#!/usr/bin/env python

import os
import os.path
import sys
import time
import logging
import signal
import select
import shutil
import optparse
import fcntl
from optparse import OptionParser, SUPPRESS_HELP
from logging import Logger
from errno import EEXIST, ENOENT, EACCES, EAGAIN

from gconf import gconf
from syncdutils import FreeObject, norm
from configinterface import GConffile
import resource
from monitor import monitor

class GLogger(Logger):

    def makeRecord(self, name, level, *a):
        rv = Logger.makeRecord(self, name, level, *a)
        rv.nsecs = (rv.created - int(rv.created)) * 1000000
        fr = sys._getframe(4)
        callee = fr.f_locals.get('self')
        if callee:
            ctx = str(type(callee)).split("'")[1].split('.')[-1]
        else:
            ctx = '<top>'
        if not hasattr(rv, 'funcName'):
            rv.funcName = fr.f_code.co_name
        rv.lvlnam = logging.getLevelName(level)[0]
        rv.ctx = ctx
        return rv

    @classmethod
    def setup(cls, **kw):
        lbl = kw.get('label', "")
        if lbl:
            lbl = '(' + lbl + ')'
        lprm = {'datefmt': "%Y-%m-%d %H:%M:%S",
                'format': "[%(asctime)s.%(nsecs)d] %(lvlnam)s [%(module)s" + lbl + ":%(lineno)s:%(funcName)s] %(ctx)s: %(message)s"}
        lprm.update(kw)
        lvl = kw.get('level', logging.INFO)
        lprm['level'] = lvl
        logging.root = cls("root", lvl)
        logging.setLoggerClass(cls)
        logging.getLogger().handlers = []
        logging.basicConfig(**lprm)


def grabfile(fname, content=None):
    # damn those messy open() mode codes
    fd = os.open(fname, os.O_CREAT|os.O_RDWR)
    f = os.fdopen(fd, 'r+b', 0)
    try:
        fcntl.lockf(f, fcntl.LOCK_EX|fcntl.LOCK_NB)
    except:
        ex = sys.exc_info()[1]
        f.close()
        if isinstance(ex, IOError) and ex.errno in (EACCES, EAGAIN):
            # cannot grab, it's taken
            return
        raise
    if content:
        try:
            f.truncate()
            f.write(content)
        except:
            f.close()
            raise
    gconf.permanent_handles.append(f)
    return f

pid_file_owned = False

def grabpidfile(fname=None, setpid=True):
    if not fname:
        fname = gconf.pid_file
    content = None
    if setpid:
        content = str(os.getpid()) + '\n'
    return grabfile(fname, content=content)

def startup(**kw):
    global pid_file_owned

    if getattr(gconf, 'pid_file', None) and kw.get('go_daemon') != 'postconn':
        if not grabpidfile():
            sys.stderr.write("pidfile is taken, exiting.\n")
            sys.exit(2)
        pid_file_owned = True

    if kw.get('go_daemon') == 'should':
        x, y = os.pipe()
        gconf.cpid = os.fork()
        if gconf.cpid:
            os.close(x)
            sys.exit()
        os.close(y)
        os.setsid()
        dn = os.open(os.devnull, os.O_RDWR)
        for f in (sys.stdin, sys.stdout, sys.stderr):
            os.dup2(dn, f.fileno())
        if getattr(gconf, 'pid_file', None):
            if not grabpidfile(gconf.pid_file + '.tmp'):
                raise RuntimeError("cannot grap temporary pidfile")
            os.rename(gconf.pid_file + '.tmp', gconf.pid_file)
        # wait for parent to terminate
        # so we can start up with
        # no messing from the dirty
        # ol' bustard
        select.select((x,), (), ())
        os.close(x)

    lkw = {}
    if gconf.log_level:
        lkw['level'] = gconf.log_level
    if kw.get('log_file'):
        if kw['log_file'] in ('-', '/dev/stderr'):
            lkw['stream'] = sys.stderr
        elif kw['log_file'] == '/dev/stdout':
            lkw['stream'] = sys.stdout
        else:
            lkw['filename'] = kw['log_file']
    GLogger.setup(label=kw.get('label'), **lkw)

def finalize(*a):
    if getattr(gconf, 'pid_file', None):
        rm_pidf = pid_file_owned
        if gconf.cpid:
            # exit path from parent branch of daemonization
            rm_pidf = False
            while True:
                f = grabpidfile(setpid=False)
                if not f:
                    # child has already taken over pidfile
                    break
                if os.waitpid(gconf.cpid, os.WNOHANG)[0] == gconf.cpid:
                    # child has terminated
                    rm_pidf = True
                    break;
                time.sleep(0.1)
        if rm_pidf:
            try:
                os.unlink(gconf.pid_file)
            except:
                ex = sys.exc_info()[1]
                if ex.errno == ENOENT:
                    pass
                else:
                    raise
    if gconf.ssh_ctl_dir and not gconf.cpid:
        shutil.rmtree(gconf.ssh_ctl_dir)
    sys.stdout.flush()
    sys.stderr.flush()

