using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.DataProtection;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using ZB.MOM.WW.OtOpcUa.Configuration;
using ZB.MOM.WW.OtOpcUa.Security.Jwt;
using ZB.MOM.WW.OtOpcUa.Security.Ldap;

namespace ZB.MOM.WW.OtOpcUa.Security;

/// <summary>
///     DI registration for OtOpcUa auth. Single Cookie scheme (the JWT lives inside the
///     cookie as its credential payload); no JwtBearer parallel scheme. Matches ScadaBridge
///     structurally — see <c>docs/plans/2026-05-29-auth-alignment-design.md</c>.
/// </summary>
public static class ServiceCollectionExtensions
{
    /// <summary>
    ///     Wires cookie authentication, DataProtection key persistence to ConfigDb,
    ///     LDAP services, and the LDAP-backed JwtTokenService. Browser flows redirect to
    ///     <c>/login</c>; AJAX/JSON callers receive 401 (handled by the framework's default
    ///     challenge heuristic).
    /// </summary>
    /// <param name="services">The service collection.</param>
    /// <param name="configuration">The application configuration root.</param>
    public static IServiceCollection AddOtOpcUaAuth(this IServiceCollection services, IConfiguration configuration)
    {
        services.AddOptions<JwtOptions>().Bind(configuration.GetSection(JwtOptions.SectionName));
        services.AddOptions<OtOpcUaCookieOptions>().Bind(configuration.GetSection(OtOpcUaCookieOptions.SectionName));
        services.AddOptions<LdapOptions>().Bind(configuration.GetSection(LdapOptions.SectionName));

        services.AddSingleton<JwtTokenService>();
        // Singleton — LdapAuthService is stateless (creates an LdapConnection per call) and
        // must be consumable by the Singleton LdapOpcUaUserAuthenticator on driver-role nodes.
        services.AddSingleton<ILdapAuthService, LdapAuthService>();

        services.AddDataProtection()
            .PersistKeysToDbContext<OtOpcUaConfigDbContext>()
            .SetApplicationName("OtOpcUa");

        services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
            .AddCookie(o =>
            {
                // Static fields only — Name / ExpireTimeSpan / SecurePolicy / SlidingExpiration
                // are bound from OtOpcUaCookieOptions in the PostConfigure block below.
                o.LoginPath = "/login";
                o.LogoutPath = "/auth/logout";
                o.Cookie.HttpOnly = true;
                o.Cookie.SameSite = SameSiteMode.Strict;
                // No OnRedirectToLogin / OnRedirectToAccessDenied overrides — let the framework's
                // built-in IsAjaxRequest heuristic do its thing (302 for browsers, 401 for AJAX).
            });

        // Externalised cookie config — mirrors ScadaBridge's PostConfigure pattern. Fixes a
        // pre-existing latent bug where OtOpcUaCookieOptions was bound but ignored.
        services.AddOptions<CookieAuthenticationOptions>(CookieAuthenticationDefaults.AuthenticationScheme)
            .Configure<IOptions<OtOpcUaCookieOptions>, ILoggerFactory>((cookieOpts, ourOpts, lf) =>
            {
                var v = ourOpts.Value;
                cookieOpts.Cookie.Name = v.Name;
                cookieOpts.ExpireTimeSpan = TimeSpan.FromMinutes(v.ExpiryMinutes);
                cookieOpts.SlidingExpiration = true;
                cookieOpts.Cookie.SecurePolicy = v.RequireHttpsCookie
                    ? CookieSecurePolicy.Always
                    : CookieSecurePolicy.SameAsRequest;

                if (!v.RequireHttpsCookie)
                {
                    lf.CreateLogger("ZB.MOM.WW.OtOpcUa.Security").LogWarning(
                        "Security:Cookie:RequireHttpsCookie is DISABLED — auth cookie SecurePolicy is " +
                        "SameAsRequest. The cookie-embedded JWT will travel in cleartext over plain HTTP. " +
                        "Intended for local dev only — set Security:Cookie:RequireHttpsCookie=true in production.");
                }
            });

        services.AddAuthorization(o =>
        {
            o.FallbackPolicy = new Microsoft.AspNetCore.Authorization.AuthorizationPolicyBuilder(
                    CookieAuthenticationDefaults.AuthenticationScheme)
                .RequireAuthenticatedUser()
                .Build();

            // DriverOperator: may issue Reconnect/Restart commands against live driver instances
            // from the Admin UI DriverStatusPanel. Map LDAP group → role via GroupToRole in
            // appsettings (e.g. "ot-driver-operator": "DriverOperator").
            o.AddPolicy("DriverOperator", policy =>
                policy.RequireRole("DriverOperator", "FleetAdmin"));
        });

        return services;
    }
}