/*
 * Licensed under the Apache License, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 * See https://github.com/openiddict/openiddict-core for more information concerning
 * the license and the contributors participating to this project.
 */

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using Microsoft.IdentityModel.JsonWebTokens;
using Microsoft.IdentityModel.Tokens;
using OpenIddict.Abstractions;
using static OpenIddict.Abstractions.OpenIddictConstants;
using SR = OpenIddict.Abstractions.OpenIddictResources;

namespace OpenIddict.Server
{
    /// <summary>
    /// Provides various settings needed to configure the OpenIddict server handler.
    /// </summary>
    public class OpenIddictServerOptions
    {
        /// <summary>
        /// Gets or sets the optional base address used to uniquely identify the authorization server.
        /// The URI must be absolute and may contain a path, but no query string or fragment part.
        /// </summary>
        public Uri? Issuer { get; set; }

        /// <summary>
        /// Gets the list of encryption credentials used by the OpenIddict server services.
        /// Multiple credentials can be added to support key rollover, but if X.509 keys
        /// are used, at least one of them must have a valid creation/expiration date.
        /// Note: the encryption credentials are not used to protect/unprotect tokens issued
        /// by ASP.NET Core Data Protection, that uses its own key ring, configured separately.
        /// </summary>
        /// <remarks>
        /// Note: OpenIddict automatically sorts the credentials based on the following algorithm:
        /// <list type="bullet">
        ///   <item><description>Symmetric keys are always preferred when they can be used for the operation (e.g token encryption).</description></item>
        ///   <item><description>X.509 keys are always preferred to non-X.509 asymmetric keys.</description></item>
        ///   <item><description>X.509 keys with the furthest expiration date are preferred.</description></item>
        ///   <item><description>X.509 keys whose backing certificate is not yet valid are never preferred.</description></item>
        /// </list>
        /// </remarks>
        public List<EncryptingCredentials> EncryptionCredentials { get; } = new();

        /// <summary>
        /// Gets the list of signing credentials used by the OpenIddict server services.
        /// Multiple credentials can be added to support key rollover, but if X.509 keys
        /// are used, at least one of them must have a valid creation/expiration date.
        /// Note: the signing credentials are not used to protect/unprotect tokens issued
        /// by ASP.NET Core Data Protection, that uses its own key ring, configured separately.
        /// </summary>
        /// <remarks>
        /// Note: OpenIddict automatically sorts the credentials based on the following algorithm:
        /// <list type="bullet">
        ///   <item><description>Symmetric keys are always preferred when they can be used for the operation (e.g token signing).</description></item>
        ///   <item><description>X.509 keys are always preferred to non-X.509 asymmetric keys.</description></item>
        ///   <item><description>X.509 keys with the furthest expiration date are preferred.</description></item>
        ///   <item><description>X.509 keys whose backing certificate is not yet valid are never preferred.</description></item>
        /// </list>
        /// </remarks>
        public List<SigningCredentials> SigningCredentials { get; } = new();

        /// <summary>
        /// Gets the absolute and relative URIs associated to the authorization endpoint.
        /// </summary>
        public List<Uri> AuthorizationEndpointUris { get; } = new();

        /// <summary>
        /// Gets the absolute and relative URIs associated to the configuration endpoint.
        /// </summary>
        public List<Uri> ConfigurationEndpointUris { get; } = new()
        {
            new Uri("/.well-known/openid-configuration", UriKind.Relative),
            new Uri("/.well-known/oauth-authorization-server", UriKind.Relative)
        };

        /// <summary>
        /// Gets the absolute and relative URIs associated to the cryptography endpoint.
        /// </summary>
        public List<Uri> CryptographyEndpointUris { get; } = new List<Uri>
        {
            new Uri("/.well-known/jwks", UriKind.Relative)
        };

        /// <summary>
        /// Gets the absolute and relative URIs associated to the device endpoint.
        /// </summary>
        public List<Uri> DeviceEndpointUris { get; } = new();

        /// <summary>
        /// Gets the absolute and relative URIs associated to the introspection endpoint.
        /// </summary>
        public List<Uri> IntrospectionEndpointUris { get; } = new();

        /// <summary>
        /// Gets the absolute and relative URIs associated to the logout endpoint.
        /// </summary>
        public List<Uri> LogoutEndpointUris { get; } = new();

        /// <summary>
        /// Gets the absolute and relative URIs associated to the revocation endpoint.
        /// </summary>
        public List<Uri> RevocationEndpointUris { get; } = new();

