// JobQueue.h     Dave Reed      9/3/02
//
// JobQueue class, stores and manipulates CPU jobs
///////////////////////////////////////////////////////////////////////////////

#ifndef _JOB_QUEUE_
#define _JOB_QUEUE_

#include <fstream>
#include <strstream>
#include <string>
#include "Queue.h"
#include "PriorityQueue.h"
using namespace std;

enum JobStatus {OK, DONE, IO};

class JobQueue								
{									
  public:
	JobQueue(string filename);                // constructor
	bool JobsRemaining();                     // determines if any jobs in queue
	int GetCurrentID();                       // gets ID of current job
	int GetCurrentStart();                    // gets start time of current job
	void InterruptCurrentJob(int newStart);   // interrups current job, sets restart
	void RemoveCurrentJob();                  // removes current job from queue
	JobStatus ExecuteCurrentJob();            // executes current job one cycle
  private:
	class Job {
	  public:
	    int ID;
		Queue<int> bursts;
	};
	PriorityQueue<Job> jobQueue;
};


JobQueue::JobQueue(string filename)
// constructor: assumes filename contains data to be placed in queue
{
	ifstream infile(filename.c_str());

	char ch;
	int start, id, len;
	string line;
	while ((infile >> start >> ch >> id) && getline(infile, line)) {
		Job j;
		j.ID = id;

		istrstream istr(line.c_str());
		while (istr >> len) {
			j.bursts.Enter(len);
		}
		jobQueue.Enter(j, start);
	}
}


bool JobQueue::JobsRemaining()
// Returns: true if queue contains a job, false if empty
{
	return !jobQueue.IsEmpty();
}

int JobQueue::GetCurrentID()
// Returns: ID of current job (at front of queue)
{
    return jobQueue.Front().ID;
}

int JobQueue::GetCurrentStart()
// Returns: start time of current job (at front of queue)
{
    return jobQueue.FrontPriority();
}

void JobQueue::InterruptCurrentJob(int newStart)
// Results: replaces the current job in queue with new start time
{
	jobQueue.Enter(jobQueue.Front(), newStart);
	jobQueue.Remove();
}

void JobQueue::RemoveCurrentJob()
// Results: removes current job from queue
{
    jobQueue.Remove();
}

JobStatus JobQueue::ExecuteCurrentJob()
// Returns: status of executing current job for one cycle
{
	
	jobQueue.Front().bursts.Front()--;
	if (jobQueue.Front().bursts.Front() == 0) {
		jobQueue.Front().bursts.Remove();
		if (jobQueue.Front().bursts.IsEmpty()) {
			return DONE;
		}
		else {
			return IO;
		}
	}
	else {
		return OK;
	}
}

#endif