# -*- coding: iso-8859-1 -*-
# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
"""This modules defines func / methods for creating test repositories"""

__docformat__ = "restructuredtext en"

from random import randint, choice
from copy import deepcopy
from datetime import datetime, date, time, timedelta
from decimal import Decimal

from logilab.common import attrdict
from yams.constraints import (SizeConstraint, StaticVocabularyConstraint,
                              IntervalBoundConstraint, BoundaryConstraint,
                              Attribute, actual_value)
from rql.utils import decompose_b26 as base_decompose_b26

from cubicweb import Binary
from cubicweb.schema import RQLConstraint

def custom_range(start, stop, step):
    while start < stop:
        yield start
        start += step

def decompose_b26(index, ascii=False):
    """return a letter (base-26) decomposition of index"""
    if ascii:
        return base_decompose_b26(index)
    return base_decompose_b26(index, u'�abcdefghijklmnopqrstuvwxyz')

def get_max_length(eschema, attrname):
    """returns the maximum length allowed for 'attrname'"""
    for cst in eschema.rdef(attrname).constraints:
        if isinstance(cst, SizeConstraint) and cst.max:
            return cst.max
    return 300
    #raise AttributeError('No Size constraint on attribute "%s"' % attrname)

_GENERATED_VALUES = {}

class _ValueGenerator(object):
    """generates integers / dates / strings / etc. to fill a DB table"""

    def __init__(self, eschema, choice_func=None):
        """<choice_func> is a function that returns a list of possible
        choices for a given entity type and an attribute name. It should
        looks like :
            def values_for(etype, attrname):
                # some stuff ...
                return alist_of_acceptable_values # or None
        """
        self.choice_func = choice_func
        self.eschema = eschema

    def generate_attribute_value(self, entity, attrname, index=1, **kwargs):
        if attrname in entity:
            return entity[attrname]
        eschema = self.eschema
        if not eschema.has_unique_values(attrname):
            value = self.__generate_value(entity, attrname, index, **kwargs)
        else:
            value = self.__generate_value(entity, attrname, index, **kwargs)
            while value in _GENERATED_VALUES.get((eschema, attrname), ()):
                index += 1
                value = self.__generate_value(entity, attrname, index, **kwargs)
            _GENERATED_VALUES.setdefault((eschema, attrname), set()).add(value)
        entity[attrname] = value
        return value

    def __generate_value(self, entity, attrname, index, **kwargs):
        """generates a consistent value for 'attrname'"""
        eschema = self.eschema
        attrtype = str(eschema.destination(attrname)).lower()
        # Before calling generate_%s functions, try to find values domain
        if self.choice_func is not None:
            values_domain = self.choice_func(eschema, attrname)
            if values_domain is not None:
                return choice(values_domain)
        gen_func = getattr(self, 'generate_%s_%s' % (eschema, attrname),
                           getattr(self, 'generate_Any_%s' % attrname, None))
        if gen_func is not None:
            return gen_func(entity, index, **kwargs)
        # If no specific values domain, then generate a dummy value
        gen_func = getattr(self, 'generate_%s' % (attrtype))
        return gen_func(entity, attrname, index, **kwargs)

    def generate_string(self, entity, attrname, index, format=None):
        """generates a consistent value for 'attrname' if it's a string"""
        # First try to get choices
        choosed = self.get_choice(entity, attrname)
        if choosed is not None:
            return choosed
        # All other case, generate a default string
        attrlength = get_max_length(self.eschema, attrname)
        num_len = numlen(index)
        if num_len >= attrlength:
            ascii = self.eschema.rdef(attrname).internationalizable
            return ('&'+decompose_b26(index, ascii))[:attrlength]
        # always use plain text when no format is specified
        attrprefix = attrname[:max(attrlength-num_len-1, 0)]
        if format == 'text/html':
            value = u'<span>�%s<b>%d</b></span>' % (attrprefix, index)
        elif format == 'text/rest':
            value = u"""
title
-----

