''' database schema for books and shelves '''
from datetime import datetime
from django.db import models
from uuid import uuid4

from fedireads.settings import DOMAIN
from fedireads.utils.fields import JSONField, ArrayField
from fedireads.utils.models import FedireadsModel


class Connector(FedireadsModel):
    ''' book data source connectors '''
    name = models.CharField(max_length=255, unique=True)
    api_key = models.CharField(max_length=255, null=True)

    base_url = models.CharField(max_length=255)
    covers_url = models.CharField(max_length=255)
    search_url = models.CharField(max_length=255, null=True)

    key_name = models.CharField(max_length=255, unique=True)

    politeness_delay = models.IntegerField(null=True) #seconds
    max_query_count = models.IntegerField(null=True)
    # how many queries executed in a unit of time, like a day
    query_count = models.IntegerField(default=0)
    # when to reset the query count back to 0 (ie, after 1 day)
    query_count_expiry = models.DateTimeField(auto_now_add=True)


class Book(FedireadsModel):
    ''' a generic book, which can mean either an edition or a work '''
    # these identifiers apply to both works and editions
    openlibrary_key = models.CharField(max_length=255, unique=True, null=True)
    librarything_key = models.CharField(max_length=255, unique=True, null=True)
    local_key = models.CharField(max_length=255, unique=True, default=uuid4)
    misc_identifiers = JSONField(null=True)

    # info about where the data comes from and where/if to sync
    source_url = models.CharField(max_length=255, unique=True, null=True)
    sync = models.BooleanField(default=True)
    last_sync_date = models.DateTimeField(default=datetime.now)
    connector = models.ForeignKey(
        'Connector', on_delete=models.PROTECT, null=True)

    # TODO: edit history

    # book/work metadata
    title = models.CharField(max_length=255)
    sort_title = models.CharField(max_length=255, null=True)
    subtitle = models.TextField(blank=True, null=True)
    description = models.TextField(blank=True, null=True)
    language = models.CharField(max_length=255, null=True)
    series = models.CharField(max_length=255, blank=True, null=True)
    series_number = models.CharField(max_length=255, blank=True, null=True)
    # TODO: include an annotation about the type of authorship (ie, translator)
    authors = models.ManyToManyField('Author')
    # TODO: also store cover thumbnail
    cover = models.ImageField(upload_to='covers/', blank=True, null=True)
    first_published_date = models.DateTimeField(null=True)
    published_date = models.DateTimeField(null=True)
    shelves = models.ManyToManyField(
        'Shelf',
        symmetrical=False,
        through='ShelfBook',
        through_fields=('book', 'shelf')
    )
    # TODO: why can't I just call this work????
    parent_work = models.ForeignKey('Work', on_delete=models.PROTECT, null=True)

    @property
    def absolute_id(self):
        ''' constructs the absolute reference to any db object '''
        base_path = 'https://%s' % DOMAIN
        model_name = type(self).__name__.lower()
        return '%s/%s/%s' % (base_path, model_name, self.openlibrary_key)

    def __repr__(self):
        return "<{} key={!r} title={!r} author={!r}>".format(
            self.__class__,
            self.openlibrary_key,
            self.title,
            self.author
        )


class Work(Book):
    ''' a work (an abstract concept of a book that manifests in an edition) '''
    # library of congress catalog control number
    lccn = models.CharField(max_length=255, unique=True, null=True)


class Edition(Book):
    ''' an edition of a book '''
    # these identifiers only apply to work
    isbn = models.CharField(max_length=255, unique=True, null=True)
    oclc_number = models.CharField(max_length=255, unique=True, null=True)
    pages = models.IntegerField(null=True)


class Author(FedireadsModel):
    ''' copy of an author from OL '''
    openlibrary_key = models.CharField(max_length=255, null=True, unique=True)
    wikipedia_link = models.CharField(max_length=255, blank=True, null=True)
    # idk probably other keys would be useful here?
    born = models.DateTimeField(null=True)
    died = models.DateTimeField(null=True)
    name = models.CharField(max_length=255)
    last_name = models.CharField(max_length=255, null=True)
    first_name = models.CharField(max_length=255, null=True)
    aliases = ArrayField(
        models.CharField(max_length=255), blank=True, default=list
    )
    bio = models.TextField(null=True, blank=True)