using System;
using System.Collections.Generic;
using System.Linq;
using Chickensoft.AutoInject;
using Chickensoft.Introspection;
using Godot;

namespace Movementtests.managers;

[GlobalClass, Meta(typeof(IAutoNode))]
public partial class TokenManager : Node
{
    public override void _Notification(int what) => this.Notify(what);
    
    public record struct Token(ulong InstanceId, Action OnUse);
    
    private Dictionary<ulong, Token> Tokens { get; set; } = [];
    public int TokenCount => Tokens.Count;
    
    private List<ulong> RequestQueue { get; set; } = [];
    
    public int MaxTokens { get; set;}

    public void Initialize(int maxTokens)
    {
        MaxTokens = maxTokens;
    }

    public Token? RequestToken(Node owner)
    {
        if (Tokens.ContainsKey(owner.GetInstanceId())) return null;  // Already has a token
        if (RequestQueue.Contains(owner.GetInstanceId())) return null;  // Already in queue
        
        RequestQueue.Add(owner.GetInstanceId());
        if (TokenCount >= MaxTokens) return null;  // Max tokens reached
        if (RequestQueue.First() != owner.GetInstanceId()) return null;  // Next in line is not the requester
        
        RequestQueue.RemoveAt(0);
        var ownerInstanceId = owner.GetInstanceId();
        var token = new Token(ownerInstanceId, () => UseToken(ownerInstanceId));
        Tokens.Add(token.InstanceId, token);
        return token;
    }
    
    public void UseToken(ulong instanceId)
    {
        Tokens.Remove(instanceId);
    }
}