# Copyright (C) 2012-2021 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/>.
#
# The original `Config` design model is unproudly borrowed from
# the rough gus of pypy: pypy: http://codespeak.net/svn/pypy/dist/pypy/config/
# the whole pypy projet is under MIT licence
# ____________________________________________________________
"enables us to carry out a calculation and return an option's value"
from typing import Any, Optional, Union, Callable, Dict, List
from types import CoroutineType
from itertools import chain

from .error import PropertiesOptionError, ConfigError, LeadershipError, ValueWarning
from .i18n import _
from .setting import undefined, ConfigBag, OptionBag, Undefined
# ____________________________________________________________


class Params:
    __slots__ = ('args', 'kwargs')
    def __init__(self, args=None, kwargs=None, **kwgs):
        if args is None:
            args = tuple()
        if kwargs is None:
            kwargs = {}
        if kwgs:
            kwargs.update(kwgs)
        if isinstance(args, Param):
            args = (args,)
        else:
            if not isinstance(args, tuple):
                raise ValueError(_('args in params must be a tuple'))
            for arg in args:
                if not isinstance(arg, Param):
                    raise ValueError(_('arg in params must be a Param'))
        if not isinstance(kwargs, dict):
            raise ValueError(_('kwargs in params must be a dict'))
        for arg in kwargs.values():
            if not isinstance(arg, Param):
                raise ValueError(_('arg in params must be a Param'))
        self.args = args
        self.kwargs = kwargs


class Param:
    pass


class ParamOption(Param):
    __slots__ = ('todict',
                 'option',
                 'notraisepropertyerror',
                 'raisepropertyerror')
    def __init__(self,
                 option: 'Option',
                 notraisepropertyerror: bool=False,
                 raisepropertyerror: bool=False,
                 todict: bool=False) -> None:
        if __debug__ and not hasattr(option, 'impl_is_symlinkoption'):
            raise ValueError(_('paramoption needs an option not {}').format(type(option)))
        if option.impl_is_symlinkoption():
            cur_opt = option.impl_getopt()
        else:
            cur_opt = option
        assert isinstance(notraisepropertyerror, bool), _('param must have a boolean not a {} for notraisepropertyerror').format(type(notraisepropertyerror))
        assert isinstance(raisepropertyerror, bool), _('param must have a boolean not a {} for raisepropertyerror').format(type(raisepropertyerror))
        self.todict = todict
        self.option = cur_opt
        self.notraisepropertyerror = notraisepropertyerror
        self.raisepropertyerror = raisepropertyerror


class ParamDynOption(ParamOption):
    __slots__ = ('suffix',)
    def __init__(self,
                 option: 'Option',
                 suffix: str,
                 dynoptiondescription: 'DynOptionDescription',
                 notraisepropertyerror: bool=False,
                 raisepropertyerror: bool=False,
                 todict: bool=False,
                 ) -> None:
        super().__init__(option,
                         notraisepropertyerror,
                         raisepropertyerror,
                         todict,
                         )
        self.suffix = suffix
        self.dynoptiondescription = dynoptiondescription


class ParamSelfOption(Param):
    __slots__ = ('todict', 'whole')
    def __init__(self,
                 todict: bool=False,
                 whole: bool=undefined) -> None:
        """whole: send all value for a multi, not only indexed value"""
        self.todict = todict
        if whole is not undefined:
            self.whole = whole


class ParamValue(Param):
    __slots__ = ('value',)
    def __init__(self, value):
        self.value = value


class ParamInformation(Param):
    __slots__ = ('information_name',)
    def __init__(self,
                 information_name: str,
                 default_value: Any=undefined,
                 ) -> None:
        self.information_name = information_name
        self.default_value = default_value


class ParamSelfInformation(ParamInformation):
    __slots__ = tuple()


class ParamIndex(Param):
    __slots__ = tuple()


class ParamSuffix(Param):
    __slots__ = tuple()


