#    Copyright (C) 2009 Jeff Epler <jepler@unpythonic.net>
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
import os, time, serial, traceback, glob, random
OK, INFO, WARNING, ERROR = range(4)

def check_system(command, level=ERROR):
    print "#", command
    if os.system(command): return level
    return 0

def check_ping(hostname, level=ERROR):
    return check_system("ping -c1 -W5 %s > /dev/null 2>&1" % hostname, level)

def check_df(fs="", level=ERROR):
    return check_system("! (df %s | egrep '(99|100)%%')" % fs, level)

def check_load(*levels):
    print "# load"
    lavg = float(open("/proc/loadavg").read().split()[0])
    result = 0
    for l, v in levels:
        if lavg > l: result = max(result, v)
    return result

def check_ext():
    print "# ext"
    level = 0
    for f in glob.glob(os.path.expanduser("~/.checks/*")):
        print "#", f
        f = open(f)
        d = f.readline()
        f.close()
        d = d.split()[0]
        level = max(level, int(d))
    return level

checks = [
    (lambda:check_ping('lamp.unpy.net'), 6),
    (lambda:check_ping('bald.unpy.net'), 6),
    (lambda:check_ping('cvs.linuxcnc.org'), 6),
    (lambda:check_ping('dsl.unpy.net'), 6),
    (lambda:check_ping('199.184.119.126'), 60),
    (check_ext, 5),
    (lambda:check_df('-text3'), 5),
    (lambda:check_load((2, INFO),(5, WARNING), (15, ERROR)), 60),
]

dchecks = {}
for a, b in checks:
    now = time.time()
    dchecks[a] = (b, now + random.uniform(0, b), a())

def calc_next(now, interval, lev):
    print "calc_next", interval / 4.**lev
    return now + interval / (4.**lev)

def do_checks():
    result = 0
    now = time.time()
    maxlev = max(lev for interval, next, lev in dchecks.values())
    for f, (interval, next, lev) in dchecks.items():
        if now > next:
            lev = do_check(f)
            dchecks[f] = (interval, calc_next(now, interval, lev), lev)
        result = max(result, lev)
    return result

def do_check(f):
    try:
        return f()
    except KeyboardInterrupt:
        raise
    except:
        log_exception()
        return ERROR

def log_exception():
    traceback.print_exc()

def main():
    s = serial.Serial("/dev/ttyUSB0", 19200)
    last_level = 3
    while 1:
        level = do_checks()
        if level or last_level: print level
        last_level = level
        try:
            s.write(chr(level))
        except KeyboardInterrupt:
            raise
        except:
            log_exception()
            try:
                s.close()
            except:
                pass
            try:
                s = serial.Serial("/dev/ttyUSB0", 19200)
            except:
                s = None
        time.sleep(.1)
main()