using System.Reflection;
using System.Text.Json;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.SignalR;
using Microsoft.EntityFrameworkCore;
using RadicadeServer.API;
using RadicadeServer.API.Notifications;
using RadicadeServer.CDN;
using RadicadeServer.DB;
using RadicadeServer.RecNet;
using Xunit;

namespace RadicadeServer.Tests;

/// <summary>
/// Realtime is one socket, and it fails silently in every direction: a URL that lands
/// somewhere unmapped, or a socket the server cannot tie to an account, leaves the
/// connection looking healthy while every notification for that player is dropped - no ban
/// kick, no invite, no presence. These cover the two halves that made that possible: the
/// set of addresses the hub answers on, and putting the player's token on a socket the
/// client builds without one.
/// </summary>
[Collection(DbFactoryCollection.Name)]
public class HubRealtimeTests
{
    private sealed class TestDbContextFactory(bool failToCreate = false) : IDbContextFactory<RecDBContext>
    {
        private readonly DbContextOptions<RecDBContext> options = TestDbOptions.Create()
            .UseInMemoryDatabase(Guid.NewGuid().ToString())
            .Options;

        public RecDBContext CreateDbContext()
        {
            if (failToCreate) throw new InvalidOperationException("Database unavailable");
            return new RecDBContext(options);
        }
    }

    private sealed class TestHubContext : IHubContext<NotifyHub>
    {
        public IHubClients Clients => null!;
        public IGroupManager Groups => null!;
    }

    private static readonly string[] HealthServiceNames =
    [
        "auth", "ai", "data", "www", "cards", "notify", "images", "cdn", "commerce",
        "datacollection", "discovery", "matchmaking", "storage", "chat", "geo",
        "leaderboard", "accounts", "link", "locker", "moderation", "roomcomments",
        "roomieintegrations", "clubs", "rooms", "econ", "bugreporting", "cms",
        "gamelogs", "platformnotifications", "stringscdn", "strings", "lists",
        "studio", "studiocdn", "thorn", "videos"
    ];

    private static async Task<IActionResult> GetStatusAsync(
        string service,
        IDbContextFactory<RecDBContext>? dbFactory,
        bool hubAvailable = true)
    {
        var previousFactory = Notify.DbFactory;
        var previousContext = Notify.Context;
        try
        {
            Notify.DbFactory = dbFactory!;
            Notify.Context = hubAvailable ? new TestHubContext() : null!;
            var api = new ServiceRootHealthAPI(dbFactory!);
            var httpContext = new DefaultHttpContext();
            httpContext.Request.Path = "/" + service;
            api.ControllerContext = new ControllerContext { HttpContext = httpContext };
            return await api.GetServiceStatus();
        }
        finally
        {
            Notify.DbFactory = previousFactory;
            Notify.Context = previousContext;
        }
    }

    private static JsonElement ResponseBody(IActionResult result)
    {
        var value = Assert.IsAssignableFrom<ObjectResult>(result).Value;
        using var document = JsonDocument.Parse(JsonSerializer.Serialize(value));
        return document.RootElement.Clone();
    }

    [Fact]
    public async Task EveryNameserverServiceRootHasAnonymousHealthyStatusJson()
    {
        var method = typeof(ServiceRootHealthAPI).GetMethod(nameof(ServiceRootHealthAPI.GetServiceStatus))!;
        Assert.NotEmpty(method.GetCustomAttributes<AllowAnonymousAttribute>());
        var routeTemplates = method.GetCustomAttributes<HttpGetAttribute>()
            .Select(attribute => attribute.Template)
            .ToArray();
        var advertised = typeof(NameServerResponse).GetProperties()
            .ToDictionary(property => property.Name,
                property => new Uri((string)property.GetValue(DBConfig.NameServer)!));

        // Every advertised endpoint is a host of its own under the service domain and carries
        // no path at all: the client appends its own path literal to the base it reads here,
        // and the host label is what NameserverRedirect turns back into a route prefix. The
        // label is the route unless the server says otherwise, which is why the comparison
        // below goes through ServiceRoute: notifications is served at /notify.
        Assert.All(advertised.Values, url =>
        {
            Assert.Equal(DBConfig.ServiceDomain, url.Host.Split('.', 2).ElementAtOrDefault(1));
            Assert.Equal("/", url.AbsolutePath);
        });

        var advertisedServices = advertised
            .Where(pair => pair.Key is not nameof(NameServerResponse.API) and not nameof(NameServerResponse.PlayerSettings))
            .Select(pair => DBConfig.ServiceRoute(pair.Value.Host.Split('.')[0]))
            .OrderBy(service => service, StringComparer.Ordinal)
            .ToArray();
        var expectedRoutes = HealthServiceNames
            .Where(service => service != "data")
            .Select(service => "~/" + service)
            .OrderBy(route => route, StringComparer.Ordinal)
            .ToArray();

