using System;
using UnityEngine;

public abstract class Unit : MonoBehaviour
{
    // Meters is 1 unity unit, also a tile width/height.
    [Tooltip("How many meters per second")]
    public float speed;

    protected Transform _transform;
    private Vector3 _startPosition;
    private Vector3 _moveToPosition;
    private float _startTime;
    private float _moveDuration;
    protected Action _doThingAfterMove;

    protected virtual void Start()
    {
        _transform = transform;
    }

    protected void MovementRoutine()
    {
        _startTime += Time.deltaTime;
        _transform.position = Vector3.Lerp(_startPosition, _moveToPosition, _startTime / _moveDuration);

        if (_startTime / _moveDuration > 1.0f)
        {
            _doThingAfterMove?.Invoke();
        }
    }

    protected abstract void CancelCurrentTask();

    // TODO: replace this with pathfinding.
    public virtual void MoveTo(Vector3 position)
    {
        CancelCurrentTask();
        _startPosition = _transform.position;
        _moveToPosition = position;
        _moveDuration = Vector3.Distance(_startPosition, _moveToPosition) / speed;
        _startTime = 0;
    }
}