/* --------------------------- relation (connector) ----------- */

SQL.Relation = function(owner, row1, row2) {
	this.owner = owner;
	this.row1 = row1;
	this.row2 = row2;
	this.color = "#000";
	this.hidden = false;
	SQL.Visual.apply(this);

	/* if one of the rows already has relations, inherit color */
	var all = row1.relations.concat(row2.relations);
	if (all.length) { /* inherit */
		this.color = all[0].getColor();
	} else if (CONFIG.RELATION_COLORS) { /* pick next */
		SQL.Relation._counter++;
		var colorIndex = SQL.Relation._counter - 1;
		this.color = CONFIG.RELATION_COLORS[colorIndex % CONFIG.RELATION_COLORS.length];
	}

	this.row1.addRelation(this);
	this.row2.addRelation(this);
	this.dom = [];
	
	if (this.owner.vector) {
		var path = document.createElementNS(this.owner.svgNS, "path");
		path.setAttribute("stroke", this.color);
		path.setAttribute("stroke-width", CONFIG.RELATION_THICKNESS);
		path.setAttribute("fill", "none");
		this.owner.dom.svg.appendChild(path);
		this.dom.push(path);
	} else {
		for (var i=0;i<3;i++) {
			var div = OZ.DOM.elm("div",{position:"absolute",className:"relation",backgroundColor:this.color});
			this.dom.push(div);
			if (i & 1) { /* middle */
				OZ.Style.set(div, {width:CONFIG.RELATION_THICKNESS+"px"});
			} else { /* first & last */
				OZ.Style.set(div, {height:CONFIG.RELATION_THICKNESS+"px"});
			}
			this.owner.dom.container.appendChild(div);
		}
	}
	
	this.redraw();
}
SQL.Relation._counter = 0;
SQL.Relation.prototype = Object.create(SQL.Visual.prototype);

SQL.Relation.prototype.getColor = function() {
	return this.color;
}

SQL.Relation.prototype.show = function() {
	this.hidden = false;
	for (var i=0;i<this.dom.length;i++) {
		this.dom[i].style.visibility = "";
	}
}

SQL.Relation.prototype.hide = function() {
	this.hidden = true;
	for (var i=0;i<this.dom.length;i++) {
		this.dom[i].style.visibility = "hidden";
	}
}

SQL.Relation.prototype.redrawNormal = function(p1, p2, half) {
	if (this.owner.vector) {
		var str = "M "+p1[0]+" "+p1[1]+" C "+(p1[0] + half)+" "+p1[1]+" ";
		str += (p2[0]-half)+" "+p2[1]+" "+p2[0]+" "+p2[1];
		this.dom[0].setAttribute("d",str);
	} else {
		this.dom[0].style.left = p1[0]+"px";
		this.dom[0].style.top = p1[1]+"px";
		this.dom[0].style.width = half+"px";

		this.dom[1].style.left = (p1[0] + half) + "px";
		this.dom[1].style.top = Math.min(p1[1],p2[1]) + "px";
		this.dom[1].style.height = (Math.abs(p1[1] - p2[1])+CONFIG.RELATION_THICKNESS)+"px";

		this.dom[2].style.left = (p1[0]+half+1)+"px";
		this.dom[2].style.top = p2[1]+"px";
		this.dom[2].style.width = half+"px";
	}
}

SQL.Relation.prototype.redrawSide = function(p1, p2, x) {
	if (this.owner.vector) {
		var str = "M "+p1[0]+" "+p1[1]+" C "+x+" "+p1[1]+" ";
		str += x+" "+p2[1]+" "+p2[0]+" "+p2[1];
		this.dom[0].setAttribute("d",str);
	} else {
		this.dom[0].style.left = Math.min(x,p1[0])+"px";
		this.dom[0].style.top = p1[1]+"px";
		this.dom[0].style.width = Math.abs(p1[0]-x)+"px";
		
		this.dom[1].style.left = x+"px";
		this.dom[1].style.top = Math.min(p1[1],p2[1]) + "px";
		this.dom[1].style.height = (Math.abs(p1[1] - p2[1])+CONFIG.RELATION_THICKNESS)+"px";
		
		this.dom[2].style.left = Math.min(x,p2[0])+"px";
		this.dom[2].style.top = p2[1]+"px";
		this.dom[2].style.width = Math.abs(p2[0]-x)+"px";
	}
}

SQL.Relation.prototype.redraw = function() { /* draw connector */
	if (this.hidden) { return; }
	var t1 = this.row1.owner.dom.container;
	var t2 = this.row2.owner.dom.container;

	var l1 = t1.offsetLeft;
	var l2 = t2.offsetLeft;
	var r1 = l1 + t1.offsetWidth;
	var r2 = l2 + t2.offsetWidth;
	var t1 = t1.offsetTop + this.row1.dom.container.offsetTop + Math.round(this.row1.dom.container.offsetHeight/2);
	var t2 = t2.offsetTop + this.row2.dom.container.offsetTop + Math.round(this.row2.dom.container.offsetHeight/2);
	
	if (this.row1.owner.selected) { t1++; l1++; r1--; }
	if (this.row2.owner.selected) { t2++; l2++; r2--; }
	
	var p1 = [0,0];
	var p2 = [0,0];
	
	if (r1 < l2 || r2 < l1) { /* between tables */
		if (Math.abs(r1 - l2) < Math.abs(r2 - l1)) {
			p1 = [r1,t1];
			p2 = [l2,t2];
		} else {
			p1 = [r2,t2];
			p2 = [l1,t1];
		}
		var half = Math.floor((p2[0] - p1[0])/2);
		this.redrawNormal(p1, p2, half);
	} else { /* next to tables */
		var x = 0;
		var l = 0;
		if (Math.abs(l1 - l2) < Math.abs(r1 - r2)) { /* left of tables */
			p1 = [l1,t1];
			p2 = [l2,t2];
			x = Math.min(l1,l2) - CONFIG.RELATION_SPACING;
		} else { /* right of tables */
			p1 = [r1,t1];
			p2 = [r2,t2];
			x = Math.max(r1,r2) + CONFIG.RELATION_SPACING;
		}
		this.redrawSide(p1, p2, x);
	} /* line next to tables */
}

SQL.Relation.prototype.destroy = function() {
	this.row1.removeRelation(this);
	this.row2.removeRelation(this);
	for (var i=0;i<this.dom.length;i++) {
		this.dom[i].parentNode.removeChild(this.dom[i]);
	}
}