using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Platformer.Gameplay;
using static Platformer.Core.Simulation;
using Platformer.Model;
using Platformer.Core;
using UnityEngine.InputSystem;

namespace Platformer.Mechanics
{
    /// <summary>
    /// This is the main class used to implement control of the player.
    /// It is a superset of the AnimationController class, but is inlined to allow for any kind of customisation.
    /// </summary>
    public class PlayerController : KinematicObject
    {
        public AudioClip jumpAudio;
        public AudioClip respawnAudio;
        public AudioClip ouchAudio;
        /// <summary>
        /// Attack sound effect. 자동 발동 시 PlayerAttack.Execute가 PlayOneShot으로 재생.
        /// BT7-Plan 2026-04-24 — VS 순수형 자동 발동 전환 후에도 audio hook 유지.
        /// </summary>
        public AudioClip attackAudio;

        /// <summary>
        /// Max horizontal speed of the player.
        /// </summary>
        public float maxSpeed = 7;
        /// <summary>
        /// Initial jump velocity at the start of a jump.
        /// </summary>
        public float jumpTakeOffSpeed = 7;

        /// <summary>
        /// Attack hitbox component (자동 GetComponent, 없으면 null — PlayerAttack.Execute에서 null 체크).
        /// 공격은 PlayerAttackTicker가 주기적으로 Schedule<PlayerAttack>을 발화하여 실행.
        /// </summary>
        public AttackHitbox attackHitbox;

        public JumpState jumpState = JumpState.Grounded;
        private bool stopJump;

        // BT69 — Down + Jump Drop-Through (PD 명시 2026-05-08): Down 누른 상태에서 점프 시 발판 통과 + 점프 모션
        private float dropThroughTimer = 0f;  // 활성 시간 동안 Layer 16 mask 강제 OFF
        private const float DROP_THROUGH_DURATION = 0.3f;  // Drop-Through 활성 지속 시간 (초)
        private bool dropThroughJump = false;  // 본 frame Drop-Through 점프 발동 여부 (velocity.y 처리 분기)
        /*internal new*/ public Collider2D collider2d;
        /*internal new*/ public AudioSource audioSource;
        public Health health;
        public bool controlEnabled = true;

        bool jump;
        Vector2 move;
        SpriteRenderer spriteRenderer;
        internal Animator animator;
        readonly PlatformerModel model = Simulation.GetModel<PlatformerModel>();

        private InputAction m_MoveAction;
        private InputAction m_JumpAction;

        // 현재 facing 방향 (마지막 이동 입력 기반, 정지 시 이전 값 유지).
        // BT7-Plan 2026-04-24 — PlayerAttackTicker가 자동 발동 시 참조하므로 public 노출.
        Vector2 facing = Vector2.right;

        /// <summary>현재 플레이어 facing 방향. PlayerAttackTicker가 Schedule 시점에 참조.</summary>
        public Vector2 Facing => facing;

        public Bounds Bounds => collider2d.bounds;

        /// <summary>
        /// 마지막 grounded 위치 — 낙사 시 안전 복귀 영역 (PD 지시 2026-05-07).
        /// </summary>
        public Vector3 LastGroundedPosition { get; private set; }

        void Awake()
        {
            health = GetComponent<Health>();
            audioSource = GetComponent<AudioSource>();
            collider2d = GetComponent<Collider2D>();
            spriteRenderer = GetComponent<SpriteRenderer>();
            if (spriteRenderer == null) spriteRenderer = GetComponentInChildren<SpriteRenderer>();
            animator = GetComponent<Animator>();
            if (animator == null) animator = GetComponentInChildren<Animator>();

            // PD 지시 2026-05-07 — 동반 컴포넌트 자동 부착 (Inspector 부착 불요)
            if (GetComponent<PlayerInvulnerabilityFlash>() == null) gameObject.AddComponent<PlayerInvulnerabilityFlash>();
            if (GetComponent<Platformer.UI.ResurrectPromptUI>() == null) gameObject.AddComponent<Platformer.UI.ResurrectPromptUI>();
            // BT5-Dev #34 — PlatformDropThrough 폐기 (PlatformEffector2D 표준 패턴 활용)
            var oldDrop = GetComponent<PlatformDropThrough>();
            if (oldDrop != null) Destroy(oldDrop);