        /// <summary>
        /// Gets the absolute and relative URIs associated to the token endpoint.
        /// </summary>
        public List<Uri> TokenEndpointUris { get; } = new();

        /// <summary>
        /// Gets the absolute and relative URIs associated to the userinfo endpoint.
        /// </summary>
        public List<Uri> UserinfoEndpointUris { get; } = new();

        /// <summary>
        /// Gets the absolute and relative URIs associated to the verification endpoint.
        /// </summary>
        public List<Uri> VerificationEndpointUris { get; } = new();

        /// <summary>
        /// Gets or sets the JWT handler used to protect and unprotect tokens.
        /// </summary>
        public JsonWebTokenHandler JsonWebTokenHandler { get; set; } = new()
        {
            SetDefaultTimesOnTokenCreation = false
        };

        /// <summary>
        /// Gets the token validation parameters used by the OpenIddict server services.
        /// </summary>
        public TokenValidationParameters TokenValidationParameters { get; } = new()
        {
            AuthenticationType = TokenValidationParameters.DefaultAuthenticationType,
            ClockSkew = TimeSpan.Zero,
            NameClaimType = OpenIddictConstants.Claims.Name,
            RoleClaimType = OpenIddictConstants.Claims.Role,
            // In previous versions of OpenIddict (1.x and 2.x), all the JWT tokens (access and identity tokens)
            // were issued with the generic "typ": "JWT" header. To prevent confused deputy and token substitution
            // attacks, a special "token_usage" claim was added to the JWT payload to convey the actual token type.
            // This validator overrides the default logic used by IdentityModel to resolve the type from this claim.
            TypeValidator = (type, token, parameters) =>
            {
                // If available, try to resolve the actual type from the "token_usage" claim.
                if (((JsonWebToken) token).TryGetPayloadValue(OpenIddictConstants.Claims.TokenUsage, out string usage))
                {
                    type = usage switch
                    {
                        TokenTypeHints.AccessToken => JsonWebTokenTypes.AccessToken,
                        TokenTypeHints.IdToken     => JsonWebTokenTypes.IdentityToken,

                        _ => throw new NotSupportedException(SR.GetResourceString(SR.ID0269))
                    };
                }

                // At this point, throw an exception if the type cannot be resolved from the "typ" header
                // (provided via the type delegate parameter) or inferred from the token_usage claim.
                if (string.IsNullOrEmpty(type))
                {
                    throw new SecurityTokenInvalidTypeException(SR.GetResourceString(SR.ID0270));
                }

                // Note: unlike IdentityModel, this custom validator deliberately uses case-insensitive comparisons.
                if (parameters.ValidTypes is not null && parameters.ValidTypes.Any() &&
                   !parameters.ValidTypes.Contains(type, StringComparer.OrdinalIgnoreCase))
                {
                    throw new SecurityTokenInvalidTypeException(SR.GetResourceString(SR.ID0271))
                    {
                        InvalidType = type
                    };
                }

                return type;
            },
            // Note: audience and lifetime are manually validated by OpenIddict itself.
            ValidateAudience = false,
            ValidateLifetime = false
        };

        /// <summary>
        /// Gets or sets the period of time authorization codes remain valid after being issued. The default value is 5 minutes.
        /// While not recommended, this property can be set to <c>null</c> to issue codes that never expire.
        /// </summary>
        public TimeSpan? AuthorizationCodeLifetime { get; set; } = TimeSpan.FromMinutes(5);

        /// <summary>
        /// Gets or sets the period of time access tokens remain valid after being issued. The default value is 1 hour.
        /// The client application is expected to refresh or acquire a new access token after the token has expired.
        /// While not recommended, this property can be set to <c>null</c> to issue access tokens that never expire.
        /// </summary>
        public TimeSpan? AccessTokenLifetime { get; set; } = TimeSpan.FromHours(1);

        /// <summary>
        /// Gets or sets the period of time device codes remain valid after being issued. The default value is 10 minutes.
        /// The client application is expected to start a whole new authentication flow after the device code has expired.
        /// While not recommended, this property can be set to <c>null</c> to issue codes that never expire.
        /// Note: the same value should be chosen for both <see cref="UserCodeLifetime"/> and this property.
        /// </summary>
        public TimeSpan? DeviceCodeLifetime { get; set; } = TimeSpan.FromMinutes(10);