* %s
* %d
* �&
""" % (attrprefix, index)
        else:
            value = u'�&%s%d' % (attrprefix, index)
        return value[:attrlength]

    def generate_password(self, entity, attrname, index):
        """generates a consistent value for 'attrname' if it's a password"""
        return u'toto'

    def generate_integer(self, entity, attrname, index):
        """generates a consistent value for 'attrname' if it's an integer"""
        return self._constrained_generate(entity, attrname, 0, 1, index)
    generate_int = generate_integer

    def generate_float(self, entity, attrname, index):
        """generates a consistent value for 'attrname' if it's a float"""
        return self._constrained_generate(entity, attrname, 0.0, 1.0, index)

    def generate_decimal(self, entity, attrname, index):
        """generates a consistent value for 'attrname' if it's a float"""
        return Decimal(str(self.generate_float(entity, attrname, index)))

    def generate_datetime(self, entity, attrname, index):
        """generates a random date (format is 'yyyy-mm-dd HH:MM')"""
        base = datetime(randint(2000, 2004), randint(1, 12), randint(1, 28), 11, index%60)
        return self._constrained_generate(entity, attrname, base, timedelta(hours=1), index)

    generate_tzdatetime = generate_datetime # XXX implementation should add a timezone

    def generate_date(self, entity, attrname, index):
        """generates a random date (format is 'yyyy-mm-dd')"""
        base = date(randint(2000, 2010), 1, 1) + timedelta(randint(1, 365))
        return self._constrained_generate(entity, attrname, base, timedelta(days=1), index)

    def generate_interval(self, entity, attrname, index):
        """generates a random date (format is 'yyyy-mm-dd')"""
        base = timedelta(randint(1, 365))
        return self._constrained_generate(entity, attrname, base, timedelta(days=1), index)

    def generate_time(self, entity, attrname, index):
        """generates a random time (format is ' HH:MM')"""
        return time(11, index%60) #'11:%02d' % (index % 60)

    generate_tztime = generate_time # XXX implementation should add a timezone

    def generate_bytes(self, entity, attrname, index, format=None):
        fakefile = Binary("%s%s" % (attrname, index))
        fakefile.filename = u"file_%s" % attrname
        return fakefile

    def generate_boolean(self, entity, attrname, index):
        """generates a consistent value for 'attrname' if it's a boolean"""
        return index % 2 == 0

    def _constrained_generate(self, entity, attrname, base, step, index):
        choosed = self.get_choice(entity, attrname)
        if choosed is not None:
            return choosed
        # ensure index > 0
        index += 1
        minvalue, maxvalue = self.get_bounds(entity, attrname)
        if maxvalue is None:
            if minvalue is not None:
                base = max(minvalue, base)
            maxvalue = base + index * step
        if minvalue is None:
            minvalue = maxvalue - (index * step) # i.e. randint(-index, 0)
        return choice(list(custom_range(minvalue, maxvalue, step)))

    def _actual_boundary(self, entity, attrname, boundary):
        if isinstance(boundary, Attribute):
            # ensure we've a value for this attribute
            entity[attrname] = None # infinite loop safety belt
            if not boundary.attr in entity:
                self.generate_attribute_value(entity, boundary.attr)
            boundary = actual_value(boundary, entity)
        return boundary

    def get_bounds(self, entity, attrname):
        minvalue = maxvalue = None
        for cst in self.eschema.rdef(attrname).constraints:
            if isinstance(cst, IntervalBoundConstraint):
                minvalue = self._actual_boundary(entity, attrname, cst.minvalue)
                maxvalue = self._actual_boundary(entity, attrname, cst.maxvalue)
            elif isinstance(cst, BoundaryConstraint):
                if cst.operator[0] == '<':
                    maxvalue = self._actual_boundary(entity, attrname, cst.boundary)
                else:
                    minvalue = self._actual_boundary(entity, attrname, cst.boundary)
        return minvalue, maxvalue

    def get_choice(self, entity, attrname):
        """generates a consistent value for 'attrname' if it has some static
        vocabulary set, else return None.
        """
        for cst in self.eschema.rdef(attrname).constraints:
            if isinstance(cst, StaticVocabularyConstraint):
                return unicode(choice(cst.vocabulary()))
        return None

