/*
 * This file is a part of Winix
 * and is distributed under the 2-Clause BSD licence.
 * Author: Tomasz Sowa <t.sowa@ttmath.org>
 */

/* 
 * Copyright (c) 2008-2018, Tomasz Sowa
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 */

#include "loadavg.h"
#include "misc.h"



namespace Winix
{



LoadAvg::LoadAvg()
{
	current1.Clear();
	current5.Clear();
	current15.Clear();

	cache_load1  = 0.0;
	cache_load5  = 0.0;
	cache_load15 = 0.0;

	cache_req_per_sec1  = 0.0;
	cache_req_per_sec5  = 0.0;
	cache_req_per_sec15 = 0.0;

	timespec_old_req_stop.tv_sec = 0;
	timespec_old_req_stop.tv_nsec = 0;

	CreateTable();
}


LoadAvg & LoadAvg::operator=(const LoadAvg & l)
{
	current1  = l.current1;
	current5  = l.current5;
	current15 = l.current15;

	cache_load1  = l.cache_load1;
	cache_load5  = l.cache_load5;
	cache_load15 = l.cache_load15;

	cache_req_per_sec1  = l.cache_req_per_sec1;
	cache_req_per_sec5  = l.cache_req_per_sec5;
	cache_req_per_sec15 = l.cache_req_per_sec15;

	timespec_old_req_stop.tv_sec = l.timespec_old_req_stop.tv_sec;
	timespec_old_req_stop.tv_nsec = l.timespec_old_req_stop.tv_nsec;

	CreateTable();

return *this;
}


LoadAvg::LoadAvg(const LoadAvg & l)
{
	operator=(l);
}


LoadAvg::~LoadAvg()
{
	delete [] tab1;
	delete [] tab5;
	delete [] tab15;
}



void LoadAvg::CreateTable(size_t seconds, size_t granularity, Times* & tab, size_t & len)
{
	len = (seconds / granularity) + 1; // rounding up (len mininum is 1)
	tab = new Times[len];

	for(size_t i=0 ; i<len ; ++i)
	{
		tab[i].Clear();
		tab[i].dp = granularity; // at the beginning we assume the pause for all items
	}
}


void LoadAvg::CreateTable()
{
	CreateTable(60,      WINIX_LOADAVG_GRANULARITY1,  tab1,  len1);
	CreateTable(60 * 5,  WINIX_LOADAVG_GRANULARITY5,  tab5,  len5);
	CreateTable(60 * 15, WINIX_LOADAVG_GRANULARITY15, tab15, len15);
}



void LoadAvg::MoveTab(Times * tab, size_t len)
{
	if( len > 1 )
	{
		for(size_t i=0 ; i<len-1 ; ++i)
			tab[i] = tab[i+1];
	}

	tab[len-1].Clear();
}


void LoadAvg::UpdateTimer1()
{
	MoveTab(tab1, len1);

	tab1[len1-1] = current1;
	current1.Clear();
	cache_load1 = 0.0;
	cache_req_per_sec1 = 0.0;
}


void LoadAvg::UpdateTimer5()
{
	MoveTab(tab5, len5);

	tab5[len5-1] = current5;
	current5.Clear();
	cache_load5 = 0.0;
	cache_req_per_sec5 = 0.0;
}



void LoadAvg::UpdateTimer15()
{
	MoveTab(tab15, len15);

	tab15[len15-1] = current15;
	current15.Clear();
	cache_load15 = 0.0;
	cache_req_per_sec15 = 0.0;
}


void LoadAvg::CheckTimers()
{
	if( current1.dr + current1.dp > (double)WINIX_LOADAVG_GRANULARITY1 )
		UpdateTimer1();

	if( current5.dr + current5.dp > (double)WINIX_LOADAVG_GRANULARITY5 )
		UpdateTimer5();

	if( current15.dr + current15.dp > (double)WINIX_LOADAVG_GRANULARITY15 )
		UpdateTimer15();
}




void LoadAvg::StartRequest(Request * req)
{
	if( timespec_old_req_stop.tv_sec != 0 )
	{
		// we got at least one request in the past
		timespec diff;
		calculate_timespec_diff(timespec_old_req_stop, req->timespec_req_start, diff);
		double dp = timespec_to_double(diff);

		current1.dp  += dp;
		current5.dp  += dp;
		current15.dp += dp;

