acdream/src/AcDream.App/Program.cs

using AcDream.App;
using AcDream.App.Configuration;
using AcDream.App.Credentials;
using AcDream.App.Plugins;
using AcDream.App.Platform;
using AcDream.App.Rendering;
using AcDream.Platform;
using Serilog;

GraphicalHostPlatformServices graphicalPlatform =
    GraphicalHostPlatformServices.Resolve();
graphicalPlatform.ConfigureWindowBackend();
ApplicationPathSet applicationPaths = graphicalPlatform.Paths;
IReadOnlyList<string> migratedConfigurationFiles =
    GraphicalLegacyConfigurationMigrator.Migrate(applicationPaths);

Log.Logger = new LoggerConfiguration()
    .MinimumLevel.Debug()
    .WriteTo.Console()
    .CreateLogger();
foreach (string migratedConfigurationFile in migratedConfigurationFiles)
{
    Log.Information(
        "migrated legacy graphical configuration to {Path}",
        migratedConfigurationFile);
}
Log.Information(
    "graphical platform {RuntimeIdentifier}; native closure: {NativeDependencies}",
    graphicalPlatform.RuntimeIdentifier,
    string.Join(
        ", ",
        graphicalPlatform.NativeDependencies.Select(
            dependency =>
                $"{dependency.Feature}={dependency.PublishedFileName}")));

// Campaign LA slice LA1: --session-config <path> is purely additive — the
// existing one positional dat-dir argument and every ACDREAM_* env var keep
// working exactly as before when the flag is absent. See
// docs/plans/2026-08-14-launcher-campaign.md LA1.
//
// Review fix F5 (LA1 review round): a trailing, valueless --session-config
// (the flag typed as the LAST argument, nothing after it) must be a hard
// error, never a silent fall-through to the env-var path — a launcher that
// mis-composed its argv would otherwise appear to work while quietly
// ignoring the session-config contract entirely.
string? sessionConfigFlagPath = SessionConfigArgumentParsing.ExtractFlagValue(
    args, "--session-config", out bool sessionConfigFlagPresent);
if (sessionConfigFlagPath is null && sessionConfigFlagPresent)
{
    Log.Error(
        "--session-config requires a value (a path to the session-config document).");
    return 2;
}
string[] positionalArgs =
    SessionConfigArgumentParsing.WithoutFlagAndValue(args, "--session-config");

var datDirArg = positionalArgs.FirstOrDefault();
var envDatDir = Environment.GetEnvironmentVariable("ACDREAM_DAT_DIR");

// Single read of the startup-time process environment. Every downstream
// consumer (GameWindow + collaborators) reads the typed bundle, not the
// raw env vars. See docs/architecture/code-structure.md §2 Rule 4.
RuntimeOptions runtimeOptions;
if (sessionConfigFlagPath is not null)
{
    SessionConfiguration sessionConfig;
    SessionDescriptor session;
    try
    {
        (sessionConfig, session) = SessionConfigurationLoader.Load(sessionConfigFlagPath);
    }
    catch (Exception error)
        when (error is IOException
            or UnauthorizedAccessException
            or ArgumentException
            or NotSupportedException
            or System.Text.Json.JsonException
            or SessionConfigurationException)
    {
        Log.Error("--session-config invalid: {Error}", error.Message);
        return 2;
    }

    string? resolvedDatDir =
        NullIfEmpty(sessionConfig.Process?.Content?.DatDirectory)
        ?? NullIfEmpty(datDirArg)
        ?? NullIfEmpty(envDatDir);
    if (resolvedDatDir is null)
    {
        Log.Error(
            "usage: AcDream.App <dat-directory>  (or set ACDREAM_DAT_DIR, "
            + "or supply process.content.datDirectory in --session-config)");
        return 2;
    }

    AppCredentialSecret? secret = null;
    try
    {
        var resolver = new AppCredentialResolver(
            Console.In,
            applicationPaths.ConfigDirectory,
            graphicalPlatform.OperatingSystem
                == GraphicalHostOperatingSystem.Linux);
        secret = resolver.Resolve(session.Id, session.Credential);
        runtimeOptions = RuntimeOptions.FromSessionConfig(
            resolvedDatDir,
            Environment.GetEnvironmentVariable,
            sessionConfigFlagPath,
            sessionConfig,
            session,
            secret.Reveal());
    }
    catch (AppCredentialException error)
    {
        Log.Error("--session-config credential unavailable: {Error}", error.Message);
        return 2;
    }
    finally
    {
        secret?.Dispose();
    }

    // Env-var flow untouched when the flag is absent; when both are present
    // the flag wins — this line makes that explicit rather than silent.
    Log.Information(
        "--session-config {Path} present; overriding ACDREAM_LIVE*/ACDREAM_TEST_* "
        + "env-var live-session settings",
        sessionConfigFlagPath);
}
else
{
    var datDir = datDirArg ?? envDatDir;
    if (string.IsNullOrWhiteSpace(datDir))
    {
        Log.Error("usage: AcDream.App <dat-directory>  (or set ACDREAM_DAT_DIR)");
        return 2;
    }
    runtimeOptions = RuntimeOptions.FromEnvironment(datDir);
}

if (runtimeOptions.DevTools)
{
    Log.Information(
        "ACDREAM_DEVTOOLS=1: the ImGui developer UI was removed at Campaign V " +
        "slice V11 along with the OpenGL backend it required; this flag now " +
        "only selects the optional Vulkan validation/debug-utils extensions.");
}

var worldGameState = new AcDream.Core.Plugins.WorldGameState();
var worldEvents = new AcDream.Core.Plugins.WorldEvents();
var uiRegistry = new AcDream.App.Plugins.BufferedUiRegistry();
using var window = new GameWindow(
    runtimeOptions,
    worldGameState,
    worldEvents,
    uiRegistry,
    graphicalPlatform);
var host = new AppPluginHost(
    new SerilogAdapter(Log.Logger),
    worldGameState,
    worldEvents,
    window.Selection,
    uiRegistry);
GraphicalPluginSession pluginSession = GraphicalPluginSession.Create(
    applicationPaths,
    runtimeOptions.Plugins,
    runtimeOptions.SessionId ?? "app",
    host,
    window.StatusWriter);
window.StartPluginHosting(pluginSession);

try
{
    try
    {
        window.Run();
    }
    catch (NotSupportedException error)
    {
        Log.Error("{GraphicalStartupFailure}", error.Message);
        return 4;
    }
}
finally
{
    Log.CloseAndFlush();
}

return 0;

// Campaign LA slice LA1: --session-config value-presence helper. The
// flag/positional-argument extraction itself lives in
// AcDream.App.Configuration.SessionConfigArgumentParsing (review fix F5) so
// its trailing-flag edge case is unit testable.
static string? NullIfEmpty(string? value) =>
    string.IsNullOrWhiteSpace(value) ? null : value;