import pickle
import unittest

from django.core.exceptions import ValidationError
from django.core.files.uploadedfile import SimpleUploadedFile
from django.core.validators import validate_image_file_extension
from django.forms import FileField, FileInput
from django.test import SimpleTestCase

try:
    from PIL import Image  # NOQA
except ImportError:
    HAS_PILLOW = False
else:
    HAS_PILLOW = True


class FileFieldTest(SimpleTestCase):

    def test_filefield_1(self):
        f = FileField()
        with self.assertRaisesMessage(ValidationError, "'This field is required.'"):
            f.clean('')
        with self.assertRaisesMessage(ValidationError, "'This field is required.'"):
            f.clean('', '')
        self.assertEqual('files/test1.pdf', f.clean('', 'files/test1.pdf'))
        with self.assertRaisesMessage(ValidationError, "'This field is required.'"):
            f.clean(None)
        with self.assertRaisesMessage(ValidationError, "'This field is required.'"):
            f.clean(None, '')
        self.assertEqual('files/test2.pdf', f.clean(None, 'files/test2.pdf'))
        no_file_msg = "'No file was submitted. Check the encoding type on the form.'"
        file = SimpleUploadedFile(None, b'')
        file._name = ''
        with self.assertRaisesMessage(ValidationError, no_file_msg):
            f.clean(file)
        with self.assertRaisesMessage(ValidationError, no_file_msg):
            f.clean(file, '')
        self.assertEqual('files/test3.pdf', f.clean(None, 'files/test3.pdf'))
        with self.assertRaisesMessage(ValidationError, no_file_msg):
            f.clean('some content that is not a file')
        with self.assertRaisesMessage(ValidationError, "'The submitted file is empty.'"):
            f.clean(SimpleUploadedFile('name', None))
        with self.assertRaisesMessage(ValidationError, "'The submitted file is empty.'"):
            f.clean(SimpleUploadedFile('name', b''))
        self.assertEqual(SimpleUploadedFile, type(f.clean(SimpleUploadedFile('name', b'Some File Content'))))
        self.assertIsInstance(
            f.clean(SimpleUploadedFile('我隻氣墊船裝滿晒鱔.txt', 'मेरी मँडराने वाली नाव सर्पमीनों से भरी ह'.encode())),
            SimpleUploadedFile
        )
        self.assertIsInstance(
            f.clean(SimpleUploadedFile('name', b'Some File Content'), 'files/test4.pdf'),
            SimpleUploadedFile
        )

    def test_filefield_2(self):
        f = FileField(max_length=5)
        with self.assertRaisesMessage(ValidationError, "'Ensure this filename has at most 5 characters (it has 18).'"):
            f.clean(SimpleUploadedFile('test_maxlength.txt', b'hello world'))
        self.assertEqual('files/test1.pdf', f.clean('', 'files/test1.pdf'))
        self.assertEqual('files/test2.pdf', f.clean(None, 'files/test2.pdf'))
        self.assertIsInstance(f.clean(SimpleUploadedFile('name', b'Some File Content')), SimpleUploadedFile)

    def test_filefield_3(self):
        f = FileField(allow_empty_file=True)
        self.assertIsInstance(f.clean(SimpleUploadedFile('name', b'')), SimpleUploadedFile)

    def test_filefield_changed(self):
        """
        The value of data will more than likely come from request.FILES. The
        value of initial data will likely be a filename stored in the database.
        Since its value is of no use to a FileField it is ignored.
        """
        f = FileField()

        # No file was uploaded and no initial data.
        self.assertFalse(f.has_changed('', None))

        # A file was uploaded and no initial data.
        self.assertTrue(f.has_changed('', {'filename': 'resume.txt', 'content': 'My resume'}))

        # A file was not uploaded, but there is initial data
        self.assertFalse(f.has_changed('resume.txt', None))

        # A file was uploaded and there is initial data (file identity is not dealt
        # with here)
        self.assertTrue(f.has_changed('resume.txt', {'filename': 'resume.txt', 'content': 'My resume'}))

    def test_disabled_has_changed(self):
        f = FileField(disabled=True)
        self.assertIs(f.has_changed('x', 'y'), False)

    def test_file_picklable(self):
        self.assertIsInstance(pickle.loads(pickle.dumps(FileField())), FileField)


class MultipleFileInput(FileInput):
    allow_multiple_selected = True


class MultipleFileField(FileField):
    def __init__(self, *args, **kwargs):
        kwargs.setdefault("widget", MultipleFileInput())
        super().__init__(*args, **kwargs)

    def clean(self, data, initial=None):
        single_file_clean = super().clean
        if isinstance(data, (list, tuple)):
            result = [single_file_clean(d, initial) for d in data]
        else:
            result = single_file_clean(data, initial)
        return result


class MultipleFileFieldTest(SimpleTestCase):
    def test_file_multiple(self):
        f = MultipleFileField()
        files = [
            SimpleUploadedFile("name1", b"Content 1"),
            SimpleUploadedFile("name2", b"Content 2"),
        ]
        self.assertEqual(f.clean(files), files)

    def test_file_multiple_empty(self):
        f = MultipleFileField()
        files = [
            SimpleUploadedFile("empty", b""),
            SimpleUploadedFile("nonempty", b"Some Content"),
        ]
        msg = "'The submitted file is empty.'"
        with self.assertRaisesMessage(ValidationError, msg):
            f.clean(files)
        with self.assertRaisesMessage(ValidationError, msg):
            f.clean(files[::-1])

    @unittest.skipUnless(HAS_PILLOW, "Pillow not installed")
    def test_file_multiple_validation(self):
        f = MultipleFileField(validators=[validate_image_file_extension])

        good_files = [
            SimpleUploadedFile("image1.jpg", b"fake JPEG"),
            SimpleUploadedFile("image2.png", b"faux image"),
            SimpleUploadedFile("image3.bmp", b"fraudulent bitmap"),
        ]
        self.assertEqual(f.clean(good_files), good_files)

        evil_files = [
            SimpleUploadedFile("image1.sh", b"#!/bin/bash -c 'echo pwned!'\n"),
            SimpleUploadedFile("image2.png", b"faux image"),
            SimpleUploadedFile("image3.jpg", b"fake JPEG"),
        ]

        evil_rotations = (
            evil_files[i:] + evil_files[:i]  # Rotate by i.
            for i in range(len(evil_files))
        )
        msg = "File extension “sh” is not allowed. Allowed extensions are: "
        for rotated_evil_files in evil_rotations:
            with self.assertRaisesMessage(ValidationError, msg):
                f.clean(rotated_evil_files)