from __future__ import with_statement
import os

try:
    from cStringIO import StringIO
except ImportError:
    from StringIO import StringIO

from django.template import Template, Context
from django.test import TestCase

from compressor.conf import settings
from compressor.exceptions import OfflineGenerationError
from compressor.management.commands.compress import Command as CompressCommand
from compressor.storage import default_storage


class OfflineTestCaseMixin(object):
    template_name = "test_compressor_offline.html"
    verbosity = 0
    # Change this for each test class
    templates_dir = ""
    expected_hash = ""

    def setUp(self):
        self._old_compress = settings.COMPRESS_ENABLED
        self._old_compress_offline = settings.COMPRESS_OFFLINE
        self._old_template_dirs = settings.TEMPLATE_DIRS
        self._old_offline_context = settings.COMPRESS_OFFLINE_CONTEXT
        self._old_template_loaders = settings.TEMPLATE_LOADERS
        self.log = StringIO()

        # Force template dirs, because it enables us to force compress to
        # consider only a specific directory (helps us make true, 
        # independant unit tests).
        settings.TEMPLATE_DIRS = (
            os.path.join(settings.TEMPLATE_DIRS[0], self.templates_dir),
        )
        # Enable offline compress
        settings.COMPRESS_ENABLED = True
        settings.COMPRESS_OFFLINE = True
        self.template_path = os.path.join(settings.TEMPLATE_DIRS[0], self.template_name)
        self.template_file = open(self.template_path)
        self.template = Template(self.template_file.read().decode(settings.FILE_CHARSET))

    def tearDown(self):
        settings.COMPRESS_ENABLED = self._old_compress
        settings.COMPRESS_OFFLINE = self._old_compress_offline
        settings.TEMPLATE_DIRS = self._old_template_dirs
        settings.TEMPLATE_LOADERS = self._old_template_loaders
        self.template_file.close()
        manifest_path = os.path.join('CACHE', 'manifest.json')
        if default_storage.exists(manifest_path):
            default_storage.delete(manifest_path)

    def test_offline(self):
        count, result = CompressCommand().compress(log=self.log, verbosity=self.verbosity)
        self.assertEqual(1, count)
        self.assertEqual([
            u'<script type="text/javascript" src="/media/CACHE/js/%s.js"></script>' % (self.expected_hash, ),
        ], result)
        rendered_template = self.template.render(Context(settings.COMPRESS_OFFLINE_CONTEXT))
        self.assertEqual(rendered_template, "".join(result) + "\n")


class OfflineGenerationBlockSuperTestCase(OfflineTestCaseMixin, TestCase):
    templates_dir = "test_block_super"
    expected_hash = "7c02d201f69d"


class OfflineGenerationConditionTestCase(OfflineTestCaseMixin, TestCase):
    templates_dir = "test_condition"
    expected_hash = "4e3758d50224"

    def setUp(self):
        self.old_offline_context = settings.COMPRESS_OFFLINE_CONTEXT
        settings.COMPRESS_OFFLINE_CONTEXT = {
            'condition': 'red',
        }
        super(OfflineGenerationConditionTestCase, self).setUp()

    def tearDown(self):
        self.COMPRESS_OFFLINE_CONTEXT = self.old_offline_context
        super(OfflineGenerationConditionTestCase, self).tearDown()


class OfflineGenerationTemplateTagTestCase(OfflineTestCaseMixin, TestCase):
    templates_dir = "test_templatetag"
    expected_hash = "a27e1d3a619a"


class OfflineGenerationTestCaseWithContext(OfflineTestCaseMixin, TestCase):
    templates_dir = "test_with_context"
    expected_hash = "5838e2fd66af"

    def setUp(self):
        self.old_offline_context = settings.COMPRESS_OFFLINE_CONTEXT
        settings.COMPRESS_OFFLINE_CONTEXT = {
            'content': 'OK!',
        }
        super(OfflineGenerationTestCaseWithContext, self).setUp()

    def tearDown(self):
        self.COMPRESS_OFFLINE_CONTEXT = self.old_offline_context
        super(OfflineGenerationTestCaseWithContext, self).tearDown()


class OfflineGenerationTestCaseErrors(OfflineTestCaseMixin, TestCase):
    templates_dir = "test_error_handling"
    expected_hash = "cd8870829421"


class OfflineGenerationTestCase(OfflineTestCaseMixin, TestCase):
    templates_dir = "basic"
    expected_hash = "f5e179b8eca4"

    def test_rendering_without_compressing_raises_exception(self):
        self.assertRaises(OfflineGenerationError,
                          self.template.render, Context({}))

    def test_requires_model_validation(self):
        self.assertFalse(CompressCommand.requires_model_validation)

    def test_get_loaders(self):
        old_loaders = settings.TEMPLATE_LOADERS
        settings.TEMPLATE_LOADERS = (
            ('django.template.loaders.cached.Loader', (
                'django.template.loaders.filesystem.Loader',
                'django.template.loaders.app_directories.Loader',
            )),
        )
        try:
            from django.template.loaders.filesystem import Loader as FileSystemLoader
            from django.template.loaders.app_directories import Loader as AppDirectoriesLoader
        except ImportError:
            pass
        else:
            loaders = CompressCommand().get_loaders()
            self.assertTrue(isinstance(loaders[0], FileSystemLoader))
            self.assertTrue(isinstance(loaders[1], AppDirectoriesLoader))
        finally:
            settings.TEMPLATE_LOADERS = old_loaders