function exampleSmall( )
{
//pop some example values in the boxes
document.getElementById('costPanels').value="3822";
document.getElementById('costInverter').value="1182";
document.getElementById('costMounts').value="600";
document.getElementById('costMisc').value="400";
document.getElementById('costLabour').value="2400";
document.getElementById('wattsPeak').value="1600";
document.getElementById('rateArray').value="0.6";
document.getElementById('rateAssets').value="4";
document.getElementById('rateElectricity').value="5";
document.getElementById('initialDepreciation').value="25";
document.getElementById('avOutput').value="900";
document.getElementById('tariff').value="41.3";
document.getElementById('priceBought').value="11";
document.getElementById('priceSold').value="3";
document.getElementById('exportProportion').value="0.5";


//...and don't forget to do the calculation
updatevalues()}

function exampleMedium( )
{
//pop some example values in the boxes
document.getElementById('costPanels').value="8271";
document.getElementById('costInverter').value="1976";
document.getElementById('costMounts').value="900";
document.getElementById('costMisc').value="500";
document.getElementById('costLabour').value="3100";
document.getElementById('wattsPeak').value="3500";
document.getElementById('rateArray').value="0.6";
document.getElementById('rateAssets').value="4";
document.getElementById('rateElectricity').value="5";
document.getElementById('initialDepreciation').value="25";
document.getElementById('avOutput').value="900";
document.getElementById('tariff').value="41.3";
document.getElementById('priceBought').value="11";
document.getElementById('priceSold').value="3";
document.getElementById('exportProportion').value="0.5";


//...and don't forget to do the calculation
updatevalues()}

function exampleLarge( )
{
//pop some example values in the boxes
document.getElementById('costPanels').value="22869";
document.getElementById('costInverter').value="4928";
document.getElementById('costMounts').value="1800";
document.getElementById('costMisc').value="600";
document.getElementById('costLabour').value="4100";
document.getElementById('wattsPeak').value="9800";
document.getElementById('rateArray').value="0.6";
document.getElementById('rateAssets').value="4";
document.getElementById('rateElectricity').value="5";
document.getElementById('initialDepreciation').value="25";
document.getElementById('avOutput').value="900";
document.getElementById('tariff').value="36.1";
document.getElementById('priceBought').value="11";
document.getElementById('priceSold').value="3";
document.getElementById('exportProportion').value="0.5";


//...and don't forget to do the calculation
updatevalues()}

function examplePVL( )
{
//pop some example values in the boxes
document.getElementById('costPanels').value="8000";
document.getElementById('costInverter').value="1500";
document.getElementById('costMounts').value="000";
document.getElementById('costMisc').value="400";
document.getElementById('costLabour').value="2500";
document.getElementById('wattsPeak').value="3500";
document.getElementById('rateArray').value="0.9";
document.getElementById('rateAssets').value="4";
document.getElementById('rateElectricity').value="5";
document.getElementById('initialDepreciation').value="25";
document.getElementById('avOutput').value="900";
document.getElementById('tariff').value="41.3";
document.getElementById('priceBought').value="11";
document.getElementById('priceSold').value="3";
document.getElementById('exportProportion').value="0.5";


//...and don't forget to do the calculation
updatevalues()}

function exampleSanyo( )
{
//pop some example values in the boxes
document.getElementById('costPanels').value="5680";
document.getElementById('costInverter').value="1381";
document.getElementById('costMounts').value="800";
document.getElementById('costMisc').value="200";
document.getElementById('costLabour').value="2000";
document.getElementById('wattsPeak').value="1800";
document.getElementById('rateArray').value="0.6";
document.getElementById('rateAssets').value="4";
document.getElementById('rateElectricity').value="5";
document.getElementById('initialDepreciation').value="25";
document.getElementById('avOutput').value="900";
document.getElementById('tariff').value="41.3";
document.getElementById('priceBought').value="11";
document.getElementById('priceSold').value="3";
document.getElementById('exportProportion').value="0.5";


//...and don't forget to do the calculation
updatevalues()}

function showhelp ( )
{
//pop some example values in the boxes
document.getElementById('results').innerHTML="<p>The best guess you can!";
}

function clearform ( )
{
//pop some example values in the boxes
document.getElementById('name1').value="";
document.getElementById('hours1').value="";
document.getElementById('watts1').value="";

