"""

Part of the bsie test suite.
A copy of the license is provided with the project.
Author: Matthias Baumgartner, 2022
"""
# standard imports
import logging
import os
import unittest

# bsie imports
from bsie.utils import errors
import bsie.reader.path
import bsie.reader.stat

# objects to test
from bsie.reader.chain import ReaderChain


## code ##

class TestReaderChain(unittest.TestCase):
    def test_construct(self):
        # subreaders are built
        chain = ReaderChain(['bsie.reader.stat.Stat', 'bsie.reader.path.Path'], {})
        self.assertIsInstance(chain, ReaderChain)
        self.assertEqual(chain._children,
            (bsie.reader.stat.Stat(), bsie.reader.path.Path()))
        # subreaders that failed to build are omitted
        with self.assertLogs(logging.getLogger('bsie.reader.chain'), logging.WARNING):
            chain = ReaderChain(['bsie.reader.stat.Stat', 'bsie.reader.invalid.Invalid'], {})
            self.assertEqual(chain._children, (bsie.reader.stat.Stat(), ))
        with self.assertLogs(logging.getLogger('bsie.reader.chain'), logging.WARNING):
            chain = ReaderChain(['bsie.reader.stat.Stat', 'bsie.reader.path.Invalid'], {})
            self.assertEqual(chain._children, (bsie.reader.stat.Stat(), ))
        # warning is issued if there are no subreaders
        with self.assertLogs(logging.getLogger('bsie.reader.chain'), logging.WARNING):
            chain = ReaderChain([], {})
            self.assertEqual(chain._children, tuple())

    def test_essentials(self):
        chain = ReaderChain(['bsie.reader.stat.Stat', 'bsie.reader.path.Path'], {})
        # identity
        self.assertEqual(chain, chain)
        self.assertEqual(hash(chain), hash(chain))
        # comparison works across instances
        self.assertEqual(chain,
            ReaderChain(['bsie.reader.stat.Stat', 'bsie.reader.path.Path'], {}))
        self.assertEqual(hash(chain),
            hash(ReaderChain(['bsie.reader.stat.Stat', 'bsie.reader.path.Path'], {})))
        # comparison respects subreaders
        self.assertNotEqual(hash(chain),
            hash(ReaderChain(['bsie.reader.path.Path'], {})))
        self.assertNotEqual(hash(chain),
            hash(ReaderChain(['bsie.reader.path.Path'], {})))
        # comparison respects subreader order
        self.assertNotEqual(chain,
            ReaderChain(['bsie.reader.path.Path', 'bsie.reader.stat.Stat'], {}))
        self.assertNotEqual(hash(chain),
            hash(ReaderChain(['bsie.reader.path.Path', 'bsie.reader.stat.Stat'], {})))
        # string representation
        self.assertEqual(str(chain), 'ReaderChain(Stat, Path)')
        self.assertEqual(repr(chain), 'ReaderChain((Stat(), Path()))')

    def test_call(self):
        chain = ReaderChain(['bsie.reader.stat.Stat', 'bsie.reader.path.Path'], {})
        # chain first probes first child
        self.assertEqual(chain(__file__), os.stat(__file__))
        # chain probes second child if first one failes
        self.assertEqual(chain(''), '')
        self.assertEqual(chain('missing-file'), 'missing-file')

        # chain raises a ReaderError if childs were exhausted
        chain = ReaderChain(['bsie.reader.stat.Stat'], {})
        # chain probes second child if first one failes
        self.assertRaises(errors.ReaderError, chain, '')


## main ##

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

## EOF ##