pocket-friends/pocket_friends/game_files/game.py

"""
Main file for the entire game. Controls everything except for GPIO input.
"""
from collections import deque
import importlib.util
import json
import os
from pathlib import Path
import pocket_friends
import pygame
from pygame.locals import *
from ..hardware.gpio_handler import Constants, GPIOHandler

# FPS for the entire game to run at.
game_fps = 16
# The resolution the game is rendered at.
game_res = 80

# Gets the directory of the script for importing and the save directory
script_dir = os.path.dirname(os.path.abspath(__file__))
save_dir = os.path.join(Path.home(), '.pocket_friends')

# Tries to make the save directory. Does nothing if it already exists.
try:
    os.mkdir(save_dir)
except FileExistsError:
    pass


class SpriteSheet:
    """
    Imports a sprite sheet as separate pygame images given an image file and a json file.
    """

    def __init__(self, sprite_sheet, texture_json):
        # Load in whole sprite sheet as one image.
        self.sprite_sheet = pygame.image.load(sprite_sheet).convert_alpha()
        self.images = []

        # Get the sprite sheet json file.
        with open(texture_json, 'r') as json_file:
            self.img_attrib = json.load(json_file)
            json_file.close()

        # Count for how many images have been added in the image list
        image_count = 0

        # Get the sprite size as a tuple
        sprite_size = self.img_attrib['width'], self.img_attrib['height']

        # Iterate through every image location on the sprite sheet given the sprite size
        for i in range(self.sprite_sheet.get_size()[1] // sprite_size[1]):
            i *= sprite_size[1]
            for j in range(self.sprite_sheet.get_size()[0] // sprite_size[0]):
                j *= sprite_size[0]

                # Create a new transparent surface
                sprite = pygame.Surface(sprite_size, SRCALPHA)
                # Blit the sprite onto the image
                sprite.blit(self.sprite_sheet, (0, 0), (j, i, sprite_size[0], sprite_size[1]))
                # Add the image to the list of images
                self.images.append(sprite)

                image_count += 1

                # Break the loop if the specified number of frames has been reached.
                if image_count >= self.img_attrib['frames']:
                    break
            if image_count >= self.img_attrib['frames']:
                break


class DataHandler:
    """
    Class that handles the hardware attributes and save files.
    """

    def __init__(self):
        # Attributes that are saved to a file to recover upon startup.
        self.attributes = {
            'version': pocket_friends.__version__,
            'time_elapsed': 0,
            'bloop': '',
            'age': 0,
            'health': 0,
            'hunger': 0,
            'happiness': 0,
            'care_counter': 0,
            'missed_care': 0,
            'adult': 0,
            'evolution_stage': '',
        }

        # Frame counter
        self.frames_passed = 0

    def write_save(self):
        """
        Writes attributes of class to "save.json" file.
        """
        with open(save_dir + '/save.json', 'w') as save_file:
            json.dump(self.attributes, save_file)
            save_file.close()

    def read_save(self):
        """
        Reads from "save.json" and inserts into attributes dictionary. Creates file if it does not exist.
        """
        # Open up the save file and read it into self.attributes.
        try:
            with open(save_dir + '/save.json', 'r') as save_file:
                self.attributes = json.load(save_file)
                save_file.close()

        # If there is no save file, write one with the defaults.
        except FileNotFoundError:
            self.write_save()

    def update(self):
        """
        Run the game logic.
        """
        self.frames_passed += 1
        # Run logic of the game every second.
        if self.frames_passed >= game_fps:

            # Add one to the age of the bloop.
            self.attributes['age'] += 1

            # Save the data when the age of the bloop is a multiple of 10.
            if self.attributes['age'] % 10 == 0:
                self.write_save()

            # Reset frame counter
            self.frames_passed = 0


class PlaygroundFriend(pygame.sprite.Sprite):
    """
    Class for the sprite of the creature on the main playground.
    """

    def __init__(self, data_handler):
        pygame.sprite.Sprite.__init__(self)

