using System.Collections;
using System.Collections.Generic;
using UnityEngine;
namespace BITKit
{
    public class LineObstacleProvider : PathProvider
    {
        public LayerMask layerMask;
        public int distance;
        public float tolerance = 0.32f;
        public int accuracy;

        protected Vector3 startPos;
        protected Vector3 endPos;
        protected Vector3 currentPos;
        public override bool IsValid(ref Vector3 startPos)
        {
            if (TryGetObstacle(out var raycastHit))
            {
                if (TryGetCrossLocation(out var location))
                {
                    this.startPos = startPos;
                    endPos = location;
                    return true;
                }
            }
            return false;
        }
        void OnDrawGizmos()
        {
            Gizmos.DrawWireSphere(currentPos, 0.1f);
            Gizmos.DrawWireSphere(endPos, 0.1f);
        }
        public override Vector3 Evaluate(float time)
        {
            currentPos = Vector3.Lerp(startPos, endPos, time);
            return currentPos;
        }
        public bool TryGetObstacle(out RaycastHit raycastHit)
        {
            var originPos = transform.position;
            var endPos = originPos + distance * transform.forward;

            raycastHit = default;
            for (int i = 0; i < accuracy; i++)
            {
                var weight = i / (float)accuracy;
                var tolerance = this.tolerance * Vector3.up;
                var vectorUp = Vector3.Lerp(-tolerance, tolerance, weight);
                if (Physics.Linecast(originPos, endPos + vectorUp, out raycastHit, layerMask))
                {
                    Debug.DrawLine(originPos, endPos, Color.yellow, 2);
                    return true;
                }
            }
            return false;
        }
        public bool TryGetCrossLocation(out Location location, float radius = 0.2f, float height = 1f)
        {
            location = default;
            if (TryGetObstacle(out var raycastHit))
            {
                var rotation = Quaternion.LookRotation(-raycastHit.normal, Vector3.up);
                var edgePoint = raycastHit.point;
                for (int i = 0; i < accuracy; i++)
                {
                    var weight = i / (float)accuracy;
                    var vectorUp = Vector3.Lerp(Vector3.zero, Vector3.up * 0.32f, weight);
                    var originPos = raycastHit.point + vectorUp - transform.forward * 0.1f;
                    var endPos = originPos + transform.forward;
                    if (Physics.Linecast(originPos, endPos, out var raycast, layerMask))
                    {
                        edgePoint = raycast.point;
                        Debug.DrawLine(originPos, edgePoint, Color.red, i);
                    }
                    else
                    {
                        Debug.DrawLine(originPos, endPos, Color.green, i);
                        edgePoint.y = originPos.y;
                        var startPos = edgePoint + transform.forward * radius;
                        if (Physics.Raycast(startPos, Vector3.down, out raycast, layerMask))
                        {
                            var point0 = raycast.point;
                            point0.y += radius + 0.01f;
                            var point1 = point0 + Vector3.up * height;
                            point1.y -= radius;
                            var colliders = Physics.OverlapCapsule(point0, point1, radius, layerMask);
                            if (colliders.Length is 0)
                            {
                                location = new Location()
                                {
                                    position = raycast.point,
                                    rotation = rotation
                                };
                                return true;
                            }
                            Debug.DrawLine(startPos, raycast.point, Color.cyan, 2);
                        }
                    }
                }
            }
            return false;
        }
    }
}