from abc import abstractmethod

from parso.tree import search_ancestor

from jedi._compatibility import Parameter
from jedi.evaluate.base_context import ContextSet


class AbstractNameDefinition(object):
    start_pos = None
    string_name = None
    parent_context = None
    tree_name = None

    @abstractmethod
    def infer(self):
        raise NotImplementedError

    @abstractmethod
    def goto(self):
        # Typically names are already definitions and therefore a goto on that
        # name will always result on itself.
        return {self}

    def get_root_context(self):
        return self.parent_context.get_root_context()

    def __repr__(self):
        if self.start_pos is None:
            return '<%s: %s>' % (self.__class__.__name__, self.string_name)
        return '<%s: %s@%s>' % (self.__class__.__name__, self.string_name, self.start_pos)

    def is_import(self):
        return False

    @property
    def api_type(self):
        return self.parent_context.api_type


class AbstractTreeName(AbstractNameDefinition):
    def __init__(self, parent_context, tree_name):
        self.parent_context = parent_context
        self.tree_name = tree_name

    def goto(self):
        return self.parent_context.evaluator.goto(self.parent_context, self.tree_name)

    def is_import(self):
        imp = search_ancestor(self.tree_name, 'import_from', 'import_name')
        return imp is not None

    @property
    def string_name(self):
        return self.tree_name.value

    @property
    def start_pos(self):
        return self.tree_name.start_pos


class ContextNameMixin(object):
    def infer(self):
        return ContextSet([self._context])

    def get_root_context(self):
        if self.parent_context is None:  # A module
            return self._context
        return super(ContextNameMixin, self).get_root_context()

    @property
    def api_type(self):
        return self._context.api_type


class ContextName(ContextNameMixin, AbstractTreeName):
    def __init__(self, context, tree_name):
        super(ContextName, self).__init__(context.parent_context, tree_name)
        self._context = context


class TreeNameDefinition(AbstractTreeName):
    _API_TYPES = dict(
        import_name='module',
        import_from='module',
        funcdef='function',
        param='param',
        classdef='class',
    )

    def infer(self):
        # Refactor this, should probably be here.
        from jedi.evaluate.syntax_tree import tree_name_to_contexts
        parent = self.parent_context
        return tree_name_to_contexts(parent.evaluator, parent, self.tree_name)

    @property
    def api_type(self):
        definition = self.tree_name.get_definition(import_name_always=True)
        if definition is None:
            return 'statement'
        return self._API_TYPES.get(definition.type, 'statement')


class ParamName(AbstractTreeName):
    api_type = u'param'

    def __init__(self, parent_context, tree_name):
        self.parent_context = parent_context
        self.tree_name = tree_name

    def get_kind(self):
        tree_param = search_ancestor(self.tree_name, 'param')
        if tree_param.star_count == 1:  # *args
            return Parameter.VAR_POSITIONAL
        if tree_param.star_count == 2:  # **kwargs
            return Parameter.VAR_KEYWORD

        parent = tree_param.parent
        for p in parent.children:
            if p.type == 'param':
                if p.star_count:
                    return Parameter.KEYWORD_ONLY
                if p == tree_param:
                    break
        return Parameter.POSITIONAL_OR_KEYWORD

    def infer(self):
        return self.get_param().infer()

    def get_param(self):
        params, _ = self.parent_context.get_executed_params_and_issues()
        param_node = search_ancestor(self.tree_name, 'param')
        return params[param_node.position_index]


class ImportName(AbstractNameDefinition):
    start_pos = (1, 0)
    _level = 0

    def __init__(self, parent_context, string_name):
        self.parent_context = parent_context
        self.string_name = string_name

    def infer(self):
        from jedi.evaluate.imports import Importer
        return Importer(
            self.parent_context.evaluator,
            [self.string_name],
            self.parent_context,
            level=self._level,
        ).follow()

    def goto(self):
        return [m.name for m in self.infer()]

    def get_root_context(self):
        # Not sure if this is correct.
        return self.parent_context.get_root_context()

    @property
    def api_type(self):
        return 'module'


class SubModuleName(ImportName):
    _level = 1


class NameWrapper(object):
    def __init__(self, wrapped_name):
        self._wrapped_name = wrapped_name

    @abstractmethod
    def infer(self):
        raise NotImplementedError

    def __getattr__(self, name):
        return getattr(self._wrapped_name, name)

    def __repr__(self):
        return '%s(%s)' % (self.__class__.__name__, self._wrapped_name)