import unittest
import os
import signal
import sys
import random
import time
from commontest import abs_test_dir, old_test_dir, compare_recursive, RBBin, \
    xcopytree
from rdiff_backup import Globals, rpath, Time
"""Test consistency by killing rdiff-backup as it is backing up"""


class Local:
    """Hold some local RPaths"""

    def get_local_rp(ext):
        return rpath.RPath(
            Globals.local_connection, os.path.join(abs_test_dir, ext))

    ktrp = []
    for i in range(4):
        ktrp.append(get_local_rp(b'killtest%d' % (i + 1)))

    rpout = get_local_rp(b'output')
    rpout_inc = get_local_rp(b'output_inc')

    outrp = []
    for i in range(5):
        outrp.append(get_local_rp(b'restoretarget%d' % (i + 1)))

    backrp = []
    for i in range(5):
        backrp.append(get_local_rp(b'backup%d' % (i + 1)))


class TimingError(Exception):
    """Indicates timing error - process killed too soon or too late"""
    pass


class ProcessFuncs(unittest.TestCase):
    """Subclassed by Resume and NoResume"""

    def delete_tmpdirs(self):
        """Remove any temp directories created by previous tests"""
        Local.rpout.setdata()
        if Local.rpout.lstat():
            Local.rpout.delete()
        Local.rpout_inc.setdata()
        if Local.rpout_inc.lstat():
            Local.rpout_inc.delete()
        for rp in Local.outrp:
            rp.setdata()
            if rp.lstat():
                rp.delete()
        # TODO check if following files really need to be deleted:
        # testfiles/vft_out timbar.pyc testfiles/vft2_out

    def exec_rb(self, time, wait=None, *args):
        """Run rdiff-backup return pid.  Wait until done if wait is true"""
        arglist = [sys.executable, RBBin]
        if time:
            arglist.append("--current-time")
            arglist.append(str(time))
        arglist.extend(args)

        if wait:
            print("Waiting for ", arglist)
            return os.spawnvp(os.P_WAIT, sys.executable, arglist)
        else:
            pid = os.spawnvp(os.P_NOWAIT, sys.executable, arglist)
            print("Running ", arglist, " PID: ", pid)
            return pid

    def exec_and_kill(self, min_max_pair, backup_time, arg1, arg2):
        """Run rdiff-backup, then kill and run again

        Kill after a time between mintime and maxtime.  First process
        should not terminate before maxtime.

        """
        mintime, maxtime = min_max_pair
        pid = self.exec_rb(backup_time, None, arg1, arg2)
        time.sleep(random.uniform(mintime, maxtime))
        # kill doesn't fail on finished but still defunct (not waited) processes
        os.kill(pid, self.killsignal)
        # we can waitpid only once for a finished process, hence we need to keep state
        exitpid, exitstatus = (0, 0)
        while (exitpid, exitstatus) == (0, 0):  # until process terminates...
            exitpid, exitstatus = os.waitpid(pid, os.WNOHANG)
            time.sleep(0.1)
        if (exitpid == pid and exitstatus == 0):
            # process already terminated before we killed it (max time too big?)
            print("---------------------- missed killing PID %d" % (pid))
            return -1
        else:
            print("---------------------- killed PID/RC %d/%d" % (exitpid, exitstatus))
            # it should be like that but robust handling changes exit code:
            # assert exitstatus & (1<<8-1) == self.killsignal, (
            self.assertNotEqual(
                exitstatus, 0,
                "Pid {pid}/{exit} killed by signal {sig}, but exited "
                "with return code {rc} which should be non-zero.".format(
                    pid=pid, exit=exitpid, rc=exitstatus, sig=self.killsignal))

    def create_killtest_dirs(self):
        """Create testfiles/killtest? directories

        They are similar to the testfiles/increment? directories but
        have more files in them so they take a significant time to
        back up.

        """

        def copy_thrice(input, output):
            """Copy input directory to output directory three times"""
            xcopytree(input, output)
            xcopytree(input, os.path.join(output, b"killtesta"))
            xcopytree(input, os.path.join(output, b"killtestb"))

        for i in range(len(Local.ktrp)):
            Local.ktrp[i].setdata()
            if Local.ktrp[i].lstat():
                Local.ktrp[i].delete()
            copy_thrice(os.path.join(old_test_dir, b"increment%d" % (i + 1)),
                        Local.ktrp[i].path)


class KillTest(ProcessFuncs):
    """Test rdiff-backup by killing it, recovering, and then comparing"""
    killsignal = signal.SIGTERM