class Calculation:
    __slots__ = ('function',
                 'params',
                 'help_function',
                 '_has_index',
                 'warnings_only')
    def __init__(self,
                 function: Callable,
                 params: Params=Params(),
                 help_function: Optional[Callable]=None,
                 warnings_only: bool=False):
        assert isinstance(function, Callable), _('first argument ({0}) must be a function').format(function)
        if help_function:
            assert isinstance(help_function, Callable), _('help_function ({0}) must be a function').format(help_function)
            self.help_function = help_function
        else:
            self.help_function = None
        self.function = function
        self.params = params
        for arg in chain(self.params.args, self.params.kwargs.values()):
            if isinstance(arg, ParamIndex):
                self._has_index = True
                break
        if warnings_only is True:
            self.warnings_only = warnings_only

    async def execute(self,
                option_bag: OptionBag,
                leadership_must_have_index: bool=False,
                orig_value: Any=undefined,
                allow_value_error: bool=False,
                force_value_warning: bool=False,
                for_settings: bool=False,
                ) -> Any:
        return await carry_out_calculation(option_bag.option,
                                           callback=self.function,
                                           callback_params=self.params,
                                           index=option_bag.index,
                                           config_bag=option_bag.config_bag,
                                           leadership_must_have_index=leadership_must_have_index,
                                           orig_value=orig_value,
                                           allow_value_error=allow_value_error,
                                           force_value_warning=force_value_warning,
                                           for_settings=for_settings,
                                           )

    async def help(self,
                   option_bag: OptionBag,
                   leadership_must_have_index: bool=False,
                   for_settings: bool=False,
                   ) -> str:
        if not self.help_function:
            return await self.execute(option_bag,
                                      leadership_must_have_index=leadership_must_have_index,
                                      for_settings=for_settings,
                                      )
        return await carry_out_calculation(option_bag.option,
                                           callback=self.help_function,
                                           callback_params=self.params,
                                           index=option_bag.index,
                                           config_bag=option_bag.config_bag,
                                           leadership_must_have_index=leadership_must_have_index,
                                           for_settings=for_settings,
                                           )

    def has_index(self, current_option):
        if hasattr(self, '_has_index'):
            return self._has_index
        self._has_index = False
        for arg in chain(self.params.args, self.params.kwargs.values()):
            if isinstance(arg, ParamOption) and arg.option.impl_get_leadership() and \
                    arg.option.impl_get_leadership().in_same_group(current_option):
                self._has_index = True
                break
        return self._has_index


class Break(Exception):
    pass


async def manager_callback(callbk: Param,
                           option,
                           index: Optional[int],
                           orig_value,
                           config_bag: ConfigBag,
                           leadership_must_have_index: bool,
                           for_settings: bool,
                           ) -> Any:
    """replace Param by true value"""
    def calc_index(callbk, index, same_leadership):
        if index is not None:
            if hasattr(callbk, 'whole'):
                whole = callbk.whole
            else:
                # if value is same_leadership, follower are isolate by default
                # otherwise option is a whole option
                whole = not same_leadership
            if not whole:
                return index
        return None

    async def calc_self(callbk, option, index, value, config_bag):
        # index must be apply only if follower
        is_follower = option.impl_is_follower()
        apply_index = calc_index(callbk, index, is_follower)
        if value is undefined or (apply_index is None and is_follower):
            if config_bag is undefined:
                return undefined
            path = option.impl_getpath()
            option_bag = await get_option_bag(config_bag,
                                              option,
                                              apply_index,
                                              True)
            new_value = await get_value(callbk, option_bag, path)
            if apply_index is None and is_follower:
                new_value[index] = value
            value = new_value
        elif apply_index is not None and not is_follower:
            value = value[apply_index]
        return value

    async def get_value(callbk,
                        option_bag,
                        path,
                        ):
        try:
            # get value
            value = await config_bag.context.getattr(path,
                                                     option_bag)
        except PropertiesOptionError as err:
            # raise PropertiesOptionError (which is catched) because must not add value None in carry_out_calculation
            if callbk.notraisepropertyerror or callbk.raisepropertyerror:
                raise err
            raise ConfigError(_('unable to carry out a calculation for "{}"'
                                ', {}').format(option.impl_get_display_name(), err), err)
        except ValueError as err:
            raise ValueError(_('the option "{0}" is used in a calculation but is invalid ({1})').format(option_bag.option.impl_get_display_name(), err))
        except AttributeError as err:
            raise ConfigError(_('impossible to calculate "{0}", {1}').format(option_bag.option.impl_get_display_name(),
                                                                             err,
                                                                             ))
        return value

