# Source code for pyqtgraph.flowchart.Terminal

    __all__ = ["Terminal", "TerminalGraphicsItem"]

    import weakref

    from .. import functions as fn
    from ..graphicsItems.GraphicsObject import GraphicsObject
    from ..Point import Point
    from ..Qt import QtCore, QtGui, QtWidgets

    translate = QtCore.QCoreApplication.translate

    class Terminal(object):

        def __init__(self, node, name, io, optional=False, multi=False, pos=None, renamable=False, removable=False, multiable=False, bypass=None):
            """
            Construct a new terminal.

            ==============  =================================================================================
            **Arguments:**
            node            the node to which this terminal belongs
            name            string, the name of the terminal
            io              'in' or 'out'
            optional        bool, whether the node may process without connection to this terminal
            multi           bool, for inputs: whether this terminal may make multiple connections
                            for outputs: whether this terminal creates a different value for each connection
            pos             [x, y], the position of the terminal within its node's boundaries
            renamable       (bool) Whether the terminal can be renamed by the user
            removable       (bool) Whether the terminal can be removed by the user
            multiable       (bool) Whether the user may toggle the *multi* option for this terminal
            bypass          (str) Name of the terminal from which this terminal's value is derived
                            when the Node is in bypass mode.
            ==============  =================================================================================
            """
            self._io = io
            self._optional = optional
            self._multi = multi
            self._node = weakref.ref(node)
            self._name = name
            self._renamable = renamable
            self._removable = removable
            self._multiable = multiable
            self._connections = {}
            self._graphicsItem = TerminalGraphicsItem(self, parent=self._node().graphicsItem())
            self._bypass = bypass

            if multi:
                self._value = {}  ## dictionary of terminal:value pairs.
            else:
                self._value = None

            self.valueOk = None
            self.recolor()

        def value(self, term=None):
            """Return the value this terminal provides for the connected terminal"""
            if term is None:
                return self._value

            if self.isMultiValue():
                return self._value.get(term, None)
            else:
                return self._value

        def bypassValue(self):
            return self._bypass

        def setValue(self, val, process=True):
            """If this is a single-value terminal, val should be a single value.
            If this is a multi-value terminal, val should be a dict of terminal:value pairs"""
            if not self.isMultiValue():
                if fn.eq(val, self._value):
                    return
                self._value = val
            else:
                if not isinstance(self._value, dict):
                    self._value = {}
                if val is not None:
                    self._value.update(val)

            self.setValueAcceptable(None)  ## by default, input values are 'unchecked' until Node.update().
            if self.isInput() and process:
                self.node().update()

            self.recolor()

        def setOpts(self, **opts):
            self._renamable = opts.get('renamable', self._renamable)
            self._removable = opts.get('removable', self._removable)
            self._multiable = opts.get('multiable', self._multiable)
            if 'multi' in opts:
                self.setMultiValue(opts['multi'])

        def connected(self, term):
            """Called whenever this terminal has been connected to another. (note--this function is called on both terminals)"""
            if self.isInput() and term.isOutput():
                self.inputChanged(term)
            if self.isOutput() and self.isMultiValue():
                self.node().update()
            self.node().connected(self, term)

        def disconnected(self, term):
            """Called whenever this terminal has been disconnected from another. (note--this function is called on both terminals)"""
            if self.isMultiValue() and term in self._value:
                del self._value[term]
                self.node().update()
            else:
                if self.isInput():
                    self.setValue(None)
            self.node().disconnected(self, term)

        def inputChanged(self, term, process=True):
            """Called whenever there is a change to the input value to this terminal.
            It may often be useful to override this function."""
            if self.isMultiValue():
                self.setValue({term: term.value(self)}, process=process)
            else:
                self.setValue(term.value(self), process=process)

        def valueIsAcceptable(self):
            """Returns True->acceptable  None->unknown  False->Unacceptable"""
            return self.valueOk

        def setValueAcceptable(self, v=True):
            self.valueOk = v
            self.recolor()

        def connections(self):
            return self._connections

        def node(self):
            return self._node()

        def isInput(self):
            return self._io == 'in'

        def isMultiValue(self):
            return self._multi

        def setMultiValue(self, multi):
            """Set whether this is a multi-value terminal."""
            self._multi = multi
            if not multi and len(self.inputTerminals()) > 1:
                self.disconnectAll()

            for term in self.inputTerminals():
                self.inputChanged(term)

        def isOutput(self):
            return self._io == 'out'

        def isRenamable(self):
            return self._renamable

        def isRemovable(self):
            return self._removable

        def isMultiable(self):
            return self._multiable

        def name(self):
            return self._name

        def graphicsItem(self):
            return self._graphicsItem

        def isConnected(self):
            return len(self.connections()) > 0

        def connectedTo(self, term):
            return term in self.connections()

