/*
    project: WestLB
    type: javascript
    description: image banner randomizer
    (c) Aperto AG 2004. All rights reserved.
*/

var currTime = new Date();
var myArray = new Array();
var rotateMode, currPos, bannerWidth;

function startRotation() {
    var output;

    if (myArray.length > 0) {
        if (rotateMode == "timebased") {
            getTimeBasedImage();
        } else if (rotateMode == "random") {
            getRandomizedImage();
        } else {
            output = "No rotation mode defined on given pagehandle";
        }
    } else {
        output = "No banners defined on given pagehandle";
    }

    /* make sure output really gets set. this is for the seldom case that currPos is undefined even
       when a mode is set. this thing needs review */
    if (!output && !currPos) {
        currPos = 0;
    }

    if (currPos >= 0) {
        output = '<img src=\"' + myArray[currPos].img + '\" alt=\"' + myArray[currPos].alttext + '\" style=\"' + myArray[currPos].imagestyle + '\" />';

        if (myArray[currPos].link) {
            output = '<a href=\"' + myArray[currPos].link + '\">' + output + '<\/a>';
        }
    }

    document.write(output);
}



function getRandomizedImage() {
    var hoursArray = new Array();
    
    for (var i = 0; i < 24; i++) {
        hoursArray[i] = i;
    }

    // evens out all percentages to 100%, in case total is != 100%
    getTotalPercentage();

    // shuffles the hoursArray to get the "random" effect
    shuffleHoursArray(hoursArray);
    
    // creates timeBins, which store hours for each banner to display. amount of hours is being determined by each images's given percentage of appearance
    createTimeBins(hoursArray);
}


function getTotalPercentage() {
    var totalPercentage = 0;

    for (var j = 0; j < myArray.length; j++) {
        totalPercentage += myArray[j].seed;
    }

    if (totalPercentage != 100) {
        var multiplier = 100 / totalPercentage;
        for (var k = 0; k < myArray.length; k++) {
            myArray[k].seed = (myArray[k].seed * multiplier).toFixed();
        }
    }
}


function shuffleHoursArray(hoursArray) {
    var temp = 0;
    var newDay = 0;

    for (var i = 0; i < hoursArray.length; i++) {
        newDay = (Math.random() * hoursArray.length-1) + 1;
        newDay = parseInt(newDay, 10);
        temp = hoursArray[i];
        hoursArray[i] = hoursArray[newDay];
        hoursArray[newDay] = temp;
    }
}


function createTimeBins(hoursArray) {
    var currHour = currTime.getHours();
    var binHours = 0;
    var tmpBinName;

    for (var i in myArray) {
        binHours = (24/100 * myArray[i].seed).toFixed();
        tmpBinName = new Array();
        for (var j = 0; j < binHours; j++) {
            tmpBinName[j] = hoursArray.shift();
            if (tmpBinName[j] == currHour) {
                currPos = i;
            }
        }
    }
}


function getTimeBasedImage() {
    var referenceTime = new Date();
    referenceTime.setHours(0, 0, 0);

    // calculate elapsed time
    var timeDiff = currTime.getHours() - referenceTime.getHours();

    // decrease elapsed time by set seed values in the array till now and store last arrayPosition to remember image
    while (timeDiff > 0) {
        for (var i in myArray) {
            if (timeDiff < 0) break;
            timeDiff = timeDiff - myArray[i].seed;
            currPos = i; // count where we are while iterating through myArray
        }
    }
}