        # All attributes of the bloops
        self.bloop = data_handler.attributes['bloop']
        self.adult = data_handler.attributes['adult']
        self.evolution_stage = data_handler.attributes['evolution_stage']
        self.direction = 0

        if self.evolution_stage == 'adult':
            image = self.evolution_stage + self.adult
        else:
            image = self.evolution_stage

        # Draw the correct bloop depending on the stage
        sprite_sheet = SpriteSheet(script_dir + '/resources/images/bloops/{0}/{1}.png'.format(self.bloop, image),
                                   script_dir + '/resources/images/bloops/{0}/{1}.json'.format(self.bloop, image))

        # Load the images from the sprite sheet
        self.images = sprite_sheet.images

        # Put the egg in the middle of the screen.
        self.rect = self.images[0].get_rect()
        self.rect.x = (game_res / 2) - (self.rect.width / 2)
        self.rect.y = (game_res / 2) - (self.rect.height / 2)

        # Start animation at the beginning of the sprite sheet.
        self.index = 0
        self.image = self.images[self.index]

        self.movement_frames = game_fps / 2  # How many frames pass before the bloop moves
        self.current_frame = 0

    def pet(self):
        """
        Pet the bloop!
        """
        pass

    def update(self):
        """
        Takes the images loaded and animates it, spacing it out equally for the framerate.
        """

        margins = 9  # Margins for how far the bloop can move from the left and the right of the screen
        movement_amount = 2  # Pixels that the bloop moves in one movement

        self.current_frame += 1

        # Check to see if the number of movement frames has passed
        if self.current_frame >= self.movement_frames:
            self.current_frame = 0

            # Move only if the bloop is not in the egg stage
            if self.evolution_stage != 'egg':

                # Change direction if the bloop has reached either edge of the screen
                if self.rect.x < margins:
                    self.direction = 1
                elif self.rect.x > game_res - margins - self.rect.width:
                    self.direction = 0

                # Move according to the direction.
                if self.direction == 0:
                    self.rect.x -= movement_amount
                else:
                    self.rect.x += movement_amount

        # Animate the bloop
        self.index = (self.index + 1) % len(self.images)
        self.image = self.images[self.index]


class SelectionEgg(pygame.sprite.Sprite):
    """
    Class for the eggs on the egg selection screen.
    """

    def __init__(self, egg_color):
        pygame.sprite.Sprite.__init__(self)

        self.egg_color = egg_color

        # Loads the JSON file of the egg to read in data.
        with open(script_dir + '/resources/data/bloop_info/{0}.json'.format(egg_color), 'r') as save_file:
            json_file = json.load(save_file)
            save_file.close()

        # Gets the description off the egg from the JSON file.
        self.description = json_file.get('description')
        self.contentness = json_file.get('contentness')
        self.metabolism = json_file.get('metabolism')

        # Load the egg from the given color and get the bounding rectangle for the image.
        sprite_sheet = SpriteSheet(script_dir + '/resources/images/bloops/{0}/egg.png'.format(self.egg_color),
                                   script_dir + '/resources/images/bloops/{0}/egg.json'.format(self.egg_color))
        self.images = sprite_sheet.images

        # Get the rectangle from the first image in the list
        self.rect = self.images[0].get_rect()
        self.index = 0
        self.image = self.images[self.index]

    def update(self):
        """
        Updates the sprite object.
        """
        # Animate the sprite
        self.index = (self.index + 1) % len(self.images)
        self.image = self.images[self.index]


class EggInfo:
    """
    Class to draw the contentness and metabolism value off the egg on the info screen.
    """

    def __init__(self, contentness, metabolism, location):
        self.contentness = contentness
        self.metabolism = metabolism
        self.x = location[0]
        self.y = location[1]