            // PD 지시 2026-05-07 — 사망 시 입력 차단 / 부활 시 입력 복원
            if (health != null)
            {
                health.OnDeathEvent += OnHealthDeath;
                health.OnResurrectEvent += OnHealthResurrect;
            }
            if (attackHitbox == null) attackHitbox = GetComponent<AttackHitbox>();

            m_MoveAction = InputSystem.actions.FindAction("Player/Move");
            m_JumpAction = InputSystem.actions.FindAction("Player/Jump");

            m_MoveAction.Enable();
            m_JumpAction.Enable();

            LastGroundedPosition = transform.position;
        }

        void OnDestroy()
        {
            if (health != null)
            {
                health.OnDeathEvent -= OnHealthDeath;
                health.OnResurrectEvent -= OnHealthResurrect;
            }
        }

        // BT5-Dev #30 — 발판 GameObject 영역 식별 진단 (PD 영역 영역 영역 부딪힘 시 Console 출력)
        void OnCollisionEnter2D(Collision2D col)
        {
            if (col.gameObject == null) return;
            int layer = col.gameObject.layer;
            string name = col.gameObject.name;
            Debug.Log($"[BT30-Collide] name='{name}' layer={layer} (8=JumpThrough, 0=Default)");
        }

        void OnHealthDeath()
        {
            controlEnabled = false;
            move = Vector2.zero;
        }

        void OnHealthResurrect()
        {
            controlEnabled = true;
        }

        protected override void Update()
        {
            if (controlEnabled)
            {
                Vector2 moveInput = m_MoveAction.ReadValue<Vector2>();
                move.x = moveInput.x;
                if (jumpState == JumpState.Grounded && m_JumpAction.WasPressedThisFrame())
                {
                    // BT69 — Down + Jump = Drop-Through (PD 명시 2026-05-08)
                    // BT70 — 발판(Layer 16) 위 검증 추가 (PD 보고 2026-05-08: 지면 위 Down + Jump = 점프 X 버그)
                    //         발판 위만 Drop-Through 발동·지면 위 = 일반 점프
                    bool downHeld = moveInput.y < -0.5f;
                    bool onJumpThroughPlatform = false;
                    if (downHeld && collider2d != null)
                    {
                        Vector2 dropFootPos = new Vector2(collider2d.bounds.center.x, collider2d.bounds.min.y + 0.02f);
                        int jumpThroughMask = 1 << JUMP_THROUGH_LAYER;
                        RaycastHit2D dropFootHit = Physics2D.Raycast(dropFootPos, Vector2.down, 0.1f, jumpThroughMask);
                        onJumpThroughPlatform = dropFootHit.collider != null;
                    }
                    if (downHeld && onJumpThroughPlatform)
                    {
                        dropThroughTimer = DROP_THROUGH_DURATION;
                        dropThroughJump = true;
                    }
                    jumpState = JumpState.PrepareToJump;
                }
                else if (m_JumpAction.WasReleasedThisFrame())
                {
                    stopJump = true;
                    Schedule<PlayerStopJump>().player = this;
                }
                // 공격은 PlayerAttackTicker가 자동 주기로 Schedule<PlayerAttack>을 발화 (BT7-Plan VS 순수형).
            }
            else
            {
                move.x = 0;
            }

            // BT69 — Drop-Through Timer 감소 (Layer 16 mask 강제 OFF 지속 시간)
            if (dropThroughTimer > 0f) dropThroughTimer -= Time.deltaTime;
            UpdateJumpState();
            base.Update();

            // PD 지시 2026-05-07 — 낙사 시 복귀할 안전 위치 추적
            if (IsGrounded) LastGroundedPosition = transform.position;
        }

        // BT5-Dev #40 — 개발팀장 진단: KinematicObject.Start() contactFilter 캐싱 우회
        // Physics2D.IgnoreLayerCollision은 raycast contactFilter 영역 무관. SetLayerMask 직접 갱신 의무.
        const int JUMP_THROUGH_LAYER = 16;

