class App {
	constructor( canvasId ) {
		this.cc = document.getElementById( canvasId ).getContext( "2d" );
		this.flg = true;
		
		this.svcs = new Array();
			let svc = new SVC();

			let part1 = new SVC_Part( "part1" );
				part1.addJoint( "j1", 50, 50 );
			let part2 = new SVC_Part( "part2" );
				part2.addJoint( "j1", 100, 0 );
			let part3 = new SVC_Part( "part3" );

			//build.
			part1.connect( "j1", part2 );
			part2.connect( "j1", part3 );
			
			part1.rotation = 3.14 / 10;
			part2.rotation = -0.1;
			part3.rotation = -0.4;
			

			svc.setTopPart( part1 );
			part1.ox = 50;
			part1.oy = 50;
			svc.calc();
			
			this.svcs.push( svc );
	}
	start() {
		if( 1 ) {
			this.draw( this.cc );
		}
		if( 0 ) {
			this.timerId = setInterval( function() {
				this.draw( this.cc );
				this.flg = ! this.flg;
			}.bind( this ), 500 );
		}
	}
	stop() {
		clearInterval( this.timerId );
	}
	draw( cc ) {
		for( let i = 0; i < this.svcs.length; i++ ) {
			let svc = this.svcs[ i ];
				svc.draw( cc );
		}
	}
}//App

class SVC {
	constructor() {
		this.topPart = null;
		this.x = 0;
		this.y = 0;
	}
	setTopPart( topPart ) {
		this.topPart = topPart;

		//応急的
		topPart.parentJoint = {
			x : 0,
			y : 0,
		}
	}
	calc() {
		this.topPart.calc();
	}
	draw( cc ) {
		this.topPart.draw( cc );
	}
	
}

class SVC_Part {
	constructor( title ) {
		this.title = title;
		this.jointHash = new Object();
		this.rotation = 0;
		this.abs = new Object();
		this.parent = null;
		this.parentJoint = null;
		this.children = new Array();
	}
	addJoint( name, x, y ) {
		let joint = new Object();
			joint.name = name;
			joint.x = x;
			joint.y = y;
		this.jointHash[ name ] = joint;
	}
	
	//他のSVC_Partを自身のJointへ接続
	connect( jointName, part ) {
		this.children.push( part );
		part.parent = this;
		part.parentJoint = this.jointHash[ jointName ];
	}
	calc() {
		//自身の値の絶対座標を求める。
		if( ! this.parent ) {
			//親がない場合は
			this.abs.x = 0;
			this.abs.y = 0;
			this.abs.rotation = this.rotation;
		} else {
			//親がある場合は
			let parentJointAbs = this.parent.abs.jointHash[ this.parentJoint.name ];
			this.abs.x = parentJointAbs.x;
			this.abs.y = parentJointAbs.y;
			this.abs.rotation = this.parent.abs.rotation + this.rotation;
		}
		
		//各jointの絶対座標を求める。
		this.abs.jointHash = new Object();
		for( let name in this.jointHash ) {
			let j = this.jointHash[ name ];
			let res = this.mathRotate( j.x, j.y, this.abs.rotation );
			this.abs.jointHash[ name ] = {
				x : this.abs.x + res.X,
				y : this.abs.y + res.Y,
			}
		}		

		//子もcalc()
		for( let i = 0; i < this.children.length; i++ ) {
			let child = this.children[ i ];
				child.calc();
		}
	}//calc()

	//SVC_Part
	
	draw( cc ) {
		console.log( this.title + " draw." );
		
		//自身を描画
		cc.save();
			cc.translate( this.abs.x, this.abs.y );
			cc.rotate( this.abs.rotation );
			cc.strokeRect( 0, 0, 100, 100 );
		cc.restore();
		
		//子を描画
		for( let i = 0; i < this.children.length; i++ ) {
			let child = this.children[ i ];
			child.draw( cc );
		}
		
		//debug.
		if( 1 ) {
			//各jointを○で示す
			for( let name in this.jointHash ) {
				let joint = this.abs.jointHash[ name ];
				cc.beginPath();
				cc.arc( joint.x, joint.y, 8, 0, 6.28, false );
				cc.closePath();
				cc.stroke();
			}
		}
	}//draw()
	
	//---
	
	mathRotate( x, y, theta2 ) {
		let theta1 = Math.atan2( y, x );
		let hankei = Math.sqrt( x * x + y * y );
		return {
			X : Math.cos( theta1 + theta2 ) * hankei,
			Y : Math.sin( theta1 + theta2 ) * hankei,
		}
	}
	
}//SVC_Part