        # Create a new surface to blit onto the other surface
        self.surface = pygame.Surface((44, 15), SRCALPHA)

        # Blit the two indicator icons on screen
        smiley = pygame.image.load(script_dir + '/resources/images/gui/smiley.png').convert_alpha()
        self.surface.blit(smiley, (0, 0))
        apple = pygame.image.load(script_dir + '/resources/images/gui/apple.png').convert_alpha()
        self.surface.blit(apple, (1, 9))

        # Draw 5 stars. If the value of the contentness is less than the current star, make it a blank star.
        for i in range(5):
            if i < self.contentness:
                star = pygame.image.load(script_dir + '/resources/images/gui/star.png').convert_alpha()
            else:
                star = pygame.image.load(script_dir + '/resources/images/gui/blank_star.png').convert_alpha()
            self.surface.blit(star, (11 + (i * 6), 1))

        # Draw 5 stars. If the value of the metabolism is less than the current star, make it a blank star.
        for i in range(5):
            if i < self.metabolism:
                star = pygame.image.load(script_dir + '/resources/images/gui/star.png').convert_alpha()
            else:
                star = pygame.image.load(script_dir + '/resources/images/gui/blank_star.png').convert_alpha()
            self.surface.blit(star, (11 + (i * 6), 10))

    def draw(self, surface):
        """
        Draw the info icons on a given surface.
        :param surface: the surface to draw the icons on.
        """
        # Blit the info onto the given surface.
        surface.blit(self.surface, (self.x, self.y))


class InfoText:
    """
    Class for drawing large amounts of text on the screen at a time
    """

    def __init__(self, font, text='Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam commodo tempor '
                                  'aliquet. Suspendisse placerat accumsan neque, nec volutpat nunc porta ut.'):

        self.font = font
        self.text = []  # Text broken up into a list according to how it will fit on screen.
        self.max_lines = 6  # Max number of lines to be shown on screen at a time.
        self.offset = 0

        # Arrow icons to indicate scrolling
        self.up_arrow = pygame.image.load(script_dir + '/resources/images/gui/up_arrow.png').convert_alpha()
        self.down_arrow = pygame.image.load(script_dir + '/resources/images/gui/down_arrow.png').convert_alpha()

        raw_text = text  # Copy the text to a different variable to be cut up.

        margins = 4.5
        max_line_width = game_res - (margins * 2)  # The maximum pixel width that drawn text can be.
        cut_chars = '.,! '  # Characters that will be considered "cuts" aka when a line break can occur.

        # Prevents freezing if the end of the string does not end in a cut character
        # Will fix eventually more elegantly
        if raw_text[-1:] not in cut_chars:
            raw_text += ' '

        # Calculating line breaks.
        while len(raw_text) > 0:
            index = 0
            test_text = ''  # Chunk of text to pseudo-render and test the width of.

            # Loops until the testing text has reached the size limit.
            while True:

                # Break if the current index is larger than the remaining text.
                if index + 1 > len(raw_text):
                    index -= 1
                    break

                # Add one character to the testing text from the raw text.
                test_text += raw_text[index]
                # Get the width of the pseudo-rendered text.
                text_width = font.size(test_text)[0]

                # Break if the text is larger than the defined max width.
                if text_width > max_line_width:
                    break
                index += 1
                pass

            # Gets the chunk of text to be added to the list.
            text_chunk = raw_text[0:index + 1]
            # Determines if the chunk of text has any break characters.
            has_breaks = any(cut_chars in text_chunk for cut_chars in cut_chars)

            # If the text has break characters, start with the last character and go backwards until
            # one has been found, decreasing the index each time.
            if has_breaks:
                while raw_text[index] not in cut_chars:
                    index -= 1
                text_chunk = raw_text[0:index + 1]
            # If there are no break characters in the chunk, simply decrease the index by one and insert
            # a dash at the end of the line to indicate the word continues.
            else:
                index -= 1
                text_chunk = raw_text[0:index + 1]
                text_chunk += '-'