    # XXX nothing to do here
    def generate_Any_data_format(self, entity, index, **kwargs):
        # data_format attribute of File has no vocabulary constraint, we
        # need this method else stupid values will be set which make mtconverter
        # raise exception
        return u'application/octet-stream'

    def generate_Any_content_format(self, entity, index, **kwargs):
        # content_format attribute of EmailPart has no vocabulary constraint, we
        # need this method else stupid values will be set which make mtconverter
        # raise exception
        return u'text/plain'


class autoextend(type):
    def __new__(mcs, name, bases, classdict):
        for attrname, attrvalue in classdict.items():
            if callable(attrvalue):
                if attrname.startswith('generate_') and \
                       attrvalue.func_code.co_argcount < 2:
                    raise TypeError('generate_xxx must accept at least 1 argument')
                setattr(_ValueGenerator, attrname, attrvalue)
        return type.__new__(mcs, name, bases, classdict)

class ValueGenerator(_ValueGenerator):
    __metaclass__ = autoextend


def _default_choice_func(etype, attrname):
    """default choice_func for insert_entity_queries"""
    return None

def insert_entity_queries(etype, schema, vreg, entity_num,
                          choice_func=_default_choice_func):
    """returns a list of 'add entity' queries (couples query, args)
    :type etype: str
    :param etype: the entity's type

    :type schema: cubicweb.schema.Schema
    :param schema: the instance schema

    :type entity_num: int
    :param entity_num: the number of entities to insert

    XXX FIXME: choice_func is here for *historical* reasons, it should
               probably replaced by a nicer way to specify choices
    :type choice_func: function
    :param choice_func: a function that takes an entity type, an attrname and
                        returns acceptable values for this attribute
    """
    queries = []
    for index in xrange(entity_num):
        restrictions = []
        args = {}
        for attrname, value in make_entity(etype, schema, vreg, index, choice_func).items():
            restrictions.append('X %s %%(%s)s' % (attrname, attrname))
            args[attrname] = value
        if restrictions:
            queries.append(('INSERT %s X: %s' % (etype, ', '.join(restrictions)),
                            args))
            assert not 'eid' in args, args
        else:
            queries.append(('INSERT %s X' % etype, {}))
    return queries


def make_entity(etype, schema, vreg, index=0, choice_func=_default_choice_func,
                form=False):
    """generates a random entity and returns it as a dict

    by default, generate an entity to be inserted in the repository
    elif form, generate an form dictionnary to be given to a web controller
    """
    eschema = schema.eschema(etype)
    valgen = ValueGenerator(eschema, choice_func)
    entity = attrdict()
    # preprocessing to deal with _format fields
    attributes = []
    relatedfields = {}
    for rschema, attrschema in eschema.attribute_definitions():
        attrname = rschema.type
        if attrname == 'eid':
            # don't specify eids !
            continue
        if attrname.endswith('_format') and attrname[:-7] in eschema.subject_relations():
            relatedfields[attrname[:-7]] = attrschema
        else:
            attributes.append((attrname, attrschema))
    for attrname, attrschema in attributes:
        if attrname in relatedfields:
            # first generate a format and record it
            format = valgen.generate_attribute_value(entity, attrname + '_format', index)
            # then a value coherent with this format
            value = valgen.generate_attribute_value(entity, attrname, index, format=format)
        else:
            value = valgen.generate_attribute_value(entity, attrname, index)
        if form: # need to encode values
            if attrschema.type == 'Bytes':
                # twisted way
                fakefile = value
                filename = value.filename
                value = (filename, u"text/plain", fakefile)
            elif attrschema.type == 'Date':
                value = value.strftime(vreg.property_value('ui.date-format'))
            elif attrschema.type == 'Datetime':
                value = value.strftime(vreg.property_value('ui.datetime-format'))
            elif attrschema.type == 'Time':
                value = value.strftime(vreg.property_value('ui.time-format'))
            elif attrschema.type == 'Float':
                fmt = vreg.property_value('ui.float-format')
                value = fmt % value
            else:
                value = unicode(value)
    return entity



def select(constraints, cursor, selectvar='O', objtype=None):
    """returns list of eids matching <constraints>

