using HPJ.Presentation.Agents;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace HPJ.Presentation
{
    /// <summary>
    /// Displays a line of the Navigation Agents Remaining Path
    /// </summary>
    [RequireComponent(typeof(LineRenderer))]
    [RequireComponent(typeof(NavigationAgent))]
    public class AgentLine : MonoBehaviour
    {
        /// <summary>
        /// How Often the line is updated
        /// </summary>
        [SerializeField]
        private float _updateInterval = 0.1f;
        private float _updateTime = 0;

        private LineRenderer _line;
        private NavigationAgent _agent;
        private List<Vector3> _linePoints;

        private void Awake()
        {
            _agent = GetComponent<NavigationAgent>();
            _line = GetComponent<LineRenderer>();
            _linePoints = new List<Vector3>();
        }

        // Update is called once per frame
        void Update()
        {
            _updateTime += Time.deltaTime;
            if (_updateTime > _updateInterval)
            {
                _updateTime = 0;
                UpdateLine();
            }
        }

        /// <summary>
        /// Updates the Line Renderer to the navigation agent remaining path
        /// </summary>
        public void UpdateLine()
        {
            _linePoints.Clear();

            if (_agent.Path.Count <= 0)
            {
                _line.positionCount = 0;
                return;
            }

            if (_agent.CurrentPathingIndex + 1 >= _agent.Path.Count)
            {
                Vector3 EndPoint = _agent.Path[_agent.Path.Count - 1];
                _linePoints.Add(EndPoint);

                EndPoint.x = transform.position.x;
                EndPoint.z = transform.position.z;
                _linePoints.Add(EndPoint);

                _line.positionCount = 2;
                _line.SetPositions(_linePoints.ToArray());
                return;
            }

            Vector3 StartPoint = _agent.Path[_agent.CurrentPathingIndex + 1];
            StartPoint.x = transform.position.x;
            StartPoint.z = transform.position.z;
            _linePoints.Add(StartPoint);
            int PathCount = 1;


            for(int i = _agent.CurrentPathingIndex + 1; i < _agent.Path.Count; i++)
            {
                PathCount++;
                Vector3 NextPoint = _agent.Path[i];
                _linePoints.Add(NextPoint);
            }

            _line.positionCount = PathCount;
            _line.SetPositions(_linePoints.ToArray());
        }
    }
}