using UnityEngine;
using UnityEngine.InputSystem;
using Unity.Netcode;
using Colosseum.Network;
using Colosseum.Skills;

namespace Colosseum.Player
{
    /// <summary>
    /// 서버 권한 이동.
    /// - 오너(클라이언트/호스트): 입력 수집 → NetworkVariable에 월드 방향 기록
    /// - 서버: NetworkVariable을 읽어 CharacterController 구동 → NetworkTransform으로 동기화
    /// </summary>
    [RequireComponent(typeof(CharacterController))]
    [RequireComponent(typeof(PlayerActionState))]
    public class PlayerMovement : NetworkBehaviour
    {
        [Header("Movement Settings")]
        [SerializeField] private float moveSpeed = 5f;
        [SerializeField] private float rotationSpeed = 10f;
        [SerializeField] private float gravity = -9.81f;

        [Header("Jump Settings")]
        [SerializeField] private float jumpForce = 5f;

        [Header("References")]
        [SerializeField] private SkillController skillController;
        [SerializeField] private Animator animator;
        [SerializeField] private PlayerActionState actionState;

        private CharacterController characterController;
        private Vector3 velocity;
        private Vector2 moveInput;             // 로컬 원시 입력 (IsOwner 전용)
        private InputSystem_Actions inputActions;
        private bool gameplayInputEnabled = true;
        private bool isJumping;
        private bool wasGrounded;
        private Vector3 forcedMovementVelocity;
        private float forcedMovementRemaining;

        // 클라이언트가 기록, 서버가 소비하는 월드 스페이스 이동 방향
        private NetworkVariable<Vector2> netMoveInput = new NetworkVariable<Vector2>(
            Vector2.zero,
            NetworkVariableReadPermission.Everyone,
            NetworkVariableWritePermission.Owner);

        // 적 충돌 차단용
        private Vector3 blockedDirection;
        private readonly Collider[] overlapBuffer = new Collider[8];

        public float CurrentMoveSpeed => netMoveInput.Value.magnitude * moveSpeed * GetMoveSpeedMultiplier();
        public bool IsGrounded => characterController != null ? characterController.isGrounded : false;
        public bool IsJumping => isJumping;
        public bool IsForcedMoving => forcedMovementRemaining > 0f && forcedMovementVelocity.sqrMagnitude > 0.0001f;

        public override void OnNetworkSpawn()
        {
            Debug.Log($"[PlayerMovement] LOCAL OnNetworkSpawn: OwnerClientId={OwnerClientId}, IsOwner={IsOwner}, IsServer={IsServer}, LocalClientId={NetworkManager.LocalClientId}");
            ReportSpawnRpc(IsOwner, IsServer, IsLocalPlayer, NetworkManager.LocalClientId);

            // 서버: 모든 플레이어의 이동 처리 담당
            if (IsServer)
            {
                characterController = GetComponent<CharacterController>();
                characterController.enableOverlapRecovery = false;

                if (skillController == null)
                    skillController = GetComponent<SkillController>();
                if (animator == null)
                    animator = GetComponentInChildren<Animator>();
                if (actionState == null)
                    actionState = GetOrCreateActionState();

                SetSpawnPosition();
            }

            // 오너: 입력 및 카메라 초기화
            if (IsOwner)
            {
                if (actionState == null)
                    actionState = GetOrCreateActionState();

                InitializeInputActions();
                SetupCamera();
            }

            // 서버도 오너도 아닌 클라이언트: 비활성화
            if (!IsOwner && !IsServer)
                enabled = false;
        }

        [Rpc(SendTo.Server)]
        private void ReportSpawnRpc(bool isOwner, bool isServer, bool isLocalPlayer, ulong localClientId)
        {
            Debug.Log($"[PlayerMovement] SPAWN REPORT: OwnerClientId={OwnerClientId}, IsOwner={isOwner}, IsServer={isServer}, IsLocalPlayer={isLocalPlayer}, LocalClientId={localClientId}");
        }

        private void InitializeInputActions()
        {
            inputActions = new InputSystem_Actions();
            inputActions.Player.Move.performed += OnMovePerformed;
            inputActions.Player.Move.canceled  += OnMoveCanceled;
            inputActions.Player.Jump.performed += OnJumpPerformed;
            SetGameplayInputEnabled(true);
        }

        private void CleanupInputActions()
        {
            if (inputActions != null)
            {
                inputActions.Player.Move.performed -= OnMovePerformed;
                inputActions.Player.Move.canceled  -= OnMoveCanceled;
                inputActions.Player.Jump.performed -= OnJumpPerformed;
                inputActions.Player.Disable();
            }
        }

        private void OnDisable()
        {
            CleanupInputActions();
            moveInput = Vector2.zero;
            ClearForcedMovement();
        }

        private void OnEnable()
        {
            if (IsOwner && inputActions != null)
            {
                SetGameplayInputEnabled(gameplayInputEnabled);
            }
        }

        private void SetSpawnPosition()
        {
            Transform spawnPoint = PlayerSpawnPoint.GetRandomSpawnPoint();
            if (spawnPoint != null)
            {
                characterController.enabled = false;
                transform.position = spawnPoint.position;
                transform.rotation = spawnPoint.rotation;
                characterController.enabled = true;
            }
        }

        public override void OnNetworkDespawn()
        {
            CleanupInputActions();
            ClearForcedMovement();
        }

        private void OnMovePerformed(InputAction.CallbackContext context) => moveInput = context.ReadValue<Vector2>();
        private void OnMoveCanceled(InputAction.CallbackContext context)  => moveInput = Vector2.zero;

