/*
 * library for ajaxcourse formats, the classes and related functions for drag and drop blocks
 * 
 * this library requires a 'main' object created in calling document
 * 
 */


        //set Drag and Drop to Intersect mode: 
        YAHOO.util.DDM.mode = YAHOO.util.DDM.INTERSECT; 

/*
 * class for draggable block, extends YAHOO.util.DDProxy
 */
function block_class(id,group,config){
    this.init_block(id,group,config);
}
YAHOO.extend(block_class, YAHOO.util.DDProxy);

block_class.prototype.debug = true;

block_class.prototype.init_block = function(id, sGroup, config){
    if (!id) { return; }

    //Drag and Drop 
    this.init(id, sGroup, config);
    this.initFrame();
    this.createFrame();
    
    this.is = 'block'; 
    this.instanceId = this.getEl().id.replace(/inst/i,'');
 
    
    this.addInvalidHandleType('a');
    
    var s = this.getEl().style;
    s.opacity = 0.76;
    s.filter = "alpha(opacity=76)";
    
    
    // specify that this is not currently a drop target
    this.isTarget = false;
    
        this.region = YAHOO.util.Region.getRegion(this.getEl());

    this.type = block_class.TYPE;
    
    
    //DHTML 
    this.viewbutton = null;
    this.originalClass = this.getEl().className;
    
    this.init_buttons();
    }

block_class.prototype.startDrag = function(x, y) {
    //operates in intersect mode
    YAHOO.util.DDM.mode = YAHOO.util.DDM.INTERSECT;
    
    YAHOO.log(this.id + " startDrag");

    var dragEl = this.getDragEl();
    var clickEl = this.getEl();

    dragEl.innerHTML = clickEl.innerHTML;
    dragEl.className = clickEl.className;
    dragEl.style.color = this.DDM.getStyle(clickEl, "color");;
    dragEl.style.backgroundColor = this.DDM.getStyle(clickEl, "backgroundColor");
    dragEl.style.border = '0px';

    var s = clickEl.style;
    s.opacity = .1;
    s.filter = "alpha(opacity=10)";

    var targets = YAHOO.util.DDM.getRelated(this, true);
    YAHOO.log(targets.length + " targets");
    
    //restyle side boxes to highlight
    for (var i=0; i<targets.length; i++) {
        
        var targetEl = targets[i].getEl();
        
        targetEl.style.background = "#fefff0";
        targetEl.opacity = .3;
        targetEl.filter = "alpha(opacity=30)";
    }
    }

block_class.prototype.endDrag = function() {
    // reset the linked element styles
    var s = this.getEl().style;
    s.opacity = 1;
    s.filter = "alpha(opacity=100)";
    this.resetTargets();
    }

block_class.prototype.onDragDrop = function(e, id) {
    // get the drag and drop object that was targeted
    var oDD;
    
    if ("string" == typeof id) {
        oDD = YAHOO.util.DDM.getDDById(id);
    } else {
        oDD = YAHOO.util.DDM.getBestMatch(id);
    }

    
    var el = this.getEl();

    YAHOO.log("id="+id+" el = "+e+" x="+YAHOO.util.Dom.getXY(this.getDragEl()));
    
    //var collisions = this.find_collisions(e,id);

    this.move_block(id);
    //YAHOO.util.DDM.moveToEl(el, oDD.getEl());
 

    
    this.resetTargets();

    }

block_class.prototype.find_target = function(column){
        var collisions = column.find_sub_collision(YAHOO.util.Region.getRegion(this.getDragEl()));
         
        //determine position
        var insertbefore = null;
        if(collisions.length == 0)
          return;
       
       insertbefore = column.blocks[collisions[0][0]];    
         
        return insertbefore;
    }

block_class.prototype.resetTargets = function() {
        // reset the target styles
        var targets = YAHOO.util.DDM.getRelated(this, true);
        for (var i=0; i<targets.length; i++) {
            var targetEl = targets[i].getEl();
            targetEl.style.background = "";
            targetEl.opacity = 1;
            targetEl.filter = "alpha(opacity=100)";        
        }
    }

block_class.prototype.move_block = function(columnid){
        if(this.debug)YAHOO.log("Dropped on "+columnid[0]);
        //var column = YAHOO.util.DDM.getDDById(columnid[0].);
        column = columnid[0];
        var inserttarget = this.find_target(column);

        if(this.debug && inserttarget != null)YAHOO.log("moving "+this.getEl().id+" before "+inserttarget.getEl().id+" - parentNode="+this.getEl().parentNode.id);
        
        if(this == inserttarget){
            if(this.debug)YAHOO.log("Dropping on self, resetting");
            this.endDrag();
            return;
        }
        
        //remove from document        
        if(this.getEl().parentNode != null)
          this.getEl().parentNode.removeChild(this.getEl());     
                
        //insert into correct place
        if(inserttarget != null ){
            inserttarget.getEl().parentNode.insertBefore(this.getEl(),inserttarget.getEl());
            
        }else if(column == main.rightcolumn){//if right side insert before admin block
            column.getEl().insertBefore(this.getEl(),main.adminBlock);  
            
        }else{ 
            column.getEl().appendChild(this.getEl());    
        }
               
        this.reset_regions();
        
        //remove block from current array
        if(main.rightcolumn.has_block(this))
              main.rightcolumn.remove_block(this);
              
        else if(main.leftcolumn.has_block(this))
              main.leftcolumn.remove_block(this);
        
        //insert into new array
        column.insert_block(this,inserttarget);
        
