/**************************************************
    * Filename.......: calendar.js                    *
    * Project........: Popup Calendar                 *
    * Last Modified..: 16th January 2011              *
    * Copyright......: 2011 Richard Heyes             *
    * License........: http://www.phpguru.org/license *
    **************************************************/

    /**
    * Global variables
    */
    dynCalendar_layers          = new Array();
    dynCalendar_mouseoverStatus = false;
    dynCalendar_mouseX          = 0;
    dynCalendar_mouseY          = 0;

    /**
    * The calendar constructor
    *
    * @access public
    * @param string objName      Name of the object that you create
    * @param string callbackFunc Name of the callback function
    * @param string OPTIONAL     Optional layer name
    * @param string OPTIONAL     Optional images path
    */
    function dynCalendar(objName, callbackFunc)
    {
        /**
        * Properties
        */
        // Todays date
        this.today          = new Date();
        this.date           = this.today.getDate();
        this.month          = this.today.getMonth();
        this.year           = this.today.getFullYear();

        this.objName        = objName;
        this.callbackFunc   = callbackFunc;
        this.imagesPath     = arguments[2] ? arguments[2] : '/images/';
        this.layerID        = arguments[3] ? arguments[3] : 'dynCalendar_layer_' + dynCalendar_layers.length;

        this.offsetX        = 5;
        this.offsetY        = 5;

        this.useMonthCombo  = true;
        this.useYearCombo   = true;
        this.yearComboRange = 5;

        this.currentMonth   = this.month;
        this.currentYear    = this.year;

        /**
        * Public Methods
        */
        this.show              = dynCalendar_show;
        this.writeHTML         = dynCalendar_writeHTML;

        // Accessor methods
        this.setOffset         = dynCalendar_setOffset;
        this.setOffsetX        = dynCalendar_setOffsetX;
        this.setOffsetY        = dynCalendar_setOffsetY;
        this.setImagesPath     = dynCalendar_setImagesPath;
        this.setMonthCombo     = dynCalendar_setMonthCombo;
        this.setYearCombo      = dynCalendar_setYearCombo;
        this.setCurrentMonth   = dynCalendar_setCurrentMonth;
        this.setCurrentYear    = dynCalendar_setCurrentYear;
        this.setYearComboRange = dynCalendar_setYearComboRange;

        /**
        * Private methods
        */
        // Layer manipulation
        this._getLayer         = dynCalendar_getLayer;
        this._hideLayer        = dynCalendar_hideLayer;
        this._showLayer        = dynCalendar_showLayer;
        this._setLayerPosition = dynCalendar_setLayerPosition;
        this._setHTML          = dynCalendar_setHTML;

        // Miscellaneous
        this._getDaysInMonth   = dynCalendar_getDaysInMonth;
        this._mouseover        = dynCalendar_mouseover;

        /**
        * Constructor type code
        */
        dynCalendar_layers[dynCalendar_layers.length] = this;
        this.writeHTML();
    }

    /**
    * Shows the calendar, or updates the layer if
    * already visible.
    *
    * @access public
    * @param integer month Optional month number (0-11)
    * @param integer year  Optional year (YYYY format)
    */
    function dynCalendar_show()
    {
        // Variable declarations to prevent globalisation
        var month, year, monthnames, numdays, thisMonth, firstOfMonth;
        var ret, row, i, cssClass, linkHTML, previousMonth, previousYear;
        var nextMonth, nextYear, prevImgHTML, prevLinkHTML, nextImgHTML, nextLinkHTML;
        var monthComboOptions, monthCombo, yearComboOptions, yearCombo, html;
        
        this.currentMonth = month = arguments[0] != null ? arguments[0] : this.currentMonth;
        this.currentYear  = year  = arguments[1] != null ? arguments[1] : this.currentYear;

        monthnames = new Array('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December');
        numdays    = this._getDaysInMonth(month, year);

        thisMonth    = new Date(year, month, 1);
        firstOfMonth = thisMonth.getDay();

        if (firstOfMonth == 0) {
            firstOfMonth = 7;
        }

        // First few blanks up to first day
        ret = new Array(new Array());
        for(var i=0; (i+1)<firstOfMonth; ++i){
            ret[0][ret[0].length] = '<td>&nbsp;</td>';
        }

        /**
        * Main body of calendar
        */
        row = 0;
        for (var i=0; i<numdays; ++i) {

            if(ret[row].length == 7){
                ret[++row] = new Array();
            }

            /**
            * Generate this cells' HTML
            */
            cssClass = ((i+1) == this.date && month == this.month && year == this.year) ? 'dynCalendar_today' : 'dynCalendar_day';
            linkHTML = sprintf('<a href="javascript: %s(%s, %s, %s); %s._hideLayer()">%s</a>',
                               this.callbackFunc,
                               (i + 1),
                               Number(month) + 1,
                               year,
                               this.objName,
                               i + 1);

            ret[row][ret[row].length] = sprintf('<td align="center" class="%s">%s</td>', cssClass, linkHTML);
        }

