#!/usr/bin/env python
#
# Copyright (c) 2011, 2012 iXsystems, Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#

import cPickle as pickle
import logging
import os
import re
import sys
import uuid
sys.path.append('/usr/local/www')
sys.path.append('/usr/local/www/freenasUI')

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'freenasUI.settings')

# Make sure to load all modules
from django.db.models.loading import cache
cache.get_apps()

from freenasUI.freeadmin.apppool import appPool
from freenasUI.storage.models import Task, Replication
from datetime import datetime, time, timedelta

from freenasUI.common.locks import mntlock
from freenasUI.common.pipesubr import pipeopen
from freenasUI.common.system import send_mail
from freenasUI.common.timesubr import isTimeBetween
from freenasUI.storage.models import VMWarePlugin

from lockfile import LockFile

log = logging.getLogger('tools.autosnap')

# NOTE
#
# In this script there is no asynchnous programming so ALL locks are obtained
# in the blocking way.
#
# With this assumption, the mntlock SHOULD only be instansized once during the
# whole lifetime of this script.
#
MNTLOCK = mntlock()

VMWARE_FAILS = '/var/tmp/.vmwaresnap_fails'

# Set to True if verbose log desired
debug = False


def snapinfodict2datetime(snapinfo):
    year = int(snapinfo['year'])
    month = int(snapinfo['month'])
    day = int(snapinfo['day'])
    hour = int(snapinfo['hour'])
    minute = int(snapinfo['minute'])
    return datetime(year, month, day, hour, minute)


def snap_expired(snapinfo, snaptime):
    snapinfo_expirationtime = snapinfodict2datetime(snapinfo)
    snap_ttl_value = int(snapinfo['retcount'])
    snap_ttl_unit = snapinfo['retunit']

    if snap_ttl_unit == 'h':
        snapinfo_expirationtime = snapinfo_expirationtime + timedelta(hours=snap_ttl_value)
    elif snap_ttl_unit == 'd':
        snapinfo_expirationtime = snapinfo_expirationtime + timedelta(days=snap_ttl_value)
    elif snap_ttl_unit == 'w':
        snapinfo_expirationtime = snapinfo_expirationtime + timedelta(days=7 * snap_ttl_value)
    elif snap_ttl_unit == 'm':
        snapinfo_expirationtime = snapinfo_expirationtime + timedelta(days=int(30.436875 * snap_ttl_value))
    elif snap_ttl_unit == 'y':
        snapinfo_expirationtime = snapinfo_expirationtime + timedelta(days=int(365.2425 * snap_ttl_value))

    return snapinfo_expirationtime <= snaptime


def isMatchingTime(task, snaptime):
    curtime = time(snaptime.hour, snaptime.minute)
    repeat_type = task.task_repeat_unit

    if not isTimeBetween(curtime, task.task_begin, task.task_end):
        return False

    if repeat_type == 'daily':
        return True

    if repeat_type == 'weekly':
        cur_weekday = snaptime.weekday() + 1
        if ('%d' % cur_weekday) in task.task_byweekday.split(','):
            return True

    return False


# Detect if another instance is running
def exit_if_running(pid):
    log.debug("Checking if process %d is still alive", pid)
    try:
        os.kill(pid, 0)
        # If we reached here, there is another process in progress
        log.debug("Process %d still working, quitting", pid)
        sys.exit(0)
    except OSError:
        log.debug("Process %d gone", pid)


def autorepl_running():
    if not os.path.exists('/var/run/autorepl.pid'):
        return False
    with open('/var/run/autorepl.pid', 'r') as f:
        pid = f.read().strip('\n')
    if not pid.isdigit():
        return False
    try:
        os.kill(int(pid), 0)
        return True
    except OSError:
        return False


appPool.hook_tool_run('autosnap')

mypid = os.getpid()

# (mis)use MNTLOCK as PIDFILE lock.
locked = True
try:
    MNTLOCK.lock_try()
except IOError:
    locked = False
if not locked:
    sys.exit(0)

