from PyQt5.QtGui import QPen, QBrush
from PyQt5.QtCore import Qt, QPointF
from PyQt5.QtWidgets import (
    QWidget,
    QGraphicsView,
    QGraphicsScene,
    QGraphicsEllipseItem,
    QGraphicsLineItem,
    QVBoxLayout
)


class GridDots(QWidget):
    def __init__(self):
        super().__init__()
        self.view = QGraphicsView()
        self.scene = QGraphicsScene()
        self.scene.setSceneRect(0, 0, 800, 800)
        self.view.setScene(self.scene)

        self.dots = []
        self.lines = set()
        self.setup_ui()
        self.create_grid()

    def setup_ui(self):
        layout = QVBoxLayout(self)
        layout.addWidget(self.view)

    def create_grid(self):
        """Draw 3x3 grid of dots"""
        dot_radius = 30
        spacing = 240
        offset = 150

        for row in range(3):
            for col in range(3):
                x, y, = offset + col * spacing, offset + row * spacing
                dot = QGraphicsEllipseItem(
                    x - dot_radius, y - dot_radius,
                    2 * dot_radius, 2 * dot_radius)
                dot.setBrush(QBrush(Qt.black))
                self.scene.addItem(dot)
                self.dots.append((x, y))

    def draw_line(self, start, end):
        line_id = tuple(sorted((start, end)))
        if line_id not in self.lines:
            start_pos = QPointF(*self.dots[start])
            end_pos = QPointF(*self.dots[end])

            line = QGraphicsLineItem(
                start_pos.x(), start_pos.y(),
                end_pos.x(), end_pos.y())

            line.setPen(QPen(Qt.black, 2))
            self.scene.addItem(line)
            self.lines.add(line_id)