            # Append the text chunk to the list of text to draw.
            self.text.append(text_chunk)

            # Cut the text to repeat the process with the new cut string.
            raw_text = raw_text[index + 1:]

    def draw(self, surface):
        """
        Draws the text on a given surface.
        :param surface: The surface for the text to be drawn on.
        """
        # Constants to help draw the text
        line_separation = 7
        left_margin = 3
        top_margin = 25
        bottom_margin = 10

        # Draw the lines on the screen
        for i in range(min(len(self.text), self.max_lines)):
            text = self.font.render(self.text[i + self.offset], False, (64, 64, 64))
            surface.blit(text, (left_margin, top_margin + (i * line_separation)))

        # Draw the arrows if there is more text than is on screen.
        if self.offset != 0:
            surface.blit(self.up_arrow, ((game_res / 2) - (self.up_arrow.get_rect().width / 2), top_margin - 3))
        if len(self.text) - (self.offset + 1) >= self.max_lines:
            surface.blit(self.down_arrow,
                         ((game_res / 2) - (self.down_arrow.get_rect().width / 2), game_res - bottom_margin))

    def scroll_down(self):
        """
        Scrolls the text on the screen down.
        """
        # Ensures that the offset cannot be too big as to try to render non-existent lines.
        if len(self.text) - (self.offset + 1) >= self.max_lines:
            self.offset += 1

    def scroll_up(self):
        """
        Scrolls the text on the screen up.
        """
        if self.offset > 0:  # Ensures a non-zero offset is not possible.
            self.offset -= 1


class MenuIcon(pygame.sprite.Sprite):
    """
    Sprite for an icon on the main popup menu.
    """

    def __init__(self, icon):
        pygame.sprite.Sprite.__init__(self)
        self.icon = icon

        # Load the sprite sheet from the icon name
        sprite_sheet = SpriteSheet(script_dir + '/resources/images/gui/popup_menu/{0}.png'.format(self.icon),
                                   script_dir + '/resources/images/gui/popup_menu/{0}.json'.format(self.icon))
        self.images = sprite_sheet.images

        # Get the rectangle from the first image in the list
        self.rect = self.images[0].get_rect()
        self.image = self.images[0]

    def select(self):
        """
        Change the icon sprite to the selected icon.
        """
        self.image = self.images[1]

    def deselect(self):
        """
        Change the icon sprite to the not selected icon.
        """
        self.image = self.images[0]


class PopupMenu:
    """
    Class to create a popup menu that can be hidden and shown at will
    """

    def __init__(self, position):
        # Background frame of the popup menu
        self.frame = pygame.image.load(script_dir + '/resources/images/gui/popup_menu/frame.png').convert_alpha()

        self.draw_menu = False  # Whether or not to draw the popup menu
        self.menu_sprites = pygame.sprite.Group()  # Sprite group for the icons
        self.selected = 0  # The currently selected icon

        # The names of the icons to be drawn
        icon_names = ['apple', 'dumbbell', 'stats', 'controller', 'bed']

        self.icons = []
        # Create an icon sprite for each name in the list and add it to the icon list
        for i in icon_names:
            self.icons.append(MenuIcon(i))

        # Add each sprite in the icon list to the sprite group
        for i in range(len(self.icons)):
            icon = self.icons[i]
            if i == self.selected:  # Make the default selected icon glow
                icon.select()

            # Calculate the position of the icon on screen
            icon.rect.x = 10 + (i * 15) - (icon.image.get_width() / 2)
            icon.rect.y = position[1] + self.frame.get_height() / 2 - icon.image.get_height() / 2