        Assert.Equal(HealthServiceNames.OrderBy(service => service, StringComparer.Ordinal), advertisedServices);
        Assert.Equal(expectedRoutes, routeTemplates.OrderBy(route => route, StringComparer.Ordinal));
        Assert.Contains("~/platformnotifications", routeTemplates);
        Assert.DoesNotContain(routeTemplates, route => route!.Contains('*'));
        Assert.DoesNotContain(routeTemplates, route => route is "~/" or "~/ns");

        var factory = new TestDbContextFactory();
        foreach (var service in HealthServiceNames)
        {
            if (service == "data")
            {
                var dataRoot = typeof(DataCDN).GetMethod(nameof(DataCDN.Index))!;
                Assert.Contains(dataRoot.GetCustomAttributes<HttpGetAttribute>(), attribute => string.IsNullOrEmpty(attribute.Template));
                Assert.Contains("data/", typeof(DataCDN).GetCustomAttributes<RouteAttribute>().Select(attribute => attribute.Template));
                continue;
            }

            Assert.Contains("~/" + service, routeTemplates);
            var result = Assert.IsType<OkObjectResult>(await GetStatusAsync(service, factory));
            var body = ResponseBody(result);
            Assert.Equal(service, body.GetProperty("service").GetString());
            Assert.Equal("ok", body.GetProperty("status").GetString());
        }
    }

    // The nameserver names each service on its own host, and the patch has to turn that host
    // back into the route this server serves it under: the client appends its own path literal
    // to the advertised base, so a host that lands anywhere else is a service that answers
    // nothing - with no error anywhere to say so. This reads the advertised names, the
    // redirect and the server's own routes together, so the three cannot drift apart: a name
    // misspelled in either list fails here rather than in a client that half-works.
    [Fact]
    public void EveryAdvertisedServiceHostLandsOnAServiceRootTheServerServes()
    {
        var roots = typeof(ServiceRootHealthAPI)
            .GetMethod(nameof(ServiceRootHealthAPI.GetServiceStatus))!
            .GetCustomAttributes<HttpGetAttribute>()
            .Select(attribute => attribute.Template!.TrimStart('~', '/').ToLowerInvariant())
            .ToHashSet(StringComparer.Ordinal);
        // data answers from its own controller at /data rather than from the health roots.
        roots.Add("data");

        foreach (var property in typeof(NameServerResponse).GetProperties())
        {
            var advertised = (string)property.GetValue(DBConfig.NameServer)!;
            var label = new Uri(advertised).Host.Split('.')[0];
            var rewritten = new Uri(NameserverRedirect.Rewrite(advertised + "/probe", DBConfig.ServerUrl));
            var segment = rewritten.AbsolutePath.TrimStart('/').Split('/')[0].ToLowerInvariant();

            Assert.Equal(new Uri(DBConfig.ServerUrl).Host, rewritten.Host);

            // api is the bare base every unprefixed call already went to, so it must not gain
            // a segment at all.
            if (property.Name == nameof(NameServerResponse.API))
            {
                Assert.Equal("probe", rewritten.AbsolutePath.TrimStart('/'));
                continue;
            }

            Assert.Equal(DBConfig.ServiceRoute(label), segment);

            // playersettings is advertised for completeness; the client's settings calls go to
            // /api/settings/v2, so there is no root of that name to land on.
            if (property.Name == nameof(NameServerResponse.PlayerSettings))
                continue;

            Assert.Contains(segment, roots);
        }
    }

    [Fact]
    public async Task NotificationServiceRootReturnsAnErrorCodeWhenTheHubIsUnavailable()
    {
        var result = Assert.IsType<ObjectResult>(await GetStatusAsync("notify", new TestDbContextFactory(), hubAvailable: false));

        Assert.Equal(StatusCodes.Status503ServiceUnavailable, result.StatusCode);
        var body = ResponseBody(result);
        Assert.Equal("notify", body.GetProperty("service").GetString());
        Assert.Equal("NOTIFY_HUB_UNAVAILABLE", body.GetProperty("status").GetString());
    }

