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

public class RayTest : MonoBehaviour
{
    public static class DiagnosticsHelper
    {
        public static Stopwatch Watch = new Stopwatch();
        private static string CurrentMeasurementName;

        public static void StartMeasurement(string measurementName)
        {
            CurrentMeasurementName = measurementName;
            Watch.Reset();
            Watch.Start();
        }

        public static void ReportMeasurement()
        {
            Watch.Stop();
            UnityEngine.Debug.Log(string.Format("{0} ended in {1}ms", CurrentMeasurementName, Watch.ElapsedMilliseconds));
        }
    }


    public List<Collider> OwnedColliders;
    public float RayLength = 10;


    public RaycastHit? Raycast_ExcludeCollider(Vector3 origin, Vector3 direction, float distance, List<Collider> ignore)
    {
        var ray = new Ray(origin, direction);
        var hits = new List<RaycastHit>(Physics.RaycastAll(ray, distance));
        hits.Sort((a, b) => (a.distance.CompareTo(b.distance)));
        foreach(var hit in hits)
        {
            if (ignore.Contains(hit.collider)) continue;
            return hit;
        }
        return null;
    }

    public RaycastHit? Raycast_NoIgnore(Vector3 origin, Vector3 direction, float distance)
    {
        RaycastHit hit;
        var ray = new Ray(origin, direction);
        if (Physics.Raycast(ray, out hit, distance, 1))
            return hit;
        return null;
    }

    public RaycastHit? Raycast_DisableColliders(Vector3 origin, Vector3 direction, float distance, List<Collider> ignore)
    {
        for (var i = 0; i < ignore.Count; i++) ignore[i].enabled = false;
        var result = Raycast_NoIgnore(origin, direction, distance);
        for (var i = 0; i < ignore.Count; i++) ignore[i].enabled = true;
        return result;
    }

    public RaycastHit? Raycast_DisableGameObjects(Vector3 origin, Vector3 direction, float distance, List<Collider> ignore)
    {
        for (var i = 0; i < ignore.Count; i++) ignore[i].gameObject.SetActive(false);
        var result = Raycast_NoIgnore(origin, direction, distance);
        for (var i = 0; i < ignore.Count; i++) ignore[i].gameObject.SetActive(true);
        return result;
    }

    private static Collider[] _excludedColliders;
    private static int[] _colliderLayers;

    public static void ExcludeCollidersFromNextRaycast(Collider[] colliders)
    {
        _excludedColliders = colliders;
        _colliderLayers = new int[colliders.Length];
        for (var i = 0; i < _colliderLayers.Length; i++)
        {
            var gameObject = colliders[i].gameObject;
            _colliderLayers[i] = gameObject.layer;
            gameObject.layer = 31;
        }
    }

    public static void RollbackColliders()
    {
        for (var i = 0; i < _excludedColliders.Length; i++)
            _excludedColliders[i].gameObject.layer = _colliderLayers[i];
    }

    public RaycastHit? Raycast_ChangeLayer(Vector3 origin, Vector3 direction, float distance, Collider[] ignore)
    {
        ExcludeCollidersFromNextRaycast(ignore);
        var result = Raycast_NoIgnore(origin, direction, distance);
        RollbackColliders();
        return result;
    }

    private void Start()
    {
        var toIgnore = OwnedColliders.ToArray();
        var hit = Raycast_ChangeLayer(transform.position, transform.forward, RayLength, toIgnore);

        DiagnosticsHelper.StartMeasurement("No ignore (1000k)");
        for (var i = 0; i < 1000000; i++) hit = Raycast_NoIgnore(transform.position, transform.forward, RayLength);
        DiagnosticsHelper.ReportMeasurement();

        DiagnosticsHelper.StartMeasurement("Change layer (1000k)");
        for (var i = 0; i < 1000000; i++) hit = Raycast_ChangeLayer(transform.position, transform.forward, RayLength, toIgnore);
        DiagnosticsHelper.ReportMeasurement();

        DiagnosticsHelper.StartMeasurement("Excluding colliders (1000k)");
        for (var i = 0; i < 1000000; i++) hit = Raycast_ExcludeCollider(transform.position, transform.forward, RayLength, OwnedColliders);
        DiagnosticsHelper.ReportMeasurement();

        DiagnosticsHelper.StartMeasurement("Disable colliders (1000k)");
        for (var i = 0; i < 1000000; i++) hit = Raycast_DisableColliders(transform.position, transform.forward, RayLength, OwnedColliders);
        DiagnosticsHelper.ReportMeasurement();


        DiagnosticsHelper.StartMeasurement("Disable game objects (1000k)");
        for (var i = 0; i < 1000000; i++) hit = Raycast_DisableGameObjects(transform.position, transform.forward, RayLength, OwnedColliders);
        DiagnosticsHelper.ReportMeasurement();


        if (hit != null)
            UnityEngine.Debug.DrawLine(transform.position, hit.Value.point, Color.green, 10);
        else
            UnityEngine.Debug.DrawLine(transform.position, transform.position + transform.forward * RayLength, Color.red, 10);
    }
}