# -*- coding: utf-8 -*-
"takes care of the option's values and multi values"
# Copyright (C) 2013 Team tiramisu (see AUTHORS for all contributors)
#
# This program 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 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
# ____________________________________________________________
from time import time
import sys
import weakref
from tiramisu.error import ConfigError, SlaveError, PropertiesOptionError
from tiramisu.setting import owners, expires_time, undefined
from tiramisu.autolib import carry_out_calculation
from tiramisu.i18n import _
from tiramisu.option import SymLinkOption, OptionDescription


class Values(object):
    """The `Config`'s root is indeed  in charge of the `Option()`'s values,
    but the values are physicaly located here, in `Values`, wich is also
    responsible of a caching utility.
    """
    __slots__ = ('context', '_p_', '__weakref__')

    def __init__(self, context, storage):
        """
        Initializes the values's dict.

        :param context: the context is the home config's values

        """
        self.context = weakref.ref(context)
        # the storage type is dictionary or sqlite3
        self._p_ = storage

    def _getcontext(self):
        """context could be None, we need to test it
        context is None only if all reference to `Config` object is deleted
        (for example we delete a `Config` and we manipulate a reference to
        old `SubConfig`, `Values`, `Multi` or `Settings`)
        """
        context = self.context()
        if context is None:
            raise ConfigError(_('the context does not exist anymore'))
        return context

    def _getvalue(self, opt, path, is_default, index=undefined):
        """actually retrieves the value

        :param opt: the `option.Option()` object
        :returns: the option's value (or the default value if not set)
        """
        setting = self._getcontext().cfgimpl_get_settings()
        force_default = 'frozen' in setting[opt] and \
            'force_default_on_freeze' in setting[opt]
        if not is_default and not force_default:
            value = self._p_.getvalue(path)
            if index is not undefined:
                try:
                    return value[index]
                except IndexError:
                    #value is smaller than expected
                    #so return default value
                    pass
            else:
                return value
        #so default value
        # if value has callback and is not set
        if opt.impl_has_callback():
            callback, callback_params = opt.impl_get_callback()
            if callback_params is None:
                callback_params = {}
            value = carry_out_calculation(opt, config=self._getcontext(),
                                          callback=callback,
                                          callback_params=callback_params,
                                          index=index)
            try:
                if isinstance(value, list) and index is not undefined:
                    return value[index]
                return value
            except IndexError:
                pass
        meta = self._getcontext().cfgimpl_get_meta()
        if meta is not None:
            #FIXME : problème de longueur si meta + slave
            #doit passer de meta à pas meta
            #en plus il faut gérer la longueur avec les meta !
            #FIXME SymlinkOption
            value = meta.cfgimpl_get_values()[opt]
            if isinstance(value, Multi):
                if index is not undefined:
                    value = value[index]
                else:
                    value = list(value)
            return value
        # now try to get default value
        value = opt.impl_getdefault()
        if opt.impl_is_multi() and index is not undefined:
            if value is None:
                value = opt.impl_getdefault_multi()
            else:
                try:
                    value = value[index]
                except IndexError:
                    value = opt.impl_getdefault_multi()
        return value

    def get_modified_values(self):
        context = self._getcontext()
        if context._impl_descr is not None:
            for opt, path in context.cfgimpl_get_settings(
            ).get_with_property('force_store_value'):
                self._getowner(opt, path, force_permissive=True)
        return self._p_.get_modified_values()

    def __contains__(self, opt):
        """
        implements the 'in' keyword syntax in order provide a pythonic way
        to kow if an option have a value

