from __future__ import with_statement

import os
import pickle
from StringIO import StringIO
import tempfile

from django.core.files.base import ContentFile
from django.db import models
from django.test import TestCase

from imagekit import utils
from imagekit.lib import Image
from imagekit.models.fields import ImageSpecField
from imagekit.processors import Adjust
from imagekit.processors import ResizeToFill
from imagekit.processors import SmartCrop


def generate_lenna():
    """
    See also:

    http://en.wikipedia.org/wiki/Lenna
    http://sipi.usc.edu/database/database.php?volume=misc&image=12

    """
    tmp = tempfile.TemporaryFile()
    lennapath = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'assets', 'lenna-800x600-white-border.jpg')
    with open(lennapath, "r+b") as lennafile:
        Image.open(lennafile).save(tmp, 'JPEG')
    tmp.seek(0)
    return tmp


def create_instance(model_class, image_name):
    instance = model_class()
    img = generate_lenna()
    file = ContentFile(img.read())
    instance.original_image = file
    instance.original_image.save(image_name, file)
    instance.save()
    img.close()
    return instance


def create_photo(name):
    return create_instance(Photo, name)


class Photo(models.Model):
    original_image = models.ImageField(upload_to='photos')

    thumbnail = ImageSpecField([Adjust(contrast=1.2, sharpness=1.1),
            ResizeToFill(50, 50)], image_field='original_image', format='JPEG',
            options={'quality': 90})

    smartcropped_thumbnail = ImageSpecField([Adjust(contrast=1.2,
            sharpness=1.1), SmartCrop(50, 50)], image_field='original_image',
            format='JPEG', options={'quality': 90})


class AbstractImageModel(models.Model):
    original_image = models.ImageField(upload_to='photos')
    abstract_class_spec = ImageSpecField()

    class Meta:
        abstract = True


class ConcreteImageModel1(AbstractImageModel):
    first_spec = ImageSpecField()


class ConcreteImageModel2(AbstractImageModel):
    second_spec = ImageSpecField()


class IKTest(TestCase):
    def generate_image(self):
        tmp = tempfile.TemporaryFile()
        Image.new('RGB', (800, 600)).save(tmp, 'JPEG')
        tmp.seek(0)
        return tmp

    def setUp(self):
        self.photo = create_photo('test.jpg')

    def test_nodelete(self):
        """Don't delete the spec file when the source image hasn't changed.

        """
        filename = self.photo.thumbnail.file.name
        thumbnail_timestamp = os.path.getmtime(filename)
        self.photo.save()
        self.assertTrue(self.photo.thumbnail.storage.exists(filename))

    def test_save_image(self):
        photo = Photo.objects.get(id=self.photo.id)
        self.assertTrue(os.path.isfile(photo.original_image.path))

    def test_setup(self):
        self.assertEqual(self.photo.original_image.width, 800)
        self.assertEqual(self.photo.original_image.height, 600)

    def test_thumbnail_creation(self):
        photo = Photo.objects.get(id=self.photo.id)
        self.assertTrue(os.path.isfile(photo.thumbnail.file.name))

    def test_thumbnail_size(self):
        """ Explicit and smart-cropped thumbnail size """
        self.assertEqual(self.photo.thumbnail.width, 50)
        self.assertEqual(self.photo.thumbnail.height, 50)
        self.assertEqual(self.photo.smartcropped_thumbnail.width, 50)
        self.assertEqual(self.photo.smartcropped_thumbnail.height, 50)

    def test_thumbnail_source_file(self):
        self.assertEqual(
            self.photo.thumbnail.source_file, self.photo.original_image)


class IKUtilsTest(TestCase):
    def test_extension_to_format(self):
        self.assertEqual(utils.extension_to_format('.jpeg'), 'JPEG')
        self.assertEqual(utils.extension_to_format('.rgba'), 'SGI')

        with self.assertRaises(utils.UnknownExtensionError):
            utils.extension_to_format('.txt')

    def test_format_to_extension_no_init(self):
        self.assertEqual(utils.format_to_extension('PNG'), '.png')
        self.assertEqual(utils.format_to_extension('ICO'), '.ico')

        with self.assertRaises(utils.UnknownFormatError):
            utils.format_to_extension('TXT')


class PickleTest(TestCase):
    def test_source_file(self):
        ph = create_photo('pickletest.jpg')
        pickled_model = StringIO()
        pickle.dump(ph, pickled_model)
        pickled_model.seek(0)
        unpickled_model = pickle.load(pickled_model)

        # This isn't supposed to error.
        unpickled_model.thumbnail.source_file


class InheritanceTest(TestCase):
    def test_abstract_base(self):
        self.assertEqual(set(AbstractImageModel._ik.spec_fields),
                set(['abstract_class_spec']))
        self.assertEqual(set(ConcreteImageModel1._ik.spec_fields),
                set(['abstract_class_spec', 'first_spec']))
        self.assertEqual(set(ConcreteImageModel2._ik.spec_fields),
                set(['abstract_class_spec', 'second_spec']))