using MongoDB.Bson;
using MongoDB.Bson.Serialization;
using MongoDB.Bson.Serialization.Serializers;
using MongoDB.Driver;
using MongoDB.Entities;

using PrivaPub.Infrastructure.Data;

[assembly: AssemblyFixture(typeof(PrivaPub.Tests.Support.MongoFixture))]

namespace PrivaPub.Tests.Support
{
	public sealed class MongoFixture : IAsyncLifetime
	{
		public const string Skip = "set PRIVAPUB_TEST_MONGOD=1 (and optionally PRIVAPUB_TEST_MONGO) to run the tests that need a mongod";
		const int ProductionPort = 27022;
		const int DefaultPort = 27017;

		public static bool Enabled => Environment.GetEnvironmentVariable("PRIVAPUB_TEST_MONGOD") == "1";
		static bool Required => Environment.GetEnvironmentVariable("PRIVAPUB_TEST_REQUIRE_MONGOD") == "1";
		static bool InCi => !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("CI")) || !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("GITEA_ACTIONS"));

		public static string Connection { get; } = Environment.GetEnvironmentVariable("PRIVAPUB_TEST_MONGO") ?? $"mongodb://127.0.0.1:{DefaultPort}";
		public static string Database { get; } = $"PrivaPubTests_{Guid.NewGuid():N}";

		public async ValueTask InitializeAsync()
		{
			if (Required && !Enabled)
				throw new InvalidOperationException("PRIVAPUB_TEST_REQUIRE_MONGOD=1 but PRIVAPUB_TEST_MONGOD is not 1: the integration tests would be skipped");
			if (!Enabled)
				return;
			var settings = MongoClientSettings.FromConnectionString(Connection);
			Refuse(settings);
			try
			{
				BsonSerializer.RegisterSerializer(new GuidSerializer(GuidRepresentation.Standard));
			}
			catch (BsonSerializationException)
			{
			}
			await DB.InitAsync(Database, settings);
			await RefuseProductionData();
			EntityMaps.Warm();
			await Indexes.Create();
		}

		public async ValueTask DisposeAsync()
		{
			if (Enabled)
				await DB.Default.Database().Client.DropDatabaseAsync(Database);
		}

		static void Refuse(MongoClientSettings settings)
		{
			var ports = settings.Servers.Select(s => s.Port).ToList();
			if (ports.Contains(ProductionPort))
				throw new InvalidOperationException($"the tests never run against port {ProductionPort}: that is production's mongod");
			if (InCi && (Environment.GetEnvironmentVariable("PRIVAPUB_TEST_MONGO") == default || ports.Contains(DefaultPort)))
				throw new InvalidOperationException("in CI the tests run only against a throwaway mongod: use tools/ci/with-test-mongod.sh");
		}

		static async Task RefuseProductionData()
		{
			BsonDocument options;
			try
			{
				options = await DB.Default.Database().Client.GetDatabase("admin").RunCommandAsync<BsonDocument>(new BsonDocument("getCmdLineOpts", 1));
			}
			catch (MongoCommandException)
			{
				return;
			}
			var dbPath = options.GetValue("parsed", new BsonDocument()).AsBsonDocument
				.GetValue("storage", new BsonDocument()).AsBsonDocument
				.GetValue("dbPath", BsonNull.Value);
			if (dbPath.IsString && dbPath.AsString.StartsWith("/var/lib/privapub", StringComparison.Ordinal))
				throw new InvalidOperationException($"the mongod at {Connection} keeps its data in {dbPath.AsString}: that is production's");
		}
	}
}