import base64
import hashlib
import os
import shutil
import sys
import tempfile as sys_tempfile
import unittest
from io import BytesIO, StringIO
from urllib.parse import quote

from django.core.files import temp as tempfile
from django.core.files.uploadedfile import SimpleUploadedFile
from django.http.multipartparser import (
    MultiPartParser, MultiPartParserError, parse_header,
)
from django.test import SimpleTestCase, TestCase, client, override_settings

from . import uploadhandler
from .models import FileModel

UNICODE_FILENAME = 'test-0123456789_中文_Orléans.jpg'
MEDIA_ROOT = sys_tempfile.mkdtemp()
UPLOAD_TO = os.path.join(MEDIA_ROOT, 'test_upload')


@override_settings(MEDIA_ROOT=MEDIA_ROOT, ROOT_URLCONF='file_uploads.urls', MIDDLEWARE=[])
class FileUploadTests(TestCase):

    @classmethod
    def setUpClass(cls):
        super().setUpClass()
        os.makedirs(MEDIA_ROOT, exist_ok=True)

    @classmethod
    def tearDownClass(cls):
        shutil.rmtree(MEDIA_ROOT)
        super().tearDownClass()

    def test_simple_upload(self):
        with open(__file__, 'rb') as fp:
            post_data = {
                'name': 'Ringo',
                'file_field': fp,
            }
            response = self.client.post('/upload/', post_data)
        self.assertEqual(response.status_code, 200)

    def test_large_upload(self):
        file = tempfile.NamedTemporaryFile
        with file(suffix=".file1") as file1, file(suffix=".file2") as file2:
            file1.write(b'a' * (2 ** 21))
            file1.seek(0)

            file2.write(b'a' * (10 * 2 ** 20))
            file2.seek(0)

            post_data = {
                'name': 'Ringo',
                'file_field1': file1,
                'file_field2': file2,
            }

            for key in list(post_data):
                try:
                    post_data[key + '_hash'] = hashlib.sha1(post_data[key].read()).hexdigest()
                    post_data[key].seek(0)
                except AttributeError:
                    post_data[key + '_hash'] = hashlib.sha1(post_data[key].encode()).hexdigest()

            response = self.client.post('/verify/', post_data)

            self.assertEqual(response.status_code, 200)

    def _test_base64_upload(self, content, encode=base64.b64encode):
        payload = client.FakePayload("\r\n".join([
            '--' + client.BOUNDARY,
            'Content-Disposition: form-data; name="file"; filename="test.txt"',
            'Content-Type: application/octet-stream',
            'Content-Transfer-Encoding: base64',
            '']))
        payload.write(b'\r\n' + encode(content.encode()) + b'\r\n')
        payload.write('--' + client.BOUNDARY + '--\r\n')
        r = {
            'CONTENT_LENGTH': len(payload),
            'CONTENT_TYPE': client.MULTIPART_CONTENT,
            'PATH_INFO': "/echo_content/",
            'REQUEST_METHOD': 'POST',
            'wsgi.input': payload,
        }
        response = self.client.request(**r)
        self.assertEqual(response.json()['file'], content)

    def test_base64_upload(self):
        self._test_base64_upload("This data will be transmitted base64-encoded.")

    def test_big_base64_upload(self):
        self._test_base64_upload("Big data" * 68000)  # > 512Kb

    def test_big_base64_newlines_upload(self):
        self._test_base64_upload("Big data" * 68000, encode=base64.encodebytes)

    def test_unicode_file_name(self):
        with sys_tempfile.TemporaryDirectory() as temp_dir:
            # This file contains Chinese symbols and an accented char in the name.
            with open(os.path.join(temp_dir, UNICODE_FILENAME), 'w+b') as file1:
                file1.write(b'b' * (2 ** 10))
                file1.seek(0)
                response = self.client.post('/unicode_name/', {'file_unicode': file1})
            self.assertEqual(response.status_code, 200)

