using Akari.Prototype.Server.Options;
using Akari.Prototype.Server.Utils;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.Json;
using System.Threading.Tasks;

namespace Akari.Prototype.Server.Services
{
    public class FingerprintManager : IFingerprintManager
    {
        public const string FingerprintsPath = "fingerprints.json";

        private readonly ILogger<FingerprintManager> _logger;
        private readonly IOptions<AkariOptions> _akariOptions;
        private readonly IAuthManager _authManager;

        /// <summary>
        /// Map token hash to user-friendly name
        /// </summary>
        private IDictionary<string, string> _fingerprintNames;

        public FingerprintManager(ILogger<FingerprintManager> logger, IOptions<AkariOptions> akariOptions,
                                    IAuthManager authManager)
        {
            _logger = logger;
            _akariOptions = akariOptions;
            _authManager = authManager;

            LoadFingerprints();
        }

        private void LoadFingerprints()
        {
            var path = AkariPath.GetPath(FingerprintsPath);

            // Create new
            if (!File.Exists(path))
            {
                _fingerprintNames = new Dictionary<string, string>();

                File.WriteAllText(path, JsonSerializer.Serialize(_fingerprintNames));
            }
            // Load
            else
            {
                _fingerprintNames = JsonSerializer.Deserialize<IDictionary<string, string>>(File.ReadAllText(path));
            }
        }

        public async Task VerifyToken(byte[] token)
        {
            var hash = Security.Argon2idHash(token);

            _logger.LogDebug($"Verifying hash: {hash}");

            if (!_fingerprintNames.TryGetValue(hash, out var name))
            {
                _logger.LogDebug($"Unknown hash, aborting: {hash}");

                return;
            }

            _authManager.Auth(token, name);
        }
    }
}