# Copyright (C) 2012-2013 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/>.
#
# 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 tiramisu.error import PropertiesOptionError, ConfigError
from tiramisu.i18n import _
from tiramisu.setting import undefined
# ____________________________________________________________


def carry_out_calculation(option, config, callback, callback_params,
                          index=undefined):
    """a function that carries out a calculation for an option's value

    :param option: the option
    :param config: the context config in order to have
                   the whole options available
    :param callback: the name of the callback function
    :type callback: str
    :param callback_params: the callback's parameters
                            (only keyword parameters are allowed)
    :type callback_params: dict
    :param index: if an option is multi, only calculates the nth value
    :type index: int

    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 ''.

    * if no callback_params:
      => calculate(<function func at 0x2092320>, [], {})

    * if callback_params={'': ('yes',)}
      => calculate(<function func at 0x2092320>, ['yes'], {})

    * if callback_params={'value': ('yes',)}
      => calculate(<function func at 0x165b320>, [], {'value': 'yes'})

    * if callback_params={'': ('yes', 'no')}
      => calculate('yes', 'no')

    * if callback_params={'value': ('yes', 'no')}
      => ValueError()

    * if callback_params={'': (['yes', 'no'],)}
      => calculate(<function func at 0x176b320>, ['yes', 'no'], {})

    * if callback_params={'value': ('yes', 'no')}
      => raises ValueError()

    * if callback_params={'': ((opt1, False),)}

       - a simple option:
         opt1 == 11
         => calculate(<function func at 0x1cea320>, [11], {})

       - a multi option and not master/slave:
         opt1 == [1, 2, 3]
         => calculate(<function func at 0x223c320>, [[1, 2, 3]], {})

       - option is master or slave of opt1:
         opt1 == [1, 2, 3]
         => calculate(<function func at 0x223c320>, [1], {})
         => calculate(<function func at 0x223c320>, [2], {})
         => calculate(<function func at 0x223c320>, [3], {})

      - opt is a master or slave but not related to option:
        opt1 == [1, 2, 3]
        => calculate(<function func at 0x11b0320>, [[1, 2, 3]], {})

    * if callback_params={'value': ((opt1, False),)}

       - a simple option:
         opt1 == 11
         => calculate(<function func at 0x17ff320>, [], {'value': 11})

       - a multi option:
         opt1 == [1, 2, 3]
         => calculate(<function func at 0x1262320>, [], {'value': [1, 2, 3]})

    * if callback_params={'': ((opt1, False), (opt2, False))}

      - two single options
          opt1 = 11
          opt2 = 12
          => calculate(<function func at 0x217a320>, [11, 12], {})

      - a multi option with a simple option
          opt1 == [1, 2, 3]
          opt2 == 12
          => calculate(<function func at 0x2153320>, [[1, 2, 3], 12], {})

      - a multi option with an other multi option but with same length
          opt1 == [1, 2, 3]
          opt2 == [11, 12, 13]
          => calculate(<function func at 0x1981320>, [[1, 2, 3], [11, 12, 13]], {})

      - a multi option with an other multi option but with different length
          opt1 == [1, 2, 3]
          opt2 == [11, 12]
          => calculate(<function func at 0x2384320>, [[1, 2, 3], [11, 12]], {})

      - a multi option without value with a simple option
          opt1 == []
          opt2 == 11
          => calculate(<function func at 0xb65320>, [[], 12], {})

    * if callback_params={'value': ((opt1, False), (opt2, False))}
      => raises ValueError()

    If index is not undefined, return a value, otherwise return:

    * a list if one parameters have multi option
    * a value otherwise

    If calculate return list, this list is extend to return value.
    """
    tcparams = {}
    # if callback_params has a callback, launch several time calculate()
    one_is_multi = False
    # multi's option should have same value for all option
    len_multi = None

    for key, callbacks in callback_params.items():
        for callbk in callbacks:
            if isinstance(callbk, tuple):
                if len(callbk) == 1:
                    tcparams.setdefault(key, []).append((config, False))
                else:
                    # callbk is something link (opt, True|False)
                    opt, force_permissive = callbk
                    path = config.cfgimpl_get_description(
                    ).impl_get_path_by_opt(opt)
                    # get value
                    try:
                        value = config.getattr(path, force_permissive=True,
                                               validate=False)
                        # convert to list, not modifie this multi
                        if value.__class__.__name__ == 'Multi':
                            value = list(value)
                    except PropertiesOptionError as err:
                        if force_permissive:
                            continue
                        raise ConfigError(_('unable to carry out a calculation'
                                            ', option {0} has properties: {1} '
                                            'for: {2}').format(opt.impl_getname(),
                                                               err.proptype,
                                                               option.impl_getname()))

                    if opt.impl_is_master_slaves() and \
                            opt.impl_get_master_slaves().in_same_group(option):
                        len_multi = len(value)
                        one_is_multi = True
                        is_multi = True
                    else:
                        is_multi = False
                    tcparams.setdefault(key, []).append((value, is_multi))
            else:
                # callbk is a value and not a multi
                tcparams.setdefault(key, []).append((callbk, False))

    # if one value is a multi, launch several time calculate
    # if index is set, return a value
    # if no index, return a list
    if one_is_multi:
        ret = []
        if index is not undefined:
            range_ = [index]
        else:
            range_ = range(len_multi)
        for incr in range_:
            args = []
            kwargs = {}
            for key, couples in tcparams.items():
                for couple in couples:
                    value, ismulti = couple
                    if ismulti:
                        val = value[incr]
                    else:
                        val = value
                    if key == '':
                        args.append(val)
                    else:
                        kwargs[key] = val
            calc = calculate(callback, args, kwargs)
            if index is not undefined:
                ret = calc
            else:
                ret.append(calc)
        return ret
    else:
        # no value is multi
        # return a single value
        args = []
        kwargs = {}
        for key, couples in tcparams.items():
            for couple in couples:
                # couple[1] (ismulti) is always False
                if key == '':
                    args.append(couple[0])
                else:
                    kwargs[key] = couple[0]
        ret = calculate(callback, args, kwargs)
        if callback_params != {}:
            if isinstance(ret, list) and index is not undefined:
                if len(ret) < index + 1:
                    ret = None
                else:
                    ret = ret[index]
        return ret


def calculate(callback, 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

    """
    return callback(*args, **kwargs)