using System.Collections.Generic;
using Unity.Netcode;
using UnityEngine;
using UnityEngine.Events;

[DisallowMultipleComponent]
public sealed class NetworkShockwaveEmitter : NetworkBehaviour
{
    private const int MaximumOverlaps = 256;

    [SerializeField] private ShockwaveProfile profile;
    [SerializeField] private Transform origin;
    [SerializeField] private LayerMask physicsLayers = ~0;
    [SerializeField] private UnityEvent shockwaveEmitted;

    private readonly NetworkVariable<uint> sequence = new(
        0,
        NetworkVariableReadPermission.Everyone,
        NetworkVariableWritePermission.Server);

    private readonly Collider[] overlapBuffer = new Collider[MaximumOverlaps];
    private readonly HashSet<Rigidbody> affectedBodies = new();

    public ShockwaveProfile Profile => profile;
    public Vector3 Origin => origin != null ? origin.position : transform.position;
    public uint Sequence => sequence.Value;

    public event System.Action Emitted;

    public override void OnNetworkSpawn()
    {
        sequence.OnValueChanged += HandleSequenceChanged;
    }

    public override void OnNetworkDespawn()
    {
        sequence.OnValueChanged -= HandleSequenceChanged;
    }

    public bool EmitShockwave() => EmitShockwave(Origin);

    public bool EmitShockwave(Vector3 worldOrigin)
    {
        if (!IsServer || !IsSpawned || profile == null)
            return false;

        ApplyToPlayers(worldOrigin);
        ApplyToPhysics(worldOrigin);
        sequence.Value++;
        return true;
    }

    [ContextMenu("Debug/Emit Shockwave (Server Play Mode)")]
    private void EmitFromContextMenu()
    {
        if (Application.isPlaying)
            EmitShockwave();
    }

    private void ApplyToPlayers(Vector3 worldOrigin)
    {
        foreach (PlayerImpactController player in
                 FindObjectsByType<PlayerImpactController>(FindObjectsSortMode.None))
        {
            if (!player.IsSpawned)
                continue;

            Vector3 offset = player.transform.position - worldOrigin;
            float distance = offset.magnitude;
            if (!profile.TryEvaluate(distance, out ShockwaveZone zone))
                continue;

            Vector3 direction = CreateDirection(offset, zone.UpwardBias);
            player.ApplyImpactOnServer(direction * zone.PlayerImpulse, zone);
        }
    }

    private void ApplyToPhysics(Vector3 worldOrigin)
    {
        int count = Physics.OverlapSphereNonAlloc(
            worldOrigin,
            profile.MaximumRadius,
            overlapBuffer,
            physicsLayers,
            QueryTriggerInteraction.Ignore);

        affectedBodies.Clear();
        for (int index = 0; index < count; index++)
        {
            Collider hit = overlapBuffer[index];
            Rigidbody body = hit != null ? hit.attachedRigidbody : null;
            if (body == null || body.isKinematic || !affectedBodies.Add(body) ||
                body.GetComponentInParent<PlayerImpactController>() != null)
            {
                continue;
            }

            Vector3 offset = body.worldCenterOfMass - worldOrigin;
            if (!profile.TryEvaluate(offset.magnitude, out ShockwaveZone zone) ||
                zone.RigidbodyImpulse <= 0f)
            {
                continue;
            }

            body.AddForce(
                CreateDirection(offset, zone.UpwardBias) * zone.RigidbodyImpulse,
                ForceMode.Impulse);
        }
    }

    private static Vector3 CreateDirection(Vector3 offset, float upwardBias)
    {
        if (offset.sqrMagnitude < 0.0001f)
            offset = Vector3.up;
        offset.Normalize();
        return (offset + Vector3.up * Mathf.Clamp01(upwardBias)).normalized;
    }

    private void HandleSequenceChanged(uint previous, uint current)
    {
        if (current == previous)
            return;
        Emitted?.Invoke();
        shockwaveEmitted?.Invoke();
    }
}