    <selectvar> should be either 'O' or 'S' to match schema definitions
    """
    try:
        rql = 'Any %s WHERE %s' % (selectvar, constraints)
        if objtype:
            rql += ', %s is %s' % (selectvar, objtype)
        rset = cursor.execute(rql)
    except Exception:
        print "could restrict eid_list with given constraints (%r)" % constraints
        return []
    return set(eid for eid, in rset.rows)



def make_relations_queries(schema, edict, cursor, ignored_relations=(),
                           existingrels=None):
    """returns a list of generated RQL queries for relations
    :param schema: The instance schema

    :param e_dict: mapping between etypes and eids

    :param ignored_relations: list of relations to ignore (i.e. don't try
                              to generate insert queries for these relations)
    """
    gen = RelationsQueriesGenerator(schema, cursor, existingrels)
    return gen.compute_queries(edict, ignored_relations)

def composite_relation(rschema):
    for obj in rschema.objects():
        if obj.rdef(rschema, 'object').composite == 'subject':
            return True
    for obj in rschema.subjects():
        if obj.rdef(rschema, 'subject').composite == 'object':
            return True
    return False

class RelationsQueriesGenerator(object):
    rql_tmpl = 'SET S %s O WHERE S eid %%(subjeid)s, O eid %%(objeid)s'
    def __init__(self, schema, cursor, existing=None):
        self.schema = schema
        self.cursor = cursor
        self.existingrels = existing or {}

    def compute_queries(self, edict, ignored_relations):
        queries = []
        #   1/ skip final relations and explictly ignored relations
        rels = sorted([rschema for rschema in self.schema.relations()
                       if not (rschema.final or rschema in ignored_relations)],
                      key=lambda x:not composite_relation(x))
        # for each relation
        #   2/ take each possible couple (subj, obj)
        #   3/ analyze cardinality of relation
        #      a/ if relation is mandatory, insert one relation
        #      b/ else insert N relations where N is the mininum
        #         of 20 and the number of existing targetable entities
        for rschema in rels:
            sym = set()
            sedict = deepcopy(edict)
            oedict = deepcopy(edict)
            delayed = []
            # for each couple (subjschema, objschema), insert relations
            for subj, obj in rschema.rdefs:
                sym.add( (subj, obj) )
                if rschema.symmetric and (obj, subj) in sym:
                    continue
                subjcard, objcard = rschema.rdef(subj, obj).cardinality
                # process mandatory relations first
                if subjcard in '1+' or objcard in '1+' or composite_relation(rschema):
                    for query, args in self.make_relation_queries(sedict, oedict,
                                                          rschema, subj, obj):
                        yield query, args
                else:
                    delayed.append( (subj, obj) )
            for subj, obj in delayed:
                for query, args in self.make_relation_queries(sedict, oedict, rschema,
                                                              subj, obj):
                    yield query, args

    def qargs(self, subjeids, objeids, subjcard, objcard, subjeid, objeid):
        if subjcard in '?1+':
            subjeids.remove(subjeid)
        if objcard in '?1+':
            objeids.remove(objeid)
        return {'subjeid' : subjeid, 'objeid' : objeid}