		CheckTimers();
	}
}





void LoadAvg::StopRequest(Request * req)
{
	double dr = timespec_to_double(req->timespec_req_diff);

	current1.dr  += dr;
	current5.dr  += dr;
	current15.dr += dr;

	current1.req  += 1;
	current5.req  += 1;
	current15.req += 1;

	timespec_old_req_stop = req->timespec_req_stop;
}


void LoadAvg::SumTab(Times * tab, size_t len, double expected, Times & t)
{
	size_t i = len;

	while( i-- > 0 && t.dr+t.dp < expected )
	{
		t.dr  += tab[i].dr;
		t.dp  += tab[i].dp;
		t.req += tab[i].req;
	}
}


void LoadAvg::Calculate1()
{
Times t = current1;

	SumTab(tab1, len1, 60.0, t);

	if( t.dr+t.dp == 0.0 )
	{
		cache_load1        = 0.0;
		cache_req_per_sec1 = 0.0;
	}
	else
	{
		cache_load1        = t.dr  / (t.dr+t.dp);
		cache_req_per_sec1 = t.req / (t.dr+t.dp);
	}
}


void LoadAvg::Calculate5()
{
Times t = current5;

	SumTab(tab5, len5, 60.0 * 5, t);

	if( t.dr+t.dp == 0.0 )
	{
		cache_load5        = 0.0;
		cache_req_per_sec5 = 0.0;
	}
	else
	{
		cache_load5        = t.dr  / (t.dr+t.dp);
		cache_req_per_sec5 = t.req / (t.dr+t.dp);
	}
}


void LoadAvg::Calculate15()
{
Times t = current15;

	SumTab(tab15, len15, 60.0 * 15, t);

	if( t.dr+t.dp == 0.0 )
	{
		cache_load15        = 0.0;
		cache_req_per_sec15 = 0.0;
	}
	else
	{
		cache_load15        = t.dr  / (t.dr+t.dp);
		cache_req_per_sec15 = t.req / (t.dr+t.dp);
	}
}


double LoadAvg::LoadAvgNow()
{
double load = 0.0;

	double dr = current1.dr;
	double dp = current1.dp;

	if( tab1[len1-1].dr + tab1[len1-1].dp < WINIX_LOADAVG_GRANULARITY1 * 2 )
	{
		dr  += tab1[len1-1].dr;
		dp  += tab1[len1-1].dp;
	}

	if( dr + dp != 0.0 )
		load = dr / (dr + dp);

return load;
}



double LoadAvg::LoadAvg1()
{
	if( cache_load1 != 0.0 )
		return cache_load1;

	Calculate1();

return cache_load1;
}


double LoadAvg::LoadAvg5()
{
	if( cache_load5 != 0.0 )
		return cache_load5;

	Calculate5();

return cache_load5;
}


double LoadAvg::LoadAvg15()
{
	if( cache_load15 != 0.0 )
		return cache_load15;

	Calculate15();

return cache_load15;
}



double LoadAvg::ReqPerSecNow()
{
double req_per_sec = 0.0;

	double dr  = current1.dr;
	double dp  = current1.dp;
	double req = current1.req;

	if( tab1[len1-1].dr + tab1[len1-1].dp < WINIX_LOADAVG_GRANULARITY1 * 2 )
	{
		dr  += tab1[len1-1].dr;
		dp  += tab1[len1-1].dp;
		req += tab1[len1-1].req;
	}

	if( dr + dp != 0.0 )
		req_per_sec = req / (dr + dp);

return req_per_sec;
}


double LoadAvg::ReqPerSec1()
{
	if( cache_req_per_sec1 != 0.0 )
		return cache_req_per_sec1;

	Calculate1();

return cache_req_per_sec1;
}


double LoadAvg::ReqPerSec5()
{
	if( cache_req_per_sec5 != 0.0 )
		return cache_req_per_sec5;

	Calculate5();

return cache_req_per_sec5;
}


double LoadAvg::ReqPerSec15()
{
	if( cache_req_per_sec15 != 0.0 )
		return cache_req_per_sec15;

	Calculate15();

return cache_req_per_sec15;
}



} // namespace Winix