"""
JSON serializers for the Order API
"""

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

from django.utils.translation import ugettext_lazy as _

from django.core.exceptions import ValidationError as DjangoValidationError
from django.db import models, transaction
from django.db.models import Case, When, Value
from django.db.models import BooleanField, ExpressionWrapper, F

from rest_framework import serializers
from rest_framework.serializers import ValidationError

from sql_util.utils import SubqueryCount

from common.settings import currency_code_mappings

from company.serializers import CompanyBriefSerializer, SupplierPartSerializer
from InvenTree.serializers import InvenTreeAttachmentSerializer
from InvenTree.helpers import normalize
from InvenTree.serializers import InvenTreeModelSerializer
from InvenTree.serializers import InvenTreeDecimalField
from InvenTree.serializers import InvenTreeMoneySerializer
from InvenTree.serializers import InvenTreeAttachmentSerializerField
from InvenTree.status_codes import StockStatus

import order.models

from part.serializers import PartBriefSerializer

import stock.models
import stock.serializers


class POSerializer(InvenTreeModelSerializer):
    """
    Serializer for a PurchaseOrder object
    """

    def __init__(self, *args, **kwargs):

        supplier_detail = kwargs.pop('supplier_detail', False)

        super().__init__(*args, **kwargs)

        if supplier_detail is not True:
            self.fields.pop('supplier_detail')

    @staticmethod
    def annotate_queryset(queryset):
        """
        Add extra information to the queryset

        - Number of lines in the PurchaseOrder
        - Overdue status of the PurchaseOrder
        """

        queryset = queryset.annotate(
            line_items=SubqueryCount('lines')
        )

        queryset = queryset.annotate(
            overdue=Case(
                When(
                    order.models.PurchaseOrder.OVERDUE_FILTER, then=Value(True, output_field=BooleanField()),
                ),
                default=Value(False, output_field=BooleanField())
            )
        )

        return queryset

    supplier_detail = CompanyBriefSerializer(source='supplier', many=False, read_only=True)

    line_items = serializers.IntegerField(read_only=True)

    status_text = serializers.CharField(source='get_status_display', read_only=True)

    overdue = serializers.BooleanField(required=False, read_only=True)

    reference = serializers.CharField(required=True)

    class Meta:
        model = order.models.PurchaseOrder

        fields = [
            'pk',
            'issue_date',
            'complete_date',
            'creation_date',
            'description',
            'line_items',
            'link',
            'overdue',
            'reference',
            'responsible',
            'supplier',
            'supplier_detail',
            'supplier_reference',
            'status',
            'status_text',
            'target_date',
            'notes',
        ]

        read_only_fields = [
            'status'
            'issue_date',
            'complete_date',
            'creation_date',
        ]


class POLineItemSerializer(InvenTreeModelSerializer):

    @staticmethod
    def annotate_queryset(queryset):
        """
        Add some extra annotations to this queryset:

        - Total price = purchase_price * quantity
        """

        queryset = queryset.annotate(
            total_price=ExpressionWrapper(
                F('purchase_price') * F('quantity'),
                output_field=models.DecimalField()
            )
        )

        return queryset

    def __init__(self, *args, **kwargs):

        part_detail = kwargs.pop('part_detail', False)

        super().__init__(*args, **kwargs)

        if part_detail is not True:
            self.fields.pop('part_detail')
            self.fields.pop('supplier_part_detail')

    quantity = serializers.FloatField(default=1)
    received = serializers.FloatField(default=0)

    total_price = serializers.FloatField(read_only=True)

    part_detail = PartBriefSerializer(source='get_base_part', many=False, read_only=True)
    supplier_part_detail = SupplierPartSerializer(source='part', many=False, read_only=True)

    purchase_price = InvenTreeMoneySerializer(
        allow_null=True
    )

    purchase_price_string = serializers.CharField(source='purchase_price', read_only=True)

    destination_detail = stock.serializers.LocationBriefSerializer(source='get_destination', read_only=True)

    purchase_price_currency = serializers.ChoiceField(
        choices=currency_code_mappings(),
        help_text=_('Purchase price currency'),
    )

    class Meta:
        model = order.models.PurchaseOrderLineItem

        fields = [
            'pk',
            'quantity',
            'reference',
            'notes',
            'order',
            'part',
            'part_detail',
            'supplier_part_detail',
            'received',
            'purchase_price',
            'purchase_price_currency',
            'purchase_price_string',
            'destination',
            'destination_detail',
            'total_price',
        ]


class POLineItemReceiveSerializer(serializers.Serializer):
    """
    A serializer for receiving a single purchase order line item against a purchase order
    """