        /// <summary>
        /// 로컬 플레이어의 전투 입력을 일시적으로 차단하거나 복구합니다.
        /// </summary>
        public void SetGameplayInputEnabled(bool enabled)
        {
            gameplayInputEnabled = enabled;

            if (!IsOwner || inputActions == null)
                return;

            if (enabled)
            {
                inputActions.Player.Enable();
                return;
            }

            moveInput = Vector2.zero;
            if (netMoveInput.Value != Vector2.zero)
                netMoveInput.Value = Vector2.zero;

            inputActions.Player.Disable();
        }

        private void OnJumpPerformed(InputAction.CallbackContext context)
        {
            if (!IsOwner) return;
            if (!gameplayInputEnabled) return;
            if (actionState != null && !actionState.CanJump) return;

            JumpRequestRpc();
        }

        /// <summary>
        /// 클라이언트가 점프 요청 → 서버가 검증 후 실행
        /// </summary>
        [Rpc(SendTo.Server)]
        private void JumpRequestRpc()
        {
            if (actionState != null && !actionState.CanJump)
                return;

            if (!isJumping && characterController != null && characterController.isGrounded)
                Jump();
        }

        private void SetupCamera()
        {
            var cameraController = GetComponent<PlayerCamera>();
            if (cameraController == null)
                cameraController = gameObject.AddComponent<PlayerCamera>();
            cameraController.Initialize(transform, inputActions);
        }

        public void RefreshCamera() => SetupCamera();

        private void Update()
        {
            // 오너: 카메라 기준 이동 방향을 NetworkVariable에 기록
            if (IsOwner)
                UpdateNetworkInput();

            // 서버: NetworkVariable을 읽어 실제 이동 처리
            if (IsServer)
            {
                ApplyGravity();
                UpdateBlockedDirection();
                Move();
            }
        }

        /// <summary>
        /// 로컬 입력을 카메라 기준 월드 방향으로 변환해 NetworkVariable에 기록
        /// </summary>
        private void UpdateNetworkInput()
        {
            if (actionState != null && !actionState.CanMove)
            {
                if (netMoveInput.Value != Vector2.zero)
                    netMoveInput.Value = Vector2.zero;

                return;
            }

            Vector3 dir = new Vector3(moveInput.x, 0f, moveInput.y);
            if (dir.sqrMagnitude > 0.001f)
                dir = TransformDirectionByCamera(dir).normalized;

            Vector2 worldDir = new Vector2(dir.x, dir.z);
            if (netMoveInput.Value != worldDir)
                netMoveInput.Value = worldDir;
        }

        /// <summary>
        /// 매 프레임 주변 적을 감지하여 blockedDirection 설정 (서버 전용)
        /// </summary>
        private void UpdateBlockedDirection()
        {
            blockedDirection = Vector3.zero;

            Vector3 center     = transform.position + characterController.center;
            float   radius     = characterController.radius + 0.15f;
            float   halfHeight = Mathf.Max(0f, characterController.height * 0.5f - characterController.radius);

            int count = Physics.OverlapCapsuleNonAlloc(
                center + Vector3.up * halfHeight,
                center - Vector3.up * halfHeight,
                radius, overlapBuffer);

            for (int i = 0; i < count; i++)
            {
                if (overlapBuffer[i].gameObject == gameObject) continue;
                if (!overlapBuffer[i].TryGetComponent<UnityEngine.AI.NavMeshAgent>(out _)) continue;

                Vector3 toEnemy = overlapBuffer[i].transform.position - transform.position;
                toEnemy.y = 0f;
                if (toEnemy.sqrMagnitude > 0.0001f)
                {
                    blockedDirection = toEnemy.normalized;
                    break;
                }
            }
        }

        private void ApplyGravity()
        {
            if (wasGrounded && velocity.y < 0)
                velocity.y = -2f;
            else
                velocity.y += gravity * Time.deltaTime;
        }

        private void Move()
        {
            if (characterController == null) return;

            Vector3 forcedDelta = ConsumeForcedMovementDelta(Time.deltaTime);

            if (skillController != null && skillController.IsPlayingAnimation)
            {
                if (!skillController.UsesRootMotion)
                    characterController.Move(velocity * Time.deltaTime + forcedDelta);
                return;
            }

