using System.Collections.Concurrent;
using MealPlan.Api.Models;

namespace MealPlan.Api.Services;

/// <summary>
/// Thread-safe in-memory refresh token store registered as a singleton.
/// Note: tokens live only for the lifetime of the process. For multi-instance
/// deployments this should be swapped for a shared store (e.g. Redis), but it
/// satisfies the "do not modify the database" constraint of this project.
/// </summary>
public class InMemoryRefreshTokenStore : IRefreshTokenStore
{
    private readonly ConcurrentDictionary<string, RefreshToken> _tokens = new();

    public void Add(RefreshToken token) => _tokens[token.Token] = token;

    public RefreshToken? Get(string token) =>
        _tokens.TryGetValue(token, out var found) ? found : null;

    public RefreshToken? Revoke(string token)
    {
        if (!_tokens.TryGetValue(token, out var found))
        {
            return null;
        }

        var wasActive = found.IsActive;
        found.IsRevoked = true;
        return wasActive ? found : null;
    }

    public void RemoveExpired()
    {
        foreach (var kvp in _tokens)
        {
            if (kvp.Value.IsRevoked || DateTime.UtcNow >= kvp.Value.ExpiresAtUtc)
            {
                _tokens.TryRemove(kvp.Key, out _);
            }
        }
    }
}