        def hasInput(self):
            for t in self.connections():
                if t.isOutput():
                    return True
            return False

        def inputTerminals(self):
            """Return the terminal(s) that give input to this one."""
            return [t for t in self.connections() if t.isOutput()]

        def dependentNodes(self):
            """Return the list of nodes which receive input from this terminal."""
            return set([t.node() for t in self.connections() if t.isInput()])

        def connectTo(self, term, connectionItem=None):
            try:
                if self.connectedTo(term):
                    raise Exception('Already connected')
                if term is self:
                    raise Exception('Not connecting terminal to self')
                if term.node() is self.node():
                    raise Exception("Can't connect to terminal on same node.")
                for t in [self, term]:
                    if t.isInput() and not t._multi and len(t.connections()) > 0:
                        raise Exception("Cannot connect %s <-> %s: Terminal %s is already connected to %s (and does not allow multiple connections)" % (self, term, t, list(t.connections().keys())))
            except:
                if connectionItem is not None:
                    connectionItem.close()
                raise

            if connectionItem is None:
                connectionItem = ConnectionItem(self.graphicsItem(), term.graphicsItem())
                self.graphicsItem().getViewBox().addItem(connectionItem)
            self._connections[term] = connectionItem
            term._connections[self] = connectionItem

            self.recolor()

            self.connected(term)
            term.connected(self)

            return connectionItem

        def disconnectFrom(self, term):
            if not self.connectedTo(term):
                return
            item = self._connections[term]
            item.close()
            del self._connections[term]
            del term._connections[self]
            self.recolor()
            term.recolor()

            self.disconnected(term)
            term.disconnected(self)

        def disconnectAll(self):
            for t in list(self._connections.keys()):
                self.disconnectFrom(t)

        def recolor(self, color=None, recurse=True):
            if color is None:
                if not self.isConnected():       ## disconnected terminals are black
                    color = QtGui.QColor(0,0,0)
                elif self.isInput() and not self.hasInput():   ## input terminal with no connected output terminals
                    color = QtGui.QColor(200,200,0)
                elif self._value is None or fn.eq(self._value, {}):  ## terminal is connected but has no data (possibly due to processing error)
                    color = QtGui.QColor(255,255,255)
                elif self.valueIsAcceptable() is None:   ## terminal has data, but it is unknown if the data is ok
                    color = QtGui.QColor(200, 200, 0)
                elif self.valueIsAcceptable() is True:   ## terminal has good input, all ok
                    color = QtGui.QColor(0, 200, 0)
                else:                                    ## terminal has bad input
                    color = QtGui.QColor(200, 0, 0)
            self.graphicsItem().setBrush(QtGui.QBrush(color))

            if recurse:
                for t in self.connections():
                    t.recolor(color, recurse=False)

        def rename(self, name):
            oldName = self._name
            self._name = name
            self.node().terminalRenamed(self, oldName)
            self.graphicsItem().termRenamed(name)

        def __repr__(self):
            return "<Terminal %s.%s>" % (str(self.node().name()), str(self.name()))

        def __hash__(self):
            return id(self)

        def close(self):
            self.disconnectAll()
            item = self.graphicsItem()
            if item.scene() is not None:
                item.scene().removeItem(item)

        def saveState(self):
            return {'io': self._io, 'multi': self._multi, 'optional': self._optional, 'renamable': self._renamable, 'removable': self._removable, 'multiable': self._multiable}

        def __lt__(self, other):
            """When the terminal is multi value, the data passed to the DatTreeWidget for each input or output, is {Terminal: value}.
            To make this sortable, we provide the < operator.
            """
            return self._name < other._name

    class TextItem(QtWidgets.QGraphicsTextItem):
        def __init__(self, text, parent, on_update):
            super().__init__(text, parent)
            self.on_update = on_update

        def focusOutEvent(self, ev):
            super().focusOutEvent(ev)
            if self.on_update is not None:
                self.on_update()

        def keyPressEvent(self, ev):
            if ev.key() == QtCore.Qt.Key.Key_Enter or ev.key() == QtCore.Qt.Key.Key_Return:
                if self.on_update is not None:
                    self.on_update()
                    return
            super().keyPressEvent(ev)

    class TerminalGraphicsItem(GraphicsObject):