    }

block_class.prototype.reset_regions = function(){
      var blockcount = main.blocks.length;
      for(i=0;i<blockcount;i++)
           main.blocks[i].region = YAHOO.util.Region.getRegion(main.blocks[i].getEl());
    }

block_class.prototype.init_buttons = function(){

       var viewbutton = main.mk_button('a','/pix/t/hide.gif',[['class','icon hide']]);
       YAHOO.util.Event.addListener(viewbutton,'click',this.toggle_hide,this,true);

       var deletebutton = main.mk_button('a','/pix/t/delete.gif',[['class','icon delete']]);
       YAHOO.util.Event.addListener(deletebutton,'click',this.delete_button,this,true);       
       
       
       this.viewbutton = viewbutton;
       
       buttonCont = YAHOO.util.Dom.getElementsByClassName('commands','div',this.getEl())[0];       
       buttonCont.appendChild(viewbutton);
       buttonCont.appendChild(deletebutton);       

    }

block_class.prototype.toggle_hide = function(e,target,isCosmetic){     
       if(YAHOO.util.Dom.hasClass(this.getEl(),'hidden')){
           this.getEl().className = this.originalClass;
           this.viewbutton.childNodes[0].src = this.viewbutton.childNodes[0].src.replace(/show.gif/i,'hide.gif');
           if(!isCosmetic)main.connect('post','class=block&field=visible',null,'value=1&instanceId='+this.instanceId);
           
       }else{
           this.originalClass = this.getEl().className;
           this.getEl().className = "hidden sideblock";
           this.viewbutton.childNodes[0].src = this.viewbutton.childNodes[0].src.replace(/hide.gif/i,'show.gif');
           if(!isCosmetic)main.connect('post','class=block&field=visible',null,'value=0&instanceId='+this.instanceId);
           
       }
    }

block_class.prototype.delete_button = function(){
        //remove from local model
        if(main.rightcolumn.has_block(this))
              main.rightcolumn.remove_block(this);
              
        else if(main.leftcolumn.has_block(this))
              main.leftcolumn.remove_block(this);
        
        //remove from remote model
        main.connect('delete','class=block&instanceId='+this.instanceId);
        
        //remove from view
        if(this.debug)YAHOO.log("Deleting "+this.getEl().id);
        main.blocks[main.get_block_index(this)] = null;
        this.getEl().parentNode.removeChild(this.getEl());                              
        
    } 

block_class.prototype.update_index = function(index,columnId){
       //update via AJAX the db representation of page
       main.connectQueue_add('post','class=block&field=position',null,'value='+index+'&column='+columnId+'&instanceId='+this.instanceId);
       if(this.debug)YAHOO.log("updating position of "+this.getEl().id+" to index "+index+" on column "+columnId);
    }


/*
 * column class, DD targets
 */

function column_class(id,group,config,ident){
    this.init_column(id,group,config,ident);
}
YAHOO.extend(column_class, YAHOO.util.DDTarget);

column_class.prototype.debug = true;

column_class.prototype.init_column = function(id, group,config,ident){
        if (!id) { return; }
        
        this.initTarget(id,group,config);
        this.blocks = new Array();
        this.ident = ident;
        
//      YAHOO.log("init_column "+id+"-"+el.id);
        this.region = YAHOO.util.Region.getRegion(id);    

    }


column_class.prototype.find_sub_collision = function(dragRegion){
        if(this.debug)YAHOO.log("Finding Collisions on "+this.getEl().id+" with "+this.blocks.length+" blocks");
        //find collisions with sub_elements(blocks), return array of collisions with regions of collision
        var collisions = new Array();
        for(i=0;i<this.blocks.length;i++){
            if(this.debug)YAHOO.log("testing region "+this.blocks[i].region+" against" + dragRegion + "intersect ="+this.blocks[i].region.intersect(dragRegion));
            var intersect = this.blocks[i].region.intersect(dragRegion);
            if(intersect != null){
                index = collisions.length;
                collisions[index] = new Array();
                collisions[index][0] = i;
                collisions[index][1] = this.blocks[i].region.intersect(dragRegion);
                if(this.debug)YAHOO.log(index+" Collides with "+this.blocks[i].getEl().id+" area" + collisions[index][1].getArea());
            }
        }
      return collisions;  
    }

column_class.prototype.add_block = function(el){
       this.blocks[this.blocks.length] = el;
     }

column_class.prototype.insert_block = function(el,targetel){
        var blockcount = this.blocks.length;
        var found = false;
        var tempStore = nextStore = null;
        for(var i=0;i<blockcount;i++){
            if(found){
                tempStore = this.blocks[i];
                this.blocks[i] = nextStore;
                nextStore = tempStore;           
                                                
            }else if(this.blocks[i] == targetel){
                found = true;
                nextStore = this.blocks[i];
                this.blocks[i] = el;               
                blockcount++;
            }      
            this.blocks[i].update_index(i,this.ident);                        
        }
        
        if(!found){//insert at end
            el.update_index(this.blocks.length,this.ident);
            this.add_block(el);            
        }
    }

column_class.prototype.has_block = function(el){
        var blockcount = this.blocks.length;
        for(var i=0;i<blockcount;i++)
            if(this.blocks[i]==el)
                 return true;
        return false;
    }
    
    
column_class.prototype.remove_block = function(el){
        var blockcount = this.blocks.length;
        var found = false;
        for(var i=0;i<blockcount;i++){
            if(this.blocks[i]==el || found){
               if(!found)
                    found = true;
          
               if(i < blockcount-1){
                   this.blocks[i+1].update_index(i,this.ident);
                   this.blocks[i] = this.blocks[i+1];                   
               }else{
                    this.blocks.pop();                     
               }
            }
        }
        YAHOO.log("column "+this.indent+" has "+blockcount+"blocks");
    }