        :param opt: the `option.Option()` object
        """
        path = self._get_opt_path(opt)
        return self._contains(path)

    def _contains(self, path):
        return self._p_.hasvalue(path)

    def __delitem__(self, opt):
        """overrides the builtins `del()` instructions"""
        self.reset(opt)

    def reset(self, opt, path=None):
        if path is None:
            path = self._get_opt_path(opt)
        if self._p_.hasvalue(path):
            context = self._getcontext()
            setting = context.cfgimpl_get_settings()
            opt.impl_validate(opt.impl_getdefault(),
                              context, 'validator' in setting)
            context.cfgimpl_reset_cache()
            if opt.impl_is_master_slaves('master'):
                opt.impl_get_master_slaves().reset(self)
            self._p_.resetvalue(path)

    def _isempty(self, opt, value):
        "convenience method to know if an option is empty"
        empty = opt._empty
        if value is not undefined:
            empty_not_multi = not opt.impl_is_multi() and (value is None or
                                                           value == empty)
            empty_multi = opt.impl_is_multi() and (value == [] or
                                                   None in value or
                                                   empty in value)
        else:
            empty_multi = empty_not_multi = False
        return empty_not_multi or empty_multi

    def __getitem__(self, opt):
        "enables us to use the pythonic dictionary-like access to values"
        return self.getitem(opt)

    def getitem(self, opt, validate=True, force_permissive=False):
        """
        """
        return self._get_cached_item(opt, validate=validate,
                                     force_permissive=force_permissive)

    def _get_cached_item(self, opt, path=None, validate=True,
                         force_permissive=False, force_properties=None,
                         validate_properties=True):
        if path is None:
            path = self._get_opt_path(opt)
        ntime = None
        setting = self._getcontext().cfgimpl_get_settings()
        if 'cache' in setting and self._p_.hascache(path):
            if 'expire' in setting:
                ntime = int(time())
            is_cached, value = self._p_.getcache(path, ntime)
            if is_cached:
                if opt.impl_is_multi() and not isinstance(value, Multi):
                    #load value so don't need to validate if is not a Multi
                    value = Multi(value, self.context, opt, path)
                return value
        val = self._getitem(opt, path, validate, force_permissive,
                            force_properties, validate_properties)
        if 'cache' in setting and validate and validate_properties and \
                force_permissive is False and force_properties is None:
            if 'expire' in setting:
                if ntime is None:
                    ntime = int(time())
                ntime = ntime + expires_time
            self._p_.setcache(path, val, ntime)
        return val

    def _getitem(self, opt, path, validate, force_permissive, force_properties,
                 validate_properties):
        if opt.impl_is_master_slaves():
            return opt.impl_get_master_slaves().getitem(self, opt, path,
                                                        validate,
                                                        force_permissive,
                                                        force_properties,
                                                        validate_properties)
        else:
            return self._get_validated_value(opt, path, validate,
                                             force_permissive,
                                             force_properties,
                                             validate_properties)

    def _get_validated_value(self, opt, path, validate, force_permissive,
                             force_properties, validate_properties,
                             index=undefined):
        """same has getitem but don't touch the cache"""
        #FIXME expliquer la différence entre index == undefined et index == None
        context = self._getcontext()
        setting = context.cfgimpl_get_settings()
        is_default = self._is_default_owner(opt, path,
                                            validate_properties=False,
                                            validate_meta=False)
        try:
            if index is None:
                gv_index = undefined
            else:
                gv_index = index
            value = self._getvalue(opt, path, is_default, index=gv_index)
            config_error = None
        except ConfigError as err:
            # For calculating properties, we need value (ie for mandatory
            # value).
            # If value is calculating with a PropertiesOptionError's option
            # _getvalue raise a ConfigError.
            # We can not raise ConfigError if this option should raise
            # PropertiesOptionError too. So we get config_error and raise
            # ConfigError if properties did not raise.
            # cannot assign config_err directly in python 3.3
            config_error = err
            # value is not set, for 'undefined' (cannot set None because of
            # mandatory property)
            value = undefined