AUTOSNAP_PID = -1
try:
    with open('/var/run/autosnap.pid') as pidfile:
        AUTOSNAP_PID = int(pidfile.read())
except:
    pass

if AUTOSNAP_PID != -1:
    exit_if_running(AUTOSNAP_PID)

with open('/var/run/autosnap.pid', 'w') as pidfile:
    pidfile.write('%d' % mypid)

MNTLOCK.unlock()

now = datetime.now().replace(microsecond=0)
if now.second < 30 or now.minute == 59:
    snaptime = now.replace(second=0)
else:
    snaptime = now.replace(minute=now.minute + 1, second=0)

mp_to_task_map = {}

# Grab all matching tasks into a tree.
# Since the snapshot we make have the name 'foo@auto-%Y%m%d.%H%M-{expire time}'
# format, we just keep one task.
TaskObjects = Task.objects.filter(task_enabled=True)
taskpath = {'recursive': [], 'nonrecursive': []}
for task in TaskObjects:
    if isMatchingTime(task, snaptime):
        if task.task_recursive:
            taskpath['recursive'].append(task.task_filesystem)
        else:
            taskpath['nonrecursive'].append(task.task_filesystem)
        fs = task.task_filesystem
        expire_time = ('%s%s' % (task.task_ret_count, task.task_ret_unit[0])).__str__()
        tasklist = []
        if (fs, expire_time) in mp_to_task_map:
            tasklist = mp_to_task_map[(fs, expire_time)]
            tasklist.append(task)
        else:
            tasklist = [task]
        mp_to_task_map[(fs, expire_time)] = tasklist

re_path = re.compile("^((" + '|'.join(taskpath['nonrecursive']) +
                     ")@|(" + '|'.join(taskpath['recursive']) + ")[@/])")
# Only proceed further if we are  going to generate any snapshots for this run
if len(mp_to_task_map) > 0:

    # Grab all existing snapshot and filter out the expiring ones
    snapshots = {}
    snapshots_pending_delete = set()
    previous_prefix = '/'
    zfsproc = pipeopen("/sbin/zfs list -t snapshot -H -o name", debug, logger=log)
    lines = zfsproc.communicate()[0].split('\n')
    reg_autosnap = re.compile('^auto-(?P<year>\d{4})(?P<month>\d{2})(?P<day>\d{2}).(?P<hour>\d{2})(?P<minute>\d{2})-(?P<retcount>\d+)(?P<retunit>[hdwmy])$')
    for snapshot_name in lines:
        if snapshot_name != '':
            fs, snapname = snapshot_name.split('@')
            snapname_match = reg_autosnap.match(snapname)
            if snapname_match is not None:
                snap_infodict = snapname_match.groupdict()
                snap_ret_policy = '%s%s' % (snap_infodict['retcount'], snap_infodict['retunit'])
                if snap_expired(snap_infodict, snaptime):
                    # Only delete the snapshot if there's a snapshot task enabled that created it.
                    if re_path:
                        if re_path.match(snapshot_name):
                            # Destroy of expired snapshots is recursive, so only request so on the
                            # toplevel.
                            if fs.startswith(previous_prefix):
                                if ('%s@%s' % (previous_prefix[:-1], snapname)) in snapshots_pending_delete:
                                    continue
                            else:
                                previous_prefix = '%s/' % (fs)
                            snapshots_pending_delete.add(snapshot_name)
                else:
                    if (fs, snap_ret_policy) in mp_to_task_map:
                        if (fs, snap_ret_policy) in snapshots:
                            last_snapinfo = snapshots[(fs, snap_ret_policy)]
                            if snapinfodict2datetime(last_snapinfo) < snapinfodict2datetime(snap_infodict):
                                snapshots[(fs, snap_ret_policy)] = snap_infodict
                        else:
                            snapshots[(fs, snap_ret_policy)] = snap_infodict

    list_mp = mp_to_task_map.keys()

    for mpkey in list_mp:
        tasklist = mp_to_task_map[mpkey]
        if mpkey in snapshots:
            snapshot_time = snapinfodict2datetime(snapshots[mpkey])
            for taskindex in range(len(tasklist) - 1, -1, -1):
                task = tasklist[taskindex]
                if snapshot_time + timedelta(minutes=task.task_interval) > snaptime:
                    del tasklist[taskindex]
            if len(tasklist) == 0:
                del mp_to_task_map[mpkey]

    snaptime_str = snaptime.strftime('%Y%m%d.%H%M')

    for mpkey, tasklist in mp_to_task_map.items():
        fs, expire = mpkey
        recursive = False
        for task in tasklist:
            if task.task_recursive is True:
                recursive = True
        if recursive is True:
            rflag = ' -r'
        else:
            rflag = ''

        snapname = '%s@auto-%s-%s' % (fs, snaptime_str, expire)