        /// <summary>
        /// Gets or sets the period of time identity tokens remain valid after being issued. The default value is 20 minutes.
        /// The client application is expected to refresh or acquire a new identity token after the token has expired.
        /// While not recommended, this property can be set to <c>null</c> to issue identity tokens that never expire.
        /// </summary>
        public TimeSpan? IdentityTokenLifetime { get; set; } = TimeSpan.FromMinutes(20);

        /// <summary>
        /// Gets or sets the period of time refresh tokens remain valid after being issued. The default value is 14 days.
        /// The client application is expected to start a whole new authentication flow after the refresh token has expired.
        /// While not recommended, this property can be set to <c>null</c> to issue refresh tokens that never expire.
        /// </summary>
        public TimeSpan? RefreshTokenLifetime { get; set; } = TimeSpan.FromDays(14);

        /// <summary>
        /// Gets or sets the period of time rolling refresh tokens marked as redeemed can still be
        /// used to make concurrent refresh token requests. The default value is 15 seconds.
        /// </summary>
        public TimeSpan? RefreshTokenReuseLeeway { get; set; } = TimeSpan.FromSeconds(15);

        /// <summary>
        /// Gets or sets the period of time user codes remain valid after being issued. The default value is 10 minutes.
        /// The client application is expected to start a whole new authentication flow after the user code has expired.
        /// While not recommended, this property can be set to <c>null</c> to issue codes that never expire.
        /// Note: the same value should be chosen for both <see cref="DeviceCodeLifetime"/> and this property.
        /// </summary>
        public TimeSpan? UserCodeLifetime { get; set; } = TimeSpan.FromMinutes(10);

        /// <summary>
        /// Gets or sets a boolean indicating whether the degraded mode is enabled. When this degraded mode
        /// is enabled, all the security checks that depend on the OpenIddict core managers are disabled.
        /// This option MUST be enabled with extreme caution and custom handlers MUST be registered to
        /// properly validate OpenID Connect requests.
        /// </summary>
        [EditorBrowsable(EditorBrowsableState.Advanced)]
        public bool EnableDegradedMode { get; set; }

        /// <summary>
        /// Gets the list of the handlers responsible of processing the OpenIddict server operations.
        /// Note: the list is automatically sorted based on the order assigned to each handler descriptor.
        /// As such, it MUST NOT be mutated after options initialization to preserve the exact order.
        /// </summary>
        public List<OpenIddictServerHandlerDescriptor> Handlers { get; } = new(OpenIddictServerHandlers.DefaultHandlers);

        /// <summary>
        /// Gets or sets a boolean determining whether client identification is optional.
        /// Enabling this option allows client applications to communicate with the token,
        /// introspection and revocation endpoints without having to send their client identifier.
        /// </summary>
        public bool AcceptAnonymousClients { get; set; }

        /// <summary>
        /// Gets the OAuth 2.0/OpenID Connect claims supported by this application.
        /// </summary>
        public HashSet<string> Claims { get; } = new(StringComparer.Ordinal)
        {
            OpenIddictConstants.Claims.Audience,
            OpenIddictConstants.Claims.ExpiresAt,
            OpenIddictConstants.Claims.IssuedAt,
            OpenIddictConstants.Claims.Issuer,
            OpenIddictConstants.Claims.Subject
        };

        /// <summary>
        /// Gets or sets a boolean indicating whether access token encryption should be disabled.
        /// Disabling encryption is NOT recommended and SHOULD only be done when issuing tokens
        /// to third-party resource servers/APIs you don't control and don't fully trust.
        /// Note: disabling encryption has no effect when using ASP.NET Core Data Protection.
        /// </summary>
        public bool DisableAccessTokenEncryption { get; set; }

        /// <summary>
        /// Gets or sets a boolean indicating whether authorization storage should be disabled.
        /// When disabled, ad-hoc authorizations are not created when an authorization code or
        /// refresh token is issued and can't be revoked to prevent associated tokens from being used.
        /// </summary>
        public bool DisableAuthorizationStorage { get; set; }

        /// <summary>
        /// Gets or sets a boolean indicating whether rolling tokens are disabled.
        /// When disabled, refresh tokens used in a token request are not marked
        /// as redeemed and can still be used until they expire. Disabling
        /// rolling refresh tokens is NOT recommended, for security reasons.
        /// </summary>
        public bool DisableRollingRefreshTokens { get; set; }

        /// <summary>
        /// Gets or sets a boolean indicating whether sliding expiration is disabled
        /// for refresh tokens. When this option is set to <see langword="true"/>,
        /// refresh tokens are issued with a fixed expiration date: when they expire,
        /// a complete authorization flow must be started to retrieve a new refresh token.
        /// </summary>
        public bool DisableSlidingRefreshTokenExpiration { get; set; }

