func (p *port) Connection(c bh.PortIf) bh.ConnectionIf {
	_, ok, index := p.connected.Find(c.Node().Name(), c.Name())
	if !ok {
		log.Fatalf("port.bh.ConnectionIf error: port %v not in connected list of port %v\n", c, p)
	}
	return p.conn[index]
}

func (t *signalGraphType) AddNewObject(tree tr.TreeIf, cursor tr.Cursor, obj tr.TreeElementIf) (newCursor tr.Cursor, err error) {
	switch obj.(type) {
	case bh.NodeIf:
		// TODO: Check if IO node and exists: copy position only and return
		n := obj.(bh.NodeIf)
		err = t.AddNode(n)
		if err != nil {
			err = fmt.Errorf("signalGraphType.AddNewObject error: %s", err)
			nt := n.ItsType().(*nodeType)
			if nt != nil {
				ok, _ := nt.instances.Find(n)
				if ok {
					nt.instances.Remove(n)
				}
			}
			return
		}
		newCursor = t.treeAddNewObject(tree, cursor, n)

		parent := tree.Object(cursor)
		switch parent.(type) {
		case bh.SignalGraphIf:
		case bh.ImplementationIf:
			// propagate new node to all instances of embracing type
			pCursor := tree.Parent(cursor)
			nt := tree.Object(pCursor)
			for _, nn := range nt.(bh.NodeTypeIf).Instances() {
				nCursor := tree.Cursor(nn)
				tCursor := tree.CursorAt(nCursor, parent)
				tCursor.Position = cursor.Position
				t.treeAddNewObject(tree, tCursor, n)
			}

		default:
			log.Fatalf("signalGraphType.AddNewObject error: wrong parent type %T: %v\n", parent, parent)
		}

	case bh.ConnectionIf:
		conn := obj.(bh.ConnectionIf)
		var n bh.NodeIf
		var p bh.PortIf
		for _, n = range t.Nodes() {
			if n.Name() == conn.From().Node().Name() {
				nCursor := tree.CursorAt(cursor, n)
				for _, p = range n.OutPorts() {
					if conn.From().Name() == p.Name() {
						pCursor := tree.CursorAt(nCursor, p)
						return p.AddNewObject(tree, pCursor, obj)
					}
				}
			}
		}
	default:
		log.Fatalf("signalGraphType.AddNewObject error: wrong type %t: %v\n", obj, obj)
	}
	return
}

func (p *port) RemoveConnection(c bh.PortIf) {
	_, ok, index := p.connected.Find(c.Node().Name(), c.Name())
	if !ok {
		log.Fatalf("port.bh.ConnectionIf error: port %v not in connected list of port %v\n", c, p)
	}
	p.connected.Remove(c)
	for index++; index < len(p.conn); index++ {
		p.conn[index-1] = p.conn[index]
	}
	p.conn = p.conn[:len(p.conn)-1]
}

func (p *port) RemoveObject(tree tr.TreeIf, cursor tr.Cursor) (removed []tr.IdWithObject) {
	parent := tree.Parent(cursor)
	if p != tree.Object(parent) {
		log.Fatal("port.RemoveObject error: not removing child of mine.")
	}
	obj := tree.Object(cursor)
	switch obj.(type) {
	case bh.ConnectionIf:
		conn := obj.(bh.ConnectionIf)
		var thisPort, otherPort bh.PortIf
		if p.Direction() == gr.InPort {
			otherPort = conn.From()
			thisPort = conn.To()
			if p != thisPort {
				log.Fatal("port.RemoveObject error: invalid connection ", conn)
			}
		} else {
			otherPort = conn.To()
			thisPort = conn.From()
			if p != thisPort {
				log.Fatal("port.RemoveObject error: invalid connection ", conn)
			}
		}
		contextCursor := tree.Parent(tree.Parent(tree.Parent(cursor)))
		removed = p.treeRemoveObject(tree, cursor, conn, otherPort)
		context := tree.Object(contextCursor)
		switch context.(type) {
		case bh.SignalGraphIf:
		case bh.ImplementationIf:
			// propagate removed edge to all instances of embracing type
			nt := tree.Object(tree.Parent(contextCursor))
			for _, nn := range nt.(bh.NodeTypeIf).Instances() {
				nCursor := tree.Cursor(nn)
				tCursor := tree.CursorAt(nCursor, context)
				pCursor := tree.CursorAt(tCursor, p)
				cCursor := tree.CursorAt(pCursor, conn)
				p.treeRemoveObject(tree, cCursor, conn, otherPort)
			}

		default:
			log.Fatalf("port.RemoveObject error: wrong context type %T: %v\n", context, context)
		}
		p.RemoveConnection(otherPort)
		otherPort.RemoveConnection(p)

	default:
		log.Fatalf("bh.PortIf.RemoveObject error: invalid type %T: %v\n", obj, obj)
	}
	return
}

