from django.db import models
import uuid #universal unique identifier untuk dapet kode unik buku
from django.urls import reverse


# Create your models here.
class Genre(models.Model):
	"""Model representing a book genre e.g Science Fiction, Non Fiction"""
	name = models.CharField(max_length=200, help_text="Masukan genre buku (seperti Science Fiction, Non Fiction")

	def __str__(self):
		"""yang akan muncul di /admin"""
		return self.name

class Book(models.Model):
	title = models.CharField(max_length=200)
	author = models.ForeignKey('Author', on_delete=models.SET_NULL, null=True)
	summary = models.CharField(max_length=1000, help_text='Enter a brief description of the book')
	isbn = models.CharField('ISBN', max_length=13, help_text='13 Character <a href="https://www.isbn-international.org/content/what-isbn">ISBN number</a>')
	genre = models.ManyToManyField(Genre, help_text='Select a genre for this book')
	language = models.ForeignKey('Language', on_delete=models.SET_NULL, null=True)

	def __str__(self):
		return self.title

	def get_absolute_url(self):
		"""return the url to access the detail record for this book"""
		return reverse('book-detail', args=[str(self.id)])

class BookInstance(models.Model):
	id = models.UUIDField(primary_key=True, default=uuid.uuid4, help_text='Unique ID for this particular book across whole library')
	book = models.ForeignKey('Book', on_delete=models.SET_NULL, null=True)
	imprint = models.CharField(max_length=200)
	due_back = models.DateField(null=True, blank=True)

	LOAN_STATUS = (
		('m', 'Maintenance'),
		('o', 'On loan'),
		('a', 'Available'),
		('r', 'Reserved'),
		)

	status = models.CharField(max_length=1, choices=LOAN_STATUS, blank=True, default='m', help_text='Book availability')

	class Meta:
		ordering = ['due_back']

class Author(models.Model):
	first_name = models.CharField(max_length=100)
	last_name = models.CharField(max_length=100)
	date_of_birth = models.DateField(null=True, blank=True)
	date_of_death = models.DateField('Died', null=True, blank=True)

	class Meta:
		ordering = ['last_name', 'first_name']

	def get_absolute_url(self):
		return reverse('author-detail', args=[str(self.id)])

	def __str__(self):
		return '{0}, {1}'.format(self.last_name, self.first_name)

class Language(models.Model):
	name = models.CharField(max_length=50)

	def __str__(self):
		return self.name

