#ifndef CA_UWATERLOO_ALUMNI_DWHARDER_DISK_REQUEST_EVENT
#define CA_UWATERLOO_ALUMNI_DWHARDER_DISK_REQUEST_EVENT

// Author:  Douglas Wilhelm Harder
// Copyright (c) 2012 by Douglas Wilhelm Harder.  All rights reserved.

#include <iostream>
#include <iomanip>
#include <cassert>
#include "Marsaglia_polar.h"

#include "Support.h"

class Event {
	public:
		int request_time;
		int service_time;
		int track;
		int order;

		Event():service_time( 0 ), track( 0 ), order( 0 ) {
			// emtpy constructor;
		}
};

std::ostream &operator << ( std::ostream &out, Event const &eve ) {
	return out << std::right << std::setw( 3 ) << eve.order << ". "
	           << std::right << std::setw( 5 ) << eve.track << ": "
	           << std::right << std::setw( 7 ) << eve.request_time << " to "
	           << std::right << std::setw( 7 ) << eve.service_time;
}

void analyze( Event *event_list, int N ) {
	double s = 0;
	double ss = 0;

	for ( int i = 0; i < N; ++i ) {
		double d = event_list[i].service_time - event_list[i].request_time;
		s += d;
		ss += d*d;
	}

	double mean = s/N;

	std::cout << "Mean:                " << mean/1000.0 << " ms" << std::endl;
	std::cout << "Standard Deviation:  " << std::sqrt( ss/N - mean*mean )/1000.0 << " ms" << std::endl;
}

void print( Event *event_list, int N ) {
	std::cout << "vvvvvvvvvvvvvvvvvvvvvvvvvvvvvv" << std::endl;

	for ( int i = 0; i < N; ++i ) {
		std::cout << event_list[i] << std::endl;
	}

	std::cout << "^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^" << std::endl;
}

// Generate requests that are uniformly distributed across the tracks.

void generate_uniform_events( Event *event_list, int N, double mean_arrivals, int ntracks ) {
	event_list[0].request_time = 0;
	event_list[0].track = random_track( ntracks );

	for ( int i = 1; i < N; ++i ) {
		event_list[i].request_time = event_list[i - 1].request_time + random_exponential( mean_arrivals );
		event_list[i].track = random_track( ntracks );
	}
}

// Generate requests with a probability p that they are uniformly distributed across the tracks
// and probability 1 - p that they are targetted in one area.

void generate_uniform_and_targetted_events( Event *event_list, int N, double mean_arrivals, int ntracks, double probability, double stddev ) {
	assert( (0 <= probability) && (probability <= 1) );

	event_list[0].request_time = 0;
	event_list[0].track = random_track( ntracks );

	int mean = random_track( ntracks );

	for ( int i = 1; i < N; ++i ) {
		event_list[i].request_time = event_list[i - 1].request_time + random_exponential( mean_arrivals );

		if ( drand48() < probability ) {
			event_list[i].track = random_track( ntracks );
		} else {
			double dtrack = mean + stddev*Normal_distributions::Marsaglia_polar::randn();
			int itrack = static_cast<int>( dtrack );

			itrack = std::min( std::max( 0, itrack ), ntracks - 1 );

			event_list[i].track = itrack;
		}
	}
}

#endif