using UnityEngine;
using Pathfinding;
using AppleHills.Core.Settings;
using Core;
using Core.Lifecycle;
using Core.SaveLoad;

namespace Input
{
    /// <summary>
    /// Saveable data for PlayerTouchController state
    /// </summary>
    [System.Serializable]
    public class PlayerSaveData
    {
        public Vector3 worldPosition;
        public Quaternion worldRotation;
    }

    /// <summary>
    /// Handles player movement in response to tap and hold input events.
    /// Supports both direct and pathfinding movement modes, and provides event/callbacks for arrival/cancellation.
    /// </summary>
    public class PlayerTouchController : ManagedBehaviour, ITouchInputConsumer
    {
        // --- Movement State ---
        private Vector3 targetPosition;
        private Vector3 directMoveVelocity; // default is Vector3.zero
        internal bool isHolding;
        private Vector2 lastHoldPosition;
        private Coroutine pathfindingDragCoroutine;
        private float pathfindingDragUpdateInterval = 0.1f; // Interval in seconds
        [Header("Collision Simulation")]
        public LayerMask obstacleMask;
        public float colliderRadius = 0.5f;

        // --- Settings Reference ---
        private IPlayerFollowerSettings _settings;

        // --- Movement Events ---
        private bool _isMoving = false;
        public bool IsMoving => _isMoving;
        public event System.Action OnMovementStarted;
        public event System.Action OnMovementStopped;

        // --- Unity/Component References ---
        private AIPath aiPath;

        // Note: String-based property lookup is flagged as inefficient, but is common in Unity for dynamic children.
        private Animator animator;
        private Transform artTransform;
        private SpriteRenderer spriteRenderer;

        // --- Last direct movement direction ---
        private Vector3 _lastDirectMoveDir = Vector3.right;
        public Vector3 LastDirectMoveDir => _lastDirectMoveDir;

        // --- Last movement directions for animation blend tree ---
        private float _lastDirX = 0f; // -1 (left) to 1 (right)
        private float _lastDirY = -1f; // -1 (down) to 1 (up)

        // --- MoveToAndNotify State ---
        public delegate void ArrivedAtTargetHandler();
        private Coroutine moveToCoroutine;
        public event ArrivedAtTargetHandler OnArrivedAtTarget;
        public event System.Action OnMoveToCancelled;
        private bool interruptMoveTo;
        private LogVerbosity _logVerbosity = LogVerbosity.Warning;

        // Save system configuration
        public override bool AutoRegisterForSave => true;
        // Scene-specific SaveId - each level has its own player state
        public override string SaveId => $"{gameObject.scene.name}/PlayerController";
        public override int ManagedAwakePriority => 100; // Player controller
        
        protected override void OnManagedStart()
        {
            aiPath = GetComponent<AIPath>();
            artTransform = transform.Find("CharacterArt");
            if (artTransform != null)
                animator = artTransform.GetComponent<Animator>();
            else
                animator = GetComponentInChildren<Animator>();
            // Cache SpriteRenderer for flipping
            if (artTransform != null)
                spriteRenderer = artTransform.GetComponent<SpriteRenderer>();
            if (spriteRenderer == null)
                spriteRenderer = GetComponentInChildren<SpriteRenderer>();

            // Initialize settings reference using GetSettingsObject
            _settings = GameManager.GetSettingsObject<IPlayerFollowerSettings>();
            
            // Set default input consumer
            InputManager.Instance?.SetDefaultConsumer(this);
            
            _logVerbosity = DeveloperSettingsProvider.Instance.GetSettings<DebugSettings>().inputLogVerbosity;
        }

        /// <summary>
        /// Handles tap input. Always uses pathfinding to move to the tapped location.
        /// Cancels any in-progress MoveToAndNotify.
        /// </summary>
        public void OnTap(Vector2 worldPosition)
        {
            InterruptMoveTo();
            LogDebugMessage($"OnTap at {worldPosition}");
            if (aiPath != null)
            {
                aiPath.enabled = true;
                aiPath.canMove = true;
                aiPath.isStopped = false;
                SetTargetPosition(worldPosition);
                directMoveVelocity = Vector3.zero;
                isHolding = false;
            }
        }