        if config_error is None:
            if index is undefined:
                force_index = None
            else:
                force_index = index
            if opt.impl_is_multi():
                if index is None and not isinstance(value, list):
                    value = []
                if force_index is None:
                    value = Multi(value, self.context, opt, path)
            if validate:
                opt.impl_validate(value, context, 'validator' in setting,
                                  force_index=force_index)
            #FIXME pas de test avec les metas ...
            #FIXME et les symlinkoption ...
            if is_default and 'force_store_value' in setting[opt]:
                self.setitem(opt, value, path, is_write=False,
                             force_permissive=force_permissive)
        if validate_properties:
            setting.validate_properties(opt, False, False, value=value,
                                        path=path,
                                        force_permissive=force_permissive,
                                        force_properties=force_properties)
        if config_error is not None:
            raise config_error
        return value

    def __setitem__(self, opt, value):
        raise ValueError(_('you should only set value with config'))

    def setitem(self, opt, value, path, force_permissive=False,
                is_write=True):
        # is_write is, for example, used with "force_store_value"
        # user didn't change value, so not write
        # valid opt
        context = self._getcontext()
        opt.impl_validate(value, context,
                          'validator' in context.cfgimpl_get_settings())
        if opt.impl_is_multi():
            value = Multi(value, self.context, opt, path)
            if opt.impl_is_master_slaves():
                opt.impl_get_master_slaves().setitem(self, opt, value, path)
        self._setvalue(opt, path, value, force_permissive=force_permissive,
                       is_write=is_write)

    def _setvalue(self, opt, path, value, force_permissive=False,
                  is_write=True, validate_properties=True):
        context = self._getcontext()
        context.cfgimpl_reset_cache()
        if validate_properties:
            setting = context.cfgimpl_get_settings()
            setting.validate_properties(opt, False, is_write,
                                        value=value, path=path,
                                        force_permissive=force_permissive)
        owner = context.cfgimpl_get_settings().getowner()
        if isinstance(value, Multi):
            value = list(value)
        self._p_.setvalue(path, value, owner)

    def getowner(self, opt, force_permissive=False):
        """
        retrieves the option's owner

        :param opt: the `option.Option` object
        :param force_permissive: behaves as if the permissive property
                                 was present
        :returns: a `setting.owners.Owner` object
        """
        if isinstance(opt, SymLinkOption):
            opt = opt._opt
        path = self._get_opt_path(opt)
        return self._getowner(opt, path, force_permissive=force_permissive)

    def _getowner(self, opt, path, validate_properties=True,
                  force_permissive=False, validate_meta=True):
        if validate_properties:
            self._getitem(opt, path, True, force_permissive, None, True)
        owner = self._p_.getowner(path, owners.default)
        if validate_meta:
            meta = self._getcontext().cfgimpl_get_meta()
            if owner is owners.default and meta is not None:
                owner = meta.cfgimpl_get_values()._getowner(opt, path)
        return owner

    def setowner(self, opt, owner):
        """
        sets a owner to an option

        :param opt: the `option.Option` object
        :param owner: a valid owner, that is a `setting.owners.Owner` object
        """
        if not isinstance(owner, owners.Owner):
            raise TypeError(_("invalid generic owner {0}").format(str(owner)))

        path = self._get_opt_path(opt)
        self._setowner(opt, path, owner)

    def _setowner(self, opt, path, owner):
        if self._getowner(opt, path) == owners.default:
            raise ConfigError(_('no value for {0} cannot change owner to {1}'
                                '').format(path, owner))
        self._p_.setowner(path, owner)

    def is_default_owner(self, opt, validate_properties=True,
                         validate_meta=True):
        """
        :param config: *must* be only the **parent** config
                       (not the toplevel config)
        :return: boolean
        """
        path = self._get_opt_path(opt)
        return self._is_default_owner(opt, path,
                                      validate_properties=validate_properties,
                                      validate_meta=validate_meta)

    def _is_default_owner(self, opt, path, validate_properties=True,
                          validate_meta=True):
        return self._getowner(opt, path, validate_properties,
                              validate_meta=validate_meta) == owners.default

    def reset_cache(self, only_expired):
        """
        clears the cache if necessary
        """
        if only_expired:
            self._p_.reset_expired_cache(int(time()))
        else:
            self._p_.reset_all_cache()

    def _get_opt_path(self, opt):
        """
        retrieve the option's path in the config

