import logging
from copy import deepcopy

from ..properties import InvalidField, FolderId
from ..queryset import DoesNotExist, MultipleObjectsReturned
from ..restriction import Q

# Traversal enums
SHALLOW = 'Shallow'
SOFT_DELETED = 'SoftDeleted'
DEEP = 'Deep'
FOLDER_TRAVERSAL_CHOICES = (SHALLOW, DEEP, SOFT_DELETED)


log = logging.getLogger(__name__)


class FolderQuerySet:
    """A QuerySet-like class for finding subfolders of a folder collection."""

    def __init__(self, folder_collection):
        from .collections import FolderCollection
        if not isinstance(folder_collection, FolderCollection):
            raise ValueError("'folder_collection' %r must be a FolderCollection instance" % folder_collection)
        self.folder_collection = folder_collection
        self.q = Q()  # Default to no restrictions
        self.only_fields = None
        self._depth = None

    def _copy_cls(self):
        return self.__class__(folder_collection=self.folder_collection)

    def _copy_self(self):
        """Chaining operations must make a copy of self before making any modifications."""
        new_qs = self._copy_cls()
        new_qs.q = deepcopy(self.q)
        new_qs.only_fields = self.only_fields
        new_qs._depth = self._depth
        return new_qs

    def only(self, *args):
        """Restrict the fields returned. 'name' and 'folder_class' are always returned."""
        from .base import Folder
        # Subfolders will always be of class Folder
        all_fields = self.folder_collection.get_folder_fields(target_cls=Folder, is_complex=None)
        all_fields.update(Folder.attribute_fields())
        only_fields = []
        for arg in args:
            for field_path in all_fields:
                if field_path.field.name == arg:
                    only_fields.append(field_path)
                    break
            else:
                raise InvalidField("Unknown field %r on folders %s" % (arg, self.folder_collection.folders))
        new_qs = self._copy_self()
        new_qs.only_fields = only_fields
        return new_qs

    def depth(self, depth):
        """Specify the search depth. Possible values are: SHALLOW or DEEP.

        :param depth:
        """
        new_qs = self._copy_self()
        new_qs._depth = depth
        return new_qs

    def get(self, *args, **kwargs):
        """Return the query result as exactly one item. Raises DoesNotExist if there are no results, and
        MultipleObjectsReturned if there are multiple results.
        """
        from .collections import FolderCollection
        if not args and set(kwargs) in ({'id'}, {'id', 'changekey'}):
            folders = list(FolderCollection(
                account=self.folder_collection.account, folders=[FolderId(**kwargs)]
            ).resolve())
        elif args or kwargs:
            folders = list(self.filter(*args, **kwargs))
        else:
            folders = list(self.all())
        if not folders:
            raise DoesNotExist('Could not find a child folder matching the query')
        if len(folders) != 1:
            raise MultipleObjectsReturned('Expected result length 1, but got %s' % folders)
        f = folders[0]
        if isinstance(f, Exception):
            raise f
        return f

    def all(self):
        """ """
        new_qs = self._copy_self()
        return new_qs

    def filter(self, *args, **kwargs):
        """Add restrictions to the folder search."""
        new_qs = self._copy_self()
        q = Q(*args, **kwargs)
        new_qs.q = new_qs.q & q
        return new_qs

    def __iter__(self):
        return self._query()

    def _query(self):
        from .base import Folder
        from .collections import FolderCollection
        if self.only_fields is None:
            # Subfolders will always be of class Folder
            non_complex_fields = self.folder_collection.get_folder_fields(target_cls=Folder, is_complex=False)
            complex_fields = self.folder_collection.get_folder_fields(target_cls=Folder, is_complex=True)
        else:
            non_complex_fields = {f for f in self.only_fields if not f.field.is_complex}
            complex_fields = {f for f in self.only_fields if f.field.is_complex}

        # First, fetch all non-complex fields using FindFolder. We do this because some folders do not support
        # GetFolder but we still want to get as much information as possible.
        folders = self.folder_collection.find_folders(q=self.q, depth=self._depth, additional_fields=non_complex_fields)
        if not complex_fields:
            yield from folders
            return

        # Fetch all properties for the found folders
        resolveable_folders = []
        for f in folders:
            if not f.get_folder_allowed:
                log.debug('GetFolder not allowed on folder %s. Non-complex fields must be fetched with FindFolder', f)
                yield f
            else:
                resolveable_folders.append(f)

        # Get the complex fields using GetFolder, for the folders that support it, and add the extra field values
        complex_folders = FolderCollection(
            account=self.folder_collection.account, folders=resolveable_folders
        ).get_folders(additional_fields=complex_fields)
        for f, complex_f in zip(resolveable_folders, complex_folders):
            if isinstance(f, Exception):
                yield f
                continue
            if isinstance(complex_f, Exception):
                yield complex_f
                continue
            # Add the extra field values to the folders we fetched with find_folders()
            if f.__class__ != complex_f.__class__:
                raise ValueError('Type mismatch: %s vs %s' % (f, complex_f))
            for complex_field in complex_fields:
                field_name = complex_field.field.name
                setattr(f, field_name, getattr(complex_f, field_name))
            yield f


class SingleFolderQuerySet(FolderQuerySet):
    """A helper class with simpler argument types."""

    def __init__(self, account, folder):
        from .collections import FolderCollection
        folder_collection = FolderCollection(account=account, folders=[folder])
        super().__init__(folder_collection=folder_collection)

    def _copy_cls(self):
        return self.__class__(account=self.folder_collection.account, folder=self.folder_collection.folders[0])

    def resolve(self):
        folders = list(self.folder_collection.resolve())
        if not folders:
            raise DoesNotExist('Could not find a folder matching the query')
        if len(folders) != 1:
            raise MultipleObjectsReturned('Expected result length 1, but got %s' % folders)
        f = folders[0]
        if isinstance(f, Exception):
            raise f
        return f
