using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class FPSController : MonoBehaviour
{
    // Variables to control movement behavior
    public float walkingSpeed = 7.5f;
    public float runningSpeed = 11.5f;
    public float jumpSpeed = 8.0f;
    public float gravity = 20.0f;

    // Variables to control camera look
    public Camera playerCamera;
    public float lookSpeed = 2.0f;
    public float lookXLimit = 45.0f;

    // Variables to retain player state
    private CharacterController characterController;
    private Vector3 moveDirection = Vector3.zero;
    private float rotationX = 0;

    [HideInInspector]
    public bool canMove = true;

    void Start() {
        // Latch onto existing player controller
        characterController = GetComponent<CharacterController>();

        // Lock the cursor in the view and hide it
        Cursor.lockState = CursorLockMode.Locked;
        Cursor.visible = false;
    }

    void Update() {
        // Recalculate move direction based on player axes
        Vector3 forward = transform.TransformDirection(Vector3.forward);
        Vector3 right = transform.TransformDirection(Vector3.right);

        // Store existing jump/fall movement
        float currentSpeedY = moveDirection.y;        
        
        // Press Left Shift to run
        bool isRunning = Input.GetKey(KeyCode.LeftShift);

        // Assume x and z speeds are 0
        float speedX = 0;
        float speedZ = 0;
        float currentSpeed = 0;

        // Calculate the speed if the player can move
        if(canMove) {
            // Decide whether to use running or walking speed
            if(isRunning) {
                currentSpeed = runningSpeed;
            } else {
                currentSpeed = walkingSpeed;
            }
            speedX = currentSpeed * Input.GetAxis("Vertical");
            speedZ = currentSpeed * Input.GetAxis("Horizontal");
        }
        
        // Create movement horizontal movement vector (X and Z axes)
        moveDirection = (forward * speedX) + (right * speedZ);

        // Set vertical movement (Y axis)
        if(Input.GetButton("Jump") && canMove && characterController.isGrounded) {
            moveDirection.y = jumpSpeed;
        } else {
            moveDirection.y = currentSpeedY;
        }

        // Apply gravity. Gravity is multiplied by deltaTime twice (once here, and once below
        // when the moveDirection is multiplied by deltaTime). This is because gravity should be applied
        // as an acceleration (meters / second^2)
        if(!characterController.isGrounded) {
            moveDirection.y -= gravity * Time.deltaTime;
        }

        // Actually move the controller
        characterController.Move(moveDirection * Time.deltaTime);

        // Rotate the player and camera. The player spins and the camera looks up or down.
        if(canMove) {
            rotationX += -Input.GetAxis("Mouse Y") * lookSpeed;
            rotationX = Mathf.Clamp(rotationX, -lookXLimit, lookXLimit);
            playerCamera.transform.localRotation = Quaternion.Euler(rotationX, 0, 0);
            transform.rotation *= Quaternion.Euler(0, Input.GetAxis("Mouse X") * lookSpeed, 0);
        }
    }
}