#!/usr/bin/python
from time import time
from os import getloadavg
import logging #TODO be more precise
#import pdb

class probe(object):
    """"
        An atomic measurment

        Consists of name, value and unit. Unit is optional, althought when
        available it is highly recommended to state it; bd default it is set
        to "".
    """
    def __init__(self, name, value, unit=""):
        self.name = name
        self.time = time()
        self.value = value
        self.unit = unit

class survey(object):
    """
        A survey skeleton  - a survey is a probe container.

        Inherit from this class if you want to create your on Survey. 
        "Implement" update by any means.
    """
    def __init__(self):
        self.probe = [] #just to let you know
        self.update()
        self.name = 'Generic Survey'
        
    def update(self):
        """
            Updates the list of probes

            Empty list of probes first and fill it with new ones afterwards
        """
        pass 
    
class display(object):
    """
        A display skeleton - a display updates and displays surveys
        
        Inherit from this class if you want to create your own display
        Implement display.
    """
    def __init__(self):
        self.survey = []

    def update(self):
        for s in self.survey:
           s.update()

    def display(self):
        """ 
            Displays self.survey items
            
            Don't forget to add some surveys first and update them as needed
        """
        pass

class surveyLoad(survey):
    """ Surveys unix load average """
    def __init__(self):
        super(surveyLoad,self).__init__() #call superconstructor
        self.name = 'Load Survey'

    def update(self):
        self.probe = []
        try: 
            self.load = getloadavg()
            self.probe.append(probe('lastminute',self.load[0]))
            self.probe.append(probe('last5minute',self.load[1]))
            self.probe.append(probe('last15minute',self.load[2]))
        except Exception, ex:
            logging.exception("Error ocurred while probing %s" % self.__class__.__name__)
            pass

class surveyFree(survey):
#TODO it's just a quick hack; might not work too well
    """ Primitive memory survey"""
    def __init__(self):
        super(surveyFree,self).__init__()
        self.name = 'Simple Memory Survey'
    
    def update(self):
        self.probe = []
        try:
            f = open('/proc/meminfo', "r")
            self.probe.append(self.parseline(f.next()))
            self.probe.append(self.parseline(f.next()))
            f.next() #skip Buffer
            self.probe.append(self.parseline(f.next()))
            f.close()
            self.probe.append(probe("Effective free memory",
                                     self.probe[1].value + self.probe[2].value, 'kb'))
        except Exception, ex:
            logging.exception("Error ocurred while probing %s" % self.__class__.__name__)
            pass

    def parseline(self, memline):
        tmp = memline.partition(' ')
        name = tmp[0].rstrip(':')
        tmp = tmp[2].lstrip(' ').partition(' ')
        value = int(tmp[0])
        unit = tmp[2].rstrip('\n')
        return probe(name,value,unit)


class displaycli(display):
    """ "Dumps" survey to standard out """
    def display(self):
        for s in self.survey:
            s.update()
            print "Name: %s" % s.name
            for p in s.probe:
                print "%s  \t%s %s" % (p.name,p.value,p.unit)
            print ""

if __name__ == "__main__":
    dis = displaycli()
    dis.survey.append(surveyLoad())
    dis.survey.append(surveyLoad())
    dis.survey.append(surveyFree())
    dis.display()
#pdb.set_trace()