#
# Copyright 2008-2017 Universidad Complutense de Madrid
#
# This file is part of Numina
#
# SPDX-License-Identifier: GPL-3.0+
# License-Filename: LICENSE.txt
#

"""Metaclasses for Recipes."""

from .recipeinout import RecipeResult, RecipeInput
from .dataholders import EntryHolder, Result
from .requirements import Requirement

_RECIPE_RESULT_NAME = 'RecipeResult'
_RECIPE_INPUT_NAME = 'RecipeInput'


class RecipeType(type):
    """Metaclass for Recipe."""
    def __new__(cls, classname, parents, attributes):

        filter_reqs = {}
        filter_prods = {}
        filter_attr = {}

        for name, val in attributes.items():
            if isinstance(val, EntryHolder):
                if isinstance(val, Requirement):
                    filter_reqs[name] = val
                if isinstance(val, Result):
                    filter_prods[name] = val
            else:
                filter_attr[name] = val

        BaseRecipeResult = cls.get_base_class(
            RecipeResult, parents, attributes, _RECIPE_RESULT_NAME)
        BaseRecipeInput = cls.get_base_class(
            RecipeInput, parents, attributes, _RECIPE_INPUT_NAME)

        ReqsClass = cls.create_inpt_class(
            classname, BaseRecipeInput, filter_reqs)
        ResultClass = cls.create_prod_class(
            classname, BaseRecipeResult, filter_prods)

        filter_attr[_RECIPE_RESULT_NAME] = ResultClass
        filter_attr[_RECIPE_INPUT_NAME] = ReqsClass
        filter_attr[ResultClass.__name__] = ResultClass
        filter_attr[ReqsClass.__name__] = ReqsClass

        return super(RecipeType, cls).__new__(
            cls, classname, parents, filter_attr)

    @classmethod
    def create_gen_class(cls, classname, baseclass, attributes):
        if attributes:
            klass = type(classname, (baseclass,), attributes)
            # Add docs
            klass = generate_docs(klass)
        else:
            klass = baseclass
        return klass

    @classmethod
    def get_base_class(cls, default, parents, attributes, name):
        # Find base class for RecipeResult in parents
        if name in attributes:
            return attributes[name]
        else:
            for parent in parents:
                if hasattr(parent, name):
                    return getattr(parent, name)
            else:
                return default

    @classmethod
    def create_inpt_class(cls, classname, base, attributes):
        return cls.create_gen_class(f'{classname}Input',
                                    base, attributes)

    @classmethod
    def create_prod_class(cls, classname, base, attributes):
        return cls.create_gen_class(f'{classname}Result',
                                    base, attributes)


def generate_docs(klass):
    """Add documentation to generated classes"""
    import numina.types.datatype

    attrh = ('Attributes\n'
             '----------\n')

    doc = getattr(klass, '__doc__', None)

    if doc is None or doc == '':
        doc = f"{klass.__name__} documentation."

    if len(klass.stored()):
        doc = doc + '\n\n' + attrh

    skeys = sorted(klass.stored().keys())
    for key in skeys:
        y = klass.stored()[key]

        if isinstance(y, Requirement):
            modo = 'requirement'
        elif isinstance(y, Result):
            modo = 'product'
        else:
            modo = ""
        if y.type.isproduct():
            tipo = y.type.__class__.__name__
        elif isinstance(y.type, numina.types.datatype.PlainPythonType):
            tipo = y.type.internal_type.__name__
        else:
            tipo = y.type.__class__.__name__

        if y.optional:
            if y.default_value():
                modo = f"{modo}, optional, default={y.default}"
            else:
                modo = f"{modo}, optional"

        descript = y.description
        if descript:
            field = f"{key} : {tipo}, {modo}\n {descript}\n"
        else:
            field = f"{key} : {tipo}, {modo}\n"
        doc = doc + field

    klass.__doc__ = doc
    return klass
