"""
Provides a JSON API for the Part app
"""

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django_filters.rest_framework import DjangoFilterBackend
from rest_framework import filters
from rest_framework import generics, permissions

from django.db.models import Q
from django.conf.urls import url, include

from .models import Part, PartCategory, BomItem
from .models import SupplierPart, SupplierPriceBreak

from .serializers import PartSerializer, BomItemSerializer
from .serializers import SupplierPartSerializer, SupplierPriceBreakSerializer
from .serializers import CategorySerializer

from InvenTree.views import TreeSerializer


class PartCategoryTree(TreeSerializer):

    title = "Parts"
    model = PartCategory


class CategoryList(generics.ListCreateAPIView):
    """ API endpoint for accessing a list of PartCategory objects.

    - GET: Return a list of PartCategory objects
    - POST: Create a new PartCategory object
    """

    queryset = PartCategory.objects.all()
    serializer_class = CategorySerializer

    permission_classes = [
        permissions.IsAuthenticatedOrReadOnly,
    ]

    filter_backends = [
        DjangoFilterBackend,
        # filters.SearchFilter,
        filters.OrderingFilter,
    ]

    filter_fields = [
        'parent',
    ]

    ordering_fields = [
        'name',
    ]

    ordering = 'name'

    search_fields = [
        'name',
        'description',
    ]


class CategoryDetail(generics.RetrieveUpdateDestroyAPIView):
    """ API endpoint for detail view of a single PartCategory object """
    serializer_class = CategorySerializer
    queryset = PartCategory.objects.all()


class PartDetail(generics.RetrieveUpdateAPIView):
    """ API endpoint for detail view of a single Part object """
    queryset = Part.objects.all()
    serializer_class = PartSerializer

    permission_classes = [
        permissions.IsAuthenticatedOrReadOnly,
    ]


class PartList(generics.ListCreateAPIView):
    """ API endpoint for accessing a list of Part objects

    - GET: Return list of objects
    - POST: Create a new Part object
    """

    serializer_class = PartSerializer

    def get_queryset(self):

        # Does the user wish to filter by category?
        cat_id = self.request.query_params.get('category', None)

        # Start with all objects
        parts_list = Part.objects.all()

        if cat_id:
            try:
                category = PartCategory.objects.get(pk=cat_id)
                
                # Filter by the supplied category
                flt = Q(category=cat_id)

                if self.request.query_params.get('include_child_categories', None):
                    childs = category.getUniqueChildren()
                    for child in childs:
                        # Ignore the top-level category (already filtered)
                        if str(child) == str(cat_id):
                            continue
                        flt |= Q(category=child)

                parts_list = parts_list.filter(flt)

            except PartCategory.DoesNotExist:
                pass

        return parts_list

    permission_classes = [
        permissions.IsAuthenticatedOrReadOnly,
    ]

    filter_backends = [
        DjangoFilterBackend,
        filters.SearchFilter,
        filters.OrderingFilter,
    ]

    filter_fields = [
        'buildable',
        'consumable',
        'trackable',
        'purchaseable',
        'salable',
        'active',
    ]

    ordering_fields = [
        'name',
    ]

    ordering = 'name'

    search_fields = [
        '$name',
        'description',
    ]


class BomList(generics.ListCreateAPIView):
    """ API endpoing for accessing a list of BomItem objects

    - GET: Return list of BomItem objects
    - POST: Create a new BomItem object
    """

    queryset = BomItem.objects.all()
    serializer_class = BomItemSerializer

    permission_classes = [
        permissions.IsAuthenticatedOrReadOnly,
    ]

    filter_backends = [
        DjangoFilterBackend,
        filters.SearchFilter,
        filters.OrderingFilter,
    ]

    filter_fields = [
        'part',
        'sub_part'
    ]


class BomDetail(generics.RetrieveUpdateDestroyAPIView):
    """ API endpoint for detail view of a single BomItem object """

    queryset = BomItem.objects.all()
    serializer_class = BomItemSerializer

    permission_classes = [
        permissions.IsAuthenticatedOrReadOnly,
    ]


class SupplierPartList(generics.ListCreateAPIView):
    """ API endpoint for list view of SupplierPart object

    - GET: Return list of SupplierPart objects
    - POST: Create a new SupplierPart object
    """

    queryset = SupplierPart.objects.all()
    serializer_class = SupplierPartSerializer

    permission_classes = [
        permissions.IsAuthenticatedOrReadOnly,
    ]

    filter_backends = [
        DjangoFilterBackend,
        filters.SearchFilter,
        filters.OrderingFilter,
    ]

    filter_fields = [
        'part',
        'supplier'
    ]


class SupplierPartDetail(generics.RetrieveUpdateDestroyAPIView):
    """ API endpoint for detail view of SupplierPart object

    - GET: Retrieve detail view
    - PATCH: Update object
    - DELETE: Delete objec
    """

    queryset = SupplierPart.objects.all()
    serializer_class = SupplierPartSerializer
    permission_classes = (permissions.IsAuthenticatedOrReadOnly,)

    read_only_fields = [
    ]


class SupplierPriceBreakList(generics.ListCreateAPIView):
    """ API endpoint for list view of SupplierPriceBreak object

    - GET: Retrieve list of SupplierPriceBreak objects
    - POST: Create a new SupplierPriceBreak object
    """

    queryset = SupplierPriceBreak.objects.all()
    serializer_class = SupplierPriceBreakSerializer

    permission_classes = [
        permissions.IsAuthenticatedOrReadOnly,
    ]

    filter_backends = [
        DjangoFilterBackend,
    ]

    filter_fields = [
        'part',
    ]


cat_api_urls = [

    url(r'^(?P<pk>\d+)/?', CategoryDetail.as_view(), name='api-part-category-detail'),

    url(r'^$', CategoryList.as_view(), name='api-part-category-list'),
]

supplier_part_api_urls = [

    url(r'^(?P<pk>\d+)/?', SupplierPartDetail.as_view(), name='api-supplier-part-detail'),

    # Catch anything else
    url(r'^.*$', SupplierPartList.as_view(), name='api-part-supplier-list'),
]

part_api_urls = [
    url(r'^tree/?', PartCategoryTree.as_view(), name='api-part-tree'),

    url(r'^category/', include(cat_api_urls)),
    url(r'^supplier/', include(supplier_part_api_urls)),

    url(r'^price-break/?', SupplierPriceBreakList.as_view(), name='api-part-supplier-price'),

    url(r'^(?P<pk>\d+)/', PartDetail.as_view(), name='api-part-detail'),

    url(r'^.*$', PartList.as_view(), name='api-part-list'),
]

bom_api_urls = [
    # BOM Item Detail
    url('^(?P<pk>\d+)/', BomDetail.as_view(), name='api-bom-detail'),

    # Catch-all
    url(r'^.*$', BomList.as_view(), name='api-bom-list'),
]