# -*- 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/>.
#
from random import randint, expovariate, seed
import sqlite3
from poisson import poisson


FILENAME = './game.sqlite'
MINIMUM_DISTANCE_BETWEEN_STARS = 160
WIDTH, HEIGHT = 10240, 7680


CREATE_TABLES = '''\
create table stars (x INTEGER, y INTEGER, radius INTEGER)
'''.splitlines(False)

conn = None


def initialize_db(filename):
    conn = open_db(filename)
    c = conn.cursor()
    for statement in CREATE_TABLES:
        c.execute(statement)
    c.close()
    conn.commit()
    return conn


def close_db():
    if conn:
        conn.close()
        conn = None
    else:
        raise RuntimeError('db connection already closed')


def open_db(filename=FILENAME):
    global conn
    if conn is not None:
        raise RuntimeError('db connection already open')
    conn = sqlite3.connect(filename)
    return conn


def generate_stars(width, height, minimum_distance_between_stars):
    for x, y in poisson(width, height, minimum_distance_between_stars):
        yield x, y, round(1 + expovariate(1))


def main(filename):
    print('Initializing db file', filename)
    conn = initialize_db(filename)

    print('Generating data.')
    seed(23)
    c = conn.cursor()
    for values in generate_stars(
        WIDTH,
        HEIGHT,
        MINIMUM_DISTANCE_BETWEEN_STARS,
        ):
        c.execute('insert into stars values (?, ?, ?)', values)
    c.close()
    conn.commit()


def stars():
    global conn
    c = conn.cursor()
    c.execute('select x, y, radius from stars')
    yield from c.fetchall()
    c.close()


if __name__ == '__main__':
    import pathlib

    if not pathlib.Path(FILENAME).exists():
        main(FILENAME)
    else:
        print(FILENAME, 'already exists!  Not overwriting.')