import pygame
import random
import math
from pygame import mixer
#Initialize the Pygame
pygame.init()
#Create the Screen
screen=pygame.display.set_mode((800,600))
running=True
# Title and Icon
pygame.display.set_caption("Space Innvaders")
icon= pygame.image.load("ufo.png")
pygame.display.set_icon(icon)

#Background
background = pygame.image.load("background.png")

#Music
mixer.music.load("background.wav")
mixer.music.play(-1)
#SCore
score_value = 0
font=pygame.font.Font("freesansbold.ttf",32)

textX=10
textY=10
# gameOver
over_font=pygame.font.Font("freesansbold.ttf",60)

def show_score(x,y):
    score=font.render("Score: "+ str(score_value),True, (255,255,125))
    screen.blit(score,(x,y))
def game_over_text():
    over_text=over_font.render("GAME OVER",True, (255,0,0))
    screen.blit(over_text,(200,250))
#Player
playerImg=pygame.image.load("space_invaders.png")
playerX=370
playerY=480 

#Enemy
enemyImg=[]
enemyX=[]
enemyY=[]
enemyX_change=[]
enemyY_change=[]
number_of_enemies=10
for i in range(number_of_enemies):
    enemyImg.append(pygame.image.load("alien.png"))
    enemyX.append(random.randint(0,735))
    enemyY.append(random.randint(50,150))
    enemyX_change.append(4)
    enemyY_change.append(40)
#Bullet
bulletImg=pygame.image.load("bullet.png")
bulletX=0
bulletY=480

#Variable for change
playerX_change=0
bulletY_change=10
bullet_state="ready"

def player(x,y):
    screen.blit(playerImg, (x,y))

def enemy(x,y,i):
    screen.blit(enemyImg[i],(x,y))

def fire_bullet(x,y):
    global bullet_state
    bullet_state="fire"
    screen.blit(bulletImg,(x+16,y+10))
def iscollison (enemyX,enemyY,bulletX,bulletY):
    distance=math.sqrt(math.pow((enemyX-bulletX),2)+math.pow((enemyY-bulletY),2))
    if distance < 27:
        return True
    else:
        return False

#game loop
while running:
    screen.fill((0,0,0))
    screen.blit(background,(0,0))
    for event in pygame.event.get():
        if event.type==pygame.QUIT:
            running= False
    # Keyboard input
        if event.type== pygame.KEYDOWN:
            if event.key==pygame.K_LEFT:
                playerX_change = -5
            if event.key==pygame.K_RIGHT:
               playerX_change = 5
            if event.key==pygame.K_SPACE:
                if bullet_state == "ready":
                    bullet_sound=mixer.Sound("laser.wav")
                    bullet_sound.play()
                    bulletX=playerX
                    fire_bullet(bulletX,bulletY)    
        if event.type==pygame.KEYUP:
            if event.key==pygame.K_LEFT or event.key==pygame.K_RIGHT:
                playerX_change = 0
        
    
    playerX +=playerX_change
    if playerX <= 0:
            playerX=0
    elif playerX >= 736:
             playerX=736   

    for i in range(number_of_enemies):
        if enemyY[i]>440:
            for j in range(number_of_enemies):
                enemyY[j]=2000
            game_over_text()
            break
        enemyX[i] +=enemyX_change[i]
        if enemyX[i] <= 0:
            enemyX_change[i]=4
            enemyY[i] += enemyY_change[i]
        elif enemyX[i] >= 736:
             enemyX_change[i]=-4    
             enemyY[i] += enemyY_change[i]  
            #Collison
        collison= iscollison(enemyX[i],enemyY[i],bulletX,bulletY)
        if collison:
             explosion_sound=mixer.Sound("explosion.wav")
             explosion_sound.play()
             bulletY=480
             bullet_state="ready"
             score_value +=1
             print(score_value)
             enemyX[i]=random.randint(0,735)
             enemyY[i]=random.randint(50,150)    
        
        enemy(enemyX[i],enemyY[i],i)
    player(playerX,playerY)
    
    
   # Bullet Movement
    if bulletY <= 0:
        bulletY = 480
        bullet_state="ready" 
    if bullet_state == "fire":
        fire_bullet(bulletX,bulletY)
        bulletY-=bulletY_change
    show_score(textX,textY)

    pygame.display.update()