        /// <summary>
        /// Handles the start of a hold input. Begins tracking the finger and uses the correct movement mode.
        /// Cancels any in-progress MoveToAndNotify.
        /// </summary>
        public void OnHoldStart(Vector2 worldPosition)
        {
            InterruptMoveTo();
            LogDebugMessage($"OnHoldStart at {worldPosition}");
            lastHoldPosition = worldPosition;
            isHolding = true;
            if (_settings.DefaultHoldMovementMode == HoldMovementMode.Pathfinding &&
                aiPath != null)
            {
                aiPath.enabled = true;
                if (pathfindingDragCoroutine != null) StopCoroutine(pathfindingDragCoroutine);
                pathfindingDragCoroutine = StartCoroutine(PathfindingDragUpdateCoroutine());
            }
            else // Direct movement
            {
                if (aiPath != null) aiPath.enabled = false;
                directMoveVelocity = Vector3.zero;
            }
        }

        /// <summary>
        /// Handles hold move input. Updates the target position for direct or pathfinding movement.
        /// /// </summary>
        public void OnHoldMove(Vector2 worldPosition)
        {
            if (!isHolding) return;
            lastHoldPosition = worldPosition;
            if (_settings.DefaultHoldMovementMode == HoldMovementMode.Direct)
            {
                if (aiPath != null && aiPath.enabled) aiPath.enabled = false;
                MoveDirectlyTo(worldPosition);
            }
            // If pathfinding, coroutine will update destination
        }

        /// <summary>
        /// Handles the end of a hold input. Stops tracking and disables movement as needed.
        /// </summary>
        public void OnHoldEnd(Vector2 worldPosition)
        {
            LogDebugMessage($"OnHoldEnd at {worldPosition}");
            isHolding = false;
            directMoveVelocity = Vector3.zero;
            if (aiPath != null && _settings.DefaultHoldMovementMode ==
                HoldMovementMode.Pathfinding)
            {
                if (pathfindingDragCoroutine != null)
                {
                    StopCoroutine(pathfindingDragCoroutine);
                    pathfindingDragCoroutine = null;
                }
            }

            if (aiPath != null && _settings.DefaultHoldMovementMode == HoldMovementMode.Direct)
            {
                aiPath.enabled = false;
            }
        }

        /// <summary>
        /// Sets the target position for pathfinding movement.
        /// </summary>
        private void SetTargetPosition(Vector2 worldPosition)
        {
            if (aiPath != null)
            {
                aiPath.destination = worldPosition;
                // Apply both speed and acceleration from settings
                aiPath.maxSpeed = _settings.MoveSpeed;
                aiPath.maxAcceleration = _settings.MaxAcceleration;
                aiPath.canMove = true;
                aiPath.isStopped = false;
            }
        }

        /// <summary>
        /// Moves the player directly towards the specified world position.
        /// </summary>
        public void MoveDirectlyTo(Vector2 worldPosition)
        {
            if (aiPath == null)
            {
                return;
            }
            Vector3 current = transform.position;
            Vector3 target = new Vector3(worldPosition.x, worldPosition.y, current.z);
            Vector3 toTarget = (target - current);
            Vector3 direction = toTarget.normalized;
            
            // Get speed and acceleration directly from settings 
            float maxSpeed = _settings.MoveSpeed;
            float acceleration = _settings.MaxAcceleration;
            
            directMoveVelocity = Vector3.MoveTowards(directMoveVelocity, direction * maxSpeed, acceleration * Time.deltaTime);
            if (directMoveVelocity.magnitude > maxSpeed)
            {
                directMoveVelocity = directMoveVelocity.normalized * maxSpeed;
            }
            Vector3 move = directMoveVelocity * Time.deltaTime;
            if (move.magnitude > toTarget.magnitude)
            {
                move = toTarget;
            }
            // --- Collision simulation ---
            Vector3 adjustedVelocity = AdjustVelocityForObstacles(current, directMoveVelocity);
            Vector3 adjustedMove = adjustedVelocity * Time.deltaTime;
            if (adjustedMove.magnitude > toTarget.magnitude)
            {
                adjustedMove = toTarget;
            }
            transform.position += adjustedMove;