    [Fact]
    public async Task ServiceRootsReturnTheirErrorCodeWhenTheDatabaseIsUnavailable()
    {
        var result = Assert.IsType<ObjectResult>(await GetStatusAsync("moderation", new TestDbContextFactory(failToCreate: true)));

        Assert.Equal(StatusCodes.Status503ServiceUnavailable, result.StatusCode);
        var body = ResponseBody(result);
        Assert.Equal("moderation", body.GetProperty("service").GetString());
        Assert.Equal("MODERATION_DATABASE_UNAVAILABLE", body.GetProperty("status").GetString());
    }

    [Fact]
    public async Task NotificationServiceRootReturnsAnErrorCodeWhenItsDatabaseIsNotConfigured()
    {
        var result = Assert.IsType<ObjectResult>(await GetStatusAsync("notify", null));

        Assert.Equal(StatusCodes.Status503ServiceUnavailable, result.StatusCode);
        Assert.Equal("NOTIFY_DATABASE_NOT_CONFIGURED", ResponseBody(result).GetProperty("status").GetString());
    }

    [Fact]
    public void DataServiceRootReportsHealthyAndUnavailableStorage()
    {
        var previousStorage = DBConfig.CDNStorage;
        var root = Directory.CreateTempSubdirectory("radicade-data-health-test-");
        try
        {
            DBConfig.CDNStorage = root.FullName;
            var healthy = Assert.IsType<OkObjectResult>(new DataCDN().Index());
            var healthyBody = ResponseBody(healthy);
            Assert.Equal("data", healthyBody.GetProperty("service").GetString());
            Assert.Equal("ok", healthyBody.GetProperty("status").GetString());

            DBConfig.CDNStorage = Path.Combine(root.FullName, "missing");
            var unavailable = Assert.IsType<ObjectResult>(new DataCDN().Index());
            Assert.Equal(StatusCodes.Status503ServiceUnavailable, unavailable.StatusCode);
            var errorBody = ResponseBody(unavailable);
            Assert.Equal("data", errorBody.GetProperty("service").GetString());
            Assert.Equal("DATA_STORAGE_UNAVAILABLE", errorBody.GetProperty("status").GetString());
        }
        finally
        {
            DBConfig.CDNStorage = previousStorage;
            root.Delete(recursive: true);
        }
    }

    // The client builds the hub URL as the nameserver response's "Notifications" base plus
    // the client's own "hub/v1" literal, and the two ways of joining them disagree about the
    // slash. Every shape that join can produce has to answer, or a URL-shape mismatch kills
    // realtime while every REST call keeps working.
    [Theory]
    [InlineData("/notify/hub/v1")]
    [InlineData("/notify/hub")]
    [InlineData("/notifyhub/v1")]
    [InlineData("/hub/v1")]
    [InlineData("/hub")]
    public void EveryHubAddressShapeTheClientCanBuildAnswers(string path)
    {
        Assert.Contains(path, NotifyHubRoutes.Paths);
        Assert.True(NotifyHubRoutes.IsHubPath(path));

        // SignalR negotiates over HTTP first, then upgrades.
        Assert.True(NotifyHubRoutes.IsHubPath(path + "/negotiate"));

        // Path matching never depends on the casing a proxy or a client happened to use.
        Assert.True(NotifyHubRoutes.IsHubPath(path.ToUpperInvariant()));
    }

    [Theory]
    [InlineData("/notify")]
    [InlineData("/notify/")]
    [InlineData("/rooms/rooms/1")]
    [InlineData("/matchmaking/player")]
    [InlineData("/hubris")]
    public void UnrelatedAddressesAreNotHubAddresses(string path)
        => Assert.False(NotifyHubRoutes.IsHubPath(path));

    // The socket the client opens, exactly as its own log shows it. It carries the
    // connection id and nothing else: no access_token, and no Authorization header, because
    // SignalR's WebSocket transport does not copy the one the game uses for REST calls. That
    // is what left the server with an anonymous connection whose every notification was
    // dropped.
    [Theory]
    [InlineData("wss://ns.radicade.app/notify/hub/v1?&id=abc")]
    [InlineData("wss://ns.radicade.app/notify/hub/v1?id=abc")]
    [InlineData("wss://ns.radicade.app/hub/v1?id=abc")]
    [InlineData("wss://ns.radicade.app/notifyhub/v1?id=abc")]
    [InlineData("wss://ns.radicade.app/hub?id=abc")]
    [InlineData("https://ns.radicade.app/notify/hub/v1/negotiate")]
    public void HubAddressesAreRecognised(string url) => Assert.True(NameserverRedirect.IsHubUrl(url));

