# stars class

import pygame
from pygame.locals import *
import game, gfx, math
from random import randrange
import gameinit


# Stars
MAXSTARS = 30
MINSTARS = 10
STARSIZE = [2,2] # pixels
MINLIFE = 20
MAXLIFE = 50
STARCHANGE = 2

STARDELAY = 3

BLACK = [20, 20, 40]
WHITE = [255, 255, 255]
LIGHTGRAY = [180, 180, 180]
DARKGRAY = [120, 120, 120]

STARCOLOR = [DARKGRAY,LIGHTGRAY,WHITE]

starimages = []

class Star:
    def __init__(self,activerect):
        global starimages
        val = randrange(1, 3)
        self.speed = -2, 0
        x = randrange(activerect.left,activerect.right)
        y = randrange(activerect.top,activerect.bottom)
        self.image = starimages[val-1]
        self.rect = self.image.get_rect().move(x,y)
        self.lastrect = self.rect
        self.life = randrange(MINLIFE,MAXLIFE)


class Stars:

    def __init__(self, activerect=None):
        self.counter = 0

        # build star images
        global starimages
        starimages = []
        for loop in range(0,3):
            color = STARCOLOR[loop]
            image = pygame.Surface(STARSIZE).convert(gfx.surface)
            image.fill(color)
            starimages.append(image)

        self.numstars = 20
        self.stars = []

        if activerect == None:
            # whole screen
            self.star_rect = gfx.rect
        else:
            self.star_rect = activerect
            
        for loop in range(self.numstars):
            self.stars.append(Star(self.star_rect))

        self.laststars = self.stars


    def recalc_num_stars(self, fps):
        return
    
        if isinstance(game.handler, gameinit.GameInit):
            #don't change stars while loading resources
            return

        change = randrange(-STARCHANGE,STARCHANGE)
        if (change < 0):
            for star in self.stars[0:abs(change)]:
                star.life = 0
        elif (change > 0):
            for loop in range(0,change):
                self.stars.append(Star(self.star_rect))
        #print 'STAR:', len(self.stars), fps


    def erase_tick_draw(self, background, gfx):
        self.counter = (self.counter + 1) % STARDELAY
        if self.counter != 0: return

        # local variables for speed
        R, B = gfx.rect.bottomright
        BLIT,DIRTY = gfx.surface.blit, gfx.dirty

        # erase & check life, make list of new stars
        self.stars = []
        stars_append = self.stars.append
        for star in self.laststars:
            DIRTY(background(star.lastrect))
            star.life += -1 
            if star.life  > 0:
                stars_append(star)

        # add stars if necessary
        if len(self.stars) < MINSTARS:
            for loop in range(0,MINSTARS-len(self.stars)):
                stars_append(Star(self.star_rect))

        # tick, draw
        for star in self.stars[:self.numstars]:
            star.rect.left = (star.rect.left + star.speed[0]) % R
            star.rect.top = (star.rect.top + star.speed[1]) % B
            DIRTY(BLIT(star.image, star.rect))
            star.lastrect = star.rect

        self.laststars = self.stars