            // 클라이언트가 전송한 월드 스페이스 방향 사용
            Vector3 moveDirection = new Vector3(netMoveInput.Value.x, 0f, netMoveInput.Value.y);
            if (moveDirection.sqrMagnitude > 0.001f)
                moveDirection.Normalize();

            if (actionState != null && !actionState.CanMove)
                moveDirection = Vector3.zero;

            if (blockedDirection != Vector3.zero && Vector3.Dot(moveDirection, blockedDirection) > 0f)
                moveDirection = Vector3.zero;

            float actualMoveSpeed = moveSpeed * GetMoveSpeedMultiplier();
            characterController.Move((moveDirection * actualMoveSpeed + velocity) * Time.deltaTime + forcedDelta);

            if (moveDirection != Vector3.zero)
            {
                Quaternion targetRotation = Quaternion.LookRotation(moveDirection);
                transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, rotationSpeed * Time.deltaTime);
            }

            if (!wasGrounded && characterController.isGrounded && isJumping)
                OnJumpEnd();

            wasGrounded = characterController.isGrounded;
        }

        private void Jump()
        {
            isJumping = true;
            velocity.y = jumpForce;

            var animController = GetComponent<PlayerAnimationController>();
            if (animController != null)
                animController.PlayJump();
        }

        public void OnJumpEnd() => isJumping = false;

        private Vector3 TransformDirectionByCamera(Vector3 direction)
        {
            if (Camera.main == null) return direction;

            Transform cam     = Camera.main.transform;
            Vector3   forward = new Vector3(cam.forward.x, 0f, cam.forward.z).normalized;
            Vector3   right   = new Vector3(cam.right.x,   0f, cam.right.z).normalized;

            return right * direction.x + forward * direction.z;
        }

        private float GetMoveSpeedMultiplier()
        {
            if (actionState == null)
                return 1f;

            return actionState.MoveSpeedMultiplier;
        }

        /// <summary>
        /// 넉백처럼 입력과 무관한 강제 이동을 적용합니다.
        /// </summary>
        public void ApplyForcedMovement(Vector3 worldVelocity, float duration)
        {
            if (!IsServer)
                return;

            if (duration <= 0f || worldVelocity.sqrMagnitude <= 0.0001f)
            {
                ClearForcedMovement();
                return;
            }

            forcedMovementVelocity = worldVelocity;
            forcedMovementRemaining = duration;
        }

        /// <summary>
        /// 강제 이동 상태를 즉시 초기화합니다.
        /// </summary>
        public void ClearForcedMovement()
        {
            forcedMovementVelocity = Vector3.zero;
            forcedMovementRemaining = 0f;
        }

        private PlayerActionState GetOrCreateActionState()
        {
            var foundState = GetComponent<PlayerActionState>();
            if (foundState != null)
                return foundState;

            return gameObject.AddComponent<PlayerActionState>();
        }

        /// <summary>
        /// 루트 모션 처리 (서버 전용 — NetworkTransform으로 동기화)
        /// </summary>
        private void OnAnimatorMove()
        {
            if (!IsServer) return;
            if (animator == null || characterController == null) return;
            if (skillController == null || !skillController.IsPlayingAnimation) return;
            if (!skillController.UsesRootMotion) return;

            Vector3 deltaPosition = animator.deltaPosition;
            Vector3 forcedDelta = ConsumeForcedMovementDelta(Time.deltaTime);

            if (blockedDirection != Vector3.zero)
            {
                Vector3 deltaXZ = new Vector3(deltaPosition.x, 0f, deltaPosition.z);
                if (Vector3.Dot(deltaXZ, blockedDirection) > 0f)
                {
                    deltaPosition.x = 0f;
                    deltaPosition.z = 0f;
                }
            }

            if (skillController.IgnoreRootMotionY)
            {
                deltaPosition.y = 0f;
                characterController.Move(deltaPosition + velocity * Time.deltaTime + forcedDelta);
            }
            else
            {
                characterController.Move(deltaPosition + forcedDelta);
            }

            if (animator.deltaRotation != Quaternion.identity)
                transform.rotation *= animator.deltaRotation;

            if (!wasGrounded && characterController.isGrounded && isJumping)
                OnJumpEnd();

            wasGrounded = characterController.isGrounded;
        }

        private Vector3 ConsumeForcedMovementDelta(float deltaTime)
        {
            if (forcedMovementRemaining <= 0f || forcedMovementVelocity.sqrMagnitude <= 0.0001f)
                return Vector3.zero;

            float appliedDeltaTime = Mathf.Min(deltaTime, forcedMovementRemaining);
            forcedMovementRemaining = Mathf.Max(0f, forcedMovementRemaining - appliedDeltaTime);

            Vector3 delta = forcedMovementVelocity * appliedDeltaTime;
            if (forcedMovementRemaining <= 0f)
            {
                forcedMovementVelocity = Vector3.zero;
            }

            return delta;
        }
    }
}