using UnityEngine;
using UnityEngine.AI;
using UnityEngine.InputSystem;

[RequireComponent(typeof(CharacterController))]
[RequireComponent(typeof(CombatController))]
public class PlayerController : MonoBehaviour
{
    [Header("Movement Settings")]
    [SerializeField] private float moveSpeed = 6.0f;
    [SerializeField] private float rotationSpeed = 12.0f;
    [SerializeField] private float stoppingDistance = 0.2f;
    [SerializeField] private LayerMask groundLayer = ~0; // Default to all layers

    [Header("Interaction & Combat Settings")]
    [SerializeField] private LayerMask interactableLayer = ~0;
    [SerializeField] private float defaultInteractionRadius = 2.0f;
    [Tooltip("If true, the player automatically turns to attack any enemy that damages them (RuneScape style).")]
    [SerializeField] private bool autoRetaliate = true;

    [Header("Visual Feedback Prefabs (Optional)")]
    [SerializeField] private GameObject moveClickEffectPrefab;
    [SerializeField] private GameObject interactClickEffectPrefab;

    private Camera mainCamera;
    private CharacterController characterController;
    private NavMeshAgent navAgent;
    private CombatController combatController;

    private Vector3 targetPosition;
    private IInteractable targetInteractable;
    private bool isMovingToInteractable = false;
    private bool isMoving = false;

    private void Awake()
    {
        mainCamera = Camera.main;
        characterController = GetComponent<CharacterController>();
        navAgent = GetComponent<NavMeshAgent>();
        combatController = GetComponent<CombatController>();
        targetPosition = transform.position;

        if (combatController != null && combatController.Stats != null)
        {
            combatController.Stats.onHealthChanged.AddListener(OnHealthChanged);
        }
    }

    private void Update()
    {
        HandleInput();
        ProcessMovement();
        ProcessInteractionCheck();
        ProcessCombatCheck();
    }

    private void HandleInput()
    {
        // Using New Unity Input System (UnityEngine.InputSystem)
        Mouse currentMouse = Mouse.current;
        if (currentMouse == null) return;

        Vector2 screenMousePos = currentMouse.position.ReadValue();

        // Left Click / Hold: Click or drag to move continuously
        if (currentMouse.leftButton.isPressed)
        {
            bool isFirstPress = currentMouse.leftButton.wasPressedThisFrame;
            HandleLeftClickOrDrag(screenMousePos, isFirstPress);
        }

        // Right Click: Interact with object or attack enemy
        if (currentMouse.rightButton.wasPressedThisFrame)
        {
            HandleRightClick(screenMousePos);
        }
    }

    private void HandleLeftClickOrDrag(Vector2 screenPosition, bool isFirstPress)
    {
        Ray ray = mainCamera.ScreenPointToRay(screenPosition);
        if (Physics.Raycast(ray, out RaycastHit hit, 100f, groundLayer))
        {
            SetDestination(hit.point);
            ClearTargetInteractable();
            combatController.ClearTarget();

            // Only spawn click effect on the initial click frame (not every frame while dragging)
            if (isFirstPress)
            {
                SpawnEffect(moveClickEffectPrefab, hit.point);
            }
        }
    }

    private void HandleRightClick(Vector2 screenPosition)
    {
        Ray ray = mainCamera.ScreenPointToRay(screenPosition);

        // Check for Raycast hit on Interactable or Enemy
        if (Physics.Raycast(ray, out RaycastHit hit, 100f, interactableLayer))
        {
            // Check if object is an Enemy / CharacterStats for Combat
            CharacterStats enemyStats = hit.collider.GetComponent<CharacterStats>() ?? hit.collider.GetComponentInParent<CharacterStats>() ?? hit.collider.GetComponentInChildren<CharacterStats>();
            if (enemyStats != null && enemyStats != combatController.Stats && !enemyStats.IsDead)
            {
                ClearTargetInteractable();
                combatController.SetTarget(enemyStats);
                SetDestination(enemyStats.transform.position);
                SpawnEffect(interactClickEffectPrefab, hit.point);
                return;
            }

            // Check if object is an IInteractable
            IInteractable interactable = hit.collider.GetComponent<IInteractable>() ?? hit.collider.GetComponentInParent<IInteractable>() ?? hit.collider.GetComponentInChildren<IInteractable>();
            if (interactable != null)
            {
                combatController.ClearTarget();
                targetInteractable = interactable;
                isMovingToInteractable = true;
                SetDestination(interactable.GetTransform().position);
                SpawnEffect(interactClickEffectPrefab, hit.point);
                return;
            }
        }

        // Right-clicked ground with no interactable/enemy
        if (Physics.Raycast(ray, out RaycastHit groundHit, 100f, groundLayer))
        {
            ClearTargetInteractable();
            combatController.ClearTarget();
        }
    }

    private void ProcessCombatCheck()
    {
        if (combatController.CurrentTarget == null) return;

        if (combatController.CurrentTarget.IsDead)
        {
            combatController.ClearTarget();
            return;
        }

