#nullable enable

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Configs;
using Datadog.Trace.RemoteConfigurationManagement;
using Datadog.Trace.RemoteConfigurationManagement.Protocol;
using Datadog.Trace.RemoteConfigurationManagement.Protocol.Tuf;
using Datadog.Trace.Util;
using Datadog.Trace.Util.Json;
using Datadog.Trace.Util.Streams;
using Datadog.Trace.Vendors.Newtonsoft.Json;

namespace Benchmarks.Trace
{
    /// <summary>
    /// Benchmarks for the Remote Configuration Management polling pipeline.
    /// Covers: request building, response processing (steady-state), and response deserialization.
    /// </summary>
    [MemoryDiagnoser, GroupBenchmarksBy(BenchmarkLogicalGroupRule.ByCategory), CategoriesColumn]
    public class RemoteConfigBenchmark
    {
        private static readonly Task<GetRcmResponse?> NullResponseTask = Task.FromResult<GetRcmResponse?>(null);

        private RcmSubscriptionManager _manager = null!;
        private RcmClientTracer _rcmTracer = null!;
        private Task<GetRcmResponse?> _steadyStateResponseTask = null!;
        private byte[] _serializedResponseBytes = null!;
        private byte[] _hugeSerializedResponseBytes = null!;
        private GetRcmResponse? _response;
        private string _pathToTest;
        private string _result;

        [GlobalSetup]
        public void GlobalSetup()
        {
            _rcmTracer = RcmClientTracer.Create(
                runtimeId: "benchmark-runtime-id",
                tracerVersion: "2.55.0",
                service: "benchmark-service",
                env: "benchmark",
                appVersion: "1.0.0",
                globalTags: new ReadOnlyDictionary<string, string>(new Dictionary<string, string>
                {
                    { "team", "apm" },
                    { "component", "benchmark" }
                }),
                processTags: null);

            _manager = new RcmSubscriptionManager();

            // Subscribe with a realistic subscription covering multiple products
            var subscription = new Subscription(
                (configs, removed) =>
                {
                    var results = new List<ApplyDetails>();
                    foreach (var product in configs)
                    {
                        foreach (var config in product.Value)
                        {
                            results.Add(ApplyDetails.FromOk(config.Path.Path));
                        }
                    }

                    return results.ToArray();
                },
                RcmProducts.AsmFeatures,
                RcmProducts.AsmDd);
            _manager.SubscribeToChanges(subscription);

            // Set capabilities as real code would
            _manager.SetCapability(RcmCapabilitiesIndices.AsmActivation, true);
            _manager.SetCapability(RcmCapabilitiesIndices.AsmIpBlocking, true);
            _manager.SetCapability(RcmCapabilitiesIndices.AsmDdRules, true);
            _manager.SetCapability(RcmCapabilitiesIndices.AsmExclusion, true);
            _manager.SetCapability(RcmCapabilitiesIndices.ApmTracingSampleRate, true);

            // Create initial response and prime the manager (applies all configs)
            var initialResponse = CreateResponse(configCount: 5);
            _manager.SendRequest(_rcmTracer, _ => Task.FromResult<GetRcmResponse?>(initialResponse))
                .GetAwaiter().GetResult();

            // Steady-state response: identical configs/hashes so ProcessResponse detects no changes
            _steadyStateResponseTask = Task.FromResult<GetRcmResponse?>(CreateResponse(configCount: 5));

            // Serialize for deserialization benchmark (includes base64-encoded TufRoot)
            _serializedResponseBytes = Encoding.UTF8.GetBytes(
                """
                {
                	"targets": "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",
                	"target_files": [
                		{
                			"path": "datadog/2/ASM_FEATURES/ASM_FEATURES-third/testname",
                			"raw": "ewogICJhc20iOiB7CiAgICAgICJlbmFibGVkIjogdHJ1ZQogIH0KfQo="
                		}
                	],
                	"client_configs": [
                		"datadog/2/ASM_FEATURES/ASM_FEATURES-base/config",
                		"datadog/2/ASM_FEATURES/ASM_FEATURES-second/config",
                		"datadog/2/ASM_FEATURES/ASM_FEATURES-third/testname"
                	]
                }
                """);

            _hugeSerializedResponseBytes = Encoding.UTF8.GetBytes(RemoteConfigData.HugeConfig());
            _pathToTest = "datadog/2/ASM_FEATURES/ASM_FEATURES-third/testname";
        }

        /// <summary>
        /// Full poll cycle when nothing has changed (the most common real-world scenario).
        /// Exercises BuildRequest + ProcessResponse: hash comparison, path parsing,
        /// ToDictionary creation, List.Contains lookups, LINQ in Update().
        /// </summary>
        [Benchmark]
        public Task PollSteadyState()
        {
            return _manager.SendRequest(_rcmTracer, _ => _steadyStateResponseTask);
        }

        /// <summary>
        /// Full poll cycle when nothing has changed (the most common real-world scenario).
        /// Exercises BuildRequest + ProcessResponse: hash comparison, path parsing,
        /// ToDictionary creation, List.Contains lookups, LINQ in Update().
        /// </summary>
        [Benchmark]
        public Task PollChanging()
        {
            return _manager.SendRequest(_rcmTracer, _ => _steadyStateResponseTask);
        }

        /// <summary>
        /// Request building only (callback returns null so ProcessResponse is skipped).
        /// Exercises: LINQ Select/ToList for hashes, RcmCachedTargetFile/RcmConfigState
        /// allocation, GetCapabilities byte[] creation.
        /// </summary>
        [Benchmark]
        public Task BuildRequest()
        {
            return _manager.SendRequest(_rcmTracer, _ => NullResponseTask);
        }
    }
}