import arvados
import arvados_fuse as fuse
import arvados.safeapi
import llfuse
import logging
import multiprocessing
import os
import run_test_server
import shutil
import signal
import subprocess
import sys
import tempfile
import threading
import time
import unittest

logger = logging.getLogger('arvados.arv-mount')

class MountTestBase(unittest.TestCase):
    def setUp(self, api=None, local_store=True):
        # The underlying C implementation of open() makes a fstat() syscall
        # with the GIL still held.  When the GETATTR message comes back to
        # llfuse (which in these tests is in the same interpreter process) it
        # can't acquire the GIL, so it can't service the fstat() call, so it
        # deadlocks.  The workaround is to run some of our test code in a
        # separate process.  Forturnately the multiprocessing module makes this
        # relatively easy.
        self.pool = multiprocessing.Pool(1)

        if local_store:
            self.keeptmp = tempfile.mkdtemp()
            os.environ['KEEP_LOCAL_STORE'] = self.keeptmp
        else:
            self.keeptmp = None
        self.mounttmp = tempfile.mkdtemp()
        run_test_server.run()
        run_test_server.authorize_with("admin")
        self.api = api if api else arvados.safeapi.ThreadSafeApiCache(arvados.config.settings())
        self.llfuse_thread = None

    # This is a copy of Mount's method.  TODO: Refactor MountTestBase
    # to use a Mount instead of copying its code.
    def _llfuse_main(self):
        try:
            llfuse.main()
        except:
            llfuse.close(unmount=False)
            raise
        llfuse.close()

    def make_mount(self, root_class, **root_kwargs):
        self.operations = fuse.Operations(
            os.getuid(), os.getgid(),
            api_client=self.api,
            enable_write=True)
        self.operations.inodes.add_entry(root_class(
            llfuse.ROOT_INODE, self.operations.inodes, self.api, 0, **root_kwargs))
        llfuse.init(self.operations, self.mounttmp, [])
        self.llfuse_thread = threading.Thread(None, lambda: self._llfuse_main())
        self.llfuse_thread.daemon = True
        self.llfuse_thread.start()
        # wait until the driver is finished initializing
        self.operations.initlock.wait()
        return self.operations.inodes[llfuse.ROOT_INODE]

    def tearDown(self):
        if self.llfuse_thread:
            subprocess.call(["fusermount", "-u", "-z", self.mounttmp])
            t0 = time.time()
            self.llfuse_thread.join(timeout=10)
            if self.llfuse_thread.is_alive():
                logger.warning("MountTestBase.tearDown():"
                               " llfuse thread still alive 10s after umount"
                               " -- exiting with SIGKILL")
                os.kill(os.getpid(), signal.SIGKILL)
            waited = time.time() - t0
            if waited > 0.1:
                logger.warning("MountTestBase.tearDown(): waited %f s for llfuse thread to end", waited)

        os.rmdir(self.mounttmp)
        if self.keeptmp:
            shutil.rmtree(self.keeptmp)
            os.environ.pop('KEEP_LOCAL_STORE')
        run_test_server.reset()
        self.pool.close()
        self.pool.join()

    def assertDirContents(self, subdir, expect_content):
        path = self.mounttmp
        if subdir:
            path = os.path.join(path, subdir)
        self.assertEqual(sorted(expect_content), sorted(llfuse.listdir(path)))