import pygame
import random
import math
from pygame import mixer

# intialize pygame

pygame.init()

#Background music
mixer.music.load('background.wav')
mixer.music.play(-1)

# create the screen

height = 600
width = 800
screen = pygame.display.set_mode((width, height))  # there must be 2 parenthesis

# Title and Icon

pygame.display.set_caption("Space Invader")
icon = pygame.image.load('ufo.png')
pygame.display.set_icon(icon)

#score
score_value = 0

font = pygame.font.Font('freesansbold.ttf',32)

textx = 10
texty = 10





# Player

player_image = pygame.image.load('arcade.png')
player_x = width / 2 - 36
player_y = height * 4 / 5
player_x_change = 0

# enemy
enemy_image = []
enemy_x = []
enemy_y = []
enemy_x_change = []
enemy_y_change = []
num_of_enemies = 6

for i in range(num_of_enemies):
    enemy_image.append(pygame.image.load('alien.png'))
    enemy_x.append(random.randint(0, width - 65))
    enemy_y.append(random.randint(int(height / 12), int(height / 4)))
    enemy_x_change.append(0.3)
    enemy_y_change.append(40)

# Bullet

# ready = you can't see the bullet on screen
# Fire = Bullet is moving
bullet_image = pygame.image.load('bullet.png')
bullet_x = 0
bullet_y = height * 4 / 5
bullet_x_change = 0
bullet_y_change = 0.5
bullet_state = 'ready'

#GameOver

over_font = pygame.font.Font('freesansbold.ttf',64)
def gameovertext():
    game_over = over_font.render('* GAME OVER *', True, (255, 255, 255))
    screen.blit(game_over, (200, 250))


def show_score (x,y):
    score = font.render('score:' +str(score_value),True,(255,255,255))
    screen.blit(score, (x, y))


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


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


def fire_bullet(x, y):
    global bullet_state
    bullet_state = 'fire'
    screen.blit(bullet_image, (x + 16, y + 10))


def iscollision(enemy_x, enemy_y, bullet_x, bullet_y):
    distance = math.sqrt(pow(enemy_x - bullet_x, 2) + pow(enemy_y - bullet_y, 2))
    if distance <= 27:
        return True
    else:
        return False


running = True
while running:

    # RGB Red Green Blue
    screen.fill((0, 0, 0))
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                player_x_change = -0.3
            if event.key == pygame.K_RIGHT:
                player_x_change = 0.3
            if bullet_state == 'ready':
                if event.key == pygame.K_SPACE:
                    bullet_sound = mixer.Sound('laser.wav')
                    bullet_sound.play()
                    # Get the current x co-ordinate of spaceship
                    bullet_x = player_x
                    fire_bullet(bullet_x, bullet_y)
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                player_x_change = 0
    # Checking for boundaries so that spaceship doesn't go out of boundary.
    player_x += player_x_change
    if player_x <= 0:
        player_x = 0
    elif player_x > width - 64:
        player_x = width - 64
    # Enemy movement
    for i in range(num_of_enemies):
        if enemy_y[i] > 200:
            for j in range (num_of_enemies):
                enemy_y[j] = 2000
            gameovertext()
            break

        enemy_x[i] += enemy_x_change[i]
        if enemy_x[i] <= 0:
            enemy_x_change[i] = 0.3
            enemy_y[i] += enemy_y_change[i]
        elif enemy_x[i] >= width - 64:
            enemy_x_change[i] = -0.3
            enemy_y[i] += enemy_y_change[i]
            # Checking for collission
        collision = iscollision(enemy_x[i], enemy_y[i], bullet_x, bullet_y)
        if collision:
            explosion_sound = mixer.Sound('explosion.wav')
            explosion_sound.play()
            bullet_y = height * 4 / 5
            bullet_state = 'ready'
            score_value += 1
            enemy_x[i] = random.randint(0, width - 65)
            enemy_y[i] = random.randint(int(height / 12), int(height / 4))

        enemy(enemy_x[i], enemy_y[i], i)
    player(player_x, player_y)
    show_score(textx,texty)

    # Bullet movement
    if bullet_y <= 0:
        bullet_y = height * 4 / 5
        bullet_state = 'ready'
    if bullet_state == 'fire':
        fire_bullet(bullet_x, bullet_y)
        bullet_y -= bullet_y_change

    pygame.display.update()