import uuid

from django.db import models
from django.contrib.auth import get_user_model

# Product in DB vs. product in code
# DB:
# - need to define params (+param types) in db -> messy?
# - get /products/ is easy / automatic
#
# code
# - can have serializer/verification of fields easily in DRF
# - can have per product side effects / extra code running
# - might (??) make features easier??
# - how to setup / query the recurring period (?)
# - could get products list via getattr() + re ...Product() classes
# -> this could include the url for ordering => /order/vm_snapshot (params)
# ---> this would work with urlpatterns

# Combination: create specific product in DB (?)
# - a table per product (?) with 1 entry?

# Orders
# define state in DB
# select a price from a product => product might change, order stays
# params:
# - the product uuid or name (?) => productuuid
# - the product parameters => for each feature
#

# logs
# Should have a log = ... => 1:n field for most models!

class Product(models.Model):
    uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    owner = models.ForeignKey(get_user_model(),
                              on_delete=models.CASCADE,
                              editable=False)

    # override these fields by default

    description = ""
    recurring_period = "not_recurring"

    status = models.CharField(max_length=256,
                              choices = (
                                  ('pending', 'Pending'),
                                  ('being_created', 'Being created'),
                                  ('active', 'Active'),
                                  ('deleted', 'Deleted')
                              ),
                              default='pending'
    )

    # This is calculated by each product and saved in the DB
    recurring_price = models.FloatField(editable=False)
    one_time_price = models.FloatField(editable=False)

    # FIXME: need recurring_time_frame

    class Meta:
        abstract = True

    def __str__(self):
        return "{}".format(self.name)


class VMSnapshotProduct(Product):
    price_per_gb_ssd = 0.35
    price_per_gb_hdd = 1.5/100

    # This we need to get from the VM
    gb_ssd = models.FloatField(editable=False)
    gb_hdd = models.FloatField(editable=False)

    vm_uuid = models.UUIDField()

    # Need to setup recurring_price and one_time_price and recurring period

    sample_ssd = 10
    sample_hdd = 100

    def recurring_price(self):
        return 0

    def one_time_price(self):
        return 0

    @classmethod
    def sample_price(cls):
        return cls.sample_ssd * cls.price_per_gb_ssd + cls.sample_hdd * cls.price_per_gb_hdd

    description = "Create snapshot of a VM"
    recurring_period = "monthly"

    @classmethod
    def pricing_model(cls):
        return """
Pricing is on monthly basis and storage prices are equivalent to the storage
price in the VM.

Price per GB SSD is: {}
Price per GB HDD is: {}


Sample price for a VM with {} GB SSD and {} GB HDD VM is: {}.
""".format(cls.price_per_gb_ssd, cls.price_per_gb_hdd,
           cls.sample_ssd, cls.sample_hdd, cls.sample_price())








class Feature(models.Model):
    uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    name = models.CharField(max_length=256)

    recurring_price = models.FloatField(default=0)
    one_time_price = models.FloatField()

    product = models.ForeignKey(Product, on_delete=models.CASCADE)

    # params for "cpu": cpu_count -> int
    # each feature can only have one parameters
    # could call this "value" and set whether it is user usable
    # has_value = True/False
    # value = string  -> int (?)
    # value_int
    # value_str
    # value_float

    class Meta:
        abstract = True

    def __str__(self):
        return "'{}' - '{}'".format(self.product, self.name)