    def test_unicode_file_name_rfc2231(self):
        """
        Test receiving file upload when filename is encoded with RFC2231
        (#22971).
        """
        payload = client.FakePayload()
        payload.write('\r\n'.join([
            '--' + client.BOUNDARY,
            'Content-Disposition: form-data; name="file_unicode"; filename*=UTF-8\'\'%s' % quote(UNICODE_FILENAME),
            'Content-Type: application/octet-stream',
            '',
            'You got pwnd.\r\n',
            '\r\n--' + client.BOUNDARY + '--\r\n'
        ]))

        r = {
            'CONTENT_LENGTH': len(payload),
            'CONTENT_TYPE': client.MULTIPART_CONTENT,
            'PATH_INFO': "/unicode_name/",
            'REQUEST_METHOD': 'POST',
            'wsgi.input': payload,
        }
        response = self.client.request(**r)
        self.assertEqual(response.status_code, 200)

    def test_unicode_name_rfc2231(self):
        """
        Test receiving file upload when filename is encoded with RFC2231
        (#22971).
        """
        payload = client.FakePayload()
        payload.write(
            '\r\n'.join([
                '--' + client.BOUNDARY,
                'Content-Disposition: form-data; name*=UTF-8\'\'file_unicode; filename*=UTF-8\'\'%s' % quote(
                    UNICODE_FILENAME
                ),
                'Content-Type: application/octet-stream',
                '',
                'You got pwnd.\r\n',
                '\r\n--' + client.BOUNDARY + '--\r\n'
            ])
        )

        r = {
            'CONTENT_LENGTH': len(payload),
            'CONTENT_TYPE': client.MULTIPART_CONTENT,
            'PATH_INFO': "/unicode_name/",
            'REQUEST_METHOD': 'POST',
            'wsgi.input': payload,
        }
        response = self.client.request(**r)
        self.assertEqual(response.status_code, 200)

    def test_blank_filenames(self):
        """
        Receiving file upload when filename is blank (before and after
        sanitization) should be okay.
        """
        # The second value is normalized to an empty name by
        # MultiPartParser.IE_sanitize()
        filenames = ['', 'C:\\Windows\\']

        payload = client.FakePayload()
        for i, name in enumerate(filenames):
            payload.write('\r\n'.join([
                '--' + client.BOUNDARY,
                'Content-Disposition: form-data; name="file%s"; filename="%s"' % (i, name),
                'Content-Type: application/octet-stream',
                '',
                'You got pwnd.\r\n'
            ]))
        payload.write('\r\n--' + client.BOUNDARY + '--\r\n')

        r = {
            'CONTENT_LENGTH': len(payload),
            'CONTENT_TYPE': client.MULTIPART_CONTENT,
            'PATH_INFO': '/echo/',
            'REQUEST_METHOD': 'POST',
            'wsgi.input': payload,
        }
        response = self.client.request(**r)
        self.assertEqual(response.status_code, 200)

        # Empty filenames should be ignored
        received = response.json()
        for i, name in enumerate(filenames):
            self.assertIsNone(received.get('file%s' % i))

    def test_dangerous_file_names(self):
        """Uploaded file names should be sanitized before ever reaching the view."""
        # This test simulates possible directory traversal attacks by a
        # malicious uploader We have to do some monkeybusiness here to construct
        # a malicious payload with an invalid file name (containing os.sep or
        # os.pardir). This similar to what an attacker would need to do when
        # trying such an attack.
        scary_file_names = [
            "/tmp/hax0rd.txt",          # Absolute path, *nix-style.
            "C:\\Windows\\hax0rd.txt",  # Absolute path, win-style.
            "C:/Windows/hax0rd.txt",    # Absolute path, broken-style.
            "\\tmp\\hax0rd.txt",        # Absolute path, broken in a different way.
            "/tmp\\hax0rd.txt",         # Absolute path, broken by mixing.
            "subdir/hax0rd.txt",        # Descendant path, *nix-style.
            "subdir\\hax0rd.txt",       # Descendant path, win-style.
            "sub/dir\\hax0rd.txt",      # Descendant path, mixed.
            "../../hax0rd.txt",         # Relative path, *nix-style.
            "..\\..\\hax0rd.txt",       # Relative path, win-style.
            "../..\\hax0rd.txt"         # Relative path, mixed.
        ]

