// 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;
using Microsoft.CodeAnalysis.Internal.Log;
 
namespace Microsoft.CodeAnalysis.Editor.Implementation.IntelliSense.AsyncCompletion;
 
internal static class AsyncCompletionLogger
{
    private static readonly CountLogAggregator<ActionInfo> s_countLogAggregator = new();
    private static readonly StatisticLogAggregator<ActionInfo> s_statisticLogAggregator = new();
    private static readonly HistogramLogAggregator<ActionInfo> s_histogramLogAggregator = new(25, 500);
 
    private enum ActionInfo
    {
        // # of sessions where import completion is enabled by default
        SessionWithTypeImportCompletionEnabled,
 
        // # of session among SessionWithImportCompletionDelayed where import completion items
        // are later included in list update. Note this doesn't include using of expander.
        SessionWithDelayedImportCompletionIncludedInUpdate,
 
        ExpanderUsageCount,
 
        SourceInitializationTicks,
        SourceGetContextCompletedTicks,
        SourceGetContextCanceledTicks,
 
        ItemManagerSortTicks,
        ItemManagerUpdateCompletedTicks,
        ItemManagerUpdateCanceledTicks,
    }
 
    internal static void LogImportCompletionGetContext()
        => s_countLogAggregator.IncreaseCount(ActionInfo.SessionWithTypeImportCompletionEnabled);
 
    internal static void LogSessionWithDelayedImportCompletionIncludedInUpdate()
        => s_countLogAggregator.IncreaseCount(ActionInfo.SessionWithDelayedImportCompletionIncludedInUpdate);
 
    internal static void LogExpanderUsage()
        => s_countLogAggregator.IncreaseCount(ActionInfo.ExpanderUsageCount);
 
    internal static void LogSourceInitializationTicksDataPoint(TimeSpan elapsed)
    {
        s_statisticLogAggregator.AddDataPoint(ActionInfo.SourceInitializationTicks, elapsed);
        s_histogramLogAggregator.LogTime(ActionInfo.SourceInitializationTicks, elapsed);
    }
 
    internal static void LogSourceGetContextTicksDataPoint(TimeSpan elapsed, bool isCanceled)
    {
        var key = isCanceled
            ? ActionInfo.SourceGetContextCanceledTicks
            : ActionInfo.SourceGetContextCompletedTicks;
 
        s_statisticLogAggregator.AddDataPoint(key, elapsed);
        s_histogramLogAggregator.LogTime(key, elapsed);
    }
 
    internal static void LogItemManagerSortTicksDataPoint(TimeSpan elapsed)
    {
        s_statisticLogAggregator.AddDataPoint(ActionInfo.ItemManagerSortTicks, elapsed);
        s_histogramLogAggregator.LogTime(ActionInfo.ItemManagerSortTicks, elapsed);
    }
 
    internal static void LogItemManagerUpdateDataPoint(TimeSpan elapsed, bool isCanceled)
    {
        var key = isCanceled
            ? ActionInfo.ItemManagerUpdateCanceledTicks
            : ActionInfo.ItemManagerUpdateCompletedTicks;
 
        s_statisticLogAggregator.AddDataPoint(key, elapsed);
        s_histogramLogAggregator.LogTime(key, elapsed);
    }
 
    internal static void ReportTelemetry()
    {
        Logger.Log(FunctionId.Intellisense_AsyncCompletion_Data, KeyValueLogMessage.Create(m =>
        {
            foreach (var kv in s_statisticLogAggregator)
            {
                var statistics = kv.Value.GetStatisticResult();
                statistics.WriteTelemetryPropertiesTo(m, prefix: kv.Key.ToString());
            }
 
            foreach (var kv in s_countLogAggregator)
            {
                m[kv.Key.ToString()] = kv.Value.GetCount();
            }
 
            foreach (var kv in s_histogramLogAggregator)
            {
                kv.Value.WriteTelemetryPropertiesTo(m, prefix: kv.Key.ToString());
            }
        }));
    }
}