        // Format the HTML
        for(i=0; i<ret.length; i++){
            ret[i] = ret[i].join('\n') + '\n';
        }

        previousYear  = thisMonth.getFullYear();
        previousMonth = thisMonth.getMonth() - 1;
        if(previousMonth < 0){
            previousMonth = 11;
            previousYear--;
        }
        
        nextYear  = thisMonth.getFullYear();
        nextMonth = thisMonth.getMonth() + 1;
        if(nextMonth > 11){
            nextMonth = 0;
            nextYear++;
        }

        prevImgHTML  = sprintf('<img src="%s/prev.gif" alt="<<" border="0" />', this.imagesPath);
        prevLinkHTML = sprintf('<a href="javascript: %s.show(%s, %s)">%s</a>',  this.objName, previousMonth, previousYear, prevImgHTML);
        nextImgHTML  = sprintf('<img src="%s/next.gif" alt="<<" border="0" />', this.imagesPath);
        nextLinkHTML = sprintf('<a href="javascript: %s.show(%s, %s)">%s</a>',  this.objName, nextMonth, nextYear, nextImgHTML);

        /**
        * Build month combo
        */
        if (this.useMonthCombo) {
            monthComboOptions = '';
            for (i=0; i<12; i++) {
                selected = (i == thisMonth.getMonth() ? 'selected="selected"' : '');
                monthComboOptions += sprintf('<option value="%s" %s>%s</option>', i, selected, monthnames[i]);
            }
            monthCombo = sprintf('<select name="months" onchange="%s.show(this.options[this.selectedIndex].value, %s.currentYear)">%s</select>', this.objName, this.objName, monthComboOptions);
        } else {
            monthCombo = monthnames[thisMonth.getMonth()];
        }
        
        /**
        * Build year combo
        */
        if (this.useYearCombo) {
            yearComboOptions = '';
            for (i = thisMonth.getFullYear() - this.yearComboRange; i <= (thisMonth.getFullYear() + this.yearComboRange); i++) {
                selected = (i == thisMonth.getFullYear() ? 'selected="selected"' : '');
                yearComboOptions += sprintf('<option value="%s" %s>%s</option>', i, selected, i);
            }
            yearCombo = sprintf('<select style="border: 1px groove" name="years" onchange="%s.show(%s.currentMonth, this.options[this.selectedIndex].value)">%s</select>', this.objName, this.objName, yearComboOptions);
        } else {
            yearCombo = thisMonth.getFullYear();
        }

        html = '<table border="0" bgcolor="#eeeeee" style="margin-left: 1px">';
        html += sprintf('<tr><td class="dynCalendar_header">%s</td><td colspan="5" align="center" class="dynCalendar_header">%s %s</td><td align="right" class="dynCalendar_header">%s</td></tr>', prevLinkHTML, monthCombo, yearCombo, nextLinkHTML);
        html += '<tr>';
        html += '<td class="dynCalendar_dayname">Mon</td>';
        html += '<td class="dynCalendar_dayname">Tue</td>';
        html += '<td class="dynCalendar_dayname">Wed</td>';
        html += '<td class="dynCalendar_dayname">Thu</td>';
        html += '<td class="dynCalendar_dayname">Fri</td>';
        html += '<td class="dynCalendar_dayname">Sat</td>';
        html += '<td class="dynCalendar_dayname">Sun</td></tr>';
        html += '<tr>' + ret.join('</tr>\n<tr>') + '</tr>';
        html += '</table>';

        this._setHTML(html);
        if (!arguments[0] && !arguments[1]) {
            this._showLayer();
            this._setLayerPosition();
        }
    }

    /**
    * Writes HTML to document for layer
    *
    * @access public
    */
    function dynCalendar_writeHTML()
    {
        if (is_ie5up || is_nav6up || is_gecko) {
            document.write(sprintf('<a href="javascript: %s.show()"><img src="%sdynCalendar.gif" border="0" width="16" height="16" /></a>', this.objName, this.imagesPath));
            document.write(sprintf('<div class="dynCalendar" id="%s" onmouseover="%s._mouseover(true)" onmouseout="%s._mouseover(false)"></div>', this.layerID, this.objName, this.objName));
        }
    }

    /**
    * Sets the offset to the mouse position
    * that the calendar appears at.
    *
    * @access public
    * @param integer Xoffset Number of pixels for vertical
    *                        offset from mouse position
    * @param integer Yoffset Number of pixels for horizontal
    *                        offset from mouse position
    */
    function dynCalendar_setOffset(Xoffset, Yoffset)
    {
        this.setOffsetX(Xoffset);
        this.setOffsetY(Yoffset);
    }

    /**
    * Sets the X offset to the mouse position
    * that the calendar appears at.
    *
    * @access public
    * @param integer Xoffset Number of pixels for horizontal
    *                        offset from mouse position
    */
    function dynCalendar_setOffsetX(Xoffset)
    {
        this.offsetX = Xoffset;
    }

    /**
    * Sets the Y offset to the mouse position
    * that the calendar appears at.
    *
    * @access public
    * @param integer Yoffset Number of pixels for vertical
    *                        offset from mouse position
    */
    function dynCalendar_setOffsetY(Yoffset)
    {
        this.offsetY = Yoffset;
    }
    
