using System.ComponentModel.DataAnnotations;

namespace StellaOps.Signer.Keyless;

/// <summary>
/// Configuration options for keyless signing.
/// </summary>
public sealed class SignerKeylessOptions
{
    /// <summary>
    /// Configuration section name.
    /// </summary>
    public const string SectionName = "Signer:Keyless";

    /// <summary>
    /// Whether keyless signing is enabled.
    /// </summary>
    public bool Enabled { get; set; }

    /// <summary>
    /// Fulcio CA configuration.
    /// </summary>
    public FulcioOptions Fulcio { get; set; } = new();

    /// <summary>
    /// OIDC configuration for token acquisition.
    /// </summary>
    public OidcOptions Oidc { get; set; } = new();

    /// <summary>
    /// Algorithm configuration.
    /// </summary>
    public AlgorithmOptions Algorithms { get; set; } = new();

    /// <summary>
    /// Certificate validation configuration.
    /// </summary>
    public CertificateOptions Certificate { get; set; } = new();

    /// <summary>
    /// Identity verification configuration.
    /// </summary>
    public IdentityOptions Identity { get; set; } = new();
}

/// <summary>
/// Fulcio CA configuration options.
/// </summary>
public sealed class FulcioOptions
{
    /// <summary>
    /// The Fulcio CA URL.
    /// </summary>
    [Required]
    public string Url { get; set; } = "https://fulcio.sigstore.dev";

    /// <summary>
    /// Request timeout.
    /// </summary>
    public TimeSpan Timeout { get; set; } = TimeSpan.FromSeconds(30);

    /// <summary>
    /// Number of retry attempts.
    /// </summary>
    public int Retries { get; set; } = 3;

    /// <summary>
    /// Base duration for exponential backoff.
    /// </summary>
    public TimeSpan BackoffBase { get; set; } = TimeSpan.FromSeconds(1);

    /// <summary>
    /// Maximum backoff duration.
    /// </summary>
    public TimeSpan BackoffMax { get; set; } = TimeSpan.FromSeconds(30);
}

/// <summary>
/// OIDC configuration for token acquisition.
/// </summary>
public sealed class OidcOptions
{
    /// <summary>
    /// The OIDC issuer URL.
    /// </summary>
    public string? Issuer { get; set; }

    /// <summary>
    /// The OAuth2 client ID.
    /// </summary>
    public string? ClientId { get; set; }

    /// <summary>
    /// Reference to the client secret (e.g., "env:SIGNER_OIDC_CLIENT_SECRET").
    /// </summary>
    public string? ClientSecretRef { get; set; }

    /// <summary>
    /// Use ambient OIDC token from CI runner.
    /// </summary>
    public bool UseAmbientToken { get; set; }

    /// <summary>
    /// Path to ambient OIDC token file.
    /// </summary>
    public string? AmbientTokenPath { get; set; } = "/var/run/secrets/tokens/oidc";

    /// <summary>
    /// Token refresh interval before expiry.
    /// </summary>
    public TimeSpan RefreshBefore { get; set; } = TimeSpan.FromMinutes(1);
}

/// <summary>
/// Algorithm configuration options.
/// </summary>
public sealed class AlgorithmOptions
{
    /// <summary>
    /// Preferred algorithm for new signings.
    /// </summary>
    public string Preferred { get; set; } = KeylessAlgorithms.EcdsaP256;

    /// <summary>
    /// Allowed algorithms for signing.
    /// </summary>
    public List<string> Allowed { get; set; } = [KeylessAlgorithms.EcdsaP256, KeylessAlgorithms.Ed25519];
}

/// <summary>
/// Certificate validation configuration options.
/// </summary>
public sealed class CertificateOptions
{
    /// <summary>
    /// Path to Fulcio root CA bundle.
    /// </summary>
    public string? RootBundlePath { get; set; }

    /// <summary>
    /// Additional trusted root certificates (PEM format).
    /// </summary>
    public List<string> AdditionalRoots { get; set; } = [];

    /// <summary>
    /// Whether to validate the certificate chain.
    /// </summary>
    public bool ValidateChain { get; set; } = true;

    /// <summary>
    /// Whether to require Signed Certificate Timestamp (SCT).
    /// </summary>
    public bool RequireSct { get; set; } = true;
}

/// <summary>
/// Identity verification configuration options.
/// </summary>
public sealed class IdentityOptions
{
    /// <summary>
    /// Expected OIDC issuers for verification.
    /// </summary>
    public List<string> ExpectedIssuers { get; set; } = [];

    /// <summary>
    /// Expected subject patterns (regex) for SAN verification.
    /// </summary>
    public List<string> ExpectedSubjectPatterns { get; set; } = [];
}