import os
import unittest

from django.core.exceptions import ValidationError
from django.core.files.uploadedfile import (
    SimpleUploadedFile, TemporaryUploadedFile,
)
from django.forms import ClearableFileInput, FileInput, ImageField, Widget
from django.test import SimpleTestCase

from . import FormFieldAssertionsMixin

try:
    from PIL import Image
except ImportError:
    Image = None


def get_img_path(path):
    return os.path.join(os.path.abspath(os.path.join(__file__, '..', '..')), 'tests', path)


@unittest.skipUnless(Image, "Pillow is required to test ImageField")
class ImageFieldTest(FormFieldAssertionsMixin, SimpleTestCase):

    def test_imagefield_annotate_with_image_after_clean(self):
        f = ImageField()

        img_path = get_img_path('filepath_test_files/1x1.png')
        with open(img_path, 'rb') as img_file:
            img_data = img_file.read()

        img_file = SimpleUploadedFile('1x1.png', img_data)
        img_file.content_type = 'text/plain'

        uploaded_file = f.clean(img_file)

        self.assertEqual('PNG', uploaded_file.image.format)
        self.assertEqual('image/png', uploaded_file.content_type)

    def test_imagefield_annotate_with_bitmap_image_after_clean(self):
        """
        This also tests the situation when Pillow doesn't detect the MIME type
        of the image (#24948).
        """
        from PIL.BmpImagePlugin import BmpImageFile
        try:
            Image.register_mime(BmpImageFile.format, None)
            f = ImageField()
            img_path = get_img_path('filepath_test_files/1x1.bmp')
            with open(img_path, 'rb') as img_file:
                img_data = img_file.read()

            img_file = SimpleUploadedFile('1x1.bmp', img_data)
            img_file.content_type = 'text/plain'

            uploaded_file = f.clean(img_file)

            self.assertEqual('BMP', uploaded_file.image.format)
            self.assertIsNone(uploaded_file.content_type)
        finally:
            Image.register_mime(BmpImageFile.format, 'image/bmp')

    def test_file_extension_validation(self):
        f = ImageField()
        img_path = get_img_path('filepath_test_files/1x1.png')
        with open(img_path, 'rb') as img_file:
            img_data = img_file.read()
        img_file = SimpleUploadedFile('1x1.txt', img_data)
        with self.assertRaisesMessage(ValidationError, 'File extension “txt” is not allowed.'):
            f.clean(img_file)

    def test_corrupted_image(self):
        f = ImageField()
        img_file = SimpleUploadedFile('not_an_image.jpg', b'not an image')
        msg = (
            'Upload a valid image. The file you uploaded was either not an '
            'image or a corrupted image.'
        )
        with self.assertRaisesMessage(ValidationError, msg):
            f.clean(img_file)
        with TemporaryUploadedFile('not_an_image_tmp.png', 'text/plain', 1, 'utf-8') as tmp_file:
            with self.assertRaisesMessage(ValidationError, msg):
                f.clean(tmp_file)

    def test_widget_attrs_default_accept(self):
        f = ImageField()
        # Nothing added for non-FileInput widgets.
        self.assertEqual(f.widget_attrs(Widget()), {})
        self.assertEqual(f.widget_attrs(FileInput()), {'accept': 'image/*'})
        self.assertEqual(f.widget_attrs(ClearableFileInput()), {'accept': 'image/*'})
        self.assertWidgetRendersTo(f, '<input type="file" name="f" accept="image/*" required id="id_f" />')

    def test_widget_attrs_accept_specified(self):
        f = ImageField(widget=FileInput(attrs={'accept': 'image/png'}))
        self.assertEqual(f.widget_attrs(f.widget), {})
        self.assertWidgetRendersTo(f, '<input type="file" name="f" accept="image/png" required id="id_f" />')

    def test_widget_attrs_accept_false(self):
        f = ImageField(widget=FileInput(attrs={'accept': False}))
        self.assertEqual(f.widget_attrs(f.widget), {})
        self.assertWidgetRendersTo(f, '<input type="file" name="f" required id="id_f" />')