from __future__ import absolute_import

import gzip
import shutil
import tempfile

from django.core.cache import cache
from django.core.exceptions import ValidationError
from django.core.files import File
from django.core.files.base import ContentFile
from django.core.files.uploadedfile import SimpleUploadedFile
from django.test import TestCase
from django.utils import unittest

from .models import Storage, temp_storage, temp_storage_location


class FileStorageTests(TestCase):
    def tearDown(self):
        shutil.rmtree(temp_storage_location)

    def test_files(self):
        temp_storage.save('tests/default.txt', ContentFile(b'default content'))
        # Attempting to access a FileField from the class raises a descriptive
        # error
        self.assertRaises(AttributeError, lambda: Storage.normal)

        # An object without a file has limited functionality.
        obj1 = Storage()
        self.assertEqual(obj1.normal.name, "")
        self.assertRaises(ValueError, lambda: obj1.normal.size)

        # Saving a file enables full functionality.
        obj1.normal.save("django_test.txt", ContentFile(b"content"))
        self.assertEqual(obj1.normal.name, "tests/django_test.txt")
        self.assertEqual(obj1.normal.size, 7)
        self.assertEqual(obj1.normal.read(), b"content")
        obj1.normal.close()

        # File objects can be assigned to FileField attributes, but shouldn't
        # get committed until the model it's attached to is saved.
        obj1.normal = SimpleUploadedFile("assignment.txt", b"content")
        dirs, files = temp_storage.listdir("tests")
        self.assertEqual(dirs, [])
        self.assertEqual(sorted(files), ["default.txt", "django_test.txt"])

        obj1.save()
        dirs, files = temp_storage.listdir("tests")
        self.assertEqual(
            sorted(files), ["assignment.txt", "default.txt", "django_test.txt"]
        )

        # Files can be read in a little at a time, if necessary.
        obj1.normal.open()
        self.assertEqual(obj1.normal.read(3), b"con")
        self.assertEqual(obj1.normal.read(), b"tent")
        self.assertEqual(list(obj1.normal.chunks(chunk_size=2)), [b"co", b"nt", b"en", b"t"])
        obj1.normal.close()

        # Save another file with the same name.
        obj2 = Storage()
        obj2.normal.save("django_test.txt", ContentFile(b"more content"))
        self.assertEqual(obj2.normal.name, "tests/django_test_1.txt")
        self.assertEqual(obj2.normal.size, 12)

        # Push the objects into the cache to make sure they pickle properly
        cache.set("obj1", obj1)
        cache.set("obj2", obj2)
        self.assertEqual(cache.get("obj2").normal.name, "tests/django_test_1.txt")

        # Deleting an object does not delete the file it uses.
        obj2.delete()
        obj2.normal.save("django_test.txt", ContentFile(b"more content"))
        self.assertEqual(obj2.normal.name, "tests/django_test_2.txt")

        # Multiple files with the same name get _N appended to them.
        objs = [Storage() for i in range(3)]
        for o in objs:
            o.normal.save("multiple_files.txt", ContentFile(b"Same Content"))
        self.assertEqual(
            [o.normal.name for o in objs],
            ["tests/multiple_files.txt", "tests/multiple_files_1.txt", "tests/multiple_files_2.txt"]
        )
        for o in objs:
            o.delete()

        # Default values allow an object to access a single file.
        obj3 = Storage.objects.create()
        self.assertEqual(obj3.default.name, "tests/default.txt")
        self.assertEqual(obj3.default.read(), b"default content")
        obj3.default.close()

        # But it shouldn't be deleted, even if there are no more objects using
        # it.
        obj3.delete()
        obj3 = Storage()
        self.assertEqual(obj3.default.read(), b"default content")
        obj3.default.close()

        # Verify the fix for #5655, making sure the directory is only
        # determined once.
        obj4 = Storage()
        obj4.random.save("random_file", ContentFile(b"random content"))
        self.assertTrue(obj4.random.name.endswith("/random_file"))

    def test_max_length(self):
        """
        Test that FileField validates the length of the generated file name
        that will be stored in the database. Regression for #9893.
        """
        # upload_to = 'unused', so file names are saved as '456/xxxxx'.
        # max_length = 16, so names longer than 12 characters are rejected.
        s1 = Storage(random=SimpleUploadedFile(12 * 'x', b"content"))
        s1.full_clean()
        with self.assertRaises(ValidationError):
            Storage(random=SimpleUploadedFile(13 * 'x', b"content")).full_clean()

        # Ticket #18515: validation for an already saved file should not check
        # against a regenerated file name (and potentially raise a ValidationError
        # if max_length is exceeded
        s1.save()
        s1.full_clean()


class FileTests(unittest.TestCase):
    def test_context_manager(self):
        orig_file = tempfile.TemporaryFile()
        base_file = File(orig_file)
        with base_file as f:
            self.assertIs(base_file, f)
            self.assertFalse(f.closed)
        self.assertTrue(f.closed)
        self.assertTrue(orig_file.closed)

    def test_file_mode(self):
        # Should not set mode to None if it is not present.
        # See #14681, stdlib gzip module crashes if mode is set to None
        file = SimpleUploadedFile("mode_test.txt", b"content")
        self.assertFalse(hasattr(file, 'mode'))
        g = gzip.GzipFile(fileobj=file)