# MIT License
#
# Copyright (c) 2021 Templin Konstantin
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import logging
from itertools import product
from typing import List, Optional, Generator

import numpy

from feijoa.models.configuration import Configuration
from feijoa.search.algorithms import SearchAlgorithm
from feijoa.search.parameters import (Categorical, Integer,
                                         ParametersVisitor, Real)

__all__ = ["GridSearch"]

log = logging.getLogger(__name__)


class GridMaker(ParametersVisitor):

    EPS = 0.1

    def visit_integer(self, p: Integer):
        return range(p.low, p.high + 1)

    def visit_real(self, p: Real):
        return numpy.round(
            numpy.arange(p.low, p.high + GridMaker.EPS, GridMaker.EPS), 2)

    def visit_categorical(self, p: Categorical):
        return p.choices


class GridSearch(SearchAlgorithm):
    def __init__(self, search_space, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.search_space = search_space
        grids = [p.accept(GridMaker()) for p in self.search_space.params]
        self.prod_iter = product(*grids)
        self._ask_gen = None

    def ask(self, n: int = 1) -> Optional[List[Configuration]]:
        if not self._ask_gen:
            self._ask_gen = self._ask(n)
        return next(self._ask_gen)

    def _ask(self, n: int) -> Generator:

        while True:
            cfgs = []

            for i in range(n):
                try:
                    generation = next(self.prod_iter)
                except StopIteration:
                    break

                cfg = {
                    h.name: v
                    for h, v in zip(self.search_space, generation)
                }

                cfgs.append(Configuration(cfg, requestor=self.name))

            if not cfgs:
                yield None

            yield cfgs

    def tell(self, config, result):
        # no needed
        pass
