#! /usr/bin/env python

import sys
from optparse import OptionParser
import random

# finds the highest nonempty queue
# -1 if they are all empty
def FindQueue():
    q = hiQueue
    while q > 0:
        if len(queue[q]) > 0:
            return q
        q -= 1
    if len(queue[0]) > 0:
        return 0
    return -1

def LowerQueue(currJob, currQueue, issuedIO):
    if currQueue > 0:
        # in this case, have to change the priority of the job
        job[currJob]['currPri'] = currQueue - 1
        if issuedIO == False:
            queue[currQueue-1].append(currJob)
        job[currJob]['ticksLeft'] = quantum[currQueue-1]
    else:
        if issuedIO == False:
            queue[currQueue].append(currJob)
        job[currJob]['ticksLeft'] = quantum[currQueue]

def Abort(str):
    sys.stderr.write(str + '\n')
    exit(1)


#
# PARSE ARGUMENTS
#

parser = OptionParser()
parser.add_option('-s', '--seed', default=0, help='the random seed', 
                  action='store', type='int', dest='seed')
parser.add_option('-n', '--numQueues', help='number of queues in MLFQ (if not using -Q)', default=3, 
                  action='store', type='int', dest='numQueues')
parser.add_option('-q', '--quantum', help='length of time slice (if not using -Q)', default=10, 
                  action='store', type='int', dest='quantum')
parser.add_option('-Q', '--quantumList', help='length of time slice per queue level, specified as x,y,z,... where x is the quantum length for the highest priority queue, y the next highest, and so forth', 
                  default='', action='store', type='string', dest='quantumList')
parser.add_option('-j', '--numJobs', default=3, help='number of jobs in the system',
                  action='store', type='int', dest='numJobs')
parser.add_option('-m', '--maxlen', default=100, help='max run-time of a job (if randomly generating)',
                  action='store', type='int', dest='maxlen')
parser.add_option('-M', '--maxio', default=10, help='max I/O frequency of a job (if randomly generating)',
                  action='store', type='int', dest='maxio')
parser.add_option('-B', '--boost', default=0, help='how often to boost the priority of all jobs back to high priority',
                  action='store', type='int', dest='boost')
parser.add_option('-i', '--iotime', default=5, help='how long an I/O should last (fixed constant)',
                  action='store', type='int', dest='ioTime')
parser.add_option('-S', '--stay', default=False, help='reset and stay at same priority level when issuing I/O',
                  action='store_true', dest='stay')
parser.add_option('-I', '--iobump', default=False, help='if specified, jobs that finished I/O move immediately to front of current queue',
                  action='store_true', dest='iobump')
parser.add_option('-l', '--jlist', default='', help='a comma-separated list of jobs to run, in the form x1,y1,z1:x2,y2,z2:... where x is start time, y is run time, and z is how often the job issues an I/O request',
                  action='store', type='string', dest='jlist')
parser.add_option('-c', help='compute answers for me', action='store_true', default=False, dest='solve')

(options, args) = parser.parse_args()

random.seed(options.seed)


# MLFQ: How Many Queues
numQueues = options.numQueues

quantum = {}
if options.quantumList != '':
    # instead, extract number of queues and their time slic
    quantumLengths = options.quantumList.split(',')
    numQueues = len(quantumLengths)
    qc = numQueues - 1
    for i in range(numQueues):
        quantum[qc] = int(quantumLengths[i])
        qc -= 1
else:
    for i in range(numQueues):
        quantum[i] = int(options.quantum)