        def __init__(self, term, parent=None):
            self.term = term
            GraphicsObject.__init__(self, parent)
            self.brush = fn.mkBrush(0,0,0)
            self.box = QtWidgets.QGraphicsRectItem(0, 0, 10, 10, self)
            on_update = self.labelChanged if self.term.isRenamable() else None
            self.label = TextItem(self.term.name(), self, on_update)
            self.label.setScale(0.7)
            self.newConnection = None
            self.setFiltersChildEvents(True)  ## to pick up mouse events on the rectitem
            if self.term.isRenamable():
                self.label.setTextInteractionFlags(QtCore.Qt.TextInteractionFlag.TextEditorInteraction)
            self.setZValue(1)
            self.menu = None

        def labelChanged(self):
            newName = self.label.toPlainText()
            if newName != self.term.name():
                self.term.rename(newName)

        def termRenamed(self, name):
            self.label.setPlainText(name)

        def setBrush(self, brush):
            self.brush = brush
            self.box.setBrush(brush)

        def disconnect(self, target):
            self.term.disconnectFrom(target.term)

        def boundingRect(self):
            br = self.box.mapRectToParent(self.box.boundingRect())
            lr = self.label.mapRectToParent(self.label.boundingRect())
            return br | lr

        def paint(self, p, *args):
            pass

        def setAnchor(self, x, y):
            pos = QtCore.QPointF(x, y)
            self.anchorPos = pos
            br = self.box.mapRectToParent(self.box.boundingRect())
            lr = self.label.mapRectToParent(self.label.boundingRect())

            if self.term.isInput():
                self.box.setPos(pos.x(), pos.y()-br.height()/2.)
                self.label.setPos(pos.x() + br.width(), pos.y() - lr.height()/2.)
            else:
                self.box.setPos(pos.x()-br.width(), pos.y()-br.height()/2.)
                self.label.setPos(pos.x()-br.width()-lr.width(), pos.y()-lr.height()/2.)
            self.updateConnections()

        def updateConnections(self):
            for t, c in self.term.connections().items():
                c.updateLine()

        def mousePressEvent(self, ev):
            #ev.accept()
            ev.ignore() ## necessary to allow click/drag events to process correctly

        def mouseClickEvent(self, ev):
            if ev.button() == QtCore.Qt.MouseButton.LeftButton:
                ev.accept()
                self.label.setFocus(QtCore.Qt.FocusReason.MouseFocusReason)
            elif ev.button() == QtCore.Qt.MouseButton.RightButton:
                ev.accept()
                self.raiseContextMenu(ev)

        def raiseContextMenu(self, ev):
            ## only raise menu if this terminal is removable
            menu = self.getMenu()
            menu = self.scene().addParentContextMenus(self, menu, ev)
            pos = ev.screenPos()
            menu.popup(QtCore.QPoint(int(pos.x()), int(pos.y())))

        def getMenu(self):
            if self.menu is None:
                self.menu = QtWidgets.QMenu()
                self.menu.setTitle(translate("Context Menu", "Terminal"))
                remAct = QtGui.QAction(translate("Context Menu", "Remove terminal"), self.menu)
                remAct.triggered.connect(self.removeSelf)
                self.menu.addAction(remAct)
                self.menu.remAct = remAct
                if not self.term.isRemovable():
                    remAct.setEnabled(False)
                multiAct = QtGui.QAction(translate("Context Menu", "Multi-value"), self.menu)
                multiAct.setCheckable(True)
                multiAct.setChecked(self.term.isMultiValue())
                multiAct.setEnabled(self.term.isMultiable())

                multiAct.triggered.connect(self.toggleMulti)
                self.menu.addAction(multiAct)
                self.menu.multiAct = multiAct
                if self.term.isMultiable():
                    multiAct.setEnabled = False
            return self.menu

        def toggleMulti(self):
            multi = self.menu.multiAct.isChecked()
            self.term.setMultiValue(multi)

        def removeSelf(self):
            self.term.node().removeTerminal(self.term)

        def mouseDragEvent(self, ev):
            if ev.button() != QtCore.Qt.MouseButton.LeftButton:
                ev.ignore()
                return

            ev.accept()
            if ev.isStart():
                if self.newConnection is None:
                    self.newConnection = ConnectionItem(self)
                    #self.scene().addItem(self.newConnection)
                    self.getViewBox().addItem(self.newConnection)
                    #self.newConnection.setParentItem(self.parent().parent())

                self.newConnection.setTarget(self.mapToView(ev.pos()))
            elif ev.isFinish():
                if self.newConnection is not None:
                    items = self.scene().items(ev.scenePos())
                    gotTarget = False
                    for i in items:
                        if isinstance(i, TerminalGraphicsItem):
                            self.newConnection.setTarget(i)
                            try:
                                self.term.connectTo(i.term, self.newConnection)
                                gotTarget = True
                            except:
                                self.scene().removeItem(self.newConnection)
                                self.newConnection = None
                                raise
                            break