        payload = client.FakePayload()
        for i, name in enumerate(scary_file_names):
            payload.write('\r\n'.join([
                '--' + client.BOUNDARY,
                'Content-Disposition: form-data; name="file%s"; filename="%s"' % (i, name),
                'Content-Type: application/octet-stream',
                '',
                'You got pwnd.\r\n'
            ]))
        payload.write('\r\n--' + client.BOUNDARY + '--\r\n')

        r = {
            'CONTENT_LENGTH': len(payload),
            'CONTENT_TYPE': client.MULTIPART_CONTENT,
            'PATH_INFO': "/echo/",
            'REQUEST_METHOD': 'POST',
            'wsgi.input': payload,
        }
        response = self.client.request(**r)
        # The filenames should have been sanitized by the time it got to the view.
        received = response.json()
        for i, name in enumerate(scary_file_names):
            got = received["file%s" % i]
            self.assertEqual(got, "hax0rd.txt")

    def test_filename_overflow(self):
        """File names over 256 characters (dangerous on some platforms) get fixed up."""
        long_str = 'f' * 300
        cases = [
            # field name, filename, expected
            ('long_filename', '%s.txt' % long_str, '%s.txt' % long_str[:251]),
            ('long_extension', 'foo.%s' % long_str, '.%s' % long_str[:254]),
            ('no_extension', long_str, long_str[:255]),
            ('no_filename', '.%s' % long_str, '.%s' % long_str[:254]),
            ('long_everything', '%s.%s' % (long_str, long_str), '.%s' % long_str[:254]),
        ]
        payload = client.FakePayload()
        for name, filename, _ in cases:
            payload.write("\r\n".join([
                '--' + client.BOUNDARY,
                'Content-Disposition: form-data; name="{}"; filename="{}"',
                'Content-Type: application/octet-stream',
                '',
                'Oops.',
                ''
            ]).format(name, filename))
        payload.write('\r\n--' + client.BOUNDARY + '--\r\n')
        r = {
            'CONTENT_LENGTH': len(payload),
            'CONTENT_TYPE': client.MULTIPART_CONTENT,
            'PATH_INFO': "/echo/",
            'REQUEST_METHOD': 'POST',
            'wsgi.input': payload,
        }
        response = self.client.request(**r)
        result = response.json()
        for name, _, expected in cases:
            got = result[name]
            self.assertEqual(expected, got, 'Mismatch for {}'.format(name))
            self.assertLess(len(got), 256,
                            "Got a long file name (%s characters)." % len(got))

    def test_file_content(self):
        file = tempfile.NamedTemporaryFile
        with file(suffix=".ctype_extra") as no_content_type, file(suffix=".ctype_extra") as simple_file:
            no_content_type.write(b'no content')
            no_content_type.seek(0)

            simple_file.write(b'text content')
            simple_file.seek(0)
            simple_file.content_type = 'text/plain'

            string_io = StringIO('string content')
            bytes_io = BytesIO(b'binary content')

            response = self.client.post('/echo_content/', {
                'no_content_type': no_content_type,
                'simple_file': simple_file,
                'string': string_io,
                'binary': bytes_io,
            })
            received = response.json()
            self.assertEqual(received['no_content_type'], 'no content')
            self.assertEqual(received['simple_file'], 'text content')
            self.assertEqual(received['string'], 'string content')
            self.assertEqual(received['binary'], 'binary content')

