var settings = {
    'force_size':           1,              //  if set to 1 all banners will be resized to the width and height in the next to settings
    'img_width':            938,            //  width to resize all banners to, only takes effect if above is 1
    'img_height':           383,             //  height to resize all banners to, only takes effect if above is 1
    'refresh_time':         5000,           //  the seconds between refreshs of the banners - use 0 to disable
    'refresh_max':          1000,           //  maximum number of refreshs on each page load
    'duplicate_banners':    1,              //  keep as 0 to make sure the same banner won't show on the same page. will only take effect
                                            //  if show_banners(); is used more than once. You must make sure you have enough banners to fill
                                            //  all the slots else the browser may freeze or give a stack overflow error
    'location_prefix':      'adLocation-',  //  The prefix of the IDs of the <div> which wraps the banners - this div is generated dynamically.
                                            //  a number will be added on the end of this string. adLocation- was used by default before version 1.4.x
    'location_class':       'swb',          //  A class to add to all of the <div>s which wrap the banners, ideal to use for styling banners - use .swb img in your CSS 
    'window':               '_self',        //  Window to open links in, _self = current, _blank = new. Use _top if in a frame!     
    'default_ad_loc':       'default'       //  The default adLocation. This is assigned to any banners not given an adLocation in the below banner list
                                            //  There is no real reason to need to change this
}

var prev             = 0;
var used             = 0;
var location_counter = 0;
var refresh_counter  = 1;
var map              = new Array();
var banners          = new Array();

function addBanner(i, name, url, image, date, loc) {
    banners[i] = new banner(name, url, image, date, loc);
}

/**
 * creates a banner object
 */
function banner(name, url, image, date, loc) {
    this.name   = name;
    this.url    = url;
    this.image  = image;
    this.date   = date;
    this.active = 1;
    this.oid = 0;
    
    // if no adlocation is given use the default a adlocation setting
    // this is used if adlocations aren't being used or using pre-1.4.x code
    if(loc != '')
    {
        this.loc = loc;
    }
    else
    {
        this.loc = settings.default_ad_loc;
    }
}

/**
 * writes banner <div> HTML and maps ad locations to <div> ID tags
 */
function show_banners(banner_location) {
    // increase the counter ready for further calls
    location_counter = location_counter + 1;

    // this part maps the adlocation name supplied by the user to the adlocation
    // ID used by the script
    if(banner_location != '' && banner_location != undefined){
        map[location_counter] = banner_location;
    }
    else{
        map[location_counter] = settings.default_ad_loc;
    }

    // writes banner html
    var html = '<div id="' + settings.location_prefix + location_counter + '" class="' + settings.location_class + '"></div>';
    document.write(html);
    // calls the display banners script to fill this ad location
    display_banners(location_counter);
}

/**
 * displays banners for a given location number
 */
function display_banners(location) {
    // used in this function to hold tempoary copy of banners array
    var location_banners = new Array();
    
    // if no location is given, do nothing
    if(location == '' || !location || location < 0) {
        return;
    }
    
    // get total banners
    var am = banners.length;
    
    // all banners have been displayed in this pass and the user doesnt
    // want to have duplicate banners showing
    if((am == used) && settings.duplicate_banners == 0) {
        return;
    }

    // new for 1.4.x, this takes the list of banners and creates a tempoary list
    // with only the banners for the current adlocation in
    for(i = 0; i < (banners.length); i++) {
        banners[i].oid = i;
        if((banners[i].loc == map[location]) && (banners[i].active == 1)) {
            location_banners.push(banners[i]);
        }
    }

    // same as 1.2.x - finds the banner randomly
    var rand = Math.floor(Math.random()*location_banners.length);

    while (prev == rand){
        var rand = Math.floor(Math.random()*location_banners.length);
    }
    prev = rand;
    var bn = location_banners[rand];
    
    // creates html
    var image_size  = (settings.force_size == 1) ? ' width="' + settings.img_width + '" height="' + settings.img_height + '"' : '';
    var html        = '<a href="' + bn.url + '" title="' + bn.name + '" target="' + settings.window + '"><img border="0" src="' + bn.image + '"' + image_size + ' alt="' + bn.name + '" /></a>';
    
    // calculates the date from inputted string, expected formate is DD/MM/YYYY
    var now     = new Date(); 
    var input   = bn.date;
    input       = input.split('/', 3);
    
    // creates a date object with info
    var end_date    = new Date();
    end_date.setFullYear(parseInt(input[2]), parseInt(input[1]) - 1, parseInt(input[0]));
    
    // compares curent date with banner end date
    if((now < end_date) && bn.active == 1) {
        // attempt to find adlocation div
        var location_element = document.getElementById(settings.location_prefix + location);
        
        // couldn't find it, if this message shows there is a problem with show_banners
        if(location_element == null) {
            alert('spyka Webmaster banner rotator\nError: adLocation doesn\'t exist!');
        }
        // output banner HTML
        else {
            location_element.innerHTML = html;
            
            // if the user doesn't want the same banner to show again deactive it and increase
            // the users banners counter
            if(settings.duplicate_banners == 0) {
                banners[bn.oid].active = 0;
                used++;
            }
            return;
        }
    }
    else {
        // inactive banner, find another
        // if no banners fit this adlocation you'll have an endless loop !
//        display_banners(location);
    }
    return;
}

/**
 * resets counters and active settings
 */
function refresh_banners() {
    if((refresh_counter == settings.refresh_max) || settings.refresh_time < 1) {
        clearInterval(banner_refresh);  
    }
    used = 0;
    for(j = 0; j < (banners.length); j++) {
        banners[j].active = 1;
    }

    for(j = 1; j < (location_counter+1); j++) {
        display_banners(j);
    }
    refresh_counter++;
}

// set timeout
var banner_refresh = window.setInterval(refresh_banners, settings.refresh_time);