#!/usr/bin/env racket
#lang racket/base

(module+ main
  (require raylib/generated/unsafe)

  (define (sync-camera camera camera_pos target_pos)
      (set-Camera3D-target! camera target_pos)
      (set-Vector3-x! camera_pos (Vector3-x target_pos))
      (set-Vector3-y! camera_pos (+ (Vector3-y target_pos) 10.0))
      (set-Vector3-z! camera_pos (+ (Vector3-z target_pos) 10.0))
      (set-Camera3D-position! camera camera_pos))
  
  (define (move-user camera pos scale)
      (when (IsKeyDown KEY_RIGHT)
        (set-Vector3-x! pos (+ (Vector3-x (Camera3D-target camera)) scale)))
      (when (IsKeyDown KEY_LEFT)
        (set-Vector3-x! pos (- (Vector3-x (Camera3D-target camera)) scale)))
      (when (IsKeyDown KEY_UP)
        (set-Vector3-z! pos (- (Vector3-z (Camera3D-target camera)) scale)))
      (when (IsKeyDown KEY_DOWN)
        (set-Vector3-z! pos (+ (Vector3-z (Camera3D-target camera)) scale))))

  (InitWindow 800 450 "racket lisp client : raylib")

  (define camera_pos (make-Vector3 0.0 12.0 14.0))
  (define target_pos (make-Vector3 0.0 2.0 0.0))

  (define camera (make-Camera3D camera_pos target_pos (make-Vector3 0.0 1.0 0.0) 60.0 CAMERA_PERSPECTIVE))

  (SetTargetFPS 60)
  
  (let loop ()
    (when (not (WindowShouldClose))
      (BeginDrawing)
      (ClearBackground RAYWHITE)

      (move-user camera target_pos 0.2)
      (sync-camera camera camera_pos target_pos)

      (BeginMode3D camera)

      (DrawGrid 30 1.0)
      (DrawCube (Camera3D-target camera) 0.5 0.5 0.5 PURPLE)

      (EndMode3D)
      (EndDrawing)
      (loop)))

  (CloseWindow))