    line_item = serializers.PrimaryKeyRelatedField(
        queryset=order.models.PurchaseOrderLineItem.objects.all(),
        many=False,
        allow_null=False,
        required=True,
        label=_('Line Item'),
    )

    def validate_line_item(self, item):

        if item.order != self.context['order']:
            raise ValidationError(_('Line item does not match purchase order'))

        return item

    location = serializers.PrimaryKeyRelatedField(
        queryset=stock.models.StockLocation.objects.all(),
        many=False,
        allow_null=True,
        required=False,
        label=_('Location'),
        help_text=_('Select destination location for received items'),
    )

    quantity = serializers.DecimalField(
        max_digits=15,
        decimal_places=5,
        min_value=0,
        required=True,
    )

    def validate_quantity(self, quantity):

        if quantity <= 0:
            raise ValidationError(_("Quantity must be greater than zero"))

        return quantity

    status = serializers.ChoiceField(
        choices=list(StockStatus.items()),
        default=StockStatus.OK,
        label=_('Status'),
    )

    barcode = serializers.CharField(
        label=_('Barcode Hash'),
        help_text=_('Unique identifier field'),
        default='',
        required=False,
        allow_null=True,
        allow_blank=True,
    )

    def validate_barcode(self, barcode):
        """
        Cannot check in a LineItem with a barcode that is already assigned
        """

        # Ignore empty barcode values
        if not barcode or barcode.strip() == '':
            return None

        if stock.models.StockItem.objects.filter(uid=barcode).exists():
            raise ValidationError(_('Barcode is already in use'))

        return barcode

    class Meta:
        fields = [
            'barcode',
            'line_item',
            'location',
            'quantity',
            'status',
        ]


class POReceiveSerializer(serializers.Serializer):
    """
    Serializer for receiving items against a purchase order
    """

    items = POLineItemReceiveSerializer(many=True)

    location = serializers.PrimaryKeyRelatedField(
        queryset=stock.models.StockLocation.objects.all(),
        many=False,
        allow_null=True,
        label=_('Location'),
        help_text=_('Select destination location for received items'),
    )

    def validate(self, data):

        super().validate(data)

        items = data.get('items', [])

        location = data.get('location', None)

        if len(items) == 0:
            raise ValidationError(_('Line items must be provided'))

        # Check if the location is not specified for any particular item
        for item in items:

            line = item['line_item']

            if not item.get('location', None):
                # If a global location is specified, use that
                item['location'] = location

            if not item['location']:
                # The line item specifies a location?
                item['location'] = line.get_destination()

            if not item['location']:
                raise ValidationError({
                    'location': _("Destination location must be specified"),
                })

        # Ensure barcodes are unique
        unique_barcodes = set()

        for item in items:
            barcode = item.get('barcode', '')

            if barcode:
                if barcode in unique_barcodes:
                    raise ValidationError(_('Supplied barcode values must be unique'))
                else:
                    unique_barcodes.add(barcode)

        return data

    def save(self):
        """
        Perform the actual database transaction to receive purchase order items
        """

        data = self.validated_data

        request = self.context['request']
        order = self.context['order']

        items = data['items']
        location = data.get('location', None)

        # Now we can actually receive the items into stock
        with transaction.atomic():
            for item in items:

                # Select location
                loc = item.get('location', None) or item['line_item'].get_destination() or location

                try:
                    order.receive_line_item(
                        item['line_item'],
                        loc,
                        item['quantity'],
                        request.user,
                        status=item['status'],
                        barcode=item.get('barcode', ''),
                    )
                except (ValidationError, DjangoValidationError) as exc:
                    # Catch model errors and re-throw as DRF errors
                    raise ValidationError(detail=serializers.as_serializer_error(exc))

    class Meta:
        fields = [
            'items',
            'location',
        ]


class POAttachmentSerializer(InvenTreeAttachmentSerializer):
    """
    Serializers for the PurchaseOrderAttachment model
    """

    attachment = InvenTreeAttachmentSerializerField(required=True)

    class Meta:
        model = order.models.PurchaseOrderAttachment

        fields = [
            'pk',
            'order',
            'attachment',
            'filename',
            'comment',
            'upload_date',
        ]

        read_only_fields = [
            'upload_date',
        ]


class SalesOrderSerializer(InvenTreeModelSerializer):
    """
    Serializers for the SalesOrder object
    """

    def __init__(self, *args, **kwargs):

        customer_detail = kwargs.pop('customer_detail', False)

        super().__init__(*args, **kwargs)

        if customer_detail is not True:
            self.fields.pop('customer_detail')

