# standard imports
from functools import partial
import os
import shutil
import tempfile
import unittest

# external imports
import PIL.Image

# bsie imports
from bsie.utils import errors

# objects to test
from bsie.reader.preview._pg import PreviewGeneratorReader


## code ##

class TestPreviewGeneratorReader(unittest.TestCase):
    def test_call(self):
        rdr = PreviewGeneratorReader()
        # inexistent file raises a ReaderError
        self.assertRaises(errors.ReaderError, rdr,
            os.path.join(os.path.dirname(__file__), 'missing.jpg'))
        # unsupported file type raises an UnsupportedFileFormatError
        self.assertRaises(errors.UnsupportedFileFormatError, rdr,
            os.path.join(os.path.dirname(__file__), 'invalid.foo'))
        # invalid file raises a ReaderError
        self.assertRaises(errors.ReaderError,
            rdr(os.path.join(os.path.dirname(__file__), 'invalid.jpg')), 100)

        # proper file produces a generator
        gen = rdr(os.path.join(os.path.dirname(__file__), 'testimage.jpg'))
        self.assertIsInstance(gen, partial)
        # generator produces an image
        img = gen(10)
        self.assertIsInstance(img, PIL.Image.Image)
        self.assertEqual(img.size, (10, 10))
        self.assertEqual(sum(img.getdata()), 0)
        # cleanup
        img.close()

        # preview generator can also extract data from non-image files
        gen = rdr(os.path.join(os.path.dirname(__file__), 'testfile.pdf'))
        self.assertIsInstance(gen, partial)
        # generator produces an image
        img = gen(10)
        self.assertIsInstance(img, PIL.Image.Image)
        self.assertEqual(img.size, (8, 10))
        self.assertEqual(sum(img.getdata()), 20258)
        # cleanup
        img.close()

        # can define a cache dir
        pg_dir = tempfile.mkdtemp(prefix='bsie-test')
        self.assertTrue(os.path.exists(pg_dir))
        rdr = PreviewGeneratorReader(cache=pg_dir)
        gen = rdr(os.path.join(os.path.dirname(__file__), 'testimage.jpg'))
        img = gen(10)
        self.assertIsInstance(img, PIL.Image.Image)
        self.assertEqual(img.size, (10, 10))
        self.assertEqual(sum(img.getdata()), 0)
        img.close()
        del rdr
        # cache dir still exists after instance deletion
        self.assertTrue(os.path.exists(pg_dir))
        shutil.rmtree(pg_dir, ignore_errors=True)


## main ##

if __name__ == '__main__':
    unittest.main()

## EOF ##