//...and don't forget to do the calculation
updatevalues()}

function totalcost() 
{
costTotal=Math.round(
(1*document.getElementById('costPanels').value)
+(1*document.getElementById('costInverter').value)
+(1*document.getElementById('costMounts').value)
+(1*document.getElementById('costMisc').value)
+(1*document.getElementById('costLabour').value));
document.getElementById('costTotal').value= costTotal;
}

function updatevalues ()
{
//rates of change
initialDepreciation = 1-(0.01*document.getElementById('initialDepreciation').value);
assetDepreciationRate = 1-(0.01*document.getElementById('rateAssets').value);
electricityAppreciationRate = 1+(0.01*document.getElementById('rateElectricity').value);
arrayDegradationRate = 1-(0.01*document.getElementById('rateArray').value);

// work out total installation cost - the sum of the components and labour
if (!document.getElementById('annualOutput')){totalcost();}
costTotal=Math.round((1*document.getElementById('costTotal').value));

initialAssetValue=Math.round(
(initialDepreciation*document.getElementById('costPanels').value)
+(initialDepreciation*document.getElementById('costInverter').value));
//document.getElementById('initialAssetValue').value= initialAssetValue;


//work out annual output - the efficiency of the array multiplied by the peak power
if (document.getElementById('annualOutput'))
{
  annualOutput = document.getElementById('annualOutput').value;
  if (annualOutput <= 4000) {tariff = 0.01*41.3;}
  else if (annualOutput > 4000 && annualOutput <= 10000) {tariff = 0.01*36.1;}
  else {tariff = 0.001;}
  priceSold = 0.01*3;
}
else
{
  annualOutput = Math.round(0.001*document.getElementById('wattsPeak').value*document.getElementById('avOutput').value*document.getElementById('orientationFactor').value*document.getElementById('shadingFactor').value);
  //document.getElementById('annualOutput').value= annualOutput;
  tariff = 0.01*document.getElementById('tariff').value;
  priceSold = 0.01*document.getElementById('priceSold').value;
}
initialAnnualOutput = annualOutput;

//initial values
exportProportion = document.getElementById('exportProportion').value;
annualCost = Math.round(costTotal);
netProfit = 0;
assetValue = initialAssetValue;
priceBought = 0.01*document.getElementById('priceBought').value;
bankBalance = costTotal;
incomeInterest = 0;

//arrays for chart
var incomeFITArray = new Array();
var incomeSavedArray = new Array();
var incomeSoldArray = new Array();
incomeFITArray = [[0, 0]];
incomeSavedArray = [[0, 0]];
incomeSoldArray = [[0, 0]];


accumulatedIncome=0;
accumulatedCosts=0;
//start to make the table - here are the header rows:


outputtableable = '<table id="outputtable" class="data"><thead><tr class="headerrow"><td>year</td><td>income / savings<span class="help">?<span class="morehelp">This is the sum of income from the Feed-in Tariff, plus electricity sold to the national grid, plus money saved by electricity generated by the system that is used within the building.<br> Hover over each cell to see a breakdown of the income.</span></span></td><td>annual return<span class="help">?<span class="morehelp">This gives the &#37; return each year you get in income and savings compared to the initial cost of the investment.</span></span></td><td>asset value<span class="help">?<span class="morehelp">This is an estimate of what the system would be worth at any point if you decided to take it off your house and sell it secondhand.</span></span></td><td>net profit / loss<span class="help">?<span class="morehelp">This is the value of the system, plus all accumulated income from the system, minus the original cost of installing the system. It will initially be negative - at the break-even point where the font turns green, the system has paid for itself.</span></span></td></tr></thead><tbody>';


//now calculate for all subsequent years


for (year=1;year<=25;year++)
{
//first work out the outputs for the current year
incomeSaved = Math.round(priceBought*annualOutput*(1-exportProportion));		//amount not spent on electricity
incomeSold = Math.round(priceSold*annualOutput*exportProportion);			//payments for electricity sold
incomeFIT = Math.round(tariff*annualOutput);						//income from FIT
incomeTotal = incomeSaved+incomeSold+incomeFIT;						//sum of above income
accumulatedIncome = (1*accumulatedIncome)+incomeTotal;					//accumulated total from one year to next.
accumulatedCosts = (1*accumulatedCosts)+annualCost;					//total costs of system so far
netProfit = Math.round((1*assetValue)-(1*accumulatedCosts) + (1*accumulatedIncome));	//Assets - accumulated costs + accumulated Income
effectiveReturn = Math.round(1000*incomeTotal/costTotal)/10;
//bankProfit[year] = bankBalance-costTotal;

