#!/usr/bin/python

import os, sys, time, math
import rrdtool

from rrdui import *

# This entire module is nasty. Don't do this at home. It's a python interim
# replacement for a C daemon that needs writing. It's about the least efficient
# way to go about SNMP polling.

class Timer:
    def __init__(self, interval, cmds, item):
        self.interval = interval
        self.cmds = cmds
        self.item = item
        self.last = 0

def logMsg(msg):
    stamp = time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(time.time()))
    print >> sys.stderr, "%s: %s" % (stamp, msg)


def readItemValue(cmd):
    p = os.popen(cmd, "r")
    out = p.read()
    (pid, status) = os.wait()
    status = status >> 8

    try:
        p.close()
    except IOError:
        pass

    if status != 0:
        logMsg("WARNING: Couldn't query %s for %s" % (host, oid))
        out = "U"
    return out.strip()


def loadTimers(items):
    timers = []

    for item in items:
        (fields, interval) = item.getPollingInfo()

        if not len(fields):
            continue

        if interval < 10:
            logMsg("WARNING: Ignoring interval less than 10 seconds")
            interval = 10

        cmds = {}
        for fieldname in fields.keys():
            field = fields[fieldname]
            info = field.split("/")
            if len(info) != 4:
                logMsg("ERROR: Bad src format: %s" % field)
                sys.exit(1)
            if info[0] != "SNMP":
                logMsg("ERROR: Unknown src method: %s" % info[0])
                sys.exit(1)

            # TODO: Note that we don't check our arguments ...
            # Nasty and temporary untill we get the C daemon going
            cmd = "snmpget -c %s -Ov -OQ -v 2c %s %s" % (info[2], info[1], info[3])
            cmds[fieldname] = cmd

        timer = Timer(interval, cmds, item)
        timers.append(timer)

    return timers

def updateItem(timer):

    if not os.path.exists(timer.item.filedata):
        logMsg("WARNING: RRD file does not exist: %s" % timer.item.filedata)
        return

    values = {}
    for field in timer.cmds.keys():
        values[field] = readItemValue(timer.cmds[field])

    args = [timer.item.filedata, "--template", ":".join(values.keys()),
            "N:%s" % ":".join(values.values())]
    try:
        rrdtool.update(*args)
        print args
    except Error, e:
        logMsg("ERROR: Couldn't update RRD file: %s (args: %s)", e.value, args)



graphs = loadGraphs()
timers = loadTimers(graphs)

while True:

    # Update when and where necessary. Note we keep calling
    # time.time() as updating takes time
    for timer in timers:
        if (timer.last + timer.interval) < time.time():
            updateItem(timer)
            timer.last = time.time()

    # Now figure out how long to sleep
    next = 0
    for timer in timers:
        if not timer.last:
            continue
        if not next or (timer.last + timer.interval) < next:
            next = timer.last + timer.interval

    secs = next - time.time()
    print "%d %d %d" % (secs, next, time.time())
    if(secs > 0):
        print "sleeping for %d" % secs
        time.sleep(secs)