/**
* Convert a single file-input element into a 'multiple' input list
*
* Usage:
*
*   1. Create a file input element (no name)
*      eg. <input type="file" id="first_file_element">
*
*   2. Create a DIV for the output to be written to
*      eg. <div id="files_list"></div>
*
*   3. Instantiate a MultiSelector object, passing in the DIV and an (optional) maximum number of files
*      eg. var multi_selector = new MultiSelector( document.getElementById( 'files_list' ), 3 );
*
*   4. Add the first element
*      eg. multi_selector.addElement( document.getElementById( 'first_file_element' ) );
*
*   5. That's it.
*
*   You might (will) want to play around with the addListRow() method to make the output prettier.
*
*   You might also want to change the line 
*       element.name = 'file_' + this.count;
*   ...to a naming convention that makes more sense to you.
* 
* Licence:
*   Use this however/wherever you like, just don't blame me if it breaks anything.
*
* Credit:
*   If you're nice, you'll leave this bit:
*  
*   Class by Stickman -- http://www.the-stickman.com
*      with thanks to:
*      [for Safari fixes]
*         Luis Torrefranca -- http://www.law.pitt.edu
*         and
*         Shawn Parker & John Pennypacker -- http://www.fuzzycoconut.com
*      [for duplicate name bug]
*         'neal'
*/
function MultiSelector( list_target, max, allowed_file_types ){

// Where to write the list
this.list_target = list_target;
// How many elements?
this.count = 0;
// How many elements?
this.id = 0;
// Is there a maximum?
if( max ){
this.max = max;
} else {
this.max = -1;
};

var allowed_file_types = typeof(allowed_file_types) == 'string' ? (allowed_file_types+'').toLowerCase() : false; //comma seperated list, omit or set to false to allow all file types

/**
* Add a new file input element
*/
this.addElement = function( element ){

	// Make sure it's a file input element
	if( (element.tagName+'').toLowerCase() == 'input' && element.type == 'file' ){
	
	// Element name -- what number am I?
	element.name = 'file_' + this.id++;
	
	// Add reference to this object
	element.multi_selector = this;
	
	// What to do when a file is selected
	element.onchange = function(){
		// New file input
		var new_element = document.createElement( 'input' );
		new_element.type = 'file';
			
		//Validate
		var filename = (this.value+'').split('\\');
		filename = filename[filename.length-1];
		var suffix = filename.split('.');
		suffix = (suffix[suffix.length-1]+'').toLowerCase();
		if(allowed_file_types && allowed_file_types.indexOf(suffix) == -1) {
			alert('The file type ".' + suffix + '" is not allowed.');
			var _pn = this.parentNode;
			_pn.removeChild(this);
			_pn.appendChild(new_element);
			this.multi_selector.addElement(new_element);
			this.multi_selector.count--;
			return false;
		}
		

		
		// Add new element
		this.parentNode.insertBefore( new_element, this );
		
		// Apply 'update' to element
		this.multi_selector.addElement( new_element );
		
		// Update list
		this.multi_selector.addListRow( this );
		
		// Hide this: we can't use display:none because Safari doesn't like it
		//this.style.position = 'absolute';
		//this.style.left = '-1000px';
		this.className = 'hide';
	
	};
	
	// If we've reached maximum number, disable input element
	if( this.max != -1 && this.count >= this.max ){
		element.disabled = true;
	};
	
	// File element counter
	this.count++;
	// Most recent element
	this.current_element = element;
	
	} else {
		// This can only be applied to file input elements!
		alert( 'Error: not a file input element' );
	};

};

/**
* Add a new row to the list of files
*/
this.addListRow = function( element ){

	var filename = (element.value+'').split('\\');
	filename = filename[filename.length-1];
	
	// Row div
	var new_row = document.createElement( 'div' );
	
	// Delete button
	var new_row_button = document.createElement( 'input' );
	new_row_button.type = 'image';
	new_row_button.value = 'Delete';
	new_row_button.src = 'assets/templates/FPB2009/icons/x.png';
	new_row_button.width = 10;
	new_row_button.height = 10;
	new_row_button.valign = 'middle';
	
	// References
	new_row.element = element;
	
	// Delete function
	new_row_button.onclick= function(){
	
	// Remove element from form
	this.parentNode.element.parentNode.removeChild( this.parentNode.element );
	
	// Remove this row from the list
	this.parentNode.parentNode.removeChild( this.parentNode );
	
	// Decrement counter
	this.parentNode.element.multi_selector.count--;
	
	// Re-enable input element (if it's disabled)
	this.parentNode.element.multi_selector.current_element.disabled = false;
	
	// Appease Safari
	//    without it Safari wants to reload the browser window
	//    which nixes your already queued uploads
	return false;
	};
	
	// Set row value
	new_row.innerHTML = filename;
	
	// Add button
	new_row.appendChild( new_row_button );
	
	// Add it to the list
	this.list_target.appendChild( new_row );

};

};