using System.Diagnostics;
using System.Text.Json;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.ProcessPower.PlantInstance;

namespace PRecAnnot.Plant3D2026;

internal static class RuntimeDiagnostics
{
    private static readonly object Gate = new();
    private static readonly string LogDirectory = Path.Combine(
        Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
        "Promhimproekt", "PRecAnnot2026", "Logs");

    public static string RuntimeMode => Environment.GetEnvironmentVariable("P_REC_ANNOT_RUNTIME_MODE") ?? "Normal";

    public static bool IsOrthoStructureDiagnosticsEnabled =>
        string.Equals(RuntimeMode, "DryRun", StringComparison.OrdinalIgnoreCase) &&
        string.Equals(Environment.GetEnvironmentVariable("P_REC_ANNOT_DIAGNOSTICS"), "OrthoStructure", StringComparison.OrdinalIgnoreCase);

    public static void Write(
        string eventType,
        string level = "INFO",
        string? operationId = null,
        string? commandName = null,
        string? resultStatus = null,
        System.Exception? exception = null,
        Document? document = null,
        IReadOnlyDictionary<string, object?>? details = null)
    {
        try
        {
            var payload = new Dictionary<string, object?>(StringComparer.Ordinal)
            {
                ["Timestamp"] = DateTimeOffset.UtcNow,
                ["Level"] = level,
                ["OperationId"] = operationId,
                ["EventType"] = eventType,
                ["AssemblyVersion"] = typeof(EntryPoint).Assembly.GetName().Version?.ToString(),
                ["AutoCADVersion"] = typeof(Document).Assembly.GetName().Version?.ToString(),
                ["PlantVersion"] = typeof(PlantApplication).Assembly.GetName().Version?.ToString(),
                ["ProcessId"] = Environment.ProcessId,
                ["ThreadId"] = Environment.CurrentManagedThreadId,
                ["ApartmentState"] = Thread.CurrentThread.GetApartmentState().ToString(),
                ["ActiveDocumentName"] = SafeDocumentName(document),
                ["CommandName"] = commandName,
                ["ResultStatus"] = resultStatus,
                ["ExceptionType"] = exception?.GetType().FullName,
                ["ExceptionMessage"] = exception?.Message,
                ["StackTrace"] = level.Equals("ERROR", StringComparison.OrdinalIgnoreCase) ? exception?.StackTrace : null,
                ["RuntimeMode"] = RuntimeMode
            };

            if (details is not null)
                foreach (var item in details) payload[item.Key] = item.Value;

            var line = JsonSerializer.Serialize(payload) + Environment.NewLine;
            lock (Gate)
            {
                Directory.CreateDirectory(LogDirectory);
                File.AppendAllText(Path.Combine(LogDirectory, "runtime.jsonl"), line);
            }
        }
        catch
        {
            // Runtime diagnostics must never prevent AutoCAD command execution.
        }
    }

    private static string? SafeDocumentName(Document? document)
    {
        try { return document is null ? null : Path.GetFileName(document.Name); }
        catch { return null; }
    }
}

internal sealed class SmokeWriteBlockedException() : InvalidOperationException("SMOKE_WRITE_BLOCKED");

internal static class SmokeGuard
{
    public static bool IsSmoke => string.Equals(RuntimeDiagnostics.RuntimeMode, "Smoke", StringComparison.OrdinalIgnoreCase);
    public static void EnsureReadOnly() { if (IsSmoke) throw new SmokeWriteBlockedException(); }
}