            // Cache the last direct movement direction
            _lastDirectMoveDir = directMoveVelocity.normalized;
        }

        /// <summary>
        /// Simulates collision with obstacles by raycasting in the direction of velocity and projecting the velocity if a collision is detected.
        /// </summary>
        /// <param name="position">Player's current position.</param>
        /// <param name="velocity">Intended velocity for this frame.</param>
        /// <returns>Adjusted velocity after collision simulation.</returns>
        private Vector3 AdjustVelocityForObstacles(Vector3 position, Vector3 velocity)
        {
            if (velocity.sqrMagnitude < 0.0001f)
                return velocity;
            float moveDistance = velocity.magnitude * Time.deltaTime;
            Vector2 origin = new Vector2(position.x, position.y);
            Vector2 dir = velocity.normalized;
            float rayLength = colliderRadius + moveDistance;
            RaycastHit2D hit = Physics2D.Raycast(origin, dir, rayLength, obstacleMask);
            Debug.DrawLine(origin, origin + dir * rayLength, Color.red, 0.1f);
            if (hit.collider != null)
            {
                // Draw normal and tangent for debug
                Debug.DrawLine(hit.point, hit.point + hit.normal, Color.green, 0.2f);
                Vector2 tangent = new Vector2(-hit.normal.y, hit.normal.x);
                Debug.DrawLine(hit.point, hit.point + tangent, Color.blue, 0.2f);
                // Project velocity onto tangent to simulate sliding
                float slideAmount = Vector2.Dot(velocity, tangent);
                Vector3 slideVelocity = tangent * slideAmount;
                return slideVelocity;
            }
            return velocity;
        }

        void Update()
        {
            UpdateMovementState();
            
            if (animator != null && aiPath != null)
            {
                float normalizedSpeed = 0f;
                Vector3 velocity = Vector3.zero;
                float maxSpeed = _settings.MoveSpeed;
                
                if (isHolding && _settings.DefaultHoldMovementMode == HoldMovementMode.Direct)
                {
                    normalizedSpeed = directMoveVelocity.magnitude / maxSpeed;
                    velocity = directMoveVelocity;
                }
                else if (aiPath.enabled)
                {
                    normalizedSpeed = aiPath.velocity.magnitude / maxSpeed;
                    velocity = aiPath.velocity;
                }
                
                // Set speed parameter as before
                animator.SetFloat("Speed", Mathf.Clamp01(normalizedSpeed));
                
                // Calculate and set X and Y directions for 2D blend tree
                if (velocity.sqrMagnitude > 0.01f)
                {
                    // Normalize the velocity vector to get direction
                    Vector3 normalizedVelocity = velocity.normalized;
                    
                    // Update the stored directions when actively moving
                    _lastDirX = normalizedVelocity.x;
                    _lastDirY = normalizedVelocity.y;
                    
                    // Set the animator parameters
                    animator.SetFloat("DirX", _lastDirX);
                    animator.SetFloat("DirY", _lastDirY);
                }
                else
                {
                    // When not moving, keep using the last direction
                    animator.SetFloat("DirX", _lastDirX);
                    animator.SetFloat("DirY", _lastDirY);
                }
            }
        }

        /// <summary>
        /// Checks if the player is currently moving and fires appropriate events when movement state changes.
        /// </summary>
        private void UpdateMovementState()
        {
            bool isCurrentlyMoving = false;
            
            // Check direct movement
            if (isHolding && _settings.DefaultHoldMovementMode == HoldMovementMode.Direct)
            {
                isCurrentlyMoving = directMoveVelocity.sqrMagnitude > 0.001f;
            }
            // Check pathfinding movement
            else if (aiPath != null && aiPath.enabled)
            {
                isCurrentlyMoving = aiPath.velocity.sqrMagnitude > 0.001f;
            }
            