    # The following are lower and upper bounds on the amount of time
    # rdiff-backup is expected to run.  They are used to determine how
    # long to wait before killing the rdiff-backup process
    time_pairs = [(0.0, 1.0), (0.0, 6.0), (0.0, 4.0), (0.0, 0.5), (0.0, 0.5)]

    def setUp(self):
        """Create killtest? and backup? directories if necessary"""
        for rp in Local.ktrp:
            rp.setdata()
        if (not Local.ktrp[0].lstat() or not Local.ktrp[1].lstat()
                or not Local.ktrp[2].lstat() or not Local.ktrp[3].lstat()):
            self.create_killtest_dirs()
        self.setTiming()

    def setTiming(self):
        """Run each rdiff-backup sequence x times, gathering min/max time"""
        time_list = [[], [], [], [], []]  # List of time lists
        iterations = 2  # we don't really care about precision but time it takes

        def run_once(current_time, input_rp, index):
            start_time = time.time()
            self.exec_rb(current_time, 1, input_rp.path, Local.rpout.path)
            time_list[index].append(time.time() - start_time)

        for i in range(iterations):
            self.delete_tmpdirs()
            run_once(10000, Local.ktrp[2], 0)
            run_once(20000, Local.ktrp[0], 1)
            run_once(30000, Local.ktrp[2], 2)
            run_once(40000, Local.ktrp[2], 3)
            run_once(50000, Local.ktrp[2], 4)

        for i in range(len(time_list)):
            # overwrite time_pairs with runtime values from the actual environment
            # max time is the average of the times measured
            max_time = sum(time_list[i]) / len(time_list[i])
            self.time_pairs[i] = (0, max_time)
            print("%d -> min %s, max %s" % (i, 0, max_time))

    def mark_incomplete(self, curtime, rp):
        """Check the date of current mirror

        Return 1 if there are two current_mirror incs and last one has
        time curtime.  Return 0 if only one with time curtime, and
        then add a current_mirror marker.  Return -1 if only one and
        time is not curtime.

        """
        rbdir = rp.append_path("rdiff-backup-data")
        inclist = rbdir.append("current_mirror").get_incfiles_list()
        self.assertIn(
            len(inclist), (1, 2),
            "There must be 1 or 2 elements in '{paths_list}'.".format(
                paths_list=str([x.path for x in inclist])))

        inc_date_pairs = [(inc.getinctime(), inc) for inc in inclist]
        inc_date_pairs.sort()
        if len(inclist) == 2:
            self.assertEqual(inc_date_pairs[-1][0], curtime)
            return 1

        if inc_date_pairs[-1][0] == curtime:
            result = 0
            marker_time = curtime - 10000
        else:
            self.assertEqual(inc_date_pairs[-1][0], curtime - 10000)
            marker_time = curtime
            result = -1

        cur_mirror_rp = rbdir.append("current_mirror.%s.data" %
                                     (Time.timetostring(marker_time), ))
        self.assertFalse(cur_mirror_rp.lstat())
        cur_mirror_rp.touch()
        return result

    def testTerm(self):
        """Run rdiff-backup, terminating and regressing each time

        Because rdiff-backup must be killed, the timing should be
        updated

        """
        count, killed_too_soon, killed_too_late = 5, [0] * 4, [0] * 4
        self.delete_tmpdirs()
        # Back up killtest3 first because it is big and the first case
        # is kind of special (there's no incrementing, so different
        # code)
        self.exec_rb(10000, 1, Local.ktrp[2].path, Local.rpout.path)
        self.assertTrue(compare_recursive(Local.ktrp[2], Local.rpout))

        def cycle_once(min_max_time_pair, curtime, input_rp, old_rp):
            """Backup input_rp, kill, regress, and then compare"""
            time.sleep(1)
            self.exec_and_kill(min_max_time_pair, curtime, input_rp.path,
                               Local.rpout.path)
            result = self.mark_incomplete(curtime, Local.rpout)
            self.assertEqual(self.exec_rb(None, 1, '--check-destination-dir',
                                          Local.rpout.path),
                             Globals.RET_CODE_WARN)
            self.assertTrue(
                compare_recursive(old_rp, Local.rpout, compare_hardlinks=0))
            return result

        # Keep backing ktrp[0], and then regressing to ktrp[2].  Then go to ktrp[0]
        for i in range(count):
            result = cycle_once(self.time_pairs[1], 20000, Local.ktrp[0],
                                Local.ktrp[2])
            if result == 0:
                killed_too_late[0] += 1
            elif result == -1:
                killed_too_soon[0] += 1
        self.exec_rb(20000, 1, Local.ktrp[0].path, Local.rpout.path)

        # Now keep regressing from ktrp[1], only staying there at the end
        for i in range(count):
            result = cycle_once(self.time_pairs[2], 30000, Local.ktrp[1],
                                Local.ktrp[0])
            if result == 0:
                killed_too_late[1] += 1
            elif result == -1:
                killed_too_soon[1] += 1
        self.exec_rb(30000, 1, Local.ktrp[1].path, Local.rpout.path)

        # Now keep regressing from ktrp[2], only staying there at the end
        for i in range(count):
            result = cycle_once(self.time_pairs[3], 40000, Local.ktrp[2],
                                Local.ktrp[1])
            if result == 0:
                killed_too_late[2] += 1
            elif result == -1:
                killed_too_soon[2] += 1
        self.exec_rb(40000, 1, Local.ktrp[2].path, Local.rpout.path)

        # Now keep regressing from ktrp[3], only staying there at the end
        for i in range(count):
            result = cycle_once(self.time_pairs[4], 50000, Local.ktrp[3],
                                Local.ktrp[2])
            if result == 0:
                killed_too_late[3] += 1
            elif result == -1:
                killed_too_soon[3] += 1

        print("Killed too soon out of %s: %s" % (count, killed_too_soon))
        print("Killed too late out of %s: %s" % (count, killed_too_late))


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