using System;

using Unity.Behavior;
using Unity.Properties;
using UnityEngine;

using Colosseum;
using Colosseum.Combat;
using Colosseum.Enemy;

using Action = Unity.Behavior.Action;

/// <summary>
/// 거리 조건에 맞는 대상을 선택하는 Behavior Action입니다.
/// 가장 가까운 대상, 가장 먼 대상, 후보 중 랜덤 선택을 지원합니다.
/// </summary>
[Serializable]
public enum DistanceTargetSelectionMode
{
    Nearest = 0,
    Farthest = 1,
    Random = 2,
}

[Serializable, GeneratePropertyBag]
[NodeDescription(
    name: "Select Target By Distance",
    story: "[Tag] 대상 중 [MinRange] 이상 [MaxRange] 이하 범위에서 [SelectionMode] 방식으로 [Target] 선택",
    category: "Action",
    id: "4f6a830df3ff4ff5bf8bd2c8b433aa41")]
public partial class SelectTargetByDistanceAction : Action
{
    [SerializeReference]
    public BlackboardVariable<GameObject> Target;

    [SerializeReference]
    public BlackboardVariable<string> Tag = new BlackboardVariable<string>("Player");

    [SerializeReference]
    public BlackboardVariable<float> MinRange = new BlackboardVariable<float>(0f);

    [SerializeReference]
    public BlackboardVariable<float> MaxRange = new BlackboardVariable<float>(20f);

    [SerializeReference]
    public BlackboardVariable<DistanceTargetSelectionMode> SelectionMode =
        new BlackboardVariable<DistanceTargetSelectionMode>(DistanceTargetSelectionMode.Farthest);

    protected override Status OnStart()
    {
        if (string.IsNullOrEmpty(Tag.Value))
            return Status.Failure;

        GameObject[] candidates = GameObject.FindGameObjectsWithTag(Tag.Value);
        if (candidates == null || candidates.Length == 0)
            return Status.Failure;

        float minRange = Mathf.Max(0f, MinRange.Value);
        float maxRange = Mathf.Max(minRange, MaxRange.Value);
        BossBehaviorRuntimeState runtimeState = GameObject.GetComponent<BossBehaviorRuntimeState>();

        if (maxRange <= minRange)
        {
            EnemyBase enemyBase = GameObject.GetComponent<EnemyBase>();
            maxRange = enemyBase != null && enemyBase.Data != null ? enemyBase.Data.AggroRange : 20f;
        }

        GameObject selectedTarget = SelectionMode.Value switch
        {
            DistanceTargetSelectionMode.Nearest => FindNearestTarget(candidates, minRange, maxRange),
            DistanceTargetSelectionMode.Random => FindRandomTarget(candidates, minRange, maxRange),
            _ => FindFarthestTarget(candidates, minRange, maxRange),
        };

        if (selectedTarget == null)
            return Status.Failure;

        Target.Value = selectedTarget;
        runtimeState?.SetCurrentTarget(selectedTarget);
        runtimeState?.LogDebug(nameof(SelectTargetByDistanceAction), $"거리 기반 대상 선택: {selectedTarget.name} / Mode={SelectionMode.Value}");
        return Status.Success;
    }

    private GameObject FindNearestTarget(GameObject[] candidates, float minRange, float maxRange)
    {
        GameObject bestTarget = null;
        float bestDistance = float.MaxValue;

        for (int i = 0; i < candidates.Length; i++)
        {
            GameObject candidate = candidates[i];
            if (!IsValidTarget(candidate, minRange, maxRange, out float distance))
                continue;

            if (distance >= bestDistance)
                continue;

            bestDistance = distance;
            bestTarget = candidate;
        }

        return bestTarget;
    }

    private GameObject FindFarthestTarget(GameObject[] candidates, float minRange, float maxRange)
    {
        GameObject bestTarget = null;
        float bestDistance = minRange;

        for (int i = 0; i < candidates.Length; i++)
        {
            GameObject candidate = candidates[i];
            if (!IsValidTarget(candidate, minRange, maxRange, out float distance))
                continue;

            if (distance <= bestDistance)
                continue;

            bestDistance = distance;
            bestTarget = candidate;
        }

        return bestTarget;
    }

    private GameObject FindRandomTarget(GameObject[] candidates, float minRange, float maxRange)
    {
        System.Collections.Generic.List<GameObject> validTargets = new System.Collections.Generic.List<GameObject>();

        for (int i = 0; i < candidates.Length; i++)
        {
            GameObject candidate = candidates[i];
            if (!IsValidTarget(candidate, minRange, maxRange, out _))
                continue;

            validTargets.Add(candidate);
        }

        if (validTargets.Count == 0)
            return null;

        int randomIndex = UnityEngine.Random.Range(0, validTargets.Count);
        return validTargets[randomIndex];
    }

    private bool IsValidTarget(GameObject candidate, float minRange, float maxRange, out float distance)
    {
        distance = 0f;

        if (candidate == null || !candidate.activeInHierarchy)
            return false;

        if (Team.IsSameTeam(GameObject, candidate))
            return false;

        IDamageable damageable = candidate.GetComponent<IDamageable>();
        if (damageable != null && damageable.IsDead)
            return false;

        EnemyBase enemyBase = GameObject.GetComponent<EnemyBase>();
        float sightRange = enemyBase != null && enemyBase.Data != null
            ? enemyBase.Data.AggroRange
            : maxRange;

        distance = Vector3.Distance(GameObject.transform.position, candidate.transform.position);
        if (distance < minRange || distance > maxRange || distance > sightRange)
            return false;

        return true;
    }
}