using Cielonos.MainGame.Buffs.Character;
using Cielonos.MainGame.Characters;
using SLSUtilities.General;
using UnityEngine;

namespace Cielonos.MainGame
{
    /// <summary>
    /// 脉冲力的方向计算模式。
    /// </summary>
    public enum ImpulseForceMode
    {
        /// <summary>使用预设的固定力矢量。</summary>
        Custom,
        /// <summary>沿攻击区域 forward 方向施加力（投射物常用）。</summary>
        Dynamic,
        /// <summary> 沿攻击区域 forward 方向施加力，但在计算时将竖直分量忽略（仅在水平面内施加力，适合地面攻击）。 </summary>
        FlattenedDynamic,
        /// <summary>从攻击区域中心向外推开目标。</summary>
        Repulsion,
        /// <summary>将目标拉向攻击区域中心。</summary>
        Suction,
    }

    /// <summary>
    /// 攻击区域的脉冲子模块：配置并向命中目标施加击退/击飞力。
    /// 采用单构造函数 + 链式 With* 方法进行配置。
    /// </summary>
    public class ImpulseSubmodule : AttackAreaSubmoduleBase
    {
        private ImpulseForceMode forceMode;
        private Vector3 customForce;
        private float dynamicStrength;
        private float strengthXZ;
        private float strengthY;

        private bool isLaunch;
        private bool isParabolic;
        private float impulseDuration;
        private AnimationCurve impulseCurve;
        private bool applyStun;
        private float stunDuration;

        private float gravityMultiplier = 1f;
        private float gravityDuration;

        // ────────────────────────────────────────────────────────────────────
        //  Constructor
        // ────────────────────────────────────────────────────────────────────

        /// <summary>
        /// 创建一个新的 ImpulseSubmodule 实例。
        /// </summary>
        /// <param name="attackArea">所属的攻击区域。</param>
        /// <param name="duration">脉冲持续时间（秒）。</param>
        /// <param name="curve">速度衰减曲线。null 使用默认 EaseOut。</param>
        public ImpulseSubmodule(AttackAreaBase attackArea, float duration, AnimationCurve curve) : base(attackArea)
        {
            this.impulseDuration = duration;
            this.impulseCurve = curve;
        }

        // ────────────────────────────────────────────────────────────────────
        //  Chain Configuration
        // ────────────────────────────────────────────────────────────────────

        /// <summary>
        /// 设置为斥力模式：从攻击区域中心向外推开目标。
        /// </summary>
        public ImpulseSubmodule WithRepulsion(float strengthXZ, float strengthY = 0)
        {
            this.forceMode = ImpulseForceMode.Repulsion;
            this.strengthXZ = strengthXZ;
            this.strengthY = strengthY;
            return this;
        }

        /// <summary>
        /// 设置为吸力模式：将目标拉向攻击区域中心。
        /// </summary>
        public ImpulseSubmodule WithSuction(float strengthXZ, float strengthY = 0)
        {
            this.forceMode = ImpulseForceMode.Suction;
            this.strengthXZ = strengthXZ;
            this.strengthY = strengthY;
            return this;
        }

        /// <summary>
        /// 设置为自定义力矢量模式。
        /// </summary>
        public ImpulseSubmodule WithCustomForce(Vector3 force)
        {
            this.forceMode = ImpulseForceMode.Custom;
            this.customForce = force;
            return this;
        }

        /// <summary>
        /// 设置为动态力模式：沿攻击区域 forward 方向施加指定强度的力。
        /// </summary>
        public ImpulseSubmodule WithDynamicForce(float strength, bool isFlattened = true)
        {
            this.forceMode = isFlattened ? ImpulseForceMode.FlattenedDynamic : ImpulseForceMode.Dynamic;
            this.dynamicStrength = strength;
            return this;
        }