    def test_content_type_extra(self):
        """Uploaded files may have content type parameters available."""
        file = tempfile.NamedTemporaryFile
        with file(suffix=".ctype_extra") as no_content_type, file(suffix=".ctype_extra") as simple_file:
            no_content_type.write(b'something')
            no_content_type.seek(0)

            simple_file.write(b'something')
            simple_file.seek(0)
            simple_file.content_type = 'text/plain; test-key=test_value'

            response = self.client.post('/echo_content_type_extra/', {
                'no_content_type': no_content_type,
                'simple_file': simple_file,
            })
            received = response.json()
            self.assertEqual(received['no_content_type'], {})
            self.assertEqual(received['simple_file'], {'test-key': 'test_value'})

    def test_truncated_multipart_handled_gracefully(self):
        """
        If passed an incomplete multipart message, MultiPartParser does not
        attempt to read beyond the end of the stream, and simply will handle
        the part that can be parsed gracefully.
        """
        payload_str = "\r\n".join([
            '--' + client.BOUNDARY,
            'Content-Disposition: form-data; name="file"; filename="foo.txt"',
            'Content-Type: application/octet-stream',
            '',
            'file contents'
            '--' + client.BOUNDARY + '--',
            '',
        ])
        payload = client.FakePayload(payload_str[:-10])
        r = {
            'CONTENT_LENGTH': len(payload),
            'CONTENT_TYPE': client.MULTIPART_CONTENT,
            'PATH_INFO': '/echo/',
            'REQUEST_METHOD': 'POST',
            'wsgi.input': payload,
        }
        self.assertEqual(self.client.request(**r).json(), {})

    def test_empty_multipart_handled_gracefully(self):
        """
        If passed an empty multipart message, MultiPartParser will return
        an empty QueryDict.
        """
        r = {
            'CONTENT_LENGTH': 0,
            'CONTENT_TYPE': client.MULTIPART_CONTENT,
            'PATH_INFO': '/echo/',
            'REQUEST_METHOD': 'POST',
            'wsgi.input': client.FakePayload(b''),
        }
        self.assertEqual(self.client.request(**r).json(), {})

    def test_custom_upload_handler(self):
        file = tempfile.NamedTemporaryFile
        with file() as smallfile, file() as bigfile:
            # A small file (under the 5M quota)
            smallfile.write(b'a' * (2 ** 21))
            smallfile.seek(0)

            # A big file (over the quota)
            bigfile.write(b'a' * (10 * 2 ** 20))
            bigfile.seek(0)

            # Small file posting should work.
            self.assertIn('f', self.client.post('/quota/', {'f': smallfile}).json())

            # Large files don't go through.
            self.assertNotIn('f', self.client.post("/quota/", {'f': bigfile}).json())

    def test_broken_custom_upload_handler(self):
        with tempfile.NamedTemporaryFile() as file:
            file.write(b'a' * (2 ** 21))
            file.seek(0)

            msg = 'You cannot alter upload handlers after the upload has been processed.'
            with self.assertRaisesMessage(AttributeError, msg):
                self.client.post('/quota/broken/', {'f': file})

    def test_fileupload_getlist(self):
        file = tempfile.NamedTemporaryFile
        with file() as file1, file() as file2, file() as file2a:
            file1.write(b'a' * (2 ** 23))
            file1.seek(0)

            file2.write(b'a' * (2 * 2 ** 18))
            file2.seek(0)

            file2a.write(b'a' * (5 * 2 ** 20))
            file2a.seek(0)

            response = self.client.post('/getlist_count/', {
                'file1': file1,
                'field1': 'test',
                'field2': 'test3',
                'field3': 'test5',
                'field4': 'test6',
                'field5': 'test7',
                'file2': (file2, file2a)
            })
            got = response.json()
            self.assertEqual(got.get('file1'), 1)
            self.assertEqual(got.get('file2'), 2)

