# 3D Physics Game with Raylib and ODE - Improved with Collision Detection
# A bouncing cube demo that actually collides with the ground

fn main() -> int do
    # Initialize raylib
    init_window(800, 600, "3D Physics Game - Improved")
    defer close_window()
    set_target_fps(60)

    # Initialize ODE
    ode_init()
    defer ode_close()

    # Create physics world
    let world = ode_world_create()
    defer ode_world_destroy(world)
    let null_space = 0 as *()
    let space = ode_simple_space_create(null_space)  # null parent
    defer ode_space_destroy(space)

    # Set gravity
    ode_world_set_gravity(world, 0.0, -9.81, 0.0)

    # Create contact joint group
    let contactgroup = ode_joint_group_create(0)
    defer ode_joint_group_destroy(contactgroup)

    # Create a cube body
    let body = ode_body_create(world)
    defer ode_body_destroy(body)

    # Set cube mass (density 1.0, size 1x1x1)
    ode_body_set_box_mass(body, 1.0, 1.0, 1.0, 1.0)

    # Set initial position (5 units up)
    ode_body_set_position(body, 0.0, 5.0, 0.0)

    # Create geometry for the cube
    let geom = ode_create_box_geom(space, 1.0, 1.0, 1.0)
    defer ode_geom_destroy(geom)

    # Attach geometry to body
    ode_geom_set_body(geom, body)

    # Create ground plane (y = 0)
    let ground_geom = ode_create_plane_geom(space, 0.0, 1.0, 0.0, 0.0)
    defer ode_geom_destroy(ground_geom)

    # Camera position variables
    let mut camera_pos_x = 0.0
    let mut camera_pos_y = 2.0
    let mut camera_pos_z = 10.0

    # Cube position variables
    let mut cube_x = 0.0
    let mut cube_y = 0.0
    let mut cube_z = 0.0

    # Main game loop
    let mut frame_count = 0
    while window_should_close() == false do
        # IMPORTANT: Collision detection must happen BEFORE world step
        ode_space_collide(world, space, contactgroup)

        # Step physics simulation
        ode_world_step(world, 1.0 / 60.0)

        # Empty contact group after step to avoid accumulation
        ode_joint_group_empty(contactgroup)

        # Get cube position
        ode_body_get_position(body, &cube_x, &cube_y, &cube_z)

        # Drawing
        begin_drawing()
        clear_background(135, 206, 235, 255)  # Sky blue

        begin_mode3d(camera_pos_x, camera_pos_y, camera_pos_z, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 45.0, 0)

        # Draw ground plane
        draw_cube(0.0, -1.0, 0.0, 20.0, 0.1, 20.0, 34, 139, 34, 255)  # Green ground

        # Draw the physics cube
        draw_cube(cube_x, cube_y, cube_z, 1.0, 1.0, 1.0, 255, 0, 0, 255)  # Red cube

        # Draw wireframe for better visibility
        draw_cube_wires(cube_x, cube_y, cube_z, 1.0, 1.0, 1.0, 0, 0, 0, 255)

        end_mode3d()
        end_drawing()

        frame_count = frame_count + 1
    end

    0
end