using System;
using System.Globalization;
using UnityEngine;

namespace Vanguard.Auth
{
    /// <summary>
    /// Access/refresh токены. В dev-сборке — PlayerPrefs; для релиза нужно
    /// защищённое хранилище (DPAPI/Keychain) через лаунчер или нативную обёртку.
    /// </summary>
    public sealed class TokenStore
    {
        private const string AccessKey = "vanguard.auth.access";
        private const string RefreshKey = "vanguard.auth.refresh";
        private const string AccessExpiresKey = "vanguard.auth.accessExpires";
        private const string RefreshExpiresKey = "vanguard.auth.refreshExpires";

        public string AccessToken { get; private set; } = string.Empty;
        public string RefreshToken { get; private set; } = string.Empty;
        public DateTimeOffset AccessExpiresAt { get; private set; }
        public DateTimeOffset RefreshExpiresAt { get; private set; }

        public bool HasRefreshToken => !string.IsNullOrEmpty(RefreshToken);
        public bool IsAccessExpired => AccessExpiresAt <= DateTimeOffset.UtcNow.AddSeconds(30);

        public TokenStore()
        {
            Load();
        }

        public void Save(
            string accessToken,
            string refreshToken,
            DateTimeOffset accessExpiresAt,
            DateTimeOffset refreshExpiresAt)
        {
            AccessToken = accessToken ?? string.Empty;
            RefreshToken = refreshToken ?? string.Empty;
            AccessExpiresAt = accessExpiresAt;
            RefreshExpiresAt = refreshExpiresAt;

            PlayerPrefs.SetString(AccessKey, AccessToken);
            PlayerPrefs.SetString(RefreshKey, RefreshToken);
            PlayerPrefs.SetString(AccessExpiresKey, AccessExpiresAt.ToString("O", CultureInfo.InvariantCulture));
            PlayerPrefs.SetString(RefreshExpiresKey, RefreshExpiresAt.ToString("O", CultureInfo.InvariantCulture));
            PlayerPrefs.Save();
        }

        public void Clear()
        {
            AccessToken = string.Empty;
            RefreshToken = string.Empty;
            AccessExpiresAt = default;
            RefreshExpiresAt = default;

            PlayerPrefs.DeleteKey(AccessKey);
            PlayerPrefs.DeleteKey(RefreshKey);
            PlayerPrefs.DeleteKey(AccessExpiresKey);
            PlayerPrefs.DeleteKey(RefreshExpiresKey);
            PlayerPrefs.Save();
        }

        private void Load()
        {
            AccessToken = PlayerPrefs.GetString(AccessKey, string.Empty);
            RefreshToken = PlayerPrefs.GetString(RefreshKey, string.Empty);
            AccessExpiresAt = ParseDate(PlayerPrefs.GetString(AccessExpiresKey, string.Empty));
            RefreshExpiresAt = ParseDate(PlayerPrefs.GetString(RefreshExpiresKey, string.Empty));
        }

        private static DateTimeOffset ParseDate(string value)
        {
            return DateTimeOffset.TryParse(
                value,
                CultureInfo.InvariantCulture,
                DateTimeStyles.RoundtripKind,
                out var parsed)
                ? parsed
                : default;
        }
    }
}