        /// <summary>
        /// 标记为击飞：无视抗性，自动附加眩晕。
        /// parabolic 为 true 时使用物理弧线（距离击飞），为 false 时使用曲线衰减（空战浮空）。
        /// </summary>
        /// <param name="strengthY">竖直方向的初始击飞强度。</param>
        /// <param name="parabolic">是否使用抛物线物理。默认 true。</param>
        public ImpulseSubmodule WithLaunch(float strengthY, bool parabolic = true)
        {
            this.isLaunch = true;
            this.strengthY = strengthY;
            this.isParabolic = parabolic;
            return this;
        }

        /// <summary>
        /// 标记击退时附加眩晕（击飞始终自动眩晕，无需此方法）。
        /// </summary>
        /// <param name="duration">眩晕持续时间（秒）。0 表示跟随脉冲持续时间。</param>
        public ImpulseSubmodule WithStun(float duration = 0f)
        {
            this.applyStun = true;
            this.stunDuration = duration;
            return this;
        }

        /// <summary>
        /// 设置命中后的重力修正。通过 VerticalMoveModification Buff 实现。
        /// multiplier 小于 1 使目标浮空（空战连击），大于 1 使目标加速坠落（Finisher）。
        /// 当 multiplier 大于 1 时，会先清除目标身上已有的浮空 Buff，确保坠落生效。
        /// </summary>
        /// <param name="multiplier">重力缩放倍率。0 = 完全浮空，1 = 正常，大于 1 = 加速坠落。</param>
        /// <param name="duration">重力修正持续时间（秒）。</param>
        public ImpulseSubmodule WithGravityModifier(float multiplier, float duration)
        {
            this.gravityMultiplier = multiplier;
            this.gravityDuration = duration;
            return this;
        }

        // ────────────────────────────────────────────────────────────────────
        //  Force Calculation & Application
        // ────────────────────────────────────────────────────────────────────

        /// <summary>
        /// 根据当前力模式计算施加给目标的最终力矢量。
        /// </summary>
        public Vector3 GetFinalForce(CharacterBase target)
        {
            return forceMode switch
            {
                ImpulseForceMode.Repulsion =>
                    (target.centerPoint.position - attackArea.topParent.position).Flatten().normalized * strengthXZ
                    + Vector3.up * strengthY,

                ImpulseForceMode.Suction =>
                    (attackArea.topParent.position - target.centerPoint.position).Flatten().normalized * strengthXZ
                    + Vector3.up * strengthY,

                ImpulseForceMode.Dynamic =>
                    attackArea.topParent.forward * dynamicStrength,

                ImpulseForceMode.FlattenedDynamic =>
                    attackArea.topParent.forward.Flatten().normalized * dynamicStrength,
                
                _ => customForce,
            };
        }

        /// <summary>
        /// 对目标角色施加脉冲力。自动区分 Automata 和玩家的处理路径。
        /// </summary>
        public void ApplyImpulse(CharacterBase target)
        {
            Vector3 force = GetFinalForce(target);

            if (target.movementSc is AutomataLandMovementSubcontroller automataSc)
            {
                automataSc.ApplyHitImpact(force, isLaunch, isParabolic,
                    impulseDuration, impulseCurve, applyStun, stunDuration,
                    gravityMultiplier, gravityDuration);
            }
            else
            {
                target.movementSc.impulseSm.ApplyImpulse(force, isLaunch, impulseDuration, impulseCurve, isParabolic);
                ApplyGravityModifier(target);
            }
        }

        /// <summary>
        /// 对非 Automata 目标（玩家等）施加重力修正 Buff。
        /// </summary>
        private void ApplyGravityModifier(CharacterBase target)
        {
            if (gravityDuration <= 0f) return;

            if (gravityMultiplier > 1f)
            {
                ClearExistingGravityModifier(target);
            }

            new VerticalMoveModification(gravityDuration, gravityMultiplier).Apply(target);
        }

        /// <summary>
        /// 清除目标身上已有的 VerticalMoveModification Buff（Finisher 坠落前调用）。
        /// </summary>
        private static void ClearExistingGravityModifier(CharacterBase target)
        {
            if (target.buffSm.TryGetBuff<VerticalMoveModification>(out var existingBuff))
            {
                existingBuff.Remove();
            }
        }
    }
}