using System.Reflection;
using AcDream.Core.Physics;
using AcDream.Headless.Configuration;

namespace AcDream.Headless.Hosting;

/// <summary>
/// Rejects process-global physics probes whose mutable capture cursors and
/// last-hit fields cannot be attributed safely when several Runtime roots
/// share one process. Ordinary diagnostics remain session-labelled through
/// <see cref="Diagnostics.HeadlessDiagnosticWriter"/>.
/// </summary>
internal static class HeadlessStaticStateAudit
{
    internal static void ValidateProcessIsolation()
    {
        var enabled = new List<string>();
        foreach (PropertyInfo property in typeof(PhysicsDiagnostics)
            .GetProperties(BindingFlags.Public | BindingFlags.Static)
            .OrderBy(static property => property.Name, StringComparer.Ordinal))
        {
            if (property.PropertyType != typeof(bool)
                || property.GetMethod is null
                || (!property.Name.StartsWith(
                        "Probe",
                        StringComparison.Ordinal)
                    && !property.Name.StartsWith(
                        "Dump",
                        StringComparison.Ordinal)))
            {
                continue;
            }
            if (property.GetValue(null) is true)
                enabled.Add(property.Name);
        }
        if (PhysicsDiagnostics.CollisionShadowSampleEvery > 0)
            enabled.Add(nameof(PhysicsDiagnostics.CollisionShadowSampleEvery));
        if (PhysicsResolveCapture.IsEnabled)
            enabled.Add(nameof(PhysicsResolveCapture));

        if (enabled.Count != 0)
        {
            throw new HeadlessConfigurationException(
                "Multi-session headless mode cannot use process-global "
                + "physics probes. Disable: "
                + string.Join(", ", enabled));
        }
    }
}