        void UpdateJumpState()
        {
            jump = false;
            switch (jumpState)
            {
                case JumpState.PrepareToJump:
                    jumpState = JumpState.Jumping;
                    jump = true;
                    stopJump = false;
                    // BT41 — PrepareToJump frame 영역 즉시 contactFilter Layer 16 mask OFF (다음 ComputeVelocity 영역 velocity.y 적용 영역 영역 frame 영역 발판 영역 충돌 차단)
                    {
                        int baseMaskJump = Physics2D.GetLayerCollisionMask(gameObject.layer);
                        contactFilter.SetLayerMask(baseMaskJump & ~(1 << JUMP_THROUGH_LAYER));
                        contactFilter.useLayerMask = true;
                    }
                    break;
                case JumpState.Jumping:
                    if (!IsGrounded)
                    {
                        Schedule<PlayerJumped>().player = this;
                        jumpState = JumpState.InFlight;
                    }
                    break;
                case JumpState.InFlight:
                    if (IsGrounded)
                    {
                        Schedule<PlayerLanded>().player = this;
                        jumpState = JumpState.Landed;
                    }
                    break;
                case JumpState.Landed:
                    jumpState = JumpState.Grounded;
                    break;
            }

            // BT40 — Drop-Through: velocity.y > 0(상승) 영역 Layer 16 mask 비활성, 그 외 활성
            UpdateContactFilterForDropThrough();
        }

        void UpdateContactFilterForDropThrough()
        {
            int baseMask = Physics2D.GetLayerCollisionMask(gameObject.layer);

            // BT5-Dev #43 — IsGrounded 영역 폐기 (frame 0 미설정 → 떨어짐). footHit 단독 + 점프 영역 OFF 강제
            // BT69 — Drop-Through Timer 활성 시 Layer 16 mask 강제 OFF (Down + Jump 입력 발판 통과)
            bool isJumpingThrough = jumpState == JumpState.Jumping
                                    || (jumpState == JumpState.InFlight && velocity.y > 0.01f)
                                    || dropThroughTimer > 0f;

            bool standingOnPlatform = false;
            if (collider2d != null && !isJumpingThrough)
            {
                Vector2 footPos = new Vector2(collider2d.bounds.center.x, collider2d.bounds.min.y + 0.02f);
                int jumpThroughMask = 1 << JUMP_THROUGH_LAYER;
                RaycastHit2D footHit = Physics2D.Raycast(footPos, Vector2.down, 0.1f, jumpThroughMask);
                standingOnPlatform = footHit.collider != null;
            }

            // standingOnPlatform=true → Layer 16 ON (착지·서있는 영역 영역 X) / 그 외 → Layer 16 OFF (통과)
            int mask = standingOnPlatform ? baseMask : (baseMask & ~(1 << JUMP_THROUGH_LAYER));
            contactFilter.SetLayerMask(mask);
            contactFilter.useLayerMask = true;
        }

        protected override void ComputeVelocity()
        {
            if (jump && IsGrounded)
            {
                // BT69 — Drop-Through 점프 분기: Down + Jump 입력 시 위로 점프 X (gravity로 떨어짐 + 점프 모션만 유지)
                // BT71 — velocity.y = 0 → 음수(-0.5) 정정 (PD 보고 2026-05-08: Drop-Through 후 점프키 X 버그)
                //         원인: velocity.y=0 시 IsGrounded=true 잔존 → jumpState=Jumping 영구 → 점프 입력 무시
                //         정정: 즉시 떨어짐 → IsGrounded=false → Jumping→InFlight→착지→Grounded 정상 사이클
                if (dropThroughJump)
                {
                    velocity.y = -0.5f;  // 즉시 낙하 시작 — 발판 통과 + IsGrounded=false 확보
                    dropThroughJump = false;
                }
                else
                {
                    velocity.y = jumpTakeOffSpeed * model.jumpModifier;
                }
                jump = false;
            }
            else if (stopJump)
            {
                stopJump = false;
                if (velocity.y > 0)
                {
                    velocity.y = velocity.y * model.jumpDeceleration;
                }
            }

            if (move.x > 0.01f)
            {
                spriteRenderer.flipX = true;
                facing = Vector2.right;
            }
            else if (move.x < -0.01f)
            {
                spriteRenderer.flipX = false;
                facing = Vector2.left;
            }

            animator.SetBool("grounded", IsGrounded);
            animator.SetFloat("velocityX", Mathf.Abs(velocity.x) / maxSpeed);

            targetVelocity = move * maxSpeed;
        }

        public enum JumpState
        {
            Grounded,
            PrepareToJump,
            Jumping,
            InFlight,
            Landed
        }
    }
}