# -*- coding: utf-8 -*-
#

import coreapi
from rest_framework import filters
from django.db.models import Q

from common.utils import dict_get_any, is_uuid, get_object_or_none
from .models import Node, Label


class AssetByNodeFilterBackend(filters.BaseFilterBackend):
    fields = ['node', 'all']

    def get_schema_fields(self, view):
        return [
            coreapi.Field(
                name=field, location='query', required=False,
                type='string', example='', description='', schema=None,
            )
            for field in self.fields
        ]

    @staticmethod
    def is_query_all(request):
        query_all_arg = request.query_params.get('all')
        show_current_asset_arg = request.query_params.get('show_current_asset')

        query_all = query_all_arg == '1'
        if show_current_asset_arg is not None:
            query_all = show_current_asset_arg != '1'
        return query_all

    @staticmethod
    def get_query_node(request):
        node_id = dict_get_any(request.query_params, ['node', 'node_id'])
        if not node_id:
            return None, False

        if is_uuid(node_id):
            node = get_object_or_none(Node, id=node_id)
        else:
            node = get_object_or_none(Node, key=node_id)
        return node, True

    @staticmethod
    def perform_query(pattern, queryset):
        return queryset.filter(nodes__key__regex=pattern)

    def filter_queryset(self, request, queryset, view):
        node, has_query_arg = self.get_query_node(request)
        if not has_query_arg:
            return queryset

        if node is None:
            return queryset.none()
        query_all = self.is_query_all(request)
        if query_all:
            pattern = node.get_all_children_pattern(with_self=True)
        else:
            pattern = node.get_children_key_pattern(with_self=True)
        return self.perform_query(pattern, queryset)


class LabelFilterBackend(filters.BaseFilterBackend):
    sep = '#'
    query_arg = 'label'

    def get_schema_fields(self, view):
        example = self.sep.join(['os', 'linux'])
        return [
            coreapi.Field(
                name=self.query_arg, location='query', required=False,
                type='string', example=example, description=''
            )
        ]

    def get_query_labels(self, request):
        labels_query = request.query_params.getlist(self.query_arg)
        if not labels_query:
            return None

        q = None
        for kv in labels_query:
            if self.sep not in kv:
                continue
            key, value = kv.strip().split(self.sep)[:2]
            if not all([key, value]):
                continue
            if q:
                q |= Q(name=key, value=value)
            else:
                q = Q(name=key, value=value)
        if not q:
            return []
        labels = Label.objects.filter(q, is_active=True)\
            .values_list('id', flat=True)
        return labels

    def filter_queryset(self, request, queryset, view):
        labels = self.get_query_labels(request)
        if labels is None:
            return queryset
        if len(labels) == 0:
            return queryset.none()
        for label in labels:
            queryset = queryset.filter(labels=label)
        return queryset


class AssetRelatedByNodeFilterBackend(AssetByNodeFilterBackend):
    @staticmethod
    def perform_query(pattern, queryset):
        return queryset.filter(asset__nodes__key__regex=pattern).distinct()