        :param opt: the `option.Option` object
        :returns: a string with points like "gc.dummy.my_option"
        """
        return self._getcontext().cfgimpl_get_description(
        ).impl_get_path_by_opt(opt)

    # information
    def set_information(self, key, value):
        """updates the information's attribute

        :param key: information's key (ex: "help", "doc"
        :param value: information's value (ex: "the help string")
        """
        self._p_.set_information(key, value)

    def get_information(self, key, default=undefined):
        """retrieves one information's item

        :param key: the item string (ex: "help")
        """
        try:
            return self._p_.get_information(key)
        except ValueError:
            if default is not undefined:
                return default
            else:
                raise ValueError(_("information's item"
                                   " not found: {0}").format(key))

    def mandatory_warnings(self):
        """convenience function to trace Options that are mandatory and
        where no value has been set

        :returns: generator of mandatory Option's path

        """
        def _mandatory_warnings(description):
            #if value in cache, properties are not calculated
            for opt in description.impl_getchildren():
                if isinstance(opt, OptionDescription):
                    _mandatory_warnings(opt)
                elif isinstance(opt, SymLinkOption):
                    pass
                else:
                    path = self._get_opt_path(opt)
                    try:
                        self._get_cached_item(opt, path=path,
                                              force_properties=frozenset(('mandatory',)))
                    except PropertiesOptionError as err:
                        if err.proptype == ['mandatory']:
                            yield path
        self.reset_cache(False)
        descr = self._getcontext().cfgimpl_get_description()
        ret = list(_mandatory_warnings(descr))
        self.reset_cache(False)
        return ret

    def force_cache(self):
        """parse all option to force data in cache
        """
        context = self.context()
        if not 'cache' in context.cfgimpl_get_settings():
            raise ConfigError(_('can force cache only if cache '
                                'is actived in config'))
        #remove all cached properties and value to update "expired" time
        context.cfgimpl_reset_cache()
        for path in context.cfgimpl_get_description().impl_getpaths(
                include_groups=True):
            try:
                context.getattr(path)
            except PropertiesOptionError:
                pass

    def __getstate__(self):
        return {'_p_': self._p_}

    def _impl_setstate(self, storage):
        self._p_._storage = storage

    def __setstate__(self, states):
        self._p_ = states['_p_']


# ____________________________________________________________
# multi types


class Multi(list):
    """multi options values container
    that support item notation for the values of multi options"""
    __slots__ = ('opt', 'path', 'context')

    def __init__(self, value, context, opt, path):
        """
        :param value: the Multi wraps a list value
        :param context: the home config that has the values
        :param opt: the option object that have this Multi value
        """
        if isinstance(value, Multi):
            raise ValueError(_('{0} is already a Multi ').format(opt.impl_getname()))
        self.opt = opt
        self.path = path
        if not isinstance(context, weakref.ReferenceType):
            raise ValueError('context must be a Weakref')
        self.context = context
        if not isinstance(value, list):
            value = [value]
        super(Multi, self).__init__(value)

    def _getcontext(self):
        """context could be None, we need to test it
        context is None only if all reference to `Config` object is deleted
        (for example we delete a `Config` and we manipulate a reference to
        old `SubConfig`, `Values`, `Multi` or `Settings`)
        """
        context = self.context()
        if context is None:
            raise ConfigError(_('the context does not exist anymore'))
        return context

    def __setitem__(self, index, value):
        self._validate(value, index)
        #assume not checking mandatory property
        super(Multi, self).__setitem__(index, value)
        self._getcontext().cfgimpl_get_values()._setvalue(self.opt, self.path,
                                                          self)

