from django.contrib.auth import get_user_model
from rest_framework import serializers
from .models import *
from .helpers import get_balance_for

from functools import reduce
from uncloud_vm.serializers import VMProductSerializer
from uncloud_vm.models import VMProduct

# TODO: remove magic numbers for decimal fields
class BillRecordSerializer(serializers.Serializer):
    order = serializers.CharField()
    description = serializers.CharField()
    recurring_period = serializers.CharField()
    recurring_price = serializers.DecimalField(max_digits=10, decimal_places=2)
    amount = serializers.DecimalField(max_digits=10, decimal_places=2)

class BillSerializer(serializers.ModelSerializer):
    records = BillRecordSerializer(many=True, read_only=True)
    class Meta:
        model = Bill
        fields = ['owner', 'total', 'due_date', 'creation_date',
                'starting_date', 'ending_date', 'records']

class PaymentSerializer(serializers.ModelSerializer):
    class Meta:
        model = Payment
        fields = ['owner', 'amount', 'source', 'timestamp']

class PaymentMethodSerializer(serializers.ModelSerializer):
    class Meta:
        model = PaymentMethod
        fields = '__all__'

class ProductSerializer(serializers.Serializer):
    vms = VMProductSerializer(many=True, read_only=True)

class OrderRecordSerializer(serializers.ModelSerializer):
    class Meta:
        model = OrderRecord
        fields  = ['setup_fee', 'recurring_price', 'description']

class OrderSerializer(serializers.ModelSerializer):
    records = OrderRecordSerializer(many=True, read_only=True)
    class Meta:
        model = Order
        fields = ['uuid', 'creation_date', 'starting_date', 'ending_date',
                'bill', 'recurring_period', 'records', 'recurring_price', 'setup_fee']

class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = get_user_model()
        fields = ['username', 'email', 'balance']

    # Display current 'balance'
    balance = serializers.SerializerMethodField('get_balance')
    def __sum_balance(self, entries):
        return reduce(lambda acc, entry: acc + entry.amount, entries, 0)

    def get_balance(self, user):
        return get_balance_for(user)