// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;
using Microsoft.CodeAnalysis.Internal.Log;
using Microsoft.CodeAnalysis.PooledObjects;
 
namespace Roslyn.Hosting.Diagnostics.PerfMargin;
 
internal sealed class DataModel
{
    public ActivityLevel RootNode { get; }
 
    private readonly ImmutableArray<ActivityLevel?> _activities;
 
    public DataModel()
    {
        var fields = from field in typeof(FunctionId).GetFields()
                     where !field.IsSpecialName
                     select field;
 
        using var _ = ArrayBuilder<ActivityLevel?>.GetInstance(out var builder);
 
        var features = new Dictionary<string, ActivityLevel>();
        var root = new ActivityLevel("All");
 
        foreach (var field in fields)
        {
            var value = (int)field.GetRawConstantValue();
            var name = field.Name;
            var featureNames = name.Split('_');
            var featureName = featureNames.Length > 1 ? featureNames[0] : "Uncategorized";
 
            if (!features.TryGetValue(featureName, out var parent))
            {
                parent = new ActivityLevel(featureName, root, createChildList: true);
                features[featureName] = parent;
            }
 
            builder.SetItem(value, new ActivityLevel(name, parent, createChildList: false));
        }
 
        _activities = builder.ToImmutable();
        root.SortChildren();
        RootNode = root;
    }
 
    public void BlockStart(FunctionId functionId)
        => _activities[(int)functionId]!.Start();
 
    public void BlockDisposed(FunctionId functionId)
        => _activities[(int)functionId]!.Stop();
}