"""PortItem: a clickable, relation-colored connection anchor on a node."""
from __future__ import annotations

from PyQt6.QtCore import QPointF, QRectF, Qt
from PyQt6.QtGui import QBrush, QColor, QPen
from PyQt6.QtWidgets import QGraphicsItem

from ..model.port import Port

PORT_RADIUS = 6.0


class PortItem(QGraphicsItem):
    """Rendered anchor for a single :class:`Port`, child of its NodeItem."""

    def __init__(self, node_item, port: Port) -> None:
        super().__init__(node_item)
        self.node_item = node_item
        self.port = port
        self.setAcceptHoverEvents(True)
        self.setZValue(2)
        self._hover = False
        # Visual affordance flags set by the scene during an edge drag.
        self.compatible_hint = False
        self.setToolTip(f"{port.name} ({port.relation})")
        self.update_position()

    # -- geometry ---------------------------------------------------------
    def update_position(self) -> None:
        n = self.node_item.node
        lx, ly = self.port.local_point(n.width, n.height)
        self.setPos(lx, ly)

    def boundingRect(self) -> QRectF:
        r = PORT_RADIUS + 3
        return QRectF(-r, -r, 2 * r, 2 * r)

    def scene_center(self) -> QPointF:
        return self.mapToScene(QPointF(0, 0))

    def relation_color(self) -> QColor:
        reg = self.node_item.scene_relations()
        return QColor(reg.color(self.port.relation)) if reg else QColor("#888")

    # -- interaction ------------------------------------------------------
    def hoverEnterEvent(self, event):
        self._hover = True
        self.update()
        super().hoverEnterEvent(event)

    def hoverLeaveEvent(self, event):
        self._hover = False
        self.update()
        super().hoverLeaveEvent(event)

    def set_compatible_hint(self, value: bool) -> None:
        if self.compatible_hint != value:
            self.compatible_hint = value
            self.update()

    # -- painting ---------------------------------------------------------
    def paint(self, painter, option, widget=None):
        color = self.relation_color()
        r = PORT_RADIUS
        if self._hover or self.compatible_hint:
            r = PORT_RADIUS + 2
        painter.setRenderHint(painter.RenderHint.Antialiasing, True)
        pen = QPen(color.darker(140), 1.5)
        if self.compatible_hint:
            pen = QPen(QColor("#000000"), 2)
        painter.setPen(pen)
        fill = color.lighter(120) if self._hover else color
        painter.setBrush(QBrush(fill))
        painter.drawEllipse(QPointF(0, 0), r, r)