using System;
using UnityEngine;
using UnityEngine.InputSystem;

public class PlayerPickupController : MonoBehaviour
{
    [SerializeField] private InputActionAsset inputActions;
    [SerializeField] private string actionMapName = "Player";
    [SerializeField] private string interactActionName = "Interact";
    private InputActionAsset runtimeActions;
    private InputAction interactAction;
    [SerializeField] private string controlSchemeName = "";
    [SerializeField] private int gamepadIndex = -1;
    private bool deviceFilterEnabled;

    [Header("Setup")]
    public Transform holdPoint; // Empty GameObject above head
    public float pickupRange = 2.0f;

    private GameObject heldObject;

    private void OnEnable()
    {
        if (inputActions == null)
        {
            Debug.LogError("PlayerPickupController missing InputActionAsset reference.", this);
            return;
        }

        runtimeActions = Instantiate(inputActions);
        if (!string.IsNullOrWhiteSpace(controlSchemeName))
        {
            runtimeActions.bindingMask = InputBinding.MaskByGroup(controlSchemeName);
        }
        deviceFilterEnabled = ShouldFilterDevices();
        ApplyDeviceFilter();
        InputSystem.onDeviceChange += HandleDeviceChange;

        var map = runtimeActions.FindActionMap(actionMapName, true);
        interactAction = map.FindAction(interactActionName, true);

        if (interactAction != null)
        {
            interactAction.Enable();
            interactAction.performed += OnInteractPerformed;
        }
    }

    private void OnDisable()
    {
        if (interactAction != null)
        {
            interactAction.performed -= OnInteractPerformed;
            interactAction.Disable();
        }

        if (runtimeActions != null)
        {
            runtimeActions.Disable();
            runtimeActions = null;
        }

        InputSystem.onDeviceChange -= HandleDeviceChange;
    }

    private void OnInteractPerformed(InputAction.CallbackContext context)
    {
        Debug.Log("Interact action performed");
        if(heldObject != null)
        {
            Debug.Log("Dropping held object");
            DropObject();
            return;
        }

        TryPickUp();
    }

    void TryPickUp()
    {
        // Find all colliders within range
        Collider2D[] colliders = Physics2D.OverlapCircleAll(transform.position, pickupRange);
        Debug.Log(colliders.Length + " colliders found in range");
        foreach (var col in colliders)
        {
            if (col.CompareTag("Interactable"))
            {
                heldObject = col.gameObject;

                // Parent the object to the HoldPoint and reset its local position
                heldObject.transform.SetParent(holdPoint);
                heldObject.transform.localPosition = Vector3.zero;
                heldObject.transform.localRotation = Quaternion.identity;

                // Disable physics so it doesn't fall or collide with the player
                if (heldObject.TryGetComponent<Rigidbody2D>(out Rigidbody2D rb))
                {
                    rb.bodyType = RigidbodyType2D.Kinematic;
                    rb.gravityScale = 0;
                    rb.mass = 0;
                }

                if (col != null) col.enabled = false;
                break;
            }
        }
    }

    void DropObject()
    {
        // Re-enable physics
        if (heldObject.TryGetComponent<Rigidbody2D>(out Rigidbody2D rb))
        {
            rb.bodyType = RigidbodyType2D.Dynamic;
            rb.gravityScale = 1;
        }
        Collider2D col = heldObject.GetComponent<Collider2D>();
        if (col != null) col.enabled = true;

        // Unparent
        heldObject.transform.SetParent(null);
        heldObject = null;
    }

    private bool ShouldFilterDevices()
    {
        return string.Equals(controlSchemeName, "Gamepad", StringComparison.OrdinalIgnoreCase) || gamepadIndex >= 0;
    }

    private void ApplyDeviceFilter()
    {
        if (!deviceFilterEnabled || runtimeActions == null)
        {
            return;
        }

        var targetIndex = ResolveGamepadIndex();
        if (targetIndex < 0)
        {
            return;
        }

        if (Gamepad.all.Count <= targetIndex)
        {
            runtimeActions.devices = Array.Empty<InputDevice>();
            return;
        }

        runtimeActions.devices = new InputDevice[] { Gamepad.all[targetIndex] };
    }

    private void HandleDeviceChange(InputDevice device, InputDeviceChange change)
    {
        if (!deviceFilterEnabled)
        {
            return;
        }

        if (change == InputDeviceChange.Added || change == InputDeviceChange.Removed || change == InputDeviceChange.Reconnected)
        {
            ApplyDeviceFilter();
        }
    }

    private int ResolveGamepadIndex()
    {
        if (gamepadIndex >= 0)
        {
            return gamepadIndex;
        }

        if (string.IsNullOrWhiteSpace(actionMapName))
        {
            return -1;
        }

        if (string.Equals(actionMapName, "Player", StringComparison.OrdinalIgnoreCase))
        {
            return 0;
        }

        var end = actionMapName.Length - 1;
        var start = end;
        while (start >= 0 && char.IsDigit(actionMapName[start]))
        {
            start--;
        }

        start++;
        if (start > end)
        {
            return -1;
        }

        if (!int.TryParse(actionMapName.Substring(start, end - start + 1), out var parsed))
        {
            return -1;
        }

        return parsed > 0 ? parsed - 1 : -1;
    }
}