    [Theory]
    [InlineData("https://ns.radicade.app/rooms/rooms/1")]
    [InlineData("https://ns.radicade.app/hubris")]
    [InlineData("https://ns.radicade.app/notify/")]
    [InlineData("https://ns.radicade.app/api/settings/v2/")]
    [InlineData("https://ns.radicade.app/accounts/account/me")]
    public void OtherAddressesAreNotHubAddresses(string url) => Assert.False(NameserverRedirect.IsHubUrl(url));

    // The address the client actually opens, rebuilt the canonical way round: the player's
    // token first, the connection id kept.
    [Fact]
    public void TheClientsOwnHubAddressGetsThePlayersToken()
    {
        var opened = "wss://ns.radicade.app/notify/hub/v1?&id=z9bNeechDZOGXdxy5lQp0Q";

        var authenticated = NameserverRedirect.EnsureHubToken(opened, "eyJhbGciOi.probe.token");

        Assert.Equal("wss://ns.radicade.app/notify/hub/v1?access_token=eyJhbGciOi.probe.token&id=z9bNeechDZOGXdxy5lQp0Q", authenticated);
        Assert.True(NameserverRedirect.HasHubToken(authenticated));

        // Idempotent: a second pass must not stack a second copy on the address.
        Assert.Equal(authenticated, NameserverRedirect.EnsureHubToken(authenticated, "eyJhbGciOi.probe.token"));
    }

    [Theory]
    [InlineData("/notify/hub/v1?id=abc")]
    [InlineData("/notify/hub/v1")]
    [InlineData("/hub")]
    public void EveryHubShapeCanCarryTheToken(string path)
    {
        var authenticated = NameserverRedirect.EnsureHubToken("wss://host" + path, "token-value");

        Assert.Contains("access_token=token-value", authenticated);
        Assert.True(NameserverRedirect.HasHubToken(authenticated));
    }

    [Fact]
    public void ASocketThatAlreadyCarriesATokenIsLeftAlone()
    {
        var already = "wss://host/hub/v1?access_token=theirs&id=abc";

        Assert.Equal(already, NameserverRedirect.EnsureHubToken(already, "ours"));
        Assert.True(NameserverRedirect.HasHubToken(already));
    }

    [Fact]
    public void TheBearerPrefixIsNotPartOfTheToken()
    {
        Assert.Equal("wss://host/hub/v1?access_token=raw",
            NameserverRedirect.EnsureHubToken("wss://host/hub/v1", "Bearer raw"));
    }

    // Nothing may be added to an ordinary API call: a token in the wrong URL is a token
    // leaked into logs and into whatever the address is handed to.
    [Fact]
    public void OrdinaryCallsAreNeverTouched()
    {
        const string api = "https://host/rooms/rooms/1?include=all";
        Assert.Equal(api, NameserverRedirect.EnsureHubToken(api, "token-value"));
        Assert.Equal("wss://host/hub/v1", NameserverRedirect.EnsureHubToken("wss://host/hub/v1", null));
        Assert.Equal("wss://host/hub/v1", NameserverRedirect.EnsureHubToken("wss://host/hub/v1", ""));
        Assert.Equal("wss://host/hub/v1", NameserverRedirect.EnsureHubToken("wss://host/hub/v1", "Bearer "));
    }

    // The stock client's hub host is the real RecNet's; redirecting it and authenticating it
    // are two steps of the same journey and must compose.
    [Fact]
    public void AStockClientsHubSocketIsRedirectedAndThenAuthenticated()
    {
        var redirected = NameserverRedirect.RewriteWebSocket("wss://notify.rec.net/hub/v1?id=abc", "https://ns.radicade.app");
        Assert.Equal("wss://ns.radicade.app/notify/hub/v1?id=abc", redirected);

        var authenticated = NameserverRedirect.EnsureHubToken(redirected, "token-value");
        Assert.Equal("wss://ns.radicade.app/notify/hub/v1?access_token=token-value&id=abc", authenticated);
    }
}