    def test_fileuploads_closed_at_request_end(self):
        file = tempfile.NamedTemporaryFile
        with file() as f1, file() as f2a, file() as f2b:
            response = self.client.post('/fd_closing/t/', {
                'file': f1,
                'file2': (f2a, f2b),
            })

        request = response.wsgi_request
        # The files were parsed.
        self.assertTrue(hasattr(request, '_files'))

        file = request._files['file']
        self.assertTrue(file.closed)

        files = request._files.getlist('file2')
        self.assertTrue(files[0].closed)
        self.assertTrue(files[1].closed)

    def test_no_parsing_triggered_by_fd_closing(self):
        file = tempfile.NamedTemporaryFile
        with file() as f1, file() as f2a, file() as f2b:
            response = self.client.post('/fd_closing/f/', {
                'file': f1,
                'file2': (f2a, f2b),
            })

        request = response.wsgi_request
        # The fd closing logic doesn't trigger parsing of the stream
        self.assertFalse(hasattr(request, '_files'))

    def test_file_error_blocking(self):
        """
        The server should not block when there are upload errors (bug #8622).
        This can happen if something -- i.e. an exception handler -- tries to
        access POST while handling an error in parsing POST. This shouldn't
        cause an infinite loop!
        """
        class POSTAccessingHandler(client.ClientHandler):
            """A handler that'll access POST during an exception."""
            def handle_uncaught_exception(self, request, resolver, exc_info):
                ret = super().handle_uncaught_exception(request, resolver, exc_info)
                request.POST  # evaluate
                return ret

        # Maybe this is a little more complicated that it needs to be; but if
        # the django.test.client.FakePayload.read() implementation changes then
        # this test would fail.  So we need to know exactly what kind of error
        # it raises when there is an attempt to read more than the available bytes:
        try:
            client.FakePayload(b'a').read(2)
        except Exception as err:
            reference_error = err

        # install the custom handler that tries to access request.POST
        self.client.handler = POSTAccessingHandler()

        with open(__file__, 'rb') as fp:
            post_data = {
                'name': 'Ringo',
                'file_field': fp,
            }
            try:
                self.client.post('/upload_errors/', post_data)
            except reference_error.__class__ as err:
                self.assertNotEqual(
                    str(err),
                    str(reference_error),
                    "Caught a repeated exception that'll cause an infinite loop in file uploads."
                )
            except Exception as err:
                # CustomUploadError is the error that should have been raised
                self.assertEqual(err.__class__, uploadhandler.CustomUploadError)

    def test_filename_case_preservation(self):
        """
        The storage backend shouldn't mess with the case of the filenames
        uploaded.
        """
        # Synthesize the contents of a file upload with a mixed case filename
        # so we don't have to carry such a file in the Django tests source code
        # tree.
        vars = {'boundary': 'oUrBoUnDaRyStRiNg'}
        post_data = [
            '--%(boundary)s',
            'Content-Disposition: form-data; name="file_field"; filename="MiXeD_cAsE.txt"',
            'Content-Type: application/octet-stream',
            '',
            'file contents\n'
            '',
            '--%(boundary)s--\r\n',
        ]
        response = self.client.post(
            '/filename_case/',
            '\r\n'.join(post_data) % vars,
            'multipart/form-data; boundary=%(boundary)s' % vars
        )
        self.assertEqual(response.status_code, 200)
        id = int(response.content)
        obj = FileModel.objects.get(pk=id)
        # The name of the file uploaded and the file stored in the server-side
        # shouldn't differ.
        self.assertEqual(os.path.basename(obj.testfile.path), 'MiXeD_cAsE.txt')


@override_settings(MEDIA_ROOT=MEDIA_ROOT)
class DirectoryCreationTests(SimpleTestCase):
    """
    Tests for error handling during directory creation
    via _save_FIELD_file (ticket #6450)
    """
    @classmethod
    def setUpClass(cls):
        super().setUpClass()
        os.makedirs(MEDIA_ROOT, exist_ok=True)

