from abc import abstractmethod

from parso.tree import search_ancestor
from parso.python.tree import Name

from jedi.inference.filters import ParserTreeFilter, MergedFilter, \
    GlobalNameFilter
from jedi import parser_utils


class AbstractContext(object):
    # Must be defined: inference_state and tree_node and parent_context as an attribute/property

    def __init__(self, inference_state):
        self.inference_state = inference_state
        self.predefined_names = {}

    @abstractmethod
    def get_filters(self, until_position=None, origin_scope=None):
        raise NotImplementedError

    def goto(self, name_or_str, position):
        return self._goto(name_or_str, position)[0]

    def _goto(self, name_or_str, position):
        from jedi.inference import finder
        f = finder.NameFinder(self.inference_state, self, self, name_or_str, position)
        filters = _get_global_filters_for_name(
            self, name_or_str if isinstance(name_or_str, Name) else None, position,
        )
        return f.filter_name(filters), f

    def py__getattribute__(self, name_or_str, name_context=None, position=None,
                           analysis_errors=True):
        """
        :param position: Position of the last statement -> tuple of line, column
        """
        if name_context is None:
            name_context = self
        names, f = self._goto(name_or_str, position)
        values = f.find(names, attribute_lookup=False)
        if not names and not values and analysis_errors:
            if isinstance(name_or_str, Name):
                from jedi.inference import analysis
                message = ("NameError: name '%s' is not defined."
                           % name_or_str if isinstance(name_or_str, Name) else name_or_str)
                analysis.add(name_context, 'name-error', name_or_str, message)
        return values

    def get_root_context(self):
        parent_context = self.parent_context
        if parent_context is None:
            return self
        return parent_context.get_root_context()

    def is_module(self):
        return False

    def is_builtins_module(self):
        return False

    def is_class(self):
        return False

    def is_stub(self):
        return False

    def is_instance(self):
        return False

    def is_compiled(self):
        return False

    @abstractmethod
    def py__name__(self):
        raise NotImplementedError

    @property
    def name(self):
        return None

    def get_qualified_names(self):
        return ()

    def py__doc__(self):
        return ''

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


class ValueContext(AbstractContext):
    """
    Should be defined, otherwise the API returns empty types.
    """
    def __init__(self, value):
        super(ValueContext, self).__init__(value.inference_state)
        self._value = value

    @property
    def tree_node(self):
        return self._value.tree_node

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

    def is_module(self):
        return self._value.is_module()

    def is_builtins_module(self):
        return self._value == self.inference_state.builtins_module

    def is_class(self):
        return self._value.is_class()

    def is_stub(self):
        return self._value.is_stub()

    def is_instance(self):
        return self._value.is_instance()

    def is_compiled(self):
        return self._value.is_compiled()

    def py__name__(self):
        return self._value.py__name__()

    @property
    def name(self):
        return self._value.name

    def get_qualified_names(self):
        return self._value.get_qualified_names()

    def py__doc__(self):
        return self._value.py__doc__()

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


class TreeContextMixin(object):
    def infer_node(self, node):
        return self.inference_state.infer_element(self, node)

    def create_value(self, node):
        from jedi.inference import value

        if node == self.tree_node:
            assert self.is_module()
            return self.get_value()

        parent_context = self.create_context(node)

        if node.type in ('funcdef', 'lambdef'):
            func = value.FunctionValue.from_context(parent_context, node)
            if parent_context.is_class():
                class_value = parent_context.parent_context.create_value(parent_context.tree_node)
                instance = value.AnonymousInstance(
                    self.inference_state, parent_context.parent_context, class_value)
                func = value.BoundMethod(
                    instance=instance,
                    function=func
                )
            return func
        elif node.type == 'classdef':
            return value.ClassValue(self.inference_state, parent_context, node)
        else:
            raise NotImplementedError("Probably shouldn't happen: %s" % node)

    def create_context(self, node):
        def from_scope_node(scope_node, is_nested=True):
            if scope_node == self.tree_node:
                return self

            if scope_node.type in ('funcdef', 'lambdef', 'classdef'):
                return self.create_value(scope_node).as_context()
            elif scope_node.type in ('comp_for', 'sync_comp_for'):
                parent_scope = parser_utils.get_parent_scope(scope_node)
                parent_context = from_scope_node(parent_scope)
                if node.start_pos >= scope_node.children[-1].start_pos:
                    return parent_context
                return CompForContext(parent_context, scope_node)
            raise Exception("There's a scope that was not managed: %s" % scope_node)

        def parent_scope(node):
            while True:
                node = node.parent

                if parser_utils.is_scope(node):
                    return node
                elif node.type in ('argument', 'testlist_comp'):
                    if node.children[1].type in ('comp_for', 'sync_comp_for'):
                        return node.children[1]
                elif node.type == 'dictorsetmaker':
                    for n in node.children[1:4]:
                        # In dictionaries it can be pretty much anything.
                        if n.type in ('comp_for', 'sync_comp_for'):
                            return n

        scope_node = parent_scope(node)
        if scope_node.type in ('funcdef', 'classdef'):
            colon = scope_node.children[scope_node.children.index(':')]
            if node.start_pos < colon.start_pos:
                parent = node.parent
                if not (parent.type == 'param' and parent.name == node):
                    scope_node = parent_scope(scope_node)
        return from_scope_node(scope_node, is_nested=True)


class FunctionContext(TreeContextMixin, ValueContext):
    def get_filters(self, until_position=None, origin_scope=None):
        yield ParserTreeFilter(
            self.inference_state,
            parent_context=self,
            until_position=until_position,
            origin_scope=origin_scope
        )


class ModuleContext(TreeContextMixin, ValueContext):
    def py__file__(self):
        return self._value.py__file__()