            # Add the icon to the sprite group.
            self.menu_sprites.add(icon)

    def toggle(self):
        """
        Toggles the menu on or off.
        """
        self.draw_menu = not self.draw_menu

    def next(self):
        """
        Changes the selection to the next icon (to the right.)
        """
        if self.draw_menu:  # Only change if the menu is on screen

            self.icons[self.selected].deselect()  # Deselect the current icon
            self.selected += 1  # Change selection to the next icon
            if self.selected >= len(self.icons):  # Wrap around if new value is invalid
                self.selected = 0
            self.icons[self.selected].select()  # Select the newly selected icon

    def prev(self):
        """
        Changes the selection to the previous icon (to the left.)
        """
        if self.draw_menu:  # Only change if the menu is on screen

            self.icons[self.selected].deselect()  # Deselect the current icon
            self.selected -= 1  # Change selection to the previous icon
            if self.selected < 0:  # Wrap around if new value is invalid
                self.selected = len(self.icons) - 1
            self.icons[self.selected].select()  # Select the newly selected icon

    def draw(self, surface):
        """
        Draw the menu onto a given surface
        :param surface: the surface to draw the menu on.
        """
        # Draw the menu only if it is toggled on.
        if self.draw_menu:
            surface.blit(self.frame, (3, 3))
            self.menu_sprites.draw(surface)


# Makes Pygame draw on the display of the RPi.
os.environ["SDL_FBDEV"] = "/dev/fb1"

# Useful for debugging on the PC. Imports a fake RPi.GPIO library if one is not found (which it can't
# be on a PC, RPi.GPIO cannot be installed outside of a Raspberry Pi.
try:
    importlib.util.find_spec('RPi.GPIO')
    import RPi.GPIO as GPIO

    on_hardware = True
except ImportError:
    import pocket_friends.development.FakeGPIO as GPIO

    on_hardware = False


def game():
    """
    Starts the game.
    """
    pygame.init()

    # Hide the cursor for the Pi display.
    pygame.mouse.set_visible(False)

    # The game is normally rendered at 80 pixels and upscaled from there. If changing displays, change the
    # screen_size to reflect what the resolution of the new display is.
    screen_size = 320

    window = pygame.display.set_mode((screen_size, screen_size))
    surface = pygame.Surface((game_res, game_res))

    # Only really useful for PCs. Does nothing on the Raspberry Pi.
    pygame.display.set_caption('Pocket Friends {0}'.format(pocket_friends.__version__))

    # Add an icon to the pygame window.
    icon = pygame.image.load(script_dir + '/resources/images/icon/icon.png').convert_alpha()
    pygame.display.set_icon(icon)

    clock = pygame.time.Clock()

    # Font used for small text in the game. Bigger text is usually image files.
    small_font = pygame.font.Font(script_dir + '/resources/fonts/5Pts5.ttf', 10)

    # Default game state when the game first starts.
    game_state = 'title'
    running = True
    data_handler = DataHandler()

    # A group of all the sprites on screen. Used to update all sprites at onc
    all_sprites = pygame.sprite.Group()

    # Start the GPIO handler to take in buttons from the RPi HAT.
    GPIOHandler.setup()

    # Dev code used to exit the game. Default Down, Down, Up, Up, Down, Down, Up, Up, A, A, B
    dev_code = deque()
    for button in [Constants.buttons.get('j_d'), Constants.buttons.get('j_d'), Constants.buttons.get('j_u'),
                   Constants.buttons.get('j_u'), Constants.buttons.get('j_d'), Constants.buttons.get('j_d'),
                   Constants.buttons.get('j_u'), Constants.buttons.get('j_u'), Constants.buttons.get('a'),
                   Constants.buttons.get('a'), Constants.buttons.get('b')]:
        dev_code.append(button)

    # Log of the inputs.
    input_log = deque()

    # Time since last input. Used to help regulate double presses of buttons.
    last_input_tick = 0

    def draw():
        """
        Draws the main pygame display.
        """

        # Draws all the sprites on screen and scales the screen to the correct size from the rendered size.
        all_sprites.update()
        all_sprites.draw(surface)
        frame = pygame.transform.scale(surface, (screen_size, screen_size))
        window.blit(frame, frame.get_rect())