//bankBalancePV = Math.round((1*accumulatedIncome)-(1*accumulatedCosts));			//amount in a bank balance from profits
//if (bankBalancePV<0) {bankBalancePV=0;};
//incomeInterest = Math.round((bankBalancePV*bankInterestRate)-bankBalancePV);


//create some arrays for the graphs
//tempArray[year-1] = [year, incomeFIT];
incomeFITArray[year] = [year, incomeFIT];
incomeSavedArray[year] = [year, incomeSaved+incomeFIT];
incomeSoldArray[year] = [year, incomeSold+incomeSaved+incomeFIT];

if (netProfit<0) {colorClass="red";} else {colorClass="green";};
//if (netProfit>bankProfit[year]) {colorClass="greenbold";};


outputrow = '<tr><td>'+year+'</td><td class="mouseover"><span style="text-align:center; display:block;width:120px;">&pound; '+incomeTotal+'</span><div class="hidden"><b>Comprises:</b><br>income from FIT: &pound; '+incomeFIT+'<br>electricity saved: &pound; '+incomeSaved+'<br>electricity sold: &pound; '+incomeSold+'<br></div></td><td>'+effectiveReturn+' &#37;</td><td>&pound; '+assetValue+'</td><td class="'+colorClass+'">&pound; '+netProfit+'</td></tr>';
outputtableable = outputtableable+outputrow;
//then allow for rates of change of all the variables
annualCost = 0;
assetValue = Math.round(assetValue*assetDepreciationRate);
//tariff = tariff*tariffDepreciationRate;
priceBought = priceBought*electricityAppreciationRate;
priceSold = priceSold*electricityAppreciationRate;
annualOutput = Math.round(annualOutput*arrayDegradationRate);
//bankBalance = Math.round(bankBalance*bankInterestRate);
}

outputtableable = outputtableable+'</tbody></table>';
document.getElementById('outputtable').innerHTML = outputtableable;

//and do the funky graph thing - sort out later weh have put the outputs into some sort of appropriate array.
// var layout = new Layout("line");
//layout.addDataset("Sold", incomeSoldArray);
//layout.addDataset("Saved", incomeSavedArray);
//layout.addDataset("FIT", incomeFITArray);
//       layout.evaluate();
        
//        var chart = new SweetCanvasRenderer($("chart"), layout);
//        chart.render();

document.getElementById('results').innerHTML="<p>Based on what you have entered, we calculate your array will initally output around <b>"+initialAnnualOutput+" kWh per year</b>.  As panels degrade very slowly over time, after 25 years that will have dropped to around <b>"+annualOutput+" kWh each year</b>.<p>The total cost of installing the system was <b>&pound;"+costTotal+"</b>. As an asset, it would initially be worth approximately <b>&pound;"+initialAssetValue+"</b>, and would then gradually depreciate in value.  The asset value column below gives an indication of how the system value may change over time.<p>You can also see the income and savings you can expect from the system. The annual income is comprised of the earnings from the Feed-in Tariff itself, and from selling electricity to the grid. You also save money by using electricity that you would otherwise have had to buy from the grid. If you hover over the figures in the income column you will see a breakdown.<p>The annual return column shows the percentage return each year on your initial investment. and the net profit/loss column shows the cumulative income from the system plus the current asset value of the system, minus the cost of installation. Initially this will be negative, but will at some point break even.";


//document.getElementById('chartheader').innerHTML="<p>The graph below shows annual income from the feed-in tariff (light blue), savings from offset electricity (medium blue) and income from exported electricity (dark blue) over the 25 year lifetime of the feed-in tariff. The feed-in tariff income will very slowly drop as the array degrades, but as the price of electricity is highly likely to rise significantly over the next 25 years, the amount you will get for electricity sold (or amount saved if used in-house) is likely to increase at a faster rate, giving a higher income in later years.";
}