hiQueue = numQueues - 1

# MLFQ: I/O Model
# the time for each IO: not great to have a single fixed time but...
ioTime = int(options.ioTime)

# This tracks when IOs and other interrupts are complete
ioDone = {}

# This stores all info about the jobs
job = {}

# seed the random generator
random.seed(options.seed)

# jlist 'startTime,runTime,ioFreq:startTime,runTime,ioFreq:...'
jobCnt = 0
if options.jlist != '':
    allJobs = options.jlist.split(':')
    for j in allJobs:
        jobInfo = j.split(',')
        if len(jobInfo) != 3:
            sys.stderr.write('Badly formatted job string. Should be x1,y1,z1:x2,y2,z2:...\n')
            sys.stderr.write('where x is the startTime, y is the runTime, and z is the I/O frequency.\n')
            exit(1)
        assert(len(jobInfo) == 3)
        startTime = int(jobInfo[0])
        runTime   = int(jobInfo[1])
        ioFreq    = int(jobInfo[2])
        job[jobCnt] = {'currPri':hiQueue, 'ticksLeft':quantum[hiQueue], 'startTime':startTime,
                       'runTime':runTime, 'timeLeft':runTime, 'ioFreq':ioFreq, 'doingIO':False,
                       'firstRun':-1}
        if startTime not in ioDone:
            ioDone[startTime] = []
        ioDone[startTime].append((jobCnt, 'JOB BEGINS'))
        jobCnt += 1
else:
    # do something random
    for j in range(options.numJobs):
        startTime = 0
        runTime   = int(random.random() * options.maxlen)
        ioFreq    = int(random.random() * options.maxio)
        
        job[jobCnt] = {'currPri':hiQueue, 'ticksLeft':quantum[hiQueue], 'startTime':startTime,
                       'runTime':runTime, 'timeLeft':runTime, 'ioFreq':ioFreq, 'doingIO':False,
                       'firstRun':-1}
        if startTime not in ioDone:
            ioDone[startTime] = []
        ioDone[startTime].append((jobCnt, 'JOB BEGINS'))
        jobCnt += 1


numJobs = len(job)

print 'Here is the list of inputs:'
print 'OPTIONS jobs',            numJobs
print 'OPTIONS queues',          numQueues
for i in range(len(quantum)-1,-1,-1):
    print 'OPTIONS quantum length for queue %2d is %3d' % (i, quantum[i])
print 'OPTIONS boost',           options.boost
print 'OPTIONS ioTime',          options.ioTime
print 'OPTIONS stayAfterIO',     options.stay
print 'OPTIONS iobump',          options.iobump

print '\n'
print 'For each job, three defining characteristics are given:'
print '  startTime : at what time does the job enter the system'
print '  runTime   : the total CPU time needed by the job to finish'
print '  ioFreq    : every ioFreq time units, the job issues an I/O'
print '              (the I/O takes ioTime units to complete)\n'

print 'Job List:'
for i in range(numJobs):
    print '  Job %2d: startTime %3d - runTime %3d - ioFreq %3d' % (i, job[i]['startTime'],
                                                                   job[i]['runTime'], job[i]['ioFreq'])
print ''

if options.solve == False:
    print 'Compute the execution trace for the given workloads.'
    print 'If you would like, also compute the response and turnaround'
    print 'times for each of the jobs.'
    print ''
    print 'Use the -c flag to get the exact results when you are finished.\n'
    exit(0)

# initialize the MLFQ queues
queue = {}
for q in range(numQueues):
    queue[q] = []

# TIME IS CENTRAL
currTime = 0

# use these to know when we're finished
totalJobs    = len(job)
finishedJobs = 0

print '\nExecution Trace:\n'

while finishedJobs < totalJobs:
    # find highest priority job
    # run it until either
    # (a) the job uses up its time quantum
    # (b) the job performs an I/O

    # check for priority boost
    if options.boost > 0 and currTime != 0:
        if currTime % options.boost == 0:
            print '[ time %d ] BOOST ( every %d )' % (currTime, options.boost)
            # remove all jobs from queues (except high queue)
            for q in range(numQueues-1):
                for j in queue[q]:
                    if job[j]['doingIO'] == False:
                        queue[hiQueue].append(j)
                queue[q] = []
            # print 'BOOST: QUEUES look like:', queue

            # change priority to high priority
            # reset number of ticks left for all jobs (XXX just for lower jobs?)
            # add to highest run queue (if not doing I/O)
            for j in range(numJobs):
                # print '-> Boost %d (timeLeft %d)' % (j, job[j]['timeLeft'])
                if job[j]['timeLeft'] > 0:
                    # print '-> FinalBoost %d (timeLeft %d)' % (j, job[j]['timeLeft'])
                    job[j]['currPri']   = hiQueue
                    job[j]['ticksLeft'] = quantum[hiQueue]
            # print 'BOOST END: QUEUES look like:', queue