    def __repr__(self, *args, **kwargs):
        print args, kwargs
        return super(Multi, self).__repr__(*args, **kwargs)

    def __getitem__(self, y):
        return super(Multi, self).__getitem__(y)

    def append(self, value=undefined, force=False, setitem=True):
        """the list value can be updated (appened)
        only if the option is a master
        """
        values = self._getcontext().cfgimpl_get_values()
        if not force:
            if self.opt.impl_is_master_slaves('slave'):
                raise SlaveError(_("cannot append a value on a multi option {0}"
                                   " which is a slave").format(self.opt.impl_getname()))
        index = self.__len__()
        if value is undefined:
            try:
                value = values._get_validated_value(self.opt, self.path,
                                                    True, False, None, True,
                                                    index=index)
            except IndexError:
                value = None
        self._validate(value, index)
        super(Multi, self).append(value)
        if setitem:
            values._setvalue(self.opt, self.path, self,
                             validate_properties=not force)

    def sort(self, cmp=None, key=None, reverse=False):
        if self.opt.impl_is_master_slaves():
            raise SlaveError(_("cannot sort multi option {0} if master or slave"
                               "").format(self.opt.impl_getname()))
        if sys.version_info[0] >= 3:
            if cmp is not None:
                raise ValueError(_('cmp is not permitted in python v3 or '
                                   'greater'))
            super(Multi, self).sort(key=key, reverse=reverse)
        else:
            super(Multi, self).sort(cmp=cmp, key=key, reverse=reverse)
        self._getcontext().cfgimpl_get_values()._setvalue(self.opt, self.path,
                                                          self)

    def reverse(self):
        if self.opt.impl_is_master_slaves():
            raise SlaveError(_("cannot reverse multi option {0} if master or "
                               "slave").format(self.opt.impl_getname()))
        super(Multi, self).reverse()
        self._getcontext().cfgimpl_get_values()._setvalue(self.opt, self.path,
                                                          self)

    def insert(self, index, obj):
        if self.opt.impl_is_master_slaves():
            raise SlaveError(_("cannot insert multi option {0} if master or "
                               "slave").format(self.opt.impl_getname()))
        super(Multi, self).insert(index, obj)
        self._getcontext().cfgimpl_get_values()._setvalue(self.opt, self.path,
                                                          self)

    def extend(self, iterable):
        if self.opt.impl_is_master_slaves():
            raise SlaveError(_("cannot extend multi option {0} if master or "
                               "slave").format(self.opt.impl_getname()))
        super(Multi, self).extend(iterable)
        self._getcontext().cfgimpl_get_values()._setvalue(self.opt, self.path,
                                                          self)

    def _validate(self, value, force_index):
        if value is not None:
            try:
                self.opt.impl_validate(value, context=self._getcontext(),
                                       force_index=force_index)
            except ValueError as err:
                raise ValueError(_("invalid value {0} "
                                   "for option {1}: {2}"
                                   "").format(str(value),
                                              self.opt.impl_getname(), err))

    def pop(self, index, force=False):
        """the list value can be updated (poped)
        only if the option is a master

        :param index: remove item a index
        :type index: int
        :param force: force pop item (withoud check master/slave)
        :type force: boolean
        :returns: item at index
        """
        context = self._getcontext()
        if not force:
            if self.opt.impl_is_master_slaves('slave'):
                raise SlaveError(_("cannot pop a value on a multi option {0}"
                                   " which is a slave").format(self.opt.impl_getname()))
            if self.opt.impl_is_master_slaves('master'):
                self.opt.impl_get_master_slaves().pop(
                    context.cfgimpl_get_values(), index)
        #set value without valid properties
        ret = super(Multi, self).pop(index)
        context.cfgimpl_get_values()._setvalue(self.opt, self.path, self,
                                               validate_properties=not force)
        return ret