"""
Show how to have enemies shoot bullets aimed at the player.

If Python and Arcade are installed, this example can be run from the command line with:
python -m arcade.examples.sprite_bullets_enemy_aims
"""

import arcade
import math
import os

SCREEN_WIDTH = 800
SCREEN_HEIGHT = 600
SCREEN_TITLE = "Sprites and Bullets Enemy Aims Example"
BULLET_SPEED = 4


class MyGame(arcade.Window):
    """ Main application class """

    def __init__(self, width, height, title):
        super().__init__(width, height, title)

        # Set the working directory (where we expect to find files) to the same
        # directory this .py file is in. You can leave this out of your own
        # code, but it is needed to easily run the examples using "python -m"
        # as mentioned at the top of this program.
        file_path = os.path.dirname(os.path.abspath(__file__))
        os.chdir(file_path)

        arcade.set_background_color(arcade.color.BLACK)

        self.frame_count = 0

        self.enemy_list = None
        self.bullet_list = None
        self.player_list = None
        self.player = None

    def setup(self):
        self.enemy_list = arcade.SpriteList()
        self.bullet_list = arcade.SpriteList()
        self.player_list = arcade.SpriteList()

        # Add player ship
        self.player = arcade.Sprite(":resources:images/space_shooter/playerShip1_orange.png", 0.5)
        self.player_list.append(self.player)

        # Add top-left enemy ship
        enemy = arcade.Sprite(":resources:images/space_shooter/playerShip1_green.png", 0.5)
        enemy.center_x = 120
        enemy.center_y = SCREEN_HEIGHT - enemy.height
        enemy.angle = 180
        self.enemy_list.append(enemy)

        # Add top-right enemy ship
        enemy = arcade.Sprite(":resources:images/space_shooter/playerShip1_green.png", 0.5)
        enemy.center_x = SCREEN_WIDTH - 120
        enemy.center_y = SCREEN_HEIGHT - enemy.height
        enemy.angle = 180
        self.enemy_list.append(enemy)

    def on_draw(self):
        """Render the screen. """

        arcade.start_render()

        self.enemy_list.draw()
        self.bullet_list.draw()
        self.player_list.draw()

    def on_update(self, delta_time):
        """All the logic to move, and the game logic goes here. """

        self.frame_count += 1

        # Loop through each enemy that we have
        for enemy in self.enemy_list:

            # First, calculate the angle to the player. We could do this
            # only when the bullet fires, but in this case we will rotate
            # the enemy to face the player each frame, so we'll do this
            # each frame.

            # Position the start at the enemy's current location
            start_x = enemy.center_x
            start_y = enemy.center_y

            # Get the destination location for the bullet
            dest_x = self.player.center_x
            dest_y = self.player.center_y

            # Do math to calculate how to get the bullet to the destination.
            # Calculation the angle in radians between the start points
            # and end points. This is the angle the bullet will travel.
            x_diff = dest_x - start_x
            y_diff = dest_y - start_y
            angle = math.atan2(y_diff, x_diff)

            # Set the enemy to face the player.
            enemy.angle = math.degrees(angle)-90

            # Shoot every 60 frames change of shooting each frame
            if self.frame_count % 60 == 0:
                bullet = arcade.Sprite(":resources:images/space_shooter/laserBlue01.png")
                bullet.center_x = start_x
                bullet.center_y = start_y

                # Angle the bullet sprite
                bullet.angle = math.degrees(angle)

                # Taking into account the angle, calculate our change_x
                # and change_y. Velocity is how fast the bullet travels.
                bullet.change_x = math.cos(angle) * BULLET_SPEED
                bullet.change_y = math.sin(angle) * BULLET_SPEED

                self.bullet_list.append(bullet)

        # Get rid of the bullet when it flies off-screen
        for bullet in self.bullet_list:
            if bullet.top < 0:
                bullet.remove_from_sprite_lists()

        self.bullet_list.update()

    def on_mouse_motion(self, x, y, delta_x, delta_y):
        """Called whenever the mouse moves. """
        self.player.center_x = x
        self.player.center_y = y


def main():
    """ Main method """
    window = MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
    window.setup()
    arcade.run()


if __name__ == "__main__":
    main()

[(136, 'arcade.run', 'arcade.run', False, 'import arcade\n'), (29, 'os.chdir', 'os.chdir', False, 'import os\n'), (31, 'arcade.set_background_color', 'arcade.set_background_color', False, 'import arcade\n'), (41, 'arcade.SpriteList', 'arcade.SpriteList', False, 'import arcade\n'), (42, 'arcade.SpriteList', 'arcade.SpriteList', False, 'import arcade\n'), (43, 'arcade.SpriteList', 'arcade.SpriteList', False, 'import arcade\n'), (46, 'arcade.Sprite', 'arcade.Sprite', False, 'import arcade\n'), (50, 'arcade.Sprite', 'arcade.Sprite', False, 'import arcade\n'), (57, 'arcade.Sprite', 'arcade.Sprite', False, 'import arcade\n'), (66, 'arcade.start_render', 'arcade.start_render', False, 'import arcade\n'), (28, 'os.path.abspath', 'os.path.abspath', False, 'import os\n'), (98, 'math.atan2', 'math.atan2', False, 'import math\n'), (101, 'math.degrees', 'math.degrees', False, 'import math\n'), (105, 'arcade.Sprite', 'arcade.Sprite', False, 'import arcade\n'), (110, 'math.degrees', 'math.degrees', False, 'import math\n'), (114, 'math.cos', 'math.cos', False, 'import math\n'), (115, 'math.sin', 'math.sin', False, 'import math\n')]