    @classmethod
    def tearDownClass(cls):
        shutil.rmtree(MEDIA_ROOT)
        super().tearDownClass()

    def setUp(self):
        self.obj = FileModel()

    @unittest.skipIf(sys.platform == 'win32', "Python on Windows doesn't have working os.chmod().")
    def test_readonly_root(self):
        """Permission errors are not swallowed"""
        os.chmod(MEDIA_ROOT, 0o500)
        self.addCleanup(os.chmod, MEDIA_ROOT, 0o700)
        with self.assertRaises(PermissionError):
            self.obj.testfile.save('foo.txt', SimpleUploadedFile('foo.txt', b'x'), save=False)

    def test_not_a_directory(self):
        # Create a file with the upload directory name
        open(UPLOAD_TO, 'wb').close()
        self.addCleanup(os.remove, UPLOAD_TO)
        msg = '%s exists and is not a directory.' % UPLOAD_TO
        with self.assertRaisesMessage(FileExistsError, msg):
            with SimpleUploadedFile('foo.txt', b'x') as file:
                self.obj.testfile.save('foo.txt', file, save=False)


class MultiParserTests(SimpleTestCase):

    def test_empty_upload_handlers(self):
        # We're not actually parsing here; just checking if the parser properly
        # instantiates with empty upload handlers.
        MultiPartParser({
            'CONTENT_TYPE': 'multipart/form-data; boundary=_foo',
            'CONTENT_LENGTH': '1'
        }, StringIO('x'), [], 'utf-8')

    def test_invalid_content_type(self):
        with self.assertRaisesMessage(MultiPartParserError, 'Invalid Content-Type: text/plain'):
            MultiPartParser({
                'CONTENT_TYPE': 'text/plain',
                'CONTENT_LENGTH': '1',
            }, StringIO('x'), [], 'utf-8')

    def test_negative_content_length(self):
        with self.assertRaisesMessage(MultiPartParserError, 'Invalid content length: -1'):
            MultiPartParser({
                'CONTENT_TYPE': 'multipart/form-data; boundary=_foo',
                'CONTENT_LENGTH': -1,
            }, StringIO('x'), [], 'utf-8')

    def test_bad_type_content_length(self):
        multipart_parser = MultiPartParser({
            'CONTENT_TYPE': 'multipart/form-data; boundary=_foo',
            'CONTENT_LENGTH': 'a',
        }, StringIO('x'), [], 'utf-8')
        self.assertEqual(multipart_parser._content_length, 0)

    def test_rfc2231_parsing(self):
        test_data = (
            (b"Content-Type: application/x-stuff; title*=us-ascii'en-us'This%20is%20%2A%2A%2Afun%2A%2A%2A",
             "This is ***fun***"),
            (b"Content-Type: application/x-stuff; title*=UTF-8''foo-%c3%a4.html",
             "foo-ä.html"),
            (b"Content-Type: application/x-stuff; title*=iso-8859-1''foo-%E4.html",
             "foo-ä.html"),
        )
        for raw_line, expected_title in test_data:
            parsed = parse_header(raw_line)
            self.assertEqual(parsed[1]['title'], expected_title)

    def test_rfc2231_wrong_title(self):
        """
        Test wrongly formatted RFC 2231 headers (missing double single quotes).
        Parsing should not crash (#24209).
        """
        test_data = (
            (b"Content-Type: application/x-stuff; title*='This%20is%20%2A%2A%2Afun%2A%2A%2A",
             b"'This%20is%20%2A%2A%2Afun%2A%2A%2A"),
            (b"Content-Type: application/x-stuff; title*='foo.html",
             b"'foo.html"),
            (b"Content-Type: application/x-stuff; title*=bar.html",
             b"bar.html"),
        )
        for raw_line, expected_title in test_data:
            parsed = parse_header(raw_line)
            self.assertEqual(parsed[1]['title'], expected_title)