    # check for any I/Os done
    if currTime in ioDone:
        for (j, type) in ioDone[currTime]:
            q = job[j]['currPri']
            job[j]['doingIO'] = False
            print '[ time %d ] %s by JOB %d' % (currTime, type, j)
            if options.iobump == False:
                queue[q].append(j)
            else:
                queue[q].insert(0, j)

    # now find the highest priority job
    currQueue = FindQueue()
    if currQueue == -1:
        print '[ time %d ] IDLE' % (currTime)
        currTime += 1
        continue
    #print 'FOUND QUEUE: %d' % currQueue
    #print 'ALL QUEUES:', queue
            
    # there was at least one runnable job, and hence ...
    currJob = queue[currQueue][0]
    if job[currJob]['currPri'] != currQueue:
        Abort('currPri[%d] does not match currQueue[%d]' % (job[currJob]['currPri'], currQueue))

    job[currJob]['timeLeft']  -= 1
    job[currJob]['ticksLeft'] -= 1

    if job[currJob]['firstRun'] == -1:
        job[currJob]['firstRun'] = currTime

    runTime   = job[currJob]['runTime']
    ioFreq    = job[currJob]['ioFreq']
    ticksLeft = job[currJob]['ticksLeft']
    timeLeft  = job[currJob]['timeLeft']

    print '[ time %d ] Run JOB %d at PRIORITY %d [ TICKSLEFT %d RUNTIME %d TIMELEFT %d ]' % (currTime, currJob, currQueue, ticksLeft, runTime, timeLeft)

    if timeLeft < 0:
        Abort('Error: should never have less than 0 time left to run')


    # UPDATE TIME
    currTime += 1

    # CHECK FOR JOB ENDING
    if timeLeft == 0:
        print '[ time %d ] FINISHED JOB %d' % (currTime, currJob)
        finishedJobs += 1
        job[currJob]['endTime'] = currTime
        # print 'BEFORE POP', queue
        done = queue[currQueue].pop(0)
        # print 'AFTER POP', queue
        assert(done == currJob)
        continue

    # CHECK FOR IO
    issuedIO = False
    if ioFreq > 0 and (((runTime - timeLeft) % ioFreq) == 0):
        # time for an IO!
        print '[ time %d ] IO_START by JOB %d' % (currTime, currJob)
        issuedIO = True
        desched = queue[currQueue].pop(0)
        assert(desched == currJob)
        job[currJob]['doingIO'] = True
        # this does the bad rule -- reset your tick counter if you stay at the same level
        if options.stay == True:
            job[currJob]['ticksLeft'] = quantum[currQueue]
        # add to IO Queue: but which queue?
        futureTime = currTime + ioTime
        if futureTime not in ioDone:
            ioDone[futureTime] = []
        ioDone[futureTime].append((currJob, 'IO_DONE'))
        # print 'NEW IO EVENT at ', futureTime, ' is ', ioDone[futureTime]
        
    # CHECK FOR QUANTUM ENDING AT THIS LEVEL
    if ticksLeft == 0:
        # print '--> DESCHEDULE %d' % currJob
        if issuedIO == False:
            # print '--> BUT IO HAS NOT BEEN ISSUED (therefor pop from queue)'
            desched = queue[currQueue].pop(0)
        assert(desched == currJob)
        # move down one queue! (unless lowest queue)
        LowerQueue(currJob, currQueue, issuedIO)


# print out statistics
print ''
print 'Final statistics:'
responseSum   = 0
turnaroundSum = 0
for i in range(numJobs):
    response   = job[i]['firstRun'] - job[i]['startTime']
    turnaround = job[i]['endTime'] - job[i]['startTime']
    print '  Job %2d: startTime %3d - response %3d - turnaround %3d' % (i, job[i]['startTime'],
                                                                        response, turnaround)
    responseSum   += response
    turnaroundSum += turnaround

print '\n  Avg %2d: startTime n/a - response %.2f - turnaround %.2f' % (i, 
                                                                        float(responseSum)/numJobs,
                                                                        float(turnaroundSum)/numJobs)

print '\n'