using System.Diagnostics;

namespace IronTelemetry.Client;

/// <summary>
/// Extension methods for IronTelemetry integration.
/// </summary>
public static class TelemetryExtensions
{
    /// <summary>
    /// Configure global unhandled exception handling for console applications.
    /// </summary>
    public static void UseUnhandledExceptionHandler()
    {
        AppDomain.CurrentDomain.UnhandledException += (sender, args) =>
        {
            if (args.ExceptionObject is Exception ex)
            {
                IronTelemetry.CaptureException(ex, ctx =>
                    ctx.WithExtra("isTerminating", args.IsTerminating)
                       .WithExtra("source", "UnhandledException"));

                // Flush synchronously since the app may be terminating
                IronTelemetry.Flush(TimeSpan.FromSeconds(2));
            }
        };

        TaskScheduler.UnobservedTaskException += (sender, args) =>
        {
            IronTelemetry.CaptureException(args.Exception, ctx =>
                ctx.WithExtra("source", "UnobservedTaskException"));

            // Mark as observed to prevent app crash
            args.SetObserved();
        };
    }

    /// <summary>
    /// Capture an exception and return it (for throw expressions).
    /// </summary>
    public static Exception Capture(this Exception ex)
    {
        IronTelemetry.CaptureException(ex);
        return ex;
    }

    /// <summary>
    /// Capture an exception with context and return it.
    /// </summary>
    public static Exception Capture(this Exception ex, Action<ExceptionContext> configure)
    {
        IronTelemetry.CaptureException(ex, configure);
        return ex;
    }

    /// <summary>
    /// Create a step scope that automatically tracks duration.
    /// </summary>
    public static StepScope TimeStep(this TelemetryClient client, string name, string? category = null)
    {
        return JourneyContext.StartStep(name, category);
    }

    /// <summary>
    /// Execute an action within a tracked step.
    /// </summary>
    public static void TrackStep(string name, Action action, string? category = null)
    {
        using var step = IronTelemetry.StartStep(name, category);
        try
        {
            action();
        }
        catch (Exception ex)
        {
            step.Fail(ex.Message);
            throw;
        }
    }

    /// <summary>
    /// Execute an async action within a tracked step.
    /// </summary>
    public static async Task TrackStepAsync(string name, Func<Task> action, string? category = null)
    {
        using var step = IronTelemetry.StartStep(name, category);
        try
        {
            await action();
        }
        catch (Exception ex)
        {
            step.Fail(ex.Message);
            throw;
        }
    }

    /// <summary>
    /// Execute a function within a tracked step and return the result.
    /// </summary>
    public static T TrackStep<T>(string name, Func<T> func, string? category = null)
    {
        using var step = IronTelemetry.StartStep(name, category);
        try
        {
            return func();
        }
        catch (Exception ex)
        {
            step.Fail(ex.Message);
            throw;
        }
    }

    /// <summary>
    /// Execute an async function within a tracked step and return the result.
    /// </summary>
    public static async Task<T> TrackStepAsync<T>(string name, Func<Task<T>> func, string? category = null)
    {
        using var step = IronTelemetry.StartStep(name, category);
        try
        {
            return await func();
        }
        catch (Exception ex)
        {
            step.Fail(ex.Message);
            throw;
        }
    }

    /// <summary>
    /// Add Activity trace context to the current telemetry.
    /// </summary>
    public static ExceptionContext WithActivity(this ExceptionContext context, Activity? activity = null)
    {
        activity ??= Activity.Current;
        if (activity != null)
        {
            context.TraceId = activity.TraceId.ToString();
            context.SpanId = activity.SpanId.ToString();
        }
        return context;
    }

    /// <summary>
    /// Execute a journey and return the result.
    /// </summary>
    public static T RunJourney<T>(string name, Func<T> action)
    {
        using var journey = IronTelemetry.StartJourney(name);
        try
        {
            var result = action();
            journey.Complete();
            return result;
        }
        catch (Exception ex)
        {
            journey.Fail(ex.Message);
            IronTelemetry.CaptureException(ex);
            throw;
        }
    }

    /// <summary>
    /// Execute an async journey and return the result.
    /// </summary>
    public static async Task<T> RunJourneyAsync<T>(string name, Func<Task<T>> action)
    {
        using var journey = IronTelemetry.StartJourney(name);
        try
        {
            var result = await action();
            journey.Complete();
            return result;
        }
        catch (Exception ex)
        {
            journey.Fail(ex.Message);
            IronTelemetry.CaptureException(ex);
            throw;
        }
    }
}