using System;
using System.Collections.Generic;
using Fusion;
using UnityEngine;

namespace TPSBR
{
  public sealed class LootBoxSpawner : NetworkBehaviour
  {
    [Header("Prefab")]
    [SerializeField] private NetworkPrefabRef _itemBoxPrefab; 

    [Header("Placement")]
    [Min(1)]  [SerializeField] private int   _count           = 10;
    [Min(0f)] [SerializeField] private float _radius          = 40f;
    [Min(0f)] [SerializeField] private float _minSpacing      = 3f;
    [SerializeField] private LayerMask        _groundMask      = ~0;  
    [SerializeField] private float            _raycastUp       = 60f; 
    [SerializeField] private float            _raycastDown     = 120f;
    [SerializeField] private uint             _seed            = 12345;
    [SerializeField] private bool             _randomYaw       = true;

    // Keep references to despawn/respawn later if you extend it
    private readonly List<NetworkObject> _spawned = new();

    public override void Spawned()
    {
      if (!HasStateAuthority) return;     
      SpawnAll();
    }

    private void SpawnAll()
    {
      // If this is re-entered (e.g., soft reset), clean previous
      foreach (var no in _spawned)
        if (no && no.IsValid) Runner.Despawn(no);
      _spawned.Clear();

      var rnd = new System.Random(unchecked((int)_seed));
      var positions = SamplePositions(transform.position, _radius, _count, _minSpacing, rnd);

      foreach (var p in positions)
      {
        var rot = _randomYaw ? Quaternion.Euler(0f, (float)rnd.NextDouble() * 360f, 0f) : Quaternion.identity;
        // Spawn server-side; replicated to all clients
        var obj = Runner.Spawn(_itemBoxPrefab, p, rot);
        _spawned.Add(obj);
      }
    }

    // Deterministic sampling inside a circle with ground projection + spacing
    private List<Vector3> SamplePositions(Vector3 center, float radius, int count, float minSpacing, System.Random rnd)
    {
      var results   = new List<Vector3>(count);
      var maxTrials = 2500;                // generous to pack in cluttered areas
      int trials    = 0;

      while (results.Count < count && trials++ < maxTrials)
      {
        // pick point in disc (sqrt for uniform)
        float r   = radius * Mathf.Sqrt((float)rnd.NextDouble());
        float ang = Mathf.PI * 2f * (float)rnd.NextDouble();
        Vector3 local = new Vector3(Mathf.Cos(ang) * r, 0f, Mathf.Sin(ang) * r);
        Vector3 rayFrom = center + local + Vector3.up * _raycastUp;

        if (Physics.Raycast(rayFrom, Vector3.down, out var hit, _raycastUp + _raycastDown, _groundMask, QueryTriggerInteraction.Ignore))
        {
          var pos = hit.point;

          // spacing test
          bool ok = true;
          if (minSpacing > 0f)
          {
            for (int i = 0; i < results.Count; i++)
            {
              if (Vector3.SqrMagnitude(results[i] - pos) < minSpacing * minSpacing) { ok = false; break; }
            }
          }

          if (ok) results.Add(pos);
        }
      }

      if (results.Count < count)
        Debug.LogWarning($"[LootBoxSpawner] Only placed {results.Count}/{count}. Increase radius or lower spacing.");

      return results;
    }

    // Scene gizmo previews the exact deterministic layout you’ll get at runtime
    private void OnDrawGizmosSelected()
    {
      Gizmos.color = new Color(0.1f, 0.8f, 1f, 0.25f);
      Gizmos.DrawWireSphere(transform.position, _radius);

      // preview sample using same seed
      var rnd = new System.Random(unchecked((int)_seed));
      var preview = SamplePositions(transform.position, _radius, _count, _minSpacing, rnd);

      Gizmos.color = new Color(0.1f, 0.8f, 1f, 0.7f);
      foreach (var p in preview)
      {
        Gizmos.DrawSphere(p + Vector3.up * 0.15f, 0.25f);
        Gizmos.DrawLine(p + Vector3.up * 3f, p); // drop line
      }
    }
  }
}