        /// <summary>
        /// Gets or sets a boolean indicating whether token storage should be disabled.
        /// When disabled, no database entry is created for the tokens and codes
        /// returned by OpenIddict. Using this option is generally NOT recommended
        /// as it prevents the tokens and codes from being revoked (if needed).
        /// </summary>
        public bool DisableTokenStorage { get; set; }

        /// <summary>
        /// Gets or sets a boolean indicating whether scope validation is disabled.
        /// </summary>
        public bool DisableScopeValidation { get; set; }

        /// <summary>
        /// Gets the OAuth 2.0 code challenge methods enabled for this application.
        /// By default, only the S256 method is allowed (if the code flow is enabled).
        /// </summary>
        public HashSet<string> CodeChallengeMethods { get; } = new(StringComparer.Ordinal);

        /// <summary>
        /// Gets the OAuth 2.0/OpenID Connect flows enabled for this application.
        /// </summary>
        public HashSet<string> GrantTypes { get; } = new(StringComparer.Ordinal);

        /// <summary>
        /// Gets or sets a boolean indicating whether PKCE must be used by client applications
        /// when requesting an authorization code (e.g when using the code or hybrid flows).
        /// If this property is set to <see langword="true"/>, authorization requests that
        /// lack the code_challenge will be automatically rejected by OpenIddict.
        /// </summary>
        public bool RequireProofKeyForCodeExchange { get; set; }

        /// <summary>
        /// Gets the OAuth 2.0/OpenID Connect response types enabled for this application.
        /// </summary>
        [EditorBrowsable(EditorBrowsableState.Advanced)]
        public HashSet<string> ResponseTypes { get; } = new(StringComparer.Ordinal);

        /// <summary>
        /// Gets the OAuth 2.0/OpenID Connect response modes enabled for this application.
        /// </summary>
        [EditorBrowsable(EditorBrowsableState.Advanced)]
        public HashSet<string> ResponseModes { get; } = new(StringComparer.Ordinal);

        /// <summary>
        /// Gets or sets a boolean indicating whether endpoint permissions should be ignored.
        /// Setting this property to <see langword="true"/> is NOT recommended.
        /// </summary>
        public bool IgnoreEndpointPermissions { get; set; }

        /// <summary>
        /// Gets or sets a boolean indicating whether grant type permissions should be ignored.
        /// Setting this property to <see langword="true"/> is NOT recommended.
        /// </summary>
        public bool IgnoreGrantTypePermissions { get; set; }

        /// <summary>
        /// Gets or sets a boolean indicating whether response type permissions should be ignored.
        /// Setting this property to <see langword="true"/> is NOT recommended.
        /// </summary>
        public bool IgnoreResponseTypePermissions { get; set; }

        /// <summary>
        /// Gets or sets a boolean indicating whether scope permissions should be ignored.
        /// Setting this property to <see langword="true"/> is NOT recommended.
        /// </summary>
        public bool IgnoreScopePermissions { get; set; }

        /// <summary>
        /// Gets the OAuth 2.0/OpenID Connect scopes enabled for this application.
        /// </summary>
        public HashSet<string> Scopes { get; } = new(StringComparer.Ordinal)
        {
            OpenIddictConstants.Scopes.OpenId
        };

        /// <summary>
        /// Gets or sets a boolean indicating whether reference access tokens should be used.
        /// When set to <see langword="true"/>, the token payload is stored in the database
        /// and a crypto-secure random identifier is returned to the client application.
        /// Enabling this option is useful when storing a very large number of claims
        /// in the tokens, but it is RECOMMENDED to enable column encryption
        /// in the database or use the ASP.NET Core Data Protection integration,
        /// that provides additional protection against token leakage.
        /// </summary>
        public bool UseReferenceAccessTokens { get; set; }

        /// <summary>
        /// Gets or sets a boolean indicating whether reference refresh tokens should be used.
        /// When set to <see langword="true"/>, the token payload is stored in the database
        /// and a crypto-secure random identifier is returned to the client application.
        /// Enabling this option is useful when storing a very large number of claims
        /// in the tokens, but it is RECOMMENDED to enable column encryption
        /// in the database or use the ASP.NET Core Data Protection integration,
        /// that provides additional protection against token leakage.
        /// </summary>
        public bool UseReferenceRefreshTokens { get; set; }
    }
}