using System;
using UnityEngine;
using UnityEngine.InputSystem;

[RequireComponent(typeof(Rigidbody2D))]
[RequireComponent(typeof(BoxCollider2D))]
public class PlayerPlatformerController : MonoBehaviour
{
    [SerializeField] private InputActionAsset inputActions;
    [SerializeField] private string actionMapName = "Player";
    [SerializeField] private string moveActionName = "Move";
    [SerializeField] private string jumpActionName = "Jump";
    [SerializeField] private string controlSchemeName = "";
    [SerializeField] private int gamepadIndex = -1;
    [SerializeField] private float moveSpeed = 6f;
    [SerializeField] private float jumpImpulse = 8f;
    [SerializeField] private LayerMask groundMask = ~0;
    [SerializeField] private float groundCheckDistance = 0.05f;

    private Rigidbody2D body;
    private BoxCollider2D bodyCollider;
    private InputActionAsset runtimeActions;
    private InputAction moveAction;
    private InputAction jumpAction;
    public float LastMoveX { get; private set; }
    private bool deviceFilterEnabled;

    private void Awake()
    {
        body = GetComponent<Rigidbody2D>();
        bodyCollider = GetComponent<BoxCollider2D>();
    }

    private void OnEnable()
    {
        if (inputActions == null)
        {
            Debug.LogError("PlayerPlatformerController 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);
        moveAction = map.FindAction(moveActionName, true);
        jumpAction = map.FindAction(jumpActionName, true);

        moveAction.Enable();
        jumpAction.Enable();
        jumpAction.performed += OnJumpPerformed;
    }

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

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

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

        InputSystem.onDeviceChange -= HandleDeviceChange;
    }

    private void FixedUpdate()
    {
        if (moveAction == null)
        {
            return;
        }

        var input = moveAction.ReadValue<Vector2>();
        if (Mathf.Abs(input.x) > 0.01f)
        {
            LastMoveX = input.x;
        }
        var velocity = body.linearVelocity;
        velocity.x = input.x * moveSpeed;
        body.linearVelocity = velocity;
    }

    private void OnJumpPerformed(InputAction.CallbackContext context)
    {
        if (!IsGrounded())
        {
            return;
        }

        var velocity = body.linearVelocity;
        velocity.y = 0f;
        body.linearVelocity = velocity;
        body.AddForce(Vector2.up * jumpImpulse, ForceMode2D.Impulse);
    }

    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;
    }

    private bool IsGrounded()
    {
        var bounds = bodyCollider.bounds;
        var checkSize = new Vector2(bounds.size.x * 0.9f, groundCheckDistance * 2f);
        var checkCenter = new Vector2(bounds.center.x, bounds.min.y - groundCheckDistance);
        var hits = Physics2D.OverlapBoxAll(checkCenter, checkSize, 0f, groundMask);
        for (var i = 0; i < hits.Length; i++)
        {
            var hit = hits[i];
            if (hit != null && hit != bodyCollider)
            {
                return true;
            }
        }

        return false;
    }
}