        // Update destination to track moving target
        targetPosition = combatController.CurrentTarget.transform.position;
        if (navAgent != null && navAgent.enabled)
        {
            navAgent.stoppingDistance = combatController.Stats.AttackRange * 0.9f;
            navAgent.SetDestination(targetPosition);
        }

        // Check if inside attack range
        if (combatController.IsInAttackRange(combatController.CurrentTarget))
        {
            isMoving = false;
            if (navAgent != null && navAgent.enabled && navAgent.hasPath)
            {
                navAgent.ResetPath();
            }
            combatController.TryExecuteAttack();
        }
    }

    private void OnHealthChanged(float currentHealth, float maxHealth)
    {
        if (!autoRetaliate || combatController.CurrentTarget != null) return;

        // Scan nearby hostile objects / enemies that are attacking the player
        Collider[] hits = Physics.OverlapSphere(transform.position, 10.0f, interactableLayer);
        foreach (var hit in hits)
        {
            CharacterStats attackerStats = hit.GetComponent<CharacterStats>() ?? hit.GetComponentInParent<CharacterStats>() ?? hit.GetComponentInChildren<CharacterStats>();
            if (attackerStats != null && attackerStats != combatController.Stats && !attackerStats.IsDead)
            {
                combatController.SetTarget(attackerStats);
                SetDestination(attackerStats.transform.position);
                Debug.Log($"[PlayerController] Auto-retaliating against '{attackerStats.CharacterName}'!");
                break;
            }
        }
    }

    private void SetDestination(Vector3 destination)
    {
        targetPosition = destination;
        isMoving = true;

        if (navAgent != null && navAgent.enabled)
        {
            navAgent.SetDestination(destination);
        }
    }

    private void ProcessMovement()
    {
        if (!isMoving) return;

        // If using NavMeshAgent
        if (navAgent != null && navAgent.enabled)
        {
            float targetStoppingDistance = isMovingToInteractable && targetInteractable != null
                ? (targetInteractable.GetInteractionRadius() > 0 ? targetInteractable.GetInteractionRadius() : defaultInteractionRadius) * 0.9f
                : stoppingDistance;

            navAgent.stoppingDistance = targetStoppingDistance;

            if (!navAgent.pathPending && navAgent.remainingDistance <= navAgent.stoppingDistance)
            {
                if (!navAgent.hasPath || navAgent.velocity.sqrMagnitude == 0f)
                {
                    isMoving = false;
                }
            }
            return;
        }

        // Fallback: Manual Transform/CharacterController movement
        Vector3 direction = (targetPosition - transform.position);
        direction.y = 0; // Keep movement top-down flat

        float distance = direction.magnitude;
        float currentStoppingDistance = isMovingToInteractable && targetInteractable != null 
            ? (targetInteractable.GetInteractionRadius() > 0 ? targetInteractable.GetInteractionRadius() : defaultInteractionRadius) * 0.9f
            : stoppingDistance;

        if (distance > currentStoppingDistance)
        {
            // Smooth Rotation
            Quaternion targetRotation = Quaternion.LookRotation(direction);
            transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, rotationSpeed * Time.deltaTime);

            // Move
            Vector3 moveVelocity = direction.normalized * moveSpeed * Time.deltaTime;
            characterController.Move(moveVelocity);
        }
        else
        {
            isMoving = false;
        }
    }

    private void ProcessInteractionCheck()
    {
        if (!isMovingToInteractable || targetInteractable == null) return;

        Vector3 flatPlayerPos = new Vector3(transform.position.x, 0, transform.position.z);
        Vector3 flatTargetPos = new Vector3(targetInteractable.GetTransform().position.x, 0, targetInteractable.GetTransform().position.z);

        float distance = Vector3.Distance(flatPlayerPos, flatTargetPos);
        float radius = targetInteractable.GetInteractionRadius() > 0 ? targetInteractable.GetInteractionRadius() : defaultInteractionRadius;

        if (distance <= radius + 0.1f)
        {
            // Face target interactable
            Vector3 dir = (targetInteractable.GetTransform().position - transform.position);
            dir.y = 0;
            if (dir != Vector3.zero)
            {
                transform.rotation = Quaternion.LookRotation(dir);
            }

            // Trigger interaction
            targetInteractable.Interact(gameObject);
            ClearTargetInteractable();
        }
    }

    private void ClearTargetInteractable()
    {
        targetInteractable = null;
        isMovingToInteractable = false;
    }

    private void SpawnEffect(GameObject effectPrefab, Vector3 position)
    {
        if (effectPrefab != null)
        {
            Instantiate(effectPrefab, position + Vector3.up * 0.05f, Quaternion.identity);
        }
    }

    private void OnDrawGizmosSelected()
    {
        Gizmos.color = Color.green;
        Gizmos.DrawWireSphere(targetPosition, 0.3f);
        Gizmos.DrawLine(transform.position, targetPosition);
    }
}