namespace IronServices.Client;

/// <summary>
/// Interface for storing authentication tokens.
/// Implement this for platform-specific secure storage (e.g., MAUI SecureStorage, Windows Credential Manager).
/// </summary>
public interface ITokenStorage
{
    /// <summary>
    /// Save the session token.
    /// </summary>
    Task SaveTokenAsync(string token, DateTime? expiresAt);

    /// <summary>
    /// Get the stored session token.
    /// </summary>
    Task<(string? Token, DateTime? ExpiresAt)> GetTokenAsync();

    /// <summary>
    /// Clear the stored token.
    /// </summary>
    Task ClearTokenAsync();
}

/// <summary>
/// In-memory token storage (not persisted across app restarts).
/// </summary>
public class InMemoryTokenStorage : ITokenStorage
{
    private string? _token;
    private DateTime? _expiresAt;

    public Task SaveTokenAsync(string token, DateTime? expiresAt)
    {
        _token = token;
        _expiresAt = expiresAt;
        return Task.CompletedTask;
    }

    public Task<(string? Token, DateTime? ExpiresAt)> GetTokenAsync()
    {
        return Task.FromResult((_token, _expiresAt));
    }

    public Task ClearTokenAsync()
    {
        _token = null;
        _expiresAt = null;
        return Task.CompletedTask;
    }
}

/// <summary>
/// File-based token storage (for console apps, testing).
/// </summary>
public class FileTokenStorage : ITokenStorage
{
    private readonly string _filePath;

    public FileTokenStorage(string? filePath = null)
    {
        _filePath = filePath ?? Path.Combine(
            Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
            "IronServices",
            "session.json");
    }

    public async Task SaveTokenAsync(string token, DateTime? expiresAt)
    {
        var directory = Path.GetDirectoryName(_filePath);
        if (!string.IsNullOrEmpty(directory) && !Directory.Exists(directory))
        {
            Directory.CreateDirectory(directory);
        }

        var data = new { token, expiresAt = expiresAt?.ToString("O") };
        var json = System.Text.Json.JsonSerializer.Serialize(data);
        await File.WriteAllTextAsync(_filePath, json);
    }

    public async Task<(string? Token, DateTime? ExpiresAt)> GetTokenAsync()
    {
        if (!File.Exists(_filePath))
        {
            return (null, null);
        }

        try
        {
            var json = await File.ReadAllTextAsync(_filePath);
            var data = System.Text.Json.JsonSerializer.Deserialize<TokenData>(json);

            DateTime? expiresAt = null;
            if (!string.IsNullOrEmpty(data?.ExpiresAt))
            {
                expiresAt = DateTime.Parse(data.ExpiresAt, null, System.Globalization.DateTimeStyles.RoundtripKind);
            }

            return (data?.Token, expiresAt);
        }
        catch
        {
            return (null, null);
        }
    }

    public Task ClearTokenAsync()
    {
        if (File.Exists(_filePath))
        {
            File.Delete(_filePath);
        }
        return Task.CompletedTask;
    }

    private class TokenData
    {
        public string? Token { get; set; }
        public string? ExpiresAt { get; set; }
    }
}