    @property
    def py__package__(self):
        return self._value.py__package__

    @property
    def is_package(self):
        return self._value.is_package

    def get_filters(self, until_position=None, origin_scope=None):
        filters = self._value.get_filters(origin_scope)
        # Skip the first filter and replace it.
        next(filters)
        yield MergedFilter(
            ParserTreeFilter(
                parent_context=self,
                until_position=until_position,
                origin_scope=origin_scope
            ),
            GlobalNameFilter(self, self.tree_node),
        )
        for f in filters:  # Python 2...
            yield f

    @property
    def string_names(self):
        return self._value.string_names

    @property
    def code_lines(self):
        return self._value.code_lines

    def get_value(self):
        """
        This is the only function that converts a context back to a value.
        This is necessary for stub -> python conversion and vice versa. However
        this method shouldn't be moved to AbstractContext.
        """
        return self._value


class NamespaceContext(TreeContextMixin, ValueContext):
    def get_filters(self, until_position=None, origin_scope=None):
        return self._value.get_filters()

    def py__file__(self):
        return self._value.py__file__()


class ClassContext(TreeContextMixin, ValueContext):
    def get_filters(self, until_position=None, origin_scope=None):
        yield self.get_global_filter(until_position, origin_scope)

    def get_global_filter(self, until_position=None, origin_scope=None):
        return ParserTreeFilter(
            parent_context=self,
            until_position=until_position,
            origin_scope=origin_scope
        )


class CompForContext(TreeContextMixin, AbstractContext):
    def __init__(self, parent_context, comp_for):
        super(CompForContext, self).__init__(parent_context.inference_state)
        self.tree_node = comp_for
        self.parent_context = parent_context

    def get_filters(self, until_position=None, origin_scope=None):
        yield ParserTreeFilter(self)


class CompiledContext(ValueContext):
    def get_filters(self, until_position=None, origin_scope=None):
        return self._value.get_filters()

    def get_value(self):
        return self._value

    def py__file__(self):
        return self._value.py__file__()


def _get_global_filters_for_name(context, name_or_none, position):
    # For functions and classes the defaults don't belong to the
    # function and get inferred in the value before the function. So
    # make sure to exclude the function/class name.
    if name_or_none is not None:
        ancestor = search_ancestor(name_or_none, 'funcdef', 'classdef', 'lambdef')
        lambdef = None
        if ancestor == 'lambdef':
            # For lambdas it's even more complicated since parts will
            # be inferred later.
            lambdef = ancestor
            ancestor = search_ancestor(name_or_none, 'funcdef', 'classdef')
        if ancestor is not None:
            colon = ancestor.children[-2]
            if position is not None and position < colon.start_pos:
                if lambdef is None or position < lambdef.children[-2].start_pos:
                    position = ancestor.start_pos

    return get_global_filters(context, position, name_or_none)


def get_global_filters(context, until_position, origin_scope):
    """
    Returns all filters in order of priority for name resolution.

    For global name lookups. The filters will handle name resolution
    themselves, but here we gather possible filters downwards.

    >>> from jedi._compatibility import u, no_unicode_pprint
    >>> from jedi import Script
    >>> script = Script(u('''
    ... x = ['a', 'b', 'c']
    ... def func():
    ...     y = None
    ... '''))
    >>> module_node = script._module_node
    >>> scope = next(module_node.iter_funcdefs())
    >>> scope
    <Function: func@3-5>
    >>> context = script._get_module_context().create_context(scope)
    >>> filters = list(get_global_filters(context, (4, 0), None))

    First we get the names from the function scope.

    >>> no_unicode_pprint(filters[0])  # doctest: +ELLIPSIS
    MergedFilter(<ParserTreeFilter: ...>, <GlobalNameFilter: ...>)
    >>> sorted(str(n) for n in filters[0].values())  # doctest: +NORMALIZE_WHITESPACE
    ['<TreeNameDefinition: string_name=func start_pos=(3, 4)>',
     '<TreeNameDefinition: string_name=x start_pos=(2, 0)>']
    >>> filters[0]._filters[0]._until_position
    (4, 0)
    >>> filters[0]._filters[1]._until_position

    Then it yields the names from one level "lower". In this example, this is
    the module scope (including globals).
    As a side note, you can see, that the position in the filter is None on the
    globals filter, because there the whole module is searched.

    >>> list(filters[1].values())  # package modules -> Also empty.
    []
    >>> sorted(name.string_name for name in filters[2].values())  # Module attributes
    ['__doc__', '__name__', '__package__']

    Finally, it yields the builtin filter, if `include_builtin` is
    true (default).

    >>> list(filters[3].values())  # doctest: +ELLIPSIS
    [...]
    """
    base_context = context
    from jedi.inference.value.function import FunctionExecutionContext
    while context is not None:
        # Names in methods cannot be resolved within the class.
        for filter in context.get_filters(
                until_position=until_position,
                origin_scope=origin_scope):
            yield filter
        if isinstance(context, FunctionExecutionContext):
            # The position should be reset if the current scope is a function.
            until_position = None

        context = context.parent_context

    # Add builtins to the global scope.
    yield next(base_context.inference_state.builtins_module.get_filters())