def main():
    signal.signal(signal.SIGTERM, lambda *a: (finalize(*a), os._exit(1)))
    GLogger.setup()
    exval = 0
    try:
        try:
            main_i()
        except:
            exc = sys.exc_info()[1]
            if isinstance(exc, SystemExit):
                exval = exc.code or 0
                raise
            else:
                logging.exception("FAIL: ")
                sys.stderr.write("failed with %s.\n" % type(exc).__name__)
                exval = 1
                sys.exit(exval)
    finally:
        finalize()
        # force exit in non-main thread too
        os._exit(exval)

def main_i():
    rconf = {'go_daemon': 'should'}

    def store_abs(opt, optstr, val, parser):
        if val and val != '-':
            val = os.path.abspath(val)
        setattr(parser.values, opt.dest, val)
    def store_local(opt, optstr, val, parser):
        rconf[opt.dest] = val
    def store_local_curry(val):
        return lambda o, oo, vx, p: store_local(o, oo, val, p)
    def store_local_obj(op, dmake):
        return lambda o, oo, vx, p: store_local(o, oo, FreeObject(op=op, **dmake(vx)), p)

    op = OptionParser(usage="%prog [options...] <master> <slave>", version="%prog 0.0.1")
    op.add_option('--gluster-command',     metavar='CMD',   default='glusterfs')
    op.add_option('--gluster-log-file',    metavar='LOGF',  default=os.devnull, type=str, action='callback', callback=store_abs)
    op.add_option('--gluster-log-level',   metavar='LVL')
    op.add_option('-p', '--pid-file',      metavar='PIDF',  type=str, action='callback', callback=store_abs)
    op.add_option('-l', '--log-file',      metavar='LOGF',  type=str, action='callback', callback=store_abs)
    op.add_option('--state-file',          metavar='STATF', type=str, action='callback', callback=store_abs)
    op.add_option('-L', '--log-level',     metavar='LVL')
    op.add_option('-r', '--remote-gsyncd', metavar='CMD',   default=os.path.abspath(sys.argv[0]))
    op.add_option('--volume-id',           metavar='UUID')
    op.add_option('-s', '--ssh-command',   metavar='CMD',   default='ssh')
    op.add_option('--rsync-command',       metavar='CMD',   default='rsync')
    op.add_option('--rsync-extra',         metavar='ARGS',  default='-sS', help=SUPPRESS_HELP)
    op.add_option('--timeout',             metavar='SEC',   type=int, default=120)
    op.add_option('--sync-jobs',           metavar='N',     type=int, default=3)
    op.add_option('--turns',               metavar='N',     type=int, default=0, help=SUPPRESS_HELP)

    op.add_option('-c', '--config-file',   metavar='CONF',  type=str, action='callback', callback=store_local)
    # duh. need to specify dest or value will be mapped to None :S
    op.add_option('--monitor', dest='monitor', action='callback', callback=store_local_curry(True))
    op.add_option('--listen', dest='listen', help=SUPPRESS_HELP,      action='callback', callback=store_local_curry(True))
    op.add_option('-N', '--no-daemon', dest="go_daemon",    action='callback', callback=store_local_curry('dont'))
    op.add_option('--debug', dest="go_daemon",              action='callback', callback=lambda *a: (store_local_curry('dont')(*a),
                                                                                                    setattr(a[-1].values, 'log_file', '-'),
                                                                                                    setattr(a[-1].values, 'log_level', 'DEBUG'))),

    for a in ('check', 'get'):
        op.add_option('--config-' + a,      metavar='OPT',  type=str, dest='config', action='callback',
                      callback=store_local_obj(a, lambda vx: {'opt': vx}))
    op.add_option('--config-get-all', dest='config', action='callback', callback=store_local_obj('get', lambda vx: {'opt': None}))
    for m in ('', '-rx'):
        # call this code 'Pythonic' eh?
        # have to define a one-shot local function to be able to inject (a value depending on the)
        # iteration variable into the inner lambda
        def conf_mod_opt_regex_variant(rx):
            op.add_option('--config-set' + m,   metavar='OPT VAL', type=str, nargs=2, dest='config', action='callback',
                          callback=store_local_obj('set', lambda vx: {'opt': vx[0], 'val': vx[1], 'rx': rx}))
            op.add_option('--config-del' + m,   metavar='OPT',  type=str, dest='config', action='callback',
                          callback=store_local_obj('del', lambda vx: {'opt': vx, 'rx': rx}))
        conf_mod_opt_regex_variant(not not m)

