using System;
using Cielonos.MainGame.Buffs;
using Cielonos.MainGame.Buffs.Character;
using SLSUtilities.General;

namespace Cielonos.MainGame.Inventory.Collections
{
    /// <summary>
    /// 自适应装甲 / Adaptive Armor
    /// 玩家受到伤害时，获得一个持续10秒的（护甲+5）的Buff，最高可叠加5层，每次叠加刷新持续时间。
    /// </summary>
    public partial class AdaptiveArmor : PassiveEquipmentBase
    {
        private const string EventKey = "AdaptiveArmor";

        public override void OnObtained()
        {
            base.OnObtained();

            Action<AttackAreaBase, Attack.Result> onAfterGetAttacked = OnAfterGetAttacked;
            player.eventSm.onAfterGetAttacked.Add(EventKey, onAfterGetAttacked.ToPrioritized());
        }

        public override void OnDiscarded()
        {
            player.eventSm.onAfterGetAttacked.Remove(EventKey);

            // 移除残留的 Buff
            if (player.buffSm.TryGetBuff(out TemporaryArmor existingBuff))
            {
                existingBuff.Remove();
            }

            base.OnDiscarded();
        }

        /// <summary>
        /// 玩家被攻击后触发，施加或叠加临时护甲 Buff。
        /// </summary>
        private void OnAfterGetAttacked(AttackAreaBase attackArea, Attack.Result result)
        {
            float armorPerStack = passiveAttributeSm.GetItemAttribute("ArmorPerStack");
            float duration = passiveAttributeSm.GetItemAttribute("BuffDuration");
            int maxStacks = (int)passiveAttributeSm.GetItemAttribute("BuffMaxStacks");

            if (armorPerStack <= 0f || duration <= 0f || maxStacks <= 0) return;
            new TemporaryArmor(armorPerStack, duration, maxStacks).Apply(player, player, this);
        }
    }

    public partial class AdaptiveArmor
    {
        /// <summary>
        /// 自适应装甲的Buff。
        /// 默认持续时间为10秒，每层提供指定点护甲，最多叠加指定层。每次受到伤害时，如果已经有该Buff，则刷新持续时间并增加一层。
        /// </summary>
        public class TemporaryArmor : CharacterBuffBase
        {
            private readonly float _armorPerStack;

            public TemporaryArmor(float armorPerStack, float duration, int maxStacks)
            {
                Initialize(BuffType.Positive, BuffDispelLevel.Basic);
                _armorPerStack = armorPerStack;

                this.contentSubmodule = new ContentSubmodule(this);
                this.timeSubmodule = new TimeSubmodule(this, duration);
                this.unitedStackSubmodule = new UnitedStackSubmodule(this, true, maxStacks);
                this.attributeSubmodule = new AttributeSubmodule(this);
            }

            public override bool OnBuffApply(out CharacterBuffBase existingBuff)
            {
                if (FindExistingSameBuff(out TemporaryArmor existing))
                {
                    existingBuff = existing;
                    existing.timeSubmodule.RefreshDuration();
                    existing.unitedStackSubmodule.AddStack(1);
                    existing.UpdateArmorValue(existing.unitedStackSubmodule.stackAmount);
                    return false;
                }

                existingBuff = null;
                UpdateArmorValue(unitedStackSubmodule.stackAmount);
                return true;
            }
            
            /// <summary>
            /// 根据当前层数更新护甲加成数值。
            /// </summary>
            private void UpdateArmorValue(int stacks)
            {
                attributeSubmodule.numericChange[CharacterAttribute.Armor] = stacks * _armorPerStack;
                attributeSubmodule.RefreshAllModifiedAttributes();
            }
        }
    }
}