import os
from uuid import uuid4
from django.db import models

# from django.core.files.storage import FileSystemStorage
# from django.dispatch import receiver

from dcc.utils import get_image_preview
from metadata.models import (
    Property,
    Scale,
    Manufacturer,
    Decoder,
    Company,
    Tag,
    RollingStockType,
)

# class OverwriteMixin(FileSystemStorage):
#     def get_available_name(self, name, max_length):
#         self.delete(name)
#         return name


class RollingClass(models.Model):
    identifier = models.CharField(max_length=128, unique=False)
    type = models.ForeignKey(
        RollingStockType, on_delete=models.CASCADE, null=True, blank=True
    )
    company = models.ForeignKey(
        Company, on_delete=models.CASCADE, null=True, blank=True
    )
    description = models.CharField(max_length=256, blank=True)
    manufacturer = models.ForeignKey(
        Manufacturer, on_delete=models.CASCADE, null=True, blank=True,
        limit_choices_to={"category": "real"}
    )

    class Meta:
        ordering = ["company", "identifier"]
        verbose_name = "Class"
        verbose_name_plural = "Classes"

    def __str__(self):
        return "{0} {1}".format(self.company, self.identifier)


class RollingClassProperty(models.Model):
    rolling_class = models.ForeignKey(
        RollingClass,
        on_delete=models.CASCADE,
        null=False,
        blank=False,
        verbose_name="Class",
    )
    property = models.ForeignKey(Property, on_delete=models.CASCADE)
    value = models.CharField(max_length=256)

    def __str__(self):
        return self.property.name


class RollingStock(models.Model):
    uuid = models.UUIDField(primary_key=True, default=uuid4, editable=False)
    rolling_class = models.ForeignKey(
        RollingClass,
        on_delete=models.CASCADE,
        null=False,
        blank=False,
        verbose_name="Class",
    )
    road_number = models.CharField(max_length=128, unique=False)
    manufacturer = models.ForeignKey(
        Manufacturer, on_delete=models.CASCADE, null=True, blank=True,
        limit_choices_to={"category": "model"}
    )
    scale = models.ForeignKey(Scale, on_delete=models.CASCADE)
    sku = models.CharField(max_length=32, blank=True)
    decoder = models.ForeignKey(
        Decoder, on_delete=models.CASCADE, null=True, blank=True
    )
    address = models.SmallIntegerField(default=None, null=True, blank=True)
    era = models.CharField(max_length=32, blank=True)
    production_year = models.SmallIntegerField(null=True, blank=True)
    purchase_date = models.DateField(null=True, blank=True)
    notes = models.TextField(blank=True)
    tags = models.ManyToManyField(
        Tag, related_name="rolling_stock", blank=True
    )
    creation_time = models.DateTimeField(auto_now_add=True)
    updated_time = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["rolling_class", "road_number"]
        verbose_name_plural = "Rolling stock"

    def __str__(self):
        return "{0} {1}".format(self.rolling_class, self.road_number)

    def country(self):
        return str(self.rolling_class.company.country)

    def company(self):
        return str(self.rolling_class.company)


class RollingStockDocument(models.Model):
    rolling_stock = models.ForeignKey(RollingStock, on_delete=models.CASCADE)
    description = models.CharField(max_length=128, blank=True)
    file = models.FileField(upload_to="files/", null=True, blank=True)

    class Meta(object):
        unique_together = ("rolling_stock", "file")

    def __str__(self):
        return "{0}".format(os.path.basename(self.file.name))
        # return "{0}".format(self.description)


class RollingStockImage(models.Model):
    rolling_stock = models.ForeignKey(RollingStock, on_delete=models.CASCADE)
    image = models.ImageField(upload_to="images/", null=True, blank=True)

    def image_thumbnail(self):
        return get_image_preview(self.image.url)

    image_thumbnail.short_description = "Preview"

    class Meta(object):
        unique_together = ("rolling_stock", "image")

    def __str__(self):
        return "{0}".format(os.path.basename(self.image.name))


# @receiver(models.signals.post_delete, sender=Cab)
# def post_save_image(sender, instance, *args, **kwargs):
#     try:
#         instance.image.delete(save=False)
#     except Exception:
#         pass