        # Update the entire display.
        pygame.display.flip()

    def draw_bg():
        """
        Draws the main game background image onto a given surface.
        """
        bg_image = pygame.image.load(script_dir + '/resources/images/bg.png').convert()
        surface.blit(bg_image, (0, 0))

    def log_button(pressed_button):
        """
        Logs the button presses to register the dev code.
        :param pressed_button: The button code to be logged
        """
        input_log.append(pressed_button)
        if len(input_log) > len(dev_code):
            input_log.popleft()

    def create_event(pressed_button):
        """
        Creates a pygame event with a given keyboard code
        :param pressed_button:
        """
        nonlocal last_input_tick
        # Register a button click so long as the last button click happened no less than two frames ago
        if pygame.time.get_ticks() - last_input_tick > clock.get_time() * 2 or not on_hardware:
            pygame.event.post(pygame.event.Event(KEYDOWN, {'key': pressed_button}))
            pygame.event.post(pygame.event.Event(KEYUP, {'key': pressed_button}))
            log_button(pressed_button)
        last_input_tick = pygame.time.get_ticks()

    def check_dev_code():
        """
        Checks if the dev code has been entered. If it has, stop the program.
        """
        nonlocal running

        if dev_code == input_log:
            running = False

    def handle_gpio():
        """
        Handles getting GPIO button presses and making a pygame event when a press is detected.
        """
        for pressed_button in Constants.buttons:
            code = Constants.buttons.get(pressed_button)

            # Check if a button has been pressed. If it has, create a pygame event for it.
            if GPIOHandler.get_press(code):
                create_event(code)

    def keyboard_handler():
        """
        Simulates key presses to GPIO button presses. Also handles quitting the game.
        """
        nonlocal running

        # Checks if a corresponding keyboard key has been pressed. If it has, emulate a button press.
        for keyboard_event in pygame.event.get():
            if keyboard_event.type == pygame.QUIT:
                running = False
            if keyboard_event.type == pygame.KEYDOWN:
                if keyboard_event.key == pygame.K_a:
                    create_event(Constants.buttons.get('a'))
                if keyboard_event.key == pygame.K_b:
                    create_event(Constants.buttons.get('b'))
                if keyboard_event.key == pygame.K_PERIOD:
                    create_event(Constants.buttons.get('j_i'))
                if keyboard_event.key == pygame.K_RIGHT:
                    create_event(Constants.buttons.get('j_r'))
                if keyboard_event.key == pygame.K_LEFT:
                    create_event(Constants.buttons.get('j_l'))
                if keyboard_event.key == pygame.K_DOWN:
                    create_event(Constants.buttons.get('j_d'))
                if keyboard_event.key == pygame.K_UP:
                    create_event(Constants.buttons.get('j_u'))
                if keyboard_event.key == pygame.K_ESCAPE:
                    running = False

    def pre_handler():
        """
        Runs at the beginning of each loop, handles drawing the background, controlling game speed, and
        controlling the GPIO button inputs and keyboard handler
        """
        # Regulate the speed of the game.
        clock.tick(game_fps)

        # Handle all inputs for both debugging and real GPIO button presses.
        keyboard_handler()
        handle_gpio()
        check_dev_code()

        # Draw the background.
        draw_bg()

    while running:
        if game_state == 'title':
            all_sprites.empty()
            pre_handler()

            # Draw the title image in the middle of the screen.
            title_image = pygame.image.load(script_dir + '/resources/images/title.png').convert_alpha()
            surface.blit(title_image, (0, 0))
            draw()

            # Show the title for 1 second then move on to the initialization phase of the game.
            pygame.time.wait(1000)
            game_state = 'init'

        elif game_state == 'playground':

            # Submenu used within the playground.
            submenu = 'main'

            while running and game_state == 'playground':

                all_sprites.empty()

                if submenu == 'main':

                    # Create the bloop and the menu
                    bloop = PlaygroundFriend(data_handler)
                    all_sprites.add(bloop)
                    popup_menu = PopupMenu((3, 3))

                    while running and game_state == 'playground' and submenu == 'main':
                        pre_handler()
                        data_handler.update()

