#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
#    Copyright © 2024 Simon Forman
#
#    This file is part of game
#
#    game is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    game is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with game.  If not see <http://www.gnu.org/licenses/>.
#


class Reticule:

    def __init__(self, canvas, radius_x=35, radius_y=20, color='green'):
        self.canvas = canvas
        self.radius_x = radius_x
        self.radius_y = radius_y
        self.color = color
        self.item_ids = []
        self.init_reticule()

    def get_reticule_coords(self, x, y):
        '''
        Given the width and height of a rectangle and x-y coords in that
        rectangle yield coords for four lines and an oval suitable for
        passing to canvas.coords() method.
        '''
        width, height = int(self.canvas['width']), int(self.canvas['height'])
        top = y - self.radius_y
        left = x - self.radius_x
        bottom = y + self.radius_y
        right = x + self.radius_x
        yield 0, y, left, y
        yield right, y, width - 1, y
        yield x, 0, x, top
        yield x, bottom, x, height - 1
        yield left, top, right, bottom

    def init_reticule(self):
        append = self.item_ids.append
        w, h = int(self.canvas['width']), int(self.canvas['height'])
        coords = self.get_reticule_coords(w >> 1, h >> 1)  # Center.
        append(canvas.create_line(*next(coords), fill=self.color))
        append(canvas.create_line(*next(coords), fill=self.color))
        append(canvas.create_line(*next(coords), fill=self.color))
        append(canvas.create_line(*next(coords), fill=self.color))
        append(canvas.create_oval(*next(coords), outline=self.color))

    def set_reticule(self, x, y):
        coords = self.get_reticule_coords(x, y)
        for item_id, item_coords in zip(self.item_ids, coords):
            self.canvas.coords(item_id, *item_coords)

    def handle_set_event(self, event):
        self.set_reticule(event.x, event.y)


if __name__ == '__main__':
    from tkinter import *

    def handle_canvas_resize(event):
        # I don't know why the Tk system doesn't update these values.
        canvas['width'] = event.width
        canvas['height'] = event.height
        # update reticule here/now?
        # If the canvas window has enlarged then some of the lines will have
        # to be extended.


    canvas = Canvas(bg='black')

    canvas.bind('<Configure>', handle_canvas_resize)
    canvas.pack(expand=True, fill=BOTH)
    canvas.update()

    # Let the configure event propagate and trigger the
    # handle_canvas_resize() callback to set the width
    # and height values of the canvas correctly so that
    # the reticule lines get drawn correctly.

    reticule = Reticule(canvas)
    canvas.bind('<Button-1>', reticule.handle_set_event)
    canvas.bind('<B1-Motion>', reticule.handle_set_event)

    #canvas.mainloop()