using UnityEngine;
using Platformer.Mechanics;

namespace EerieVillage.Skills.Effectors
{
    /// <summary>
    /// 상태 효과 일괄 적용기.
    /// Projectile.OnTriggerEnter2D 등 타격 판정 후 ActiveSkillData 필드를 읽어
    /// DoT·Stun·Slow·Knockback·DebuffStack 을 EnemyController 에 적용한다.
    /// BT12-Dev Phase 2-B §4-5.
    /// </summary>
    public static class StatusApplier
    {
        public static void Apply(ActiveSkillData data, EnemyController enemy)
        {
            if (data == null || enemy == null) return;

            // DoT (화염·독 등) — DotInterval > 0 영역만 발화 (DotDuration 영역 OnDotFxPrefab.ParticleSystem.main.duration 영역 자동 영역)
            // BT12-Dev 2026-05-13 — damage = BaseDamage × DotDamageMultiplier (PD 영역: 25%) + OnDotFxPrefab 자식 spawn
            if ((data.DotDuration > 0f || data.OnDotFxPrefab != null) && data.DotInterval > 0f)
            {
                int dotDamage = Mathf.Max(1, Mathf.RoundToInt(data.BaseDamage * data.DotDamageMultiplier));
                ApplyDoT(enemy, dotDamage, data.DotDuration, data.DotInterval, data.OnDotFxPrefab, data.DotFxScale);
            }

            // 기절 (스턴)
            if (data.StunDuration > 0f)
            {
                ApplyStun(enemy, data.StunDuration);
            }

            // 감속 (슬로우)
            if (data.SlowDuration > 0f && data.SlowMultiplier < 1.0f)
            {
                ApplySlow(enemy, data.SlowDuration, data.SlowMultiplier);
            }

            // 넉백
            if (data.KnockbackForce > 0f)
            {
                ApplyKnockback(enemy, data.KnockbackForce);
            }

            // 저주 스택 (A08 저주의 화살)
            if (data.DebuffStackLimit > 0)
            {
                DebuffStack.AddStack(enemy, data.DebuffStackLimit, data.BaseDamage);
            }
        }

        // -------------------------------------------------------------------
        // 내부 헬퍼
        // -------------------------------------------------------------------

        private static void ApplyDoT(EnemyController enemy, int damagePerTick, float duration, float interval, GameObject fxPrefab = null, float fxScale = 1f)
        {
            var existing = enemy.GetComponent<EnemyDoTState>();
            if (existing == null) existing = enemy.gameObject.AddComponent<EnemyDoTState>();
            existing.AddDoT(damagePerTick, duration, interval, fxPrefab, fxScale);
        }

        private static void ApplyStun(EnemyController enemy, float duration)
        {
            var existing = enemy.GetComponent<EnemyStunState>();
            if (existing == null) existing = enemy.gameObject.AddComponent<EnemyStunState>();
            existing.ApplyStun(duration);
        }

        private static void ApplySlow(EnemyController enemy, float duration, float multiplier)
        {
            var existing = enemy.GetComponent<EnemySlowState>();
            if (existing == null) existing = enemy.gameObject.AddComponent<EnemySlowState>();
            existing.ApplySlow(duration, multiplier);
        }

        private static void ApplyKnockback(EnemyController enemy, float force)
        {
            var rb = enemy.GetComponent<Rigidbody2D>();
            if (rb != null)
            {
                // facing 반대 방향 넉백 — 단순 +x 방향 (Phase 2 범위, Phase 2-C에서 방향 정합 예정)
                rb.AddForce(Vector2.right * force, ForceMode2D.Impulse);
            }
        }
    }
}