import pygame, sys # Imports pygame and sys libraries
from pygame.locals import * # Imports pygame local library for constant variables

pygame.init() # Has to be used before any python functions, activates python library
screen = pygame.display.set_mode((400, 300)) # Sets the entire screen, width/height
background = pygame.Surface((400, 300)) 
pygame.display.set_caption("Hello world!") # Sets the title for the game in the game window

surface = pygame.Surface((10, 10)) # Creates a surface
surface.fill((0,255,0)) # Colours the surface green, without fill a surface defaults to black

#print_message = pygame.USEREVENT + 0 # 24 - 32 for user events. This has a value of 24. +1 for value of 25
#pygame.time.set_timer(print_message, 3000) # 3000 milliseconds

pos = [180, 130] # square position

while True: # Main game loop, stop when game is quit
    events = pygame.event.get()
    for event in events:
        if event.type == QUIT: # Checks for quit event
            pygame.quit() # Quits pygame, use before sys.exit, deactivates python library, opposite of pygame.init()
            sys.exit() # Quits sys
        #if event.type == print_message: # Prints hello world every 3s
            #print("Hello World")

        while 1:
            pressed_keys = pygame.key.get_pressed()

            if pressed_keys[K_a]:
                pos[0] -= 1
            if pressed_keys[K_d]:
                pos[0] += 1
            if pressed_keys[K_w]:
                pos[1] -= 1
            if pressed_keys[K_s]:
                pos[1] += 1
            break
    screen.blit(background, (0, 0)) # Paints over the square
    screen.blit(surface, pos) # Draws a surface object onto another
    pygame.display.update() # Updates the game display


   # pygame.Surface.copy() - used to create an exact copy of another surface object
    
   # pygame.Surface.get_size() - returns the width and height of a surface object
    
   # pygame.time.set_timer(print_message, 0) - stops the event for printing hello world every 3s
    
   # self.rect.colliderect(sprite.rect) - returns true if two objacts overlap, otherwise returns false
    
   # pygame.sprite.spritecollideany(sprite, group) - detects if a sprite is in collision with any group sprites
    
   # pygame.sprite.groupcollide(group1, group2) - can also have 3rd & 4th parameters (dokill1, dokill2)
   # takes true or false values and if a value is true, the sprites from corresponding group are removed


    """
    if pygame.sprite.spritecollideany(P1, enemies):
        DISPLAY.SURF.fill(RED)
        pygame.display.update()
        for entity in all_sprites:
            entity.kill()
        time.sleep(2)
        pygame.quit()
        sys.exit()       
    """

    """
    fonts:

    pygame.font.Font() is for .ttf files like pygame.font.Font("arial.ttf", 20), also has font size with "20"
    font = pygame.font.Font(None, size) will make program use system default font

    pygame.font.SysFont() is alternative if no .ttf files
    pygame.font.get_fonts() will return every font it finds on your system

    Initates the font with a variable and renders with text:
    dialogue_font = pygame.font.SysFont("arial", 15)
    dialogue = dialogue_font.render("Hey there, Beautiful weather today!", True, (0,0,0))
    screen.blit(dialogue, (40,40))
    
    "True" parameter stands for anti-aliasing which makes edges smoother
    """

# music.play() with no parameters/0 plays audio clip once, -1 plays indefinitely. any other number repeats it that amount of times
# music.queue(), music.stop(), music.pause(), music.unpause()
# music.set_endevent() takes a parameter and triggers corresponding event once music stops playing

    """
    SONG_END_EVENT = pygame.USEREVENT + 1

    while True:
        for event in pygame.event.get():
            if event.type == SONG_END:
                execute code here
    """

# pygame.mixer.music.rewind()
# pygame.mixer.music.set_volume() – Values: 0.0-1.0. Settings reset when new music plays
# pygame.mixer.music.get_busy() – Checks if music is playing, returns True/False

# sound_effect.play() to play sound effects



# pygame.draw.polygon(surface, color, pointlist, width)
# pygame.draw.line(surface, color, start_point, end_point, width)
# pygame.draw.lines(surface, color, closed, pointlist, width)
# pygame.draw.circle(surface, color, center_point, radius, width)
# pygame.draw.ellipse(surface, color, bounding_rectangle, width)
# pygame.draw.rect(surface, color, rectangle_tuple, width)

# surface - Window object to which we want to draw the shape
# start_point/end_point - a tuple/list consisting of an x and y value pair, which defines the starting and ending position of where the line will be drawn
# width lines - default value 1, width < 1 lione not drawn, values above 1 increases line thickness
# width polygons - default value 0, means polygon filled with colour, values above 0 makes it unfilled and width controls border thickness
# closed - specifies whether first and last points have a line between them, false by default
# pointlist - a list of x-y coordinate pairs, where each adjacent pair is connected to the other with a line
# center - Tuple/List which defines coordinate pair for the center of origin of the Circle.
# bounding_rectangle - Takes a Rect object which defines the rectangle it will be confined in.
# rectangle_tuple - x coordinate, y coordinate, width of rectangle, height of rectangle