wanted else return false
    # @throw TypeError if rank_mod is not an integer
    def modify_rank(self, rank_mod):
        if not isinstance(rank_mod, int):
            raise TypeError("Excepted <class int>. But got %s" % str(type(rank_mod)))
        ret = True
        new_rank = self.rank + rank_mod
        if new_rank < 1:
            ret = False
            new_rank = 1
        elif new_rank > self.get_max_rank():
            ret = False
            new_rank = self.get_max_rank()

        self.set_rank(new_rank)
        return ret

    ## @brief Return a string representation of the component
    # @return A string representation of the component
    def __repr__(self):
        if self.name is None:
            return "<%s #%s, 'non populated'>" % (type(self).__name__, self.uid)
        else:
            return "<%s #%s, '%s'>" % (type(self).__name__, self.uid, self.name)