using System;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEngine.InputSystem;
using UnityEngine.InputSystem.Utilities;

namespace InputGlyphsFramework
{
    /// <summary>
    /// Handles interactive rebinding and conflict resolution for keyboard mappings.
    /// Conflicts are detected within configured scopes (e.g. Gameplay vs UI) and the conflicting binding(s)
    /// will be cleared (erased) while keeping the new mapping.
    /// </summary>
    [DefaultExecutionOrder(-150)]
    public class RebindManager : MonoBehaviour
    {
        public static RebindManager Instance { get; private set; }

        [Tooltip("Action map names treated as Gameplay scope (conflicts resolved inside this group)")]
        public string[] gameplayMapNames = new string[] { "Player", "Other" };

        [Tooltip("Action map names treated as UI scope")]
        public string[] uiMapNames = new string[] { "UI" };

        [Header("Rebind Options")]
        public bool excludeMousePosition = true;
        public string cancelControl = "<Keyboard>/escape";

        private void Awake()
        {
            if (Instance != null && Instance != this) { Destroy(this); return; }
            Instance = this;
        }

        private void OnDestroy()
        {
            if (Instance == this) Instance = null;
        }

        /// <summary>
        /// Start interactive rebind on given action & bindingIndex. scope chooses which maps to treat as same-scope
        /// for conflict detection. Use scope = "Gameplay" or "UI".
        /// </summary>
        public void StartInteractiveRebind(InputActionReference actionRef, int bindingIndex, string scope = "Gameplay", Action onComplete = null)
        {
            if (actionRef == null || actionRef.action == null) return;
            var action = actionRef.action;

            if (bindingIndex < 0 || bindingIndex >= action.bindings.Count)
            {
                Debug.LogWarning("RebindManager: bindingIndex out of range");
                return;
            }

            var rebind = action.PerformInteractiveRebinding(bindingIndex)
                .WithCancelingThrough(cancelControl)
                .OnComplete(op =>
                {
                    try
                    {
                        var newPath = action.bindings[bindingIndex].effectivePath; // may be set via override

                        // Persist override for this binding
                        action.ApplyBindingOverride(bindingIndex, newPath);

                        // Resolve conflicts inside scope (keyboard only)
                        ResolveConflicts(action, bindingIndex, newPath, scope);

                        // Save using InputService
                        if (InputService.Instance != null) InputService.Instance.SaveOverridesToPrefs();

                        // Notify
                        if (InputService.Instance != null) InputService.Instance.NotifyBindingChanged(action, bindingIndex);

                        onComplete?.Invoke();
                    }
                    finally
                    {
                        op.Dispose();
                    }
                });

            if (excludeMousePosition)
                rebind.WithControlsExcluding("<Mouse>/position");

            rebind.Start();
        }

        private IEnumerable<string> GetMapsForScope(string scope)
        {
            if (string.Equals(scope, "UI", StringComparison.OrdinalIgnoreCase)) return uiMapNames;
            return gameplayMapNames;
        }

        private void ResolveConflicts(InputAction changedAction, int changedBindingIndex, string newPath, string scope)
        {
            if (string.IsNullOrEmpty(newPath)) return;

            // only care about keyboard rebinding conflicts
            if (!newPath.ToLowerInvariant().Contains("keyboard")) return;

            var maps = GetMapsForScope(scope);
            if (maps == null || maps.Count() == 0) return;

            if (InputService.Instance == null || InputService.Instance.playerInput == null) return;

            var asset = InputService.Instance.playerInput.actions;
            var actionsToCheck = new List<(InputAction action, int bindingIndex)>();

            // Gather candidates: all bindings in maps matching scope
            foreach (var map in asset.actionMaps)
            {
                if (!maps.Contains(map.name)) continue;
                foreach (var action in map.actions)
                {
                    for (int i = 0; i < action.bindings.Count; ++i)
                    {
                        var b = action.bindings[i];
                        // ignore the binding we just changed on the changedAction
                        if (action == changedAction && i == changedBindingIndex) continue;

                        // consider only keyboard bindings (or empty path) for conflict
                        var path = !string.IsNullOrEmpty(b.effectivePath) ? b.effectivePath : b.path;
                        if (string.IsNullOrEmpty(path)) continue;

                        if (path.Equals(newPath, StringComparison.OrdinalIgnoreCase))
                        {
                            actionsToCheck.Add((action, i));
                        }
                    }
                }
            }

            if (actionsToCheck.Count == 0) return;

            // Log conflicts, then clear conflicting bindings (erase)
            foreach (var item in actionsToCheck)
            {
                Debug.LogWarning($"Rebind conflict detected: New binding '{newPath}' for '{changedAction.name}' conflicts with '{item.action.name}' binding index {item.bindingIndex} (will be cleared)");

                try
                {
                    // Erase the conflicting binding entry
                    item.action.ChangeBinding(item.bindingIndex).Erase();

                    // Notify for the cleared action
                    if (InputService.Instance != null) InputService.Instance.NotifyBindingChanged(item.action, item.bindingIndex);
                }
                catch (Exception e)
                {
                    Debug.LogWarning("RebindManager: Failed to erase conflicting binding: " + e.Message);
                }
            }
        }
    }
}