    def make_relation_queries(self, sedict, oedict, rschema, subj, obj):
        rdef = rschema.rdef(subj, obj)
        subjcard, objcard = rdef.cardinality
        subjeids = sedict.get(subj, frozenset())
        used = self.existingrels[rschema.type]
        preexisting_subjrels = set(subj for subj, obj in used)
        preexisting_objrels = set(obj for subj, obj in used)
        # if there are constraints, only select appropriate objeids
        q = self.rql_tmpl % rschema.type
        constraints = [c for c in rdef.constraints
                       if isinstance(c, RQLConstraint)]
        if constraints:
            restrictions = ', '.join(c.expression for c in constraints)
            q += ', %s' % restrictions
            # restrict object eids if possible
            # XXX the attempt to restrict below in completely wrong
            # disabling it for now
            objeids = select(restrictions, self.cursor, objtype=obj)
        else:
            objeids = oedict.get(obj, frozenset())
        if subjcard in '?1' or objcard in '?1':
            for subjeid, objeid in used:
                if subjcard in '?1' and subjeid in subjeids:
                    subjeids.remove(subjeid)
                    # XXX why?
                    #if objeid in objeids:
                    #    objeids.remove(objeid)
                if objcard in '?1' and objeid in objeids:
                    objeids.remove(objeid)
                    # XXX why?
                    #if subjeid in subjeids:
                    #    subjeids.remove(subjeid)
        if not subjeids:
            check_card_satisfied(objcard, objeids, subj, rschema, obj)
            return
        if not objeids:
            check_card_satisfied(subjcard, subjeids, subj, rschema, obj)
            return
        if subjcard in '?1+':
            for subjeid in tuple(subjeids):
                # do not insert relation if this entity already has a relation
                if subjeid in preexisting_subjrels:
                    continue
                objeid = choose_eid(objeids, subjeid)
                if objeid is None or (subjeid, objeid) in used:
                    continue
                yield q, self.qargs(subjeids, objeids, subjcard, objcard,
                                    subjeid, objeid)
                used.add( (subjeid, objeid) )
                if not objeids:
                    check_card_satisfied(subjcard, subjeids, subj, rschema, obj)
                    break
        elif objcard in '?1+':
            for objeid in tuple(objeids):
                # do not insert relation if this entity already has a relation
                if objeid in preexisting_objrels:
                    continue
                subjeid = choose_eid(subjeids, objeid)
                if subjeid is None or (subjeid, objeid) in used:
                    continue
                yield q, self.qargs(subjeids, objeids, subjcard, objcard,
                                    subjeid, objeid)
                used.add( (subjeid, objeid) )
                if not subjeids:
                    check_card_satisfied(objcard, objeids, subj, rschema, obj)
                    break
        else:
            # FIXME: 20 should be read from config
            subjeidsiter = [choice(tuple(subjeids)) for i in xrange(min(len(subjeids), 20))]
            objeidsiter = [choice(tuple(objeids)) for i in xrange(min(len(objeids), 20))]
            for subjeid, objeid in zip(subjeidsiter, objeidsiter):
                if subjeid != objeid and not (subjeid, objeid) in used:
                    used.add( (subjeid, objeid) )
                    yield q, self.qargs(subjeids, objeids, subjcard, objcard,
                                        subjeid, objeid)

def check_card_satisfied(card, remaining, subj, rschema, obj):
    if card in '1+' and remaining:
        raise Exception("can't satisfy cardinality %s for relation %s %s %s" %
                        (card, subj, rschema, obj))


def choose_eid(values, avoid):
    values = tuple(values)
    if len(values) == 1 and values[0] == avoid:
        return None
    objeid = choice(values)
    while objeid == avoid: # avoid infinite recursion like in X comment X
        objeid = choice(values)
    return objeid



# UTILITIES FUNCS ##############################################################
def make_tel(num_tel):
    """takes an integer, converts is as a string and inserts
    white spaces each 2 chars (french notation)
    """
    num_list = list(str(num_tel))
    for index in (6, 4, 2):
        num_list.insert(index, ' ')

    return ''.join(num_list)


def numlen(number):
    """returns the number's length"""
    return len(str(number))