// Remove object mirrored in all instance node type
func (t *nodeType) treeRemoveInstObject(tree tr.TreeIf, cursor tr.Cursor) (removed []tr.IdWithObject) {
	parentId := tree.Parent(cursor)
	if t != tree.Object(parentId) {
		log.Fatal("nodeType.RemoveObject error: not removing child of mine.")
	}
	obj := tree.Object(cursor)
	switch obj.(type) {
	case bh.ImplementationIf:
		for _, n := range t.Instances() {
			nCursor := tree.Cursor(n)
			tCursor := tree.CursorAt(nCursor, t)
			iCursor := tree.CursorAt(tCursor, obj)
			iCursor.Position = cursor.Position
			tree.Remove(iCursor)
		}

	case bh.PortTypeIf:
		nt := obj.(bh.PortTypeIf)
		for _, n := range t.Instances() {
			var p bh.PortIf
			var list []bh.PortIf
			nCursor := tree.Cursor(n)
			if nt.Direction() == gr.InPort {
				list = n.InPorts()
			} else {
				list = n.OutPorts()
			}
			for _, p = range list {
				if p.Name() == nt.Name() {
					break
				}
			}
			_ = p.(*port)
			pCursor := tree.CursorAt(nCursor, p)
			prefix, index := tree.Remove(pCursor)
			removed = append(removed, tr.IdWithObject{prefix, index, p})
			tCursor := tree.CursorAt(nCursor, obj)
			del := t.treeRemoveObject(tree, tCursor)
			for _, d := range del {
				removed = append(removed, d)
			}
			tree.Remove(tCursor)
		}

	default:
		log.Fatalf("nodeType.RemoveObject error: invalid type %T\n", obj)
	}
	return
}

func (t *nodeType) treeInstObject(tree tr.TreeIf, cursor tr.Cursor, obj tr.TreeElementIf) (newCursor tr.Cursor) {
	switch obj.(type) {
	case bh.ImplementationIf:
		impl := obj.(bh.ImplementationIf)
		// update all instance nodes in the tree with new implementation
		for _, n := range t.Instances() {
			nCursor := tree.Cursor(n)
			tCursor := tree.CursorAt(nCursor, t)
			tCursor.Position = len(t.Implementation()) - 1
			newICursor := tree.Insert(tCursor)
			impl.AddToTree(tree, newICursor)
		}

	case bh.PortTypeIf:
		pt := obj.(bh.PortTypeIf)
		// update all instance nodes in the tree with new port
		for _, n := range t.Instances() {
			var p bh.PortIf
			var ok bool
			if pt.Direction() == gr.InPort {
				p, ok, _ = n.(*node).inPort.Find(n.Name(), pt.Name())
			} else {
				p, ok, _ = n.(*node).outPort.Find(n.Name(), pt.Name())
			}
			if !ok {
				log.Fatalf("nodeType.treeInstObject error: port %s not found.\n", pt.Name())
			}
			nCursor := tree.Cursor(n)
			// Insert new port at the same position as in the type:
			// Need to deal with implementations in type VS type in node
			if cursor.Position >= 0 {
				nCursor.Position = cursor.Position - len(t.Implementation()) + 1
			}
			newNCursor := tree.Insert(nCursor)
			p.AddToTree(tree, newNCursor)
			// Update mirrored type in node:
			tCursor := tree.CursorAt(nCursor, t)
			tCursor.Position = cursor.Position
			t.treeNewObject(tree, tCursor, obj)
		}

	default:
		log.Fatalf("nodeType.AddNewObject error: invalid type %T\n", obj)
	}
	return
}

// For connection only: lookup matching ports to connect.
func getMatchingPorts(fts *models.FilesTreeStore, object tr.TreeElementIf) (ret []bh.PortIf) {
	var thisPort bh.PortIf
	switch object.(type) {
	case bh.PortIf:
		thisPort = object.(bh.PortIf)
	case bh.ConnectionIf:
		log.Fatal("getMatchingPorts error: expecting Port, not Connection")
	default:
		log.Fatal("getMatchingPorts error: expecting Port")
	}
	thisNode := thisPort.Node()
	graph := thisNode.Context()
	for _, n := range graph.Nodes() {
		var ports []bh.PortIf
		if thisPort.Direction() == gr.InPort {
			ports = n.OutPorts()
		} else {
			ports = n.InPorts()
		}
		for _, p := range ports {
			if p.SignalType().TypeName() == thisPort.SignalType().TypeName() {
				ret = append(ret, p)
			}
		}
	}
	return
}

func (l *portList) Remove(p bh.PortIf) {
	var i int
	for i = range l.ports {
		if p.Node().Name() == l.ports[i].Node().Name() && p.Name() == l.ports[i].Name() {
			break
		}
	}
	if i >= len(l.ports) {
		for _, v := range l.ports {
			log.Printf("portList.RemovePort have bh.PortIf %v\n", v)
		}
		log.Fatalf("portList.RemovePort error: bh.PortIf %v not in this list\n", p)
	}
	for i++; i < len(l.ports); i++ {
		l.ports[i-1] = l.ports[i]
	}
	l.ports = l.ports[:len(l.ports)-1]
}

