// Assets/Scripts/Player/States/SwimState.cs
// 游泳状态：玩家在液体中时使用（Architecture 21_LiquidPuzzleModule §5）
// ⚠️ 遵循 PlayerStateBase 构造函数注入模式（非 MonoBehaviour）
// ⚠️ 输入通过 Input.MoveInput / Input.JumpStartedEvent 访问（项目实际 API）
using BaseGames.Player;
using BaseGames.World.Liquid;
using UnityEngine;

namespace BaseGames.Player.States
{
    /// <summary>
    /// 游泳状态：玩家在液体中时使用。
    /// 需要 AbilityType.Swim 已解锁；若未解锁则由 WaterDangerState 触发溺水流程。
    /// 由 PlayerController 在收到 EVT_LiquidEntered 后切换进入。
    /// </summary>
    public class SwimState : PlayerStateBase
    {
        private LiquidPhysicsConfigSO _currentPhysics;
        private float                 _originalGravity;

        public SwimState(PlayerController owner) : base(owner) { }

        /// <summary>由 PlayerController 在切换状态前调用，注入当前液体区域的物理配置。</summary>
        public void SetPhysicsConfig(LiquidPhysicsConfigSO config) => _currentPhysics = config;

        public override void OnStateEnter()
        {
            _originalGravity = Move.Rb.gravityScale;
            Move.SetGravityScale(_currentPhysics?.GravityScale ?? 0.3f);

            if (AnimCfg?.SwimIdle != null)
                Anim?.Play(AnimCfg.SwimIdle);

            Input.JumpStartedEvent += OnJumpStarted;
        }

        public override void OnStateExit()
        {
            Input.JumpStartedEvent -= OnJumpStarted;
            Move.SetGravityScale(_originalGravity);
        }

        public override void OnStateUpdate()
        {
            var input    = Input.MoveInput;
            var maxSpeed = _currentPhysics?.MaxSwimSpeed     ?? 4f;
            var accel    = _currentPhysics?.SwimAcceleration ?? 8f;
            var drag     = _currentPhysics?.DragCoefficient  ?? 3f;
            var rb       = Move.Rb;

            if (input != Vector2.zero)
            {
                var targetVel = input * maxSpeed;
                rb.velocity   = Vector2.MoveTowards(rb.velocity, targetVel, accel * Time.deltaTime);

                if (AnimCfg?.SwimMove != null)
                    Anim?.Play(AnimCfg.SwimMove);
            }
            else
            {
                // 水下浮力（持续向上的微弱力）
                rb.AddForce(Vector2.up * (_currentPhysics?.BuoyancyForce ?? 0.5f), ForceMode2D.Force);

                if (AnimCfg?.SwimIdle != null)
                    Anim?.Play(AnimCfg.SwimIdle);
            }

            // 施加水阻
            rb.velocity *= 1f - drag * Time.deltaTime;
        }

        public override PlayerStateBase GetNextState()
        {
            // 离开液体区域由 PlayerController 订阅 EVT_LiquidExited 后切换到 FallState
            return null;
        }

        private void OnJumpStarted()
        {
            // 跳跃键 = 跃出水面冲量
            Move.Rb.AddForce(Vector2.up * (_currentPhysics?.SurfaceExitSpeed ?? 5f),
                             ForceMode2D.Impulse);
        }
    }
}