    @staticmethod
    def annotate_queryset(queryset):
        """
        Add extra information to the queryset

        - Number of line items in the SalesOrder
        - Overdue status of the SalesOrder
        """

        queryset = queryset.annotate(
            line_items=SubqueryCount('lines')
        )

        queryset = queryset.annotate(
            overdue=Case(
                When(
                    order.models.SalesOrder.OVERDUE_FILTER, then=Value(True, output_field=BooleanField()),
                ),
                default=Value(False, output_field=BooleanField())
            )
        )

        return queryset

    customer_detail = CompanyBriefSerializer(source='customer', many=False, read_only=True)

    line_items = serializers.IntegerField(read_only=True)

    status_text = serializers.CharField(source='get_status_display', read_only=True)

    overdue = serializers.BooleanField(required=False, read_only=True)

    reference = serializers.CharField(required=True)

    class Meta:
        model = order.models.SalesOrder

        fields = [
            'pk',
            'creation_date',
            'customer',
            'customer_detail',
            'customer_reference',
            'description',
            'line_items',
            'link',
            'notes',
            'overdue',
            'reference',
            'responsible',
            'status',
            'status_text',
            'shipment_date',
            'target_date',
        ]

        read_only_fields = [
            'status',
            'creation_date',
            'shipment_date',
        ]


class SalesOrderAllocationSerializer(InvenTreeModelSerializer):
    """
    Serializer for the SalesOrderAllocation model.
    This includes some fields from the related model objects.
    """

    part = serializers.PrimaryKeyRelatedField(source='item.part', read_only=True)
    order = serializers.PrimaryKeyRelatedField(source='line.order', many=False, read_only=True)
    serial = serializers.CharField(source='get_serial', read_only=True)
    quantity = serializers.FloatField(read_only=False)
    location = serializers.PrimaryKeyRelatedField(source='item.location', many=False, read_only=True)

    # Extra detail fields
    order_detail = SalesOrderSerializer(source='line.order', many=False, read_only=True)
    part_detail = PartBriefSerializer(source='item.part', many=False, read_only=True)
    item_detail = stock.serializers.StockItemSerializer(source='item', many=False, read_only=True)
    location_detail = stock.serializers.LocationSerializer(source='item.location', many=False, read_only=True)

    def __init__(self, *args, **kwargs):

        order_detail = kwargs.pop('order_detail', False)
        part_detail = kwargs.pop('part_detail', False)
        item_detail = kwargs.pop('item_detail', False)
        location_detail = kwargs.pop('location_detail', False)

        super().__init__(*args, **kwargs)

        if not order_detail:
            self.fields.pop('order_detail')

        if not part_detail:
            self.fields.pop('part_detail')

        if not item_detail:
            self.fields.pop('item_detail')

        if not location_detail:
            self.fields.pop('location_detail')

    class Meta:
        model = order.models.SalesOrderAllocation

        fields = [
            'pk',
            'line',
            'serial',
            'quantity',
            'location',
            'location_detail',
            'item',
            'item_detail',
            'order',
            'order_detail',
            'part',
            'part_detail',
        ]


class SOLineItemSerializer(InvenTreeModelSerializer):
    """ Serializer for a SalesOrderLineItem object """

    def __init__(self, *args, **kwargs):

        part_detail = kwargs.pop('part_detail', False)
        order_detail = kwargs.pop('order_detail', False)
        allocations = kwargs.pop('allocations', False)

        super().__init__(*args, **kwargs)

        if part_detail is not True:
            self.fields.pop('part_detail')

        if order_detail is not True:
            self.fields.pop('order_detail')

        if allocations is not True:
            self.fields.pop('allocations')

    order_detail = SalesOrderSerializer(source='order', many=False, read_only=True)
    part_detail = PartBriefSerializer(source='part', many=False, read_only=True)
    allocations = SalesOrderAllocationSerializer(many=True, read_only=True, location_detail=True)

    quantity = InvenTreeDecimalField()
    
    allocated = serializers.FloatField(source='allocated_quantity', read_only=True)
    fulfilled = serializers.FloatField(source='fulfilled_quantity', read_only=True)
    
    sale_price = InvenTreeMoneySerializer(
        allow_null=True
    )

    sale_price_string = serializers.CharField(source='sale_price', read_only=True)

    sale_price_currency = serializers.ChoiceField(
        choices=currency_code_mappings(),
        help_text=_('Sale price currency'),
    )

