using System.Collections.Generic;
using UnityEngine;
using UnityEngine.AI;

[RequireComponent(typeof(CapsuleCollider))]
public class EnemyStateMachine : MonoBehaviour
{
    public enum State
    {
        Patrol,
        Suspicion,
        Alert
    }

    [Header("References")]
    public Transform[] patrolPoints;
    public NavMeshAgent agent;
    public EnemyVision vision;

    [Header("Movement")]
    public float patrolSpeed = 2.2f;
    public float suspicionSpeed = 2.8f;
    public float alertSpeed = 3.8f;
    public float manualRotationSpeed = 8f;
    public float waypointTolerance = 0.7f;

    [Header("Awareness")]
    public float hearingRange = 12f;
    public float suspicionWaitDuration = 2.5f;
    public float loseSightDelay = 1.3f;
    public float captureDistance = 1.6f;
    public int captureDamage = 10;
    public float captureCooldown = 1f;

    public State CurrentState { get; private set; } = State.Patrol;
    public static IReadOnlyList<EnemyStateMachine> ActiveEnemies => activeEnemies;

    private static readonly List<EnemyStateMachine> activeEnemies = new List<EnemyStateMachine>();

    private Transform player;
    private PlayerHealth playerHealth;
    private int patrolIndex;
    private Vector3 investigationTarget;
    private Vector3 lastKnownPlayerPosition;
    private float suspicionTimer;
    private float lastSeenTime = -999f;
    private float lastCaptureTime = -999f;
    private float lastHandledNoiseTimestamp = -999f;

    private void OnEnable()
    {
        if (!activeEnemies.Contains(this))
        {
            activeEnemies.Add(this);
        }
    }

    private void OnDisable()
    {
        activeEnemies.Remove(this);
    }

    private void Awake()
    {
        agent = agent != null ? agent : GetComponent<NavMeshAgent>();
        vision = vision != null ? vision : GetComponent<EnemyVision>();
    }

    private void Start()
    {
        AcquirePlayer();
        ApplySpeedForState(CurrentState);
    }

    private void Update()
    {
        AcquirePlayer();
        ListenForNoise();

        switch (CurrentState)
        {
            case State.Patrol:
                UpdatePatrol();
                break;
            case State.Suspicion:
                UpdateSuspicion();
                break;
            case State.Alert:
                UpdateAlert();
                break;
        }

        if (CurrentState == State.Alert && Time.time - lastSeenTime > loseSightDelay)
        {
            investigationTarget = lastKnownPlayerPosition;
            EnterState(State.Suspicion);
        }
    }

    public void OnPlayerDetected(Vector3 playerPos)
    {
        lastKnownPlayerPosition = playerPos;
        lastSeenTime = Time.time;

        if (CurrentState != State.Alert)
        {
            EnterState(State.Alert);
        }
    }

    public void OnPlayerLost()
    {
        if (CurrentState == State.Alert)
        {
            investigationTarget = lastKnownPlayerPosition;
        }
    }

    public void OnNoiseHeard(Vector3 noisePosition)
    {
        if (CurrentState == State.Alert)
        {
            return;
        }

        investigationTarget = noisePosition;
        suspicionTimer = 0f;
        EnterState(State.Suspicion);
    }

    private void UpdatePatrol()
    {
        if (patrolPoints == null || patrolPoints.Length == 0)
        {
            return;
        }

        Transform targetPoint = patrolPoints[patrolIndex];
        MoveTowards(targetPoint.position, patrolSpeed);

        if (HasReached(targetPoint.position))
        {
            patrolIndex = (patrolIndex + 1) % patrolPoints.Length;
        }
    }

    private void UpdateSuspicion()
    {
        MoveTowards(investigationTarget, suspicionSpeed);

        if (HasReached(investigationTarget))
        {
            suspicionTimer += Time.deltaTime;
            if (suspicionTimer >= suspicionWaitDuration)
            {
                suspicionTimer = 0f;
                EnterState(State.Patrol);
            }
        }
        else
        {
            suspicionTimer = 0f;
        }
    }

    private void UpdateAlert()
    {
        if (player == null)
        {
            return;
        }

        lastKnownPlayerPosition = player.position;
        MoveTowards(lastKnownPlayerPosition, alertSpeed);

        if (Vector3.Distance(transform.position, player.position) <= captureDistance && Time.time >= lastCaptureTime + captureCooldown)
        {
            lastCaptureTime = Time.time;
            if (playerHealth != null)
            {
                playerHealth.TakeDamage(captureDamage);
            }
            Debug.Log("Игрок обнаружен!");
        }
    }

    private void ListenForNoise()
    {
        NoiseManager.NoiseEvent noise = NoiseManager.GetClosestNoise(transform.position, hearingRange);
        if (noise == null || noise.timestamp <= lastHandledNoiseTimestamp)
        {
            return;
        }

        lastHandledNoiseTimestamp = noise.timestamp;
        OnNoiseHeard(noise.position);
    }

    private void EnterState(State newState)
    {
        CurrentState = newState;
        ApplySpeedForState(newState);

        switch (newState)
        {
            case State.Patrol:
                suspicionTimer = 0f;
                break;
            case State.Suspicion:
                suspicionTimer = 0f;
                break;
            case State.Alert:
                lastSeenTime = Time.time;
                break;
        }
    }

    private void ApplySpeedForState(State state)
    {
        if (agent == null)
        {
            return;
        }

        switch (state)
        {
            case State.Patrol:
                agent.speed = patrolSpeed;
                break;
            case State.Suspicion:
                agent.speed = suspicionSpeed;
                break;
            case State.Alert:
                agent.speed = alertSpeed;
                break;
        }
    }

    private void MoveTowards(Vector3 destination, float manualSpeed)
    {
        if (agent != null && agent.isActiveAndEnabled && agent.isOnNavMesh)
        {
            agent.SetDestination(destination);
            return;
        }

        // Fallback нужен на случай, если NavMesh ещё не запечён или агент не смог встать на него.
        Vector3 flatDestination = new Vector3(destination.x, transform.position.y, destination.z);
        Vector3 direction = flatDestination - transform.position;
        direction.y = 0f;

        if (direction.sqrMagnitude <= 0.001f)
        {
            return;
        }

        Vector3 step = direction.normalized * manualSpeed * Time.deltaTime;
        transform.position += step.sqrMagnitude > direction.sqrMagnitude ? direction : step;

        Quaternion targetRotation = Quaternion.LookRotation(direction.normalized, Vector3.up);
        transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, Time.deltaTime * manualRotationSpeed);
    }

    private bool HasReached(Vector3 destination)
    {
        if (agent != null && agent.isActiveAndEnabled && agent.isOnNavMesh)
        {
            if (agent.pathPending)
            {
                return false;
            }

            return agent.remainingDistance <= Mathf.Max(agent.stoppingDistance, waypointTolerance);
        }

        Vector3 flatDestination = new Vector3(destination.x, transform.position.y, destination.z);
        return Vector3.Distance(transform.position, flatDestination) <= waypointTolerance;
    }

    private void AcquirePlayer()
    {
        if (player != null)
        {
            return;
        }

        GameObject playerObject = GameObject.FindGameObjectWithTag("Player");
        if (playerObject == null)
        {
            return;
        }

        player = playerObject.transform;
        playerHealth = playerObject.GetComponent<PlayerHealth>();
    }
}