                        for event in pygame.event.get():
                            if event.type == pygame.KEYDOWN:
                                if event.key == Constants.buttons.get('j_r'):
                                    # Move selection to the next item
                                    popup_menu.next()
                                if event.key == Constants.buttons.get('j_l'):
                                    # Move selection to the previous item
                                    popup_menu.prev()
                                if event.key == Constants.buttons.get('a'):
                                    # Change submenu to the menu the icon points to
                                    if popup_menu.draw_menu:
                                        submenu = popup_menu.icons[popup_menu.selected].icon
                                    else:  # Pet the bloop otherwise
                                        bloop.pet()
                                if event.key == Constants.buttons.get('b'):
                                    # Toggle the popup menu on or off
                                    popup_menu.toggle()

                        # Draw the popup menu if toggled on
                        popup_menu.draw(surface)

                        draw()

                else:  # Go to the error state if an invalid state is set.
                    game_state = None

        elif game_state == 'init':
            all_sprites.empty()
            pre_handler()
            draw()

            # Read the save file.
            data_handler.read_save()

            # Determines if it is a new game or not by looking at the evolution stage. If it is -1, the egg has
            # not been created yet, and the game sends you to the egg selection screen. If not, the game sends
            # you to the playground.
            if data_handler.attributes['bloop'] == '':
                game_state = 'egg_select'
            else:
                game_state = 'playground'

        elif game_state == 'egg_select':

            # Submenu used within the egg selection menu.
            submenu = 'main'

            selected = 0
            selected_color = ""

            while running and game_state == 'egg_select':

                all_sprites.empty()

                if submenu == 'main':

                    # Creates and holds the egg objects in a list.
                    eggs = [SelectionEgg('dev_egg'), SelectionEgg('blue'), SelectionEgg('rainbow')]

                    # How many eggs per row should be displayed.
                    eggs_per_row = 3
                    distance_between_eggs = 36 / eggs_per_row

                    # Count the total rows.
                    total_rows = -(-len(eggs) // eggs_per_row)
                    distance_between_rows = 32 / eggs_per_row

                    # Determine the location of each egg.
                    for egg in eggs:
                        current_row = eggs.index(egg) // eggs_per_row
                        rows_after = total_rows - (current_row + 1)
                        egg_in_row = eggs.index(egg) % eggs_per_row
                        eggs_after = min(len(eggs) - (current_row * eggs_per_row), eggs_per_row) - (egg_in_row + 1)

                        x_offset = 32
                        y_offset = 30

                        # The x coordinate of an egg is determined by which egg in the row it is, and how many eggs
                        # are in that row. If there is only 1 egg in a row, it is in the middle of the screen. If
                        # there are two, they're on equal halves and so on.
                        x = x_offset - (eggs_after * distance_between_eggs) + (egg_in_row * distance_between_eggs)
                        y = y_offset - (rows_after * distance_between_rows) + (current_row * distance_between_rows)

                        egg.rect.x = x
                        egg.rect.y = y

                        # Add the egg to the sprite list.
                        all_sprites.add(egg)

                    def get_cursor_coords(selection):
                        """
                        Gets the coordinates of an egg on the selection screen by index and returns it as a tuple
                        :param selection: index of the egg to be selected
                        :return: tuple of the coordinates of the selected egg
                        """
                        cursor_x_offset = -2
                        cursor_y_offset = -2

                        return eggs[selection].rect.x + cursor_x_offset, eggs[selection].rect.y + cursor_y_offset

                    def sel_left():
                        """
                        Select the egg to the left with constraints.
                        """
                        nonlocal selected

                        if selected % eggs_per_row != 0:
                            selected -= 1

                    def sel_right():
                        """
                        Select the egg to the right with constraints.
                        """
                        nonlocal selected

                        row = selected // eggs_per_row
                        eggs_in_row = min(len(eggs) - (row * eggs_per_row), eggs_per_row)

                        if selected % eggs_per_row != eggs_in_row - 1:
                            selected += 1

                    def sel_up():
                        """
                        Select the egg above with constraints.
                        """
                        nonlocal selected

