using Unity.Netcode;
using UnityEngine;
using UnityEngine.SceneManagement;

public sealed class PlayerSpawnController : NetworkBehaviour, IPlayerSystem
{
    [Header("Start Room Spawn")]
    [SerializeField, Min(0f)] private float edgePadding = 0.75f;
    [SerializeField, Min(0f)] private float heightAboveFloor = 0.15f;

    private readonly NetworkVariable<Vector3> assignedSpawnPosition = new(
        Vector3.zero,
        NetworkVariableReadPermission.Everyone,
        NetworkVariableWritePermission.Server);

    private readonly NetworkVariable<bool> hasAssignedSpawnPosition = new(
        false,
        NetworkVariableReadPermission.Everyone,
        NetworkVariableWritePermission.Server);

    private int assignedSceneHandle = -1;

    public void Initialize(PlayerFacade facade) { }

    public override void OnNetworkSpawn()
    {
        assignedSpawnPosition.OnValueChanged += HandleSpawnPositionChanged;
        hasAssignedSpawnPosition.OnValueChanged += HandleSpawnAssignmentChanged;
        SceneManager.sceneLoaded += HandleSceneLoaded;

        if (IsServer)
            TryAssignStartRoomPosition(SceneManager.GetActiveScene());

        if (hasAssignedSpawnPosition.Value)
            ApplySpawnPosition(assignedSpawnPosition.Value);
    }

    public override void OnNetworkDespawn()
    {
        assignedSpawnPosition.OnValueChanged -= HandleSpawnPositionChanged;
        hasAssignedSpawnPosition.OnValueChanged -= HandleSpawnAssignmentChanged;
        SceneManager.sceneLoaded -= HandleSceneLoaded;
    }

    private void HandleSceneLoaded(Scene scene, LoadSceneMode _)
    {
        if (IsServer)
            TryAssignStartRoomPosition(scene);

        if (IsOwner && hasAssignedSpawnPosition.Value)
            ApplySpawnPosition(assignedSpawnPosition.Value);
    }

    private void TryAssignStartRoomPosition(Scene scene)
    {
        if (!scene.IsValid() || !scene.isLoaded || scene.handle == assignedSceneHandle)
            return;

        StartRoomZone startRoom = FindStartRoomInScene(scene);
        if (startRoom == null ||
            !startRoom.TryGetRandomSpawnPosition(
                edgePadding,
                heightAboveFloor,
                out Vector3 position))
        {
            return;
        }

        hasAssignedSpawnPosition.Value = false;
        assignedSpawnPosition.Value = position;
        hasAssignedSpawnPosition.Value = true;
        assignedSceneHandle = scene.handle;
    }

    private static StartRoomZone FindStartRoomInScene(Scene scene)
    {
        foreach (GameObject rootObject in scene.GetRootGameObjects())
        {
            StartRoomZone startRoom = rootObject.GetComponentInChildren<StartRoomZone>(true);
            if (startRoom != null)
                return startRoom;
        }

        return null;
    }

    private void HandleSpawnPositionChanged(Vector3 _, Vector3 position)
    {
        if (hasAssignedSpawnPosition.Value)
            ApplySpawnPosition(position);
    }

    private void HandleSpawnAssignmentChanged(bool _, bool isAssigned)
    {
        if (isAssigned)
            ApplySpawnPosition(assignedSpawnPosition.Value);
    }

    private void ApplySpawnPosition(Vector3 position)
    {
        if (!IsOwner)
            return;

        CharacterController characterController = GetComponent<CharacterController>();
        bool restoreCharacterController = characterController != null && characterController.enabled;

        if (restoreCharacterController)
            characterController.enabled = false;

        transform.position = position;
        Physics.SyncTransforms();

        if (restoreCharacterController)
            characterController.enabled = true;
    }
}