#nullable enable
using JetBrains.Annotations;
using UnityEngine;
using UnityEngine.InputSystem;

[RequireComponent(typeof(PlayerInput), typeof(Rigidbody2D))]
public class PlayerMovement : MonoBehaviour {
	[SerializeField] PlayerStats playerStats;
	Rigidbody2D rb;
	
	PlayerInput playerInput;
	Vector2 moveDirection;
	BaseState currentState = new NormalMovementState();

	void Awake() {
		rb = GetComponent<Rigidbody2D>();
		playerInput = GetComponent<PlayerInput>();
	}

	void FixedUpdate() {
		if (currentState.FixedUpdateState(this) is {} newState)
			SwitchState(newState);
	}

	public void OnMove(InputAction.CallbackContext ctx) {
		moveDirection = ctx.ReadValue<Vector2>();
		if (moveDirection.sqrMagnitude > 1.0f)
			moveDirection.Normalize();
	}

	public void OnJump(InputAction.CallbackContext ctx) {
		if (!ctx.ReadValueAsButton())
			return;
		
		SwitchState(new JumpingMovementState());
	}

	void SwitchState(BaseState newState) {
		currentState.LeaveState(this);
		currentState = newState;
		newState.EnterState(this);
	}
	
	class BaseState {
		//TODO If we never do anything before enter, replace with constructor?
		public virtual void EnterState(PlayerMovement playerMovement) {}

		public virtual void LeaveState(PlayerMovement playerMovement) {}

		[CanBeNull]
		public virtual BaseState UpdateState(PlayerMovement playerMovement) => null;

		[CanBeNull]
		public virtual BaseState FixedUpdateState(PlayerMovement playerMovement) => null;
	}

	class NormalMovementState : BaseState {
		public override BaseState FixedUpdateState(PlayerMovement playerMovement) {
			playerMovement.rb.velocity = (Vector3)playerMovement.moveDirection * playerMovement.playerStats.movementSpeed;
			
			return null;
		}
	}

	class JumpingMovementState : BaseState {
		Vector3 startPosition;
		float startTime;

		public override void EnterState(PlayerMovement playerMovement) {
			startPosition = playerMovement.transform.position;
			startTime = Time.time;
		}

		public override BaseState FixedUpdateState(PlayerMovement playerMovement) {
			float currentTime = Time.time - startTime;
			if (currentTime >= playerMovement.playerStats.safeZoneJumpDuration)
				return new NormalMovementState();
			
			playerMovement.rb.MovePosition(Vector3.Lerp(
				startPosition,
				playerMovement.playerStats.safeZonePosition,
				currentTime / playerMovement.playerStats.safeZoneJumpDuration
			));

			return null;
		}
	}
}