using UnityEngine;

[RequireComponent(typeof(CharacterController))]
public class SimpleFPSController : MonoBehaviour
{
    [Header("Movement")]
    public float walkSpeed = 4f;
    public float runSpeed = 7f;
    public float mouseSensitivity = 2f;
    public float gravity = -20f;

    [Header("References")]
    public CharacterController characterController;
    public Camera playerCamera;

    public Vector3 PlanarVelocity { get; private set; }
    public bool HasMovementInput { get; private set; }
    public bool IsRunning { get; private set; }
    public float CurrentMoveSpeed { get; private set; }
    public float SpeedScale { get; set; } = 1f;
    public bool AllowRunning { get; set; } = true;

    private float verticalVelocity;
    private float cameraPitch;

    private void Awake()
    {
        characterController = characterController != null ? characterController : GetComponent<CharacterController>();
        playerCamera = playerCamera != null ? playerCamera : GetComponentInChildren<Camera>();
    }

    private void Start()
    {
        LockCursor(true);
    }

    private void OnApplicationFocus(bool hasFocus)
    {
        LockCursor(hasFocus);
    }

    private void Update()
    {
        HandleMouseLook();
        HandleMovement();
    }

    private void HandleMouseLook()
    {
        float mouseX = Input.GetAxis("Mouse X") * mouseSensitivity;
        float mouseY = Input.GetAxis("Mouse Y") * mouseSensitivity;

        transform.Rotate(0f, mouseX, 0f);

        cameraPitch -= mouseY;
        cameraPitch = Mathf.Clamp(cameraPitch, -80f, 80f);

        if (playerCamera != null)
        {
            playerCamera.transform.localRotation = Quaternion.Euler(cameraPitch, 0f, 0f);
        }
    }

    private void HandleMovement()
    {
        Vector2 input = new Vector2(Input.GetAxisRaw("Horizontal"), Input.GetAxisRaw("Vertical"));
        input = Vector2.ClampMagnitude(input, 1f);
        HasMovementInput = input.sqrMagnitude > 0.001f;

        IsRunning = AllowRunning && HasMovementInput && Input.GetKey(KeyCode.LeftShift);
        CurrentMoveSpeed = (IsRunning ? runSpeed : walkSpeed) * Mathf.Max(0.01f, SpeedScale);

        Vector3 moveDirection = (transform.right * input.x + transform.forward * input.y).normalized;
        PlanarVelocity = moveDirection * (HasMovementInput ? CurrentMoveSpeed : 0f);

        if (characterController.isGrounded && verticalVelocity < 0f)
        {
            verticalVelocity = -2f;
        }

        verticalVelocity += gravity * Time.deltaTime;

        Vector3 motion = PlanarVelocity;
        motion.y = verticalVelocity;
        characterController.Move(motion * Time.deltaTime);
    }

    private static void LockCursor(bool shouldLock)
    {
        Cursor.lockState = shouldLock ? CursorLockMode.Locked : CursorLockMode.None;
        Cursor.visible = !shouldLock;
    }
}