        # If there's a VMWare Plugin object for this filesystem
        # snapshot the VMs before taking the ZFS snapshot
        from pysphere import VIServer
        server = VIServer()
        qs = VMWarePlugin.objects.filter(filesystem=fs)
        vmsnapname = str(uuid.uuid4())
        vmsnapdescription = str(datetime.now()).split('.')[0] + " FreeNAS Created Snapshot"
        snapvms = []
        snapvmfails = []
        for obj in qs:
            try:
                server.connect(obj.hostname, obj.username, obj.get_password())
            except:
                log.warn("VMware login failed to %s", obj.hostname)
                continue
            vmlist = server.get_registered_vms(status='poweredOn')
            for vm in vmlist:
                if vm.startswith("[%s]" % obj.datastore):
                    vm1 = server.get_vm_by_path(vm)
                    try:
                        vm1.create_snapshot(vmsnapname, description=vmsnapdescription, memory=False)
                    except:
                        log.warn("Snapshot of VM %s failed", vm1)
                        snapvmfails.append(vm1)
                    snapvms.append(vm1)

        if snapvmfails:
            try:
                with LockFile(VMWARE_FAILS) as lock:
                    with open(VMWARE_FAILS, 'rb') as f:
                        fails = pickle.load(f)
            except:
                fails = {}
            fails[snapname] = [str(vm) for vm in snapvmfails]
            with LockFile(VMWARE_FAILS) as lock:
                with open(VMWARE_FAILS, 'wb') as f:
                    pickle.dump(fails, f)

            send_mail(
                subject="VMware Snapshot failed! (%s)" % snapname,
                text="""
Hello,
    The following VM failed to snapshot %s:
%s
""" % (snapname, '    \n'.join([str(vm) for vm in snapvmfails])),
                channel='snapvmware'
            )

        if len(snapvms) > 0 and len(snapvmfails) == 0:
            vmflag = '-o freenas:vmsynced=Y '
        else:
            vmflag = ''

        # If there is associated replication task, mark the snapshots as 'NEW'.
        if Replication.objects.filter(repl_filesystem=fs, repl_enabled=True).count() > 0:
            MNTLOCK.lock()
            snapcmd = '/sbin/zfs snapshot%s %s"%s"' % (rflag, vmflag, snapname)
            proc = pipeopen(snapcmd, logger=log)
            err = proc.communicate()[1]
            if proc.returncode != 0:
                log.error("Failed to create snapshot '%s': %s", snapname, err)
            MNTLOCK.unlock()
        else:
            snapcmd = '/sbin/zfs snapshot%s %s"%s"' % (rflag, vmflag, snapname)
            proc = pipeopen(snapcmd, logger=log)
            err = proc.communicate()[1]
            if proc.returncode != 0:
                log.error("Failed to create snapshot '%s': %s", snapname, err)

        for vm in snapvms:
            if vm not in snapvmfails:
                vm.delete_named_snapshot(vmsnapname)

    MNTLOCK.lock()
    if not autorepl_running():
        for snapshot in snapshots_pending_delete:
            snapcmd = '/sbin/zfs destroy -r -d "%s"' % (snapshot)  # snapshots with clones will have destruction deferred
            proc = pipeopen(snapcmd, logger=log)
            err = proc.communicate()[1]
            if proc.returncode != 0:
                log.error("Failed to destroy snapshot '%s': %s", snapshot, err)
    else:
        log.debug("Autorepl running, skip destroying snapshots")
    MNTLOCK.unlock()


os.unlink('/var/run/autosnap.pid')

os.execl('/usr/local/bin/python',
         'python',
         '/usr/local/www/freenasUI/tools/autorepl.py')