func PortNew(box image.Rectangle, userObj bh.PortIf) *Port {
	var config DrawConfig
	if userObj.Direction() == gr.InPort {
		config = DrawConfig{ColorInit(ColorOption(InputPort)),
			ColorInit(ColorOption(HighlightInPort)),
			ColorInit(ColorOption(SelectInPort)),
			ColorInit(ColorOption(BoxFrame)),
			Color{},
			image.Point{}}
	} else {
		config = DrawConfig{ColorInit(ColorOption(OutputPort)),
			ColorInit(ColorOption(HighlightOutPort)),
			ColorInit(ColorOption(SelectOutPort)),
			ColorInit(ColorOption(BoxFrame)),
			Color{},
			image.Point{}}
	}
	return &Port{SelectableBoxInit(box, config), userObj}
}

func (p *port) AddNewObject(tree tr.TreeIf, cursor tr.Cursor, obj tr.TreeElementIf) (newCursor tr.Cursor, err error) {
	switch obj.(type) {
	case bh.ConnectionIf:
		conn := obj.(bh.ConnectionIf)
		var thisPort, otherPort bh.PortIf
		if p.Direction() == gr.InPort {
			otherPort = conn.From()
			thisPort = conn.To()
		} else {
			otherPort = conn.To()
			thisPort = conn.From()
		}
		if p != thisPort {
			log.Println("p =", p)
			log.Println("thisPort =", thisPort)
			log.Fatal("port.AddNewObject error: invalid connection ", conn)
		}
		sgt := thisPort.Node().Context()
		if sgt != otherPort.Node().Context() {
			log.Fatal("port.AddNewObject error: nodes have different context: ", conn)
		}
		contextCursor := tree.Parent(tree.Parent(cursor))

		thisPort.AddConnection(conn)
		newCursor = p.treeAddNewObject(tree, cursor, conn, otherPort)

		context := tree.Object(contextCursor)
		switch context.(type) {
		case bh.SignalGraphIf:
		case bh.ImplementationIf:
			// propagate new edge to all instances of embracing type
			nt := tree.Object(tree.Parent(contextCursor))
			for _, nn := range nt.(bh.NodeTypeIf).Instances() {
				nCursor := tree.Cursor(nn)
				tCursor := tree.CursorAt(nCursor, context)
				pCursor := tree.CursorAt(tCursor, p)
				pCursor.Position = cursor.Position

				p.treeAddNewObject(tree, pCursor, conn, otherPort)
			}

		default:
			log.Fatalf("port.AddNewObject error: wrong context type %T: %v\n", context, context)
		}

	default:
		log.Fatalf("port.AddNewObject error: invalid type %T: %v\n", obj, obj)
	}
	return
}

func portConnect(port1 bh.PortIf, c *connection) error {
	p1 := port1.(*port)
	var port2 bh.PortIf
	var p2 *port
	if c.from.(*port) == p1 {
		port2 = c.to
	} else if c.to.(*port) == p1 {
		port2 = c.from
	}
	p2 = port2.(*port)
	if port1.SignalType().TypeName() != port2.SignalType().TypeName() {
		return fmt.Errorf("type mismatch")
	}
	if port1.Direction() == port2.Direction() {
		return fmt.Errorf("direction mismatch")
	}
	p1.connected.Append(port2.(*port))
	p1.conn = append(p1.conn, c)
	p2.connected.Append(port1.(*port))
	p2.conn = append(p2.conn, c)
	return nil
}

func updateConnections(p bh.PortIf, fts *models.FilesTreeStore) {
	nodeCursor := fts.Cursor(p.Node())
	portCursor := fts.CursorAt(nodeCursor, p)
	for _, c := range p.Connections() {
		conn := p.Connection(c)
		connCursor := fts.CursorAt(portCursor, conn)
		otherNode := c.Node()
		otherNodeCursor := fts.Cursor(otherNode)
		otherPortCursor := fts.CursorAt(otherNodeCursor, c)
		otherConnCursor := fts.CursorAt(otherPortCursor, conn)
		connText := fmt.Sprintf("%s/%s -> %s/%s",
			conn.From().Node().Name(), conn.From().Name(),
			conn.To().Node().Name(), conn.To().Name())
		fts.SetValueById(connCursor.Path, connText)
		fts.SetValueById(otherConnCursor.Path, connText)
	}
}

func (n *Node) SelectPort(port bh.PortIf) {
	var index int
	if port.Direction() == gr.InPort {
		index = n.InPortIndex(port.Name())
	} else {
		index = n.OutPortIndex(port.Name())
		if index >= 0 {
			index += n.NumInPorts()
		}
	}
	for i, p := range n.ports {
		if i == index {
			p.Select()
		} else {
			p.Deselect()
		}
	}
	n.selectedPort = index
}

func CreateXmlOutPort(p bh.PortIf) (xmlp *backend.XmlOutPort) {
	xmlp = backend.XmlOutPortNew(p.Name(), p.SignalType().TypeName())
	xmlp.Entry = freesp.CreateXmlModePosition(p).Entry
	return
}