                        if selected // eggs_per_row != 0:
                            selected -= eggs_per_row

                    def sel_down():
                        """
                        Select the egg below with constraints.
                        """
                        nonlocal selected

                        if selected // eggs_per_row != total_rows - 1:
                            selected += eggs_per_row

                    while running and game_state == 'egg_select' and submenu == 'main':

                        pre_handler()

                        for event in pygame.event.get():
                            if event.type == pygame.KEYDOWN:
                                if event.key == Constants.buttons.get('j_r'):
                                    sel_right()
                                if event.key == Constants.buttons.get('j_l'):
                                    sel_left()
                                if event.key == Constants.buttons.get('j_d'):
                                    sel_down()
                                if event.key == Constants.buttons.get('j_u'):
                                    sel_up()
                                if event.key == Constants.buttons.get('a'):
                                    # Advance to the egg info screen for the selected egg.
                                    submenu = 'bloop_info'

                        # Draws the cursor on screen.
                        cursor = pygame.image.load(
                            script_dir + '/resources/images/gui/egg_selector.png').convert_alpha()
                        surface.blit(cursor, get_cursor_coords(selected))

                        selected_color = eggs[selected].egg_color

                        draw()

                elif submenu == 'bloop_info':

                    # Draw the selected egg on screen
                    egg = SelectionEgg(selected_color)
                    egg.rect.x = 8
                    egg.rect.y = 3
                    all_sprites.add(egg)

                    # Info screen for the eggs.
                    info_text = InfoText(small_font, egg.description)
                    info_icons = EggInfo(egg.contentness, egg.metabolism, (32, 4))

                    while running and game_state == 'egg_select' and submenu == 'bloop_info':

                        pre_handler()

                        for event in pygame.event.get():
                            if event.type == pygame.KEYDOWN:
                                if event.key == Constants.buttons.get('j_d'):
                                    # Scroll down on the info screen.
                                    info_text.scroll_down()
                                if event.key == Constants.buttons.get('j_u'):
                                    # Scroll up on the info screen.
                                    info_text.scroll_up()
                                if event.key == Constants.buttons.get('a'):
                                    # Write save file with new attributes
                                    data_handler.attributes['bloop'] = egg.egg_color
                                    data_handler.attributes['health'] = 10
                                    data_handler.attributes['hunger'] = 10
                                    data_handler.attributes['happiness'] = 10
                                    data_handler.attributes['evolution_stage'] = 'egg'
                                    data_handler.write_save()

                                    # Go to playground
                                    game_state = 'playground'
                                if event.key == Constants.buttons.get('b'):
                                    # Go back to the egg selection screen.
                                    submenu = 'main'

                        # Draw the info screen.
                        info_text.draw(surface)
                        info_icons.draw(surface)

                        draw()

                else:  # Go to the error state if an invalid state is set.
                    game_state = None

        else:
            # Error screen. This appears when an invalid game state has been selected.

            all_sprites.empty()
            frames_passed = 0  # Counter for frames, helps ensure the game isn't frozen.

            while running and game_state != 'title':

                pre_handler()

                # Draw the error screen
                error_screen = pygame.image.load(script_dir + '/resources/images/debug/invalid.png').convert_alpha()
                surface.blit(error_screen, (0, -8))

                # Counts the frames passed. Resets every second.
                frames_passed += 1
                if frames_passed >= game_fps:
                    frames_passed = 0

                # Draws the frame counter.
                frame_counter = small_font.render('frames: {0}'.format(frames_passed), False, (64, 64, 64))
                surface.blit(frame_counter, (1, game_res - 10))

                for event in pygame.event.get():
                    if event.type == pygame.KEYDOWN:
                        if event.key == Constants.buttons.get('b'):
                            # Reset back to the title screen.
                            game_state = 'title'

                draw()


def main():
    """
    Calls the game() function to start the game.
    """
    game()

    GPIOHandler.teardown()
    pygame.quit()