    async def get_option_bag(config_bag,
                             opt,
                             index_,
                             self_calc):
        # don't validate if option is option that we tried to validate
        config_bag = config_bag.copy()
        if for_settings:
            config_bag.properties = config_bag.true_properties - {'warnings'}
        config_bag.set_permissive()
        if not for_settings:
            config_bag.properties -= {'warnings'}
        option_bag = OptionBag()
        option_bag.set_option(opt,
                              index_,
                              config_bag)
        if not self_calc:
            option_bag.properties = await config_bag.context.cfgimpl_get_settings().getproperties(option_bag)
        else:
            option_bag.config_bag.unrestraint()
            option_bag.config_bag.remove_validation()
            # if we are in properties calculation, cannot calculated properties
            option_bag.properties = await config_bag.context.cfgimpl_get_settings().getproperties(option_bag,
                                                                                                  apply_requires=False)
        return option_bag

    if isinstance(callbk, ParamValue):
        return callbk.value

    if isinstance(callbk, ParamInformation):
        if isinstance(callbk, ParamSelfInformation):
            option_bag = OptionBag()
            option_bag.set_option(option,
                                  index,
                                  config_bag,
                                  )
        else:
            option_bag = None
        try:
            return await config_bag.context.impl_get_information(config_bag,
                                                                 option_bag,
                                                                 callbk.information_name,
                                                                 callbk.default_value,
                                                                 )
        except ValueError as err:
            raise ConfigError(_('option "{}" cannot be calculated: {}').format(option.impl_get_display_name(),
                                                                               str(err),
                                                                               ))

    if isinstance(callbk, ParamIndex):
        return index

    if isinstance(callbk, ParamSuffix):
        if not option.issubdyn():
            raise ConfigError(_('option "{}" is not in a dynoptiondescription').format(option.impl_get_display_name()))
        return option.impl_getsuffix()

    if isinstance(callbk, ParamSelfOption):
        if leadership_must_have_index and option.impl_get_leadership() and index is None:
            raise Break()
        value = await calc_self(callbk, option, index, orig_value, config_bag)
        if not callbk.todict:
            return value
        return {'name': option.impl_get_display_name(),
                'value': value}

    if isinstance(callbk, ParamOption):
        callbk_option = callbk.option
        if callbk_option.issubdyn():
            if isinstance(callbk, ParamDynOption):
                subdyn = callbk.dynoptiondescription
                rootpath = subdyn.impl_getpath() + callbk.suffix
                suffix = callbk.suffix
            else:
                if not option.impl_is_dynsymlinkoption():
                    msg = 'option "{}" is not dynamic but is an argument of the dynamic option "{}" in a callback'
                    raise ConfigError(_(msg).format(option.impl_get_display_name(),
                                                    callbk_option.impl_get_display_name(),
                                                    ))
                #FIXME in same dynamic option?
                rootpath = option.rootpath
                suffix = option.impl_getsuffix()
                subdyn = callbk_option.getsubdyn()
            callbk_option = callbk_option.to_dynoption(rootpath,
                                                       suffix,
                                                       subdyn)
        if leadership_must_have_index and callbk_option.impl_get_leadership() and index is None:
            raise Break()
        if config_bag is undefined:
            return undefined
        if index is not None and callbk_option.impl_get_leadership() and \
                callbk_option.impl_get_leadership().in_same_group(option):
            if not callbk_option.impl_is_follower():
                # leader
                index_ = None
                with_index = True
            else:
                # follower
                index_ = index
                with_index = False
        else:
            index_ = None
            with_index = False
        path = callbk_option.impl_getpath()
        option_bag = await get_option_bag(config_bag,
                                          callbk_option,
                                          index_,
                                          False)
        value = await get_value(callbk,
                                option_bag,
                                path,
                                )
        if with_index:
            value = value[index]
        if not callbk.todict:
            return value
        return {'name': callbk_option.impl_get_display_name(),
                'value': value}
    raise ConfigError(_('unknown callback type {} in option {}').format(callbk,
                                                                        option.impl_get_display_name()))


