# -*- 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/>.
#
'''
A field of stars.  Each has planets.  Each planet has...?

Keep it simple.

Stars have what qualities?
- Cosmetic
  - color
  - brightness
  - size
- Game stats
  - ?


'''
from random import randint, expovariate, seed, getrandbits
from poisson import poisson


seed(23)

MINIMUM_DISTANCE_BETWEEN_STARS = 160

# The old standard 4:3 ratio screen of 1024 x 768 pixels,
# let's have 10 x 10 of those.
WIDTH, HEIGHT = 10240, 7680


# Database stuff.  SQL, etc.

def generate_list_of_u64_for_ids(n):
    '''
    Return a sorted list of n random 64-bit integers
    (suitable for SQLite rowid columns.)
    See https://www.sqlite.org/lang_createtable.html#rowid
    '''
    result = set()
    safety = 10
    while n > 0:
        canidate = getrandbits(63)
        while canidate in result:
            if not safety:
                raise RuntimeError('this should not happen')
            safety -= 1
            canidate = getrandbits(63)
        result.add(canidate)
        n -= 1
    return sorted(result)


TABLES = [
    'create table stars (id INTEGER PRIMARY KEY, x INTEGER, y INTEGER, radius INTEGER)',
    ]


def init_db(conn):
    print('Generating star data.')
    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 iter_stars(conn):
    c = conn.cursor()
    c.execute('select x, y, radius from stars')
    yield from c.fetchall()
    c.close()


# Procedural Generation of solar system data


def generate_stars(width, height, minimum_distance_between_stars):
    # we could just call getrandbits(64) here for ID and hope for the best.
    # it's a large domain (u64) so collisions are unlikely(!).
    coords = list(poisson(width, height, minimum_distance_between_stars))
    ids = generate_list_of_u64_for_ids(len(coords))
    for star_id, (x, y) in zip(ids, coords):
        yield star_id, x, y, round(1 + expovariate(1))


def how_many_planets():
    n = round(gauss(5, 5))
    while n < 0:
        n = round(gauss(5, 5))
    return n