    op.add_option('--canonicalize-url',        dest='do_canon', action='callback', callback=store_local_curry('raw'))
    op.add_option('--canonicalize-escape-url', dest='do_canon', action='callback', callback=store_local_curry('escaped'))

    tunables = [ norm(o.get_opt_string()[2:]) for o in op.option_list if o.callback in (store_abs, None) and o.get_opt_string() not in ('--version', '--help') ]

    # precedence for sources of values: 1) commandline, 2) cfg file, 3) defaults
    # -- for this to work out we need to tell apart defaults from explicitly set
    # options... so churn out the defaults here and call the parser with virgin
    # values container.
    defaults = op.get_default_values()
    opts, args = op.parse_args(values=optparse.Values())
    confdata = rconf.get('config')
    if not (len(args) == 2 or \
            (len(args) == 1 and rconf.get('listen')) or \
            (len(args) <= 2 and confdata) or \
            rconf.get('do_canon')):
        sys.stderr.write("error: incorrect number of arguments\n\n")
        sys.stderr.write(op.get_usage() + "\n")
        sys.exit(1)

    if getattr(confdata, 'rx', None):
        # peers are regexen, don't try to parse them
        canon_peers = args
    else:
        rscs = [resource.parse_url(u) for u in args]
        dc = rconf.get('do_canon')
        if dc:
            for r in rscs:
                print(r.get_url(canonical=True, escaped=(dc=='escaped')))
            return
        local = remote = None
        if rscs:
          local = rscs[0]
          if len(rscs) > 1:
              remote = rscs[1]
          if not local.can_connect_to(remote):
              raise RuntimeError("%s cannot work with %s" % (local.path, remote and remote.path))
        pa = ([], [])
        canon = [False, True]
        for x in (local, remote):
            if x:
                for i in range(2):
                    pa[i].append(x.get_url(canonical=canon[i]))
        peers, canon_peers = pa
    if not 'config_file' in rconf:
        rconf['config_file'] = os.path.join(os.path.dirname(sys.argv[0]), "conf/gsyncd.conf")
    gcnf = GConffile(rconf['config_file'], canon_peers)

    if confdata:
        opt_ok = norm(confdata.opt) in tunables + [None]
        if confdata.op == 'check':
            if opt_ok:
                sys.exit(0)
            else:
                sys.exit(1)
        elif not opt_ok:
            raise RuntimeError("not a valid option: " + confdata.opt)
        if confdata.op == 'get':
            gcnf.get(confdata.opt)
        elif confdata.op == 'set':
            gcnf.set(confdata.opt, confdata.val, confdata.rx)
        elif confdata.op == 'del':
            gcnf.delete(confdata.opt, confdata.rx)
        return

    gconf.__dict__.update(defaults.__dict__)
    gcnf.update_to(gconf.__dict__)
    gconf.__dict__.update(opts.__dict__)
    gconf.configinterface = gcnf

    #normalize loglevel
    lvl0 = gconf.log_level
    if isinstance(lvl0, str):
        lvl1 = lvl0.upper()
        lvl2 = logging.getLevelName(lvl1)
        # I have _never_ _ever_ seen such an utterly braindead
        # error condition
        if lvl2 == "Level " + lvl1:
            raise RuntimeError('cannot recognize log level "%s"' % lvl0)
        gconf.log_level = lvl2

    go_daemon = rconf['go_daemon']
    be_monitor = rconf.get('monitor')

    if not be_monitor and isinstance(remote, resource.SSH) and \
       go_daemon == 'should':
        go_daemon = 'postconn'
        log_file = None
    else:
        log_file = gconf.log_file
    if be_monitor:
        label = 'monitor'
    elif remote:
        #master
        label = ''
    else:
        label = 'slave'
    startup(go_daemon=go_daemon, log_file=log_file, label=label)

    if be_monitor:
        return monitor()

    logging.info("syncing: %s" % " -> ".join(peers))
    if remote:
        go_daemon = remote.connect_remote(go_daemon=go_daemon)
        if go_daemon:
            startup(go_daemon=go_daemon, log_file=gconf.log_file)
            # complete remote connection in child
            remote.connect_remote(go_daemon='done')
    local.connect()
    local.service_loop(*[r for r in [remote] if r])

    logging.info("exiting.")


if __name__ == "__main__":
    main()