async def carry_out_calculation(option,
                                callback: Callable,
                                callback_params: Optional[Params],
                                index: Optional[int],
                                config_bag: Optional[ConfigBag],
                                orig_value=undefined,
                                leadership_must_have_index: bool=False,
                                allow_value_error: bool=False,
                                force_value_warning: bool=False,
                                for_settings: bool=False,
                                ):
    """a function that carries out a calculation for an option's value

    :param option: the option
    :param callback: the name of the callback function
    :param callback_params: the callback's parameters
                            (only keyword parameters are allowed)
    :param index: if an option is multi, only calculates the nth value
    :param allow_value_error: to know if carry_out_calculation can return ValueError or ValueWarning (for example if it's a validation)
    :param force_value_warning: transform valueError to ValueWarning object

    The callback_params is a dict. Key is used to build args (if key is '')
    and kwargs (otherwise). Values are tuple of:
    - values
    - tuple with option and boolean's force_permissive (True when don't raise
    if PropertiesOptionError)
    Values could have multiple values only when key is ''."""
    def fake_items(iterator):
        return ((None, i) for i in iterator)
    args = []
    kwargs = {}
    if callback_params:
        for key, callbk in chain(fake_items(callback_params.args), callback_params.kwargs.items()):
            try:
                value = await manager_callback(callbk,
                                               option,
                                               index,
                                               orig_value,
                                               config_bag,
                                               leadership_must_have_index,
                                               for_settings,
                                               )
                if value is undefined:
                    return undefined
                if key is None:
                    args.append(value)
                else:
                    kwargs[key] = value
            except PropertiesOptionError as err:
                if callbk.raisepropertyerror:
                    raise err
                if callbk.todict:
                    if key is None:
                        args.append({'propertyerror': str(err)})
                    else:
                        kwargs[key] = {'propertyerror': str(err)}
            except Break:
                continue
    ret = await calculate(option,
                          callback,
                          allow_value_error,
                          force_value_warning,
                          args,
                          kwargs)
    if isinstance(ret, list) and not option.impl_is_dynoptiondescription() and \
            option.impl_is_follower() and not option.impl_is_submulti():
        if args or kwargs:
            raise LeadershipError(_('the "{}" function with positional arguments "{}" '
                                    'and keyword arguments "{}" must not return '
                                    'a list ("{}") for the follower option "{}"'
                                    '').format(callback.__name__,
                                               args,
                                               kwargs,
                                               ret,
                                               option.impl_get_display_name()))
        else:
            raise LeadershipError(_('the "{}" function must not return a list ("{}") '
                                    'for the follower option "{}"'
                                    '').format(callback.__name__,
                                               ret,
                                               option.impl_get_display_name()))
    return ret


async def calculate(option,
                    callback: Callable,
                    allow_value_error: bool,
                    force_value_warning: bool,
                    args,
                    kwargs,
                    ):
    """wrapper that launches the 'callback'

    :param callback: callback function
    :param args: in the callback's arity, the unnamed parameters
    :param kwargs: in the callback's arity, the named parameters

    """
    try:
        ret = callback(*args, **kwargs)
        if isinstance(ret, CoroutineType):
            ret = await ret
        return ret
    except (ValueError, ValueWarning) as err:
        if allow_value_error:
            if force_value_warning:
                raise ValueWarning(str(err))
            raise err
        error = err
    except Exception as err:
        # import traceback
        # traceback.print_exc()
        error = err
    if args or kwargs:
        msg = _('unexpected error "{0}" in function "{1}" with arguments "{3}" and "{4}" '
                'for option "{2}"').format(str(error),
                                           callback.__name__,
                                           option.impl_get_display_name(),
                                           args,
                                           kwargs)
    else:
        msg = _('unexpected error "{0}" in function "{1}" for option "{2}"'
                '').format(str(error),
                           callback.__name__,
                           option.impl_get_display_name())
    raise ConfigError(msg) from error