                    if not gotTarget:
                        self.newConnection.close()
                    self.newConnection = None
            else:
                if self.newConnection is not None:
                    self.newConnection.setTarget(self.mapToView(ev.pos()))

        def hoverEvent(self, ev):
            if not ev.isExit() and ev.acceptDrags(QtCore.Qt.MouseButton.LeftButton):
                ev.acceptClicks(QtCore.Qt.MouseButton.LeftButton) ## we don't use the click, but we also don't want anyone else to use it.
                ev.acceptClicks(QtCore.Qt.MouseButton.RightButton)
                self.box.setBrush(fn.mkBrush('w'))
            else:
                self.box.setBrush(self.brush)
            self.update()

        def connectPoint(self):
            ## return the connect position of this terminal in view coords
            return self.mapToView(self.mapFromItem(self.box, self.box.boundingRect().center()))

        def nodeMoved(self):
            for t, item in self.term.connections().items():
                item.updateLine()

    class ConnectionItem(GraphicsObject):

        def __init__(self, source, target=None):
            GraphicsObject.__init__(self)
            self.setFlags(
                self.GraphicsItemFlag.ItemIsSelectable |
                self.GraphicsItemFlag.ItemIsFocusable
            )
            self.source = source
            self.target = target
            self.length = 0
            self.hovered = False
            self.path = None
            self.shapePath = None
            self.style = {
                'shape': 'line',
                'color': (100, 100, 250),
                'width': 1.0,
                'hoverColor': (150, 150, 250),
                'hoverWidth': 1.0,
                'selectedColor': (200, 200, 0),
                'selectedWidth': 3.0,
                }
            self.source.getViewBox().addItem(self)
            self.updateLine()
            self.setZValue(0)

        def close(self):
            if self.scene() is not None:
                self.scene().removeItem(self)

        def setTarget(self, target):
            self.target = target
            self.updateLine()

        def setStyle(self, **kwds):
            self.style.update(kwds)
            if 'shape' in kwds:
                self.updateLine()
            else:
                self.update()

        def updateLine(self):
            start = Point(self.source.connectPoint())
            if isinstance(self.target, TerminalGraphicsItem):
                stop = Point(self.target.connectPoint())
            elif isinstance(self.target, QtCore.QPointF):
                stop = Point(self.target)
            else:
                return
            self.prepareGeometryChange()

            self.path = self.generatePath(start, stop)
            self.shapePath = None
            self.update()

        def generatePath(self, start, stop):
            path = QtGui.QPainterPath()
            path.moveTo(start)
            if self.style['shape'] == 'line':
                path.lineTo(stop)
            elif self.style['shape'] == 'cubic':
                path.cubicTo(Point(stop.x(), start.y()), Point(start.x(), stop.y()), Point(stop.x(), stop.y()))
            else:
                raise Exception('Invalid shape "%s"; options are "line" or "cubic"' % self.style['shape'])
            return path

        def keyPressEvent(self, ev):
            if not self.isSelected():
                ev.ignore()
                return

            if ev.key() == QtCore.Qt.Key.Key_Delete or ev.key() == QtCore.Qt.Key.Key_Backspace:
                self.source.disconnect(self.target)
                ev.accept()
            else:
                ev.ignore()

        def mousePressEvent(self, ev):
            ev.ignore()

        def mouseClickEvent(self, ev):
            if ev.button() == QtCore.Qt.MouseButton.LeftButton:
                ev.accept()
                sel = self.isSelected()
                self.setSelected(True)
                self.setFocus()
                if not sel and self.isSelected():
                    self.update()

        def hoverEvent(self, ev):
            if (not ev.isExit()) and ev.acceptClicks(QtCore.Qt.MouseButton.LeftButton):
                self.hovered = True
            else:
                self.hovered = False
            self.update()

        def boundingRect(self):
            return self.shape().boundingRect()

        def viewRangeChanged(self):
            self.shapePath = None
            self.prepareGeometryChange()

        def shape(self):
            if self.shapePath is None:
                if self.path is None:
                    return QtGui.QPainterPath()
                stroker = QtGui.QPainterPathStroker()
                px = self.pixelWidth()
                stroker.setWidth(px*8)
                self.shapePath = stroker.createStroke(self.path)
            return self.shapePath

        def paint(self, p, *args):
            if self.isSelected():
                p.setPen(fn.mkPen(self.style['selectedColor'], width=self.style['selectedWidth']))
            else:
                if self.hovered:
                    p.setPen(fn.mkPen(self.style['hoverColor'], width=self.style['hoverWidth']))
                else:
                    p.setPen(fn.mkPen(self.style['color'], width=self.style['width']))

            p.drawPath(self.path)