    /**
    * Sets the images path
    *
    * @access public
    * @param string path Path to use for images
    */
    function dynCalendar_setImagesPath(path)
    {
        this.imagesPath = path;
    }

    /**
    * Turns on/off the month dropdown
    *
    * @access public
    * @param boolean useMonthCombo Whether to use month dropdown or not
    */
    function dynCalendar_setMonthCombo(useMonthCombo)
    {
        this.useMonthCombo = useMonthCombo;
    }

    /**
    * Turns on/off the year dropdown
    *
    * @access public
    * @param boolean useYearCombo Whether to use year dropdown or not
    */
    function dynCalendar_setYearCombo(useYearCombo)
    {
        this.useYearCombo = useYearCombo;
    }

    /**
    * Sets the current month being displayed
    *
    * @access public
    * @param boolean month The month to set the current month to
    */
    function dynCalendar_setCurrentMonth(month)
    {
        this.currentMonth = month;
    }

    /**
    * Sets the current month being displayed
    *
    * @access public
    * @param boolean year The year to set the current year to
    */
    function dynCalendar_setCurrentYear(year)
    {
        this.currentYear = year;
    }

    /**
    * Sets the range of the year combo. Displays this number of
    * years either side of the year being displayed.
    *
    * @access public
    * @param integer range The range to set
    */
    function dynCalendar_setYearComboRange(range)
    {
        this.yearComboRange = range;
    }

    /**
    * Returns the layer object
    *
    * @access private
    */
    function dynCalendar_getLayer()
    {
        var layerID = this.layerID;

        if (document.getElementById(layerID)) {

            return document.getElementById(layerID);

        } else if (document.all(layerID)) {
            return document.all(layerID);
        }
    }

    /**
    * Hides the calendar layer
    *
    * @access private
    */
    function dynCalendar_hideLayer()
    {
        this._getLayer().style.visibility = 'hidden';
    }

    /**
    * Shows the calendar layer
    *
    * @access private
    */
    function dynCalendar_showLayer()
    {
        this._getLayer().style.visibility = 'visible';
    }

    /**
    * Sets the layers position
    *
    * @access private
    */
    function dynCalendar_setLayerPosition()
    {
        this._getLayer().style.top  = (dynCalendar_mouseY + this.offsetY) + 'px';
        this._getLayer().style.left = (dynCalendar_mouseX + this.offsetX) + 'px';
    }

    /**
    * Sets the innerHTML attribute of the layer
    *
    * @access private
    */
    function dynCalendar_setHTML(html)
    {
        this._getLayer().innerHTML = html;
    }

    /**
    * Returns number of days in the supplied month
    *
    * @access private
    * @param integer month The month to get number of days in
    * @param integer year  The year of the month in question
    */
    function dynCalendar_getDaysInMonth(month, year)
    {
        monthdays = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
        if (month != 1) {
            return monthdays[month];
        } else {
            return ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0 ? 29 : 28);
        }
    }

    /**
    * onMouse(Over|Out) event handler
    *
    * @access private
    * @param boolean status Whether the mouse is over the
    *                       calendar or not
    */
    function dynCalendar_mouseover(status)
    {
        dynCalendar_mouseoverStatus = status;
        return true;
    }

    /**
    * onMouseMove event handler
    */
    if (!mouseMoveEventAssigned) {
        dynCalendar_oldOnmousemove = document.onmousemove ? document.onmousemove : new Function;
    
        document.onmousemove = function ()
        {
            if (arguments[0]) {
                dynCalendar_mouseX = arguments[0].pageX;
                dynCalendar_mouseY = arguments[0].pageY;
            } else {
                dynCalendar_mouseX = event.clientX + document.body.scrollLeft;
                dynCalendar_mouseY = event.clientY + document.body.scrollTop;
                arguments[0] = null;
            }
    
            dynCalendar_oldOnmousemove(arguments[0]);
        }
        
        var mouseMoveEventAssigned = true;
    }

    /**
    * Callbacks for document.onclick
    */
    if (!clickEventAssigned) {
        dynCalendar_oldOnclick = document.onclick ? document.onclick : new Function;
    
        document.onclick = function ()
        {
            if(!dynCalendar_mouseoverStatus){
                for(i=0; i<dynCalendar_layers.length; ++i){
                    dynCalendar_layers[i]._hideLayer();
                }
            }
    
            dynCalendar_oldOnclick(arguments[0] ? arguments[0] : null);
        }
        var clickEventAssigned = true;
    }

    /**
    * Javascript mini implementation of sprintf()
    */
    function sprintf(strInput)
    {
        var strOutput  = '';
        var currentArg = 1;
    
        for (var i=0; i<strInput.length; i++) {
            if (strInput.charAt(i) == '%' && i != (strInput.length - 1) && typeof(arguments[currentArg]) != 'undefined') {
                switch (strInput.charAt(++i)) {
                    case 's':
                        strOutput += arguments[currentArg];
                        break;
                    case '%':
                        strOutput += '%';
                        break;
                }
                currentArg++;
            } else {
                strOutput += strInput.charAt(i);
            }
        }
    
        return strOutput;
    }