    class Meta:
        model = order.models.SalesOrderLineItem

        fields = [
            'pk',
            'allocated',
            'allocations',
            'quantity',
            'fulfilled',
            'reference',
            'notes',
            'order',
            'order_detail',
            'part',
            'part_detail',
            'sale_price',
            'sale_price_currency',
            'sale_price_string',
        ]


class SalesOrderShipmentSerializer(InvenTreeModelSerializer):
    """
    Serializer for the SalesOrderShipment class
    """

    allocations = SalesOrderAllocationSerializer(many=True, read_only=True, location_detail=True)

    order_detail = SalesOrderSerializer(source='order', read_only=True, many=False)

    class Meta:
        model = order.models.SalesOrderShipment

        fields = [
            'pk',
            'order',
            'order_detail',
            'allocations',
            'shipment_date',
            'checked_by',
            'reference',
            'notes',
        ]


class SOShipmentAllocationItemSerializer(serializers.Serializer):
    """
    A serializer for allocating a single stock-item against a SalesOrder shipment
    """

    class Meta:
        fields = [
            'line_item',
            'stock_item',
            'quantity',
        ]

    line_item = serializers.PrimaryKeyRelatedField(
        queryset=order.models.SalesOrderLineItem.objects.all(),
        many=False,
        allow_null=False,
        required=True,
        label=_('Stock Item'),
    )

    def validate_line_item(self, line_item):

        order = self.context['order']

        # Ensure that the line item points to the correct order
        if line_item.order != order:
            raise ValidationError(_("Line item is not associated with this order"))

        return line_item

    stock_item = serializers.PrimaryKeyRelatedField(
        queryset=stock.models.StockItem.objects.all(),
        many=False,
        allow_null=False,
        required=True,
        label=_('Stock Item'),
    )

    quantity = serializers.DecimalField(
        max_digits=15,
        decimal_places=5,
        min_value=0,
        required=True
    )

    def validate_quantity(self, quantity):

        if quantity <= 0:
            raise ValidationError(_("Quantity must be positive"))

        return quantity

    def validate(self, data):

        super().validate(data)

        stock_item = data['stock_item']
        quantity = data['quantity']

        if stock_item.serialized and quantity != 1:
            raise ValidationError({
                'quantity': _("Quantity must be 1 for serialized stock item"),
            })

        q = normalize(stock_item.unallocated_quantity())

        if quantity > q:
            raise ValidationError({
                'quantity': _(f"Available quantity ({q}) exceeded")
            })

        return data


class SOShipmentAllocationSerializer(serializers.Serializer):
    """
    DRF serializer for allocation of stock items against a sales order / shipment
    """

    class Meta:
        fields = [
            'items',
            'shipment',
        ]

    items = SOShipmentAllocationItemSerializer(many=True)

    shipment = serializers.PrimaryKeyRelatedField(
        queryset=order.models.SalesOrderShipment.objects.all(),
        many=False,
        allow_null=False,
        required=True,
        label=_('Shipment'),
    )

    def validate_shipment(self, shipment):
        """
        Run validation against the provided shipment instance
        """

        order = self.context['order']

        if shipment.shipment_date is not None:
            raise ValidationError(_("Shipment has already been shipped"))

        if shipment.order != order:
            raise ValidationError(_("Shipment is not associated with this order"))

        return shipment

    def validate(self, data):
        """
        Serializer validation
        """

        data = super().validate(data)

        # Extract SalesOrder from serializer context
        # order = self.context['order']

        items = data.get('items', [])

        if len(items) == 0:
            raise ValidationError(_('Allocation items must be provided'))

        return data

    def save(self):
        """
        Perform the allocation of items against this order
        """

        data = self.validated_data

        items = data['items']
        shipment = data['shipment']

        with transaction.atomic():
            for entry in items:
                
                # Create a new SalesOrderAllocation
                order.models.SalesOrderAllocation.objects.create(
                    line=entry.get('line_item'),
                    item=entry.get('stock_item'),
                    quantity=entry.get('quantity'),
                    shipment=shipment,
                )

                try:
                    pass
                except (ValidationError, DjangoValidationError) as exc:
                    raise ValidationError(detail=serializers.as_serializer_error(exc))


class SOAttachmentSerializer(InvenTreeAttachmentSerializer):
    """
    Serializers for the SalesOrderAttachment model
    """

    attachment = InvenTreeAttachmentSerializerField(required=True)

    class Meta:
        model = order.models.SalesOrderAttachment

        fields = [
            'pk',
            'order',
            'attachment',
            'filename',
            'comment',
            'upload_date',
        ]

        read_only_fields = [
            'upload_date',
        ]