using System.Diagnostics;

namespace Nerfed.Runtime;

public struct ProfilerScope : IDisposable
{
    public ProfilerScope(string label) {
        Profiler.BeginSample(label);
    }

    public void Dispose() {
        Profiler.EndSample();
    }
}

public static class Profiler
{
    public struct ProfileRecord
    {
        public string label;
        public long startTime;
        public long endTime;
        public int depth;

        public readonly double ElapsedMilliseconds()
        {
            long elapsedTicks = endTime - startTime;
            return ((double)(elapsedTicks * 1000)) / Stopwatch.Frequency;
        }
    }

    public class FrameData
    {
        public uint frame;
        public readonly List<ProfileRecord> records = new List<ProfileRecord>();
        public long startTime;
        public long endTime;

        public FrameData(uint frame, long startTime)
        {
            this.frame = frame;
            this.startTime = startTime;
        }

        public double ElapsedMilliseconds()
        {
            long elapsedTicks = endTime - startTime;
            return ((double)(elapsedTicks * 1000)) / Stopwatch.Frequency;
        }
    }

    private const int maxFrames = 128;

    public static readonly BoundedQueue<FrameData> frames = new(maxFrames);
    public static bool recording = true;

    private static readonly Stopwatch stopwatch = new Stopwatch();
    private static FrameData currentFrame = null;
    private static uint currentFrameIndex = 0;
    private static int currentDepth = 0;

    static Profiler()
    {
        stopwatch.Start();
    }

    [Conditional("PROFILING")]
    public static void BeginFrame()
    {
        if (!recording)
        {
            return;
        }

        currentFrame = new FrameData(currentFrameIndex, stopwatch.ElapsedTicks);
        currentDepth = 0;
        currentFrameIndex++;
    }

    [Conditional("PROFILING")]
    public static void EndFrame()
    {
        if (!recording)
        {
            return;
        }

        currentFrame.endTime = stopwatch.ElapsedTicks;
        frames.Enqueue(currentFrame);
    }

    [Conditional("PROFILING")]
    public static void BeginSample(string label)
    {
        if (!recording)
        {
            return;
        }

        ProfileRecord record = new ProfileRecord
        {
            label = label,
            startTime = stopwatch.ElapsedTicks,
            depth = currentDepth,
        };
        currentFrame.records.Add(record);
        //Log.Info($"{record.label} {record.depth} | {record.startTime}");
        currentDepth++; // Increase depth for nested scopes
    }

    [Conditional("PROFILING")]
    public static void EndSample()
    {
        if (!recording)
        {
            return;
        }

        currentDepth--; // Decrease depth when exiting a scope

        // Find the last uncompleted record at the current depth and set the end time
        for (int i = currentFrame.records.Count - 1; i >= 0; i--)
        {
            if (currentFrame.records[i].endTime == 0)
            {
                ProfileRecord record = currentFrame.records[i];
                record.endTime = stopwatch.ElapsedTicks;
                currentFrame.records[i] = record; // Assign back to the list
                //Log.Info($"{record.label} | {record.depth} | {record.endTime}");
                break;
            }
        }
    }
}