            // Fire events only when state changes
            if (isCurrentlyMoving && !_isMoving)
            {
                _isMoving = true;
                OnMovementStarted?.Invoke();
                LogDebugMessage("Movement started");
            }
            else if (!isCurrentlyMoving && _isMoving)
            {
                _isMoving = false;
                OnMovementStopped?.Invoke();
                LogDebugMessage("Movement stopped");
            }
        }

        /// <summary>
        /// Coroutine for updating the AIPath destination during pathfinding hold movement.
        /// </summary>
        private System.Collections.IEnumerator PathfindingDragUpdateCoroutine()
        {
            while (isHolding && aiPath != null)
            {
                aiPath.destination = new Vector3(lastHoldPosition.x, lastHoldPosition.y, transform.position.z);
                yield return new WaitForSeconds(pathfindingDragUpdateInterval);
            }
        }

        /// <summary>
        /// Moves the player to a specific target position and notifies via events when arrived or cancelled.
        /// This is used by systems like Pickup.cs to orchestrate movement.
        /// </summary>
        public void MoveToAndNotify(Vector3 target)
        {
            // Cancel any previous move-to coroutine
            if (moveToCoroutine != null)
            {
                StopCoroutine(moveToCoroutine);
            }

            interruptMoveTo = false;
            // Ensure pathfinding is enabled for MoveToAndNotify
            if (aiPath != null)
            {
                aiPath.enabled = true;
                aiPath.canMove = true;
                aiPath.isStopped = false;
            }
            moveToCoroutine = StartCoroutine(MoveToTargetCoroutine(target));
        }

        /// <summary>
        /// Cancels any in-progress MoveToAndNotify operation and fires the cancellation event.
        /// </summary>
        public void InterruptMoveTo()
        {
            interruptMoveTo = true;
            isHolding = false;
            directMoveVelocity = Vector3.zero;
            if (_settings.DefaultHoldMovementMode == HoldMovementMode.Direct && aiPath != null)
                aiPath.enabled = false;
            OnMoveToCancelled?.Invoke();
        }

        /// <summary>
        /// Coroutine for moving the player to a target position and firing arrival/cancel events.
        /// </summary>
        private System.Collections.IEnumerator MoveToTargetCoroutine(Vector3 target)
        {
            if (aiPath != null)
            {
                aiPath.destination = target;
                aiPath.maxSpeed = _settings.MoveSpeed;
                aiPath.maxAcceleration = _settings.MaxAcceleration;
            }

            while (!interruptMoveTo)
            {
                Vector2 current2D = new Vector2(transform.position.x, transform.position.y);
                Vector2 target2D = new Vector2(target.x, target.y);
                float dist = Vector2.Distance(current2D, target2D);
                if (dist <= _settings.StopDistance + 0.2f)
                {
                    break;
                }

                yield return null;
            }

            moveToCoroutine = null;
            if (!interruptMoveTo)
            {
                OnArrivedAtTarget?.Invoke();
            }
        }
        
        private void LogDebugMessage(string message)
        {
            if (_logVerbosity <= LogVerbosity.Debug)
            {
                Logging.Debug($"[PlayerTouchController] {message}");
            }
        }

        #region Save/Load Lifecycle Hooks

        protected override string OnSceneSaveRequested()
        {
            var saveData = new PlayerSaveData
            {
                worldPosition = transform.position,
                worldRotation = transform.rotation
            };
            return JsonUtility.ToJson(saveData);
        }

        protected override void OnSceneRestoreRequested(string serializedData)
        {
            if (string.IsNullOrEmpty(serializedData))
            {
                Logging.Debug("[PlayerTouchController] No saved state to restore");
                return;
            }

            try
            {
                var saveData = JsonUtility.FromJson<PlayerSaveData>(serializedData);
                if (saveData != null)
                {
                    transform.position = saveData.worldPosition;
                    transform.rotation = saveData.worldRotation;
                    Logging.Debug($"[PlayerTouchController] Restored position: {saveData.worldPosition}");
                }
            }
            catch (System.Exception ex)
            {
                Logging.Warning($"[PlayerTouchController] Failed to restore state: {ex.Message}");
            }
        }

        #endregion
    }
}