# exhaust trails class

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


SIZE = [1,1] # pixels
DELAY = 3
LIFE = 50 / DELAY 

YELLOW = [249,229,9]
BLACK = [20, 20, 40]
WHITE = [255, 255, 255]
LIGHTGRAY = [180, 180, 180]
DARKGRAY = [120, 120, 120]


class ExhaustParticle:
    def __init__(self,x,y,image):
        self.image = image
        self.rect = self.image.get_rect().move(x,y)
        self.lastrect = self.rect
        self.life = LIFE
        self.dx = -game.groundspeed * DELAY


class Exhaust:

    def __init__(self, activerect=None):
        self.blit = gfx.surface.blit
        self.dirty = gfx.dirty

        self.counter = 0

        # build image
        color = YELLOW
        self.image = pygame.Surface(SIZE).convert(gfx.surface)
        self.image.fill(color)

        if activerect == None:
            # whole screen
            self.rect = gfx.rect
        else:
            self.rect = activerect
            
        self.particles = []
        self.lastparticles = self.particles

        self.timer = 0


    def add_particle(self,x,y):
        self.particles.append(ExhaustParticle(x,y,self.image))


    def erase_and_check_life(self,particle):
        self.dirty(self.background(particle.lastrect))
        particle.life += -1 
        if particle.life  > 0:
            return particle
        else:
            return None            

    def tick_and_draw(self,particle):
        particle.rect.left = (particle.rect.left + particle.dx * self.speedadjust)
        self.dirty(self.blit(particle.image, particle.rect))
        particle.lastrect = particle.rect


    def erase_tick_draw(self, background, gfx,speedadjust):
        self.timer += 1
        if self.timer % DELAY !=0:
            return

        self.speedadjust = speedadjust
        self.background = background
        
        # erase & check life, make list of new particles
        self.particles = map(self.erase_and_check_life,self.lastparticles)
        # remove extra Nones from the list
        self.particles = filter(lambda x: x != None,self.particles)

        # tick, draw
        map(self.tick_and_draw,self.particles)
            
        self.lastparticles = self.particles