using System.Reflection;

using Npgsql;

// ReSharper disable once CheckNamespace

namespace NpgsqlRestTests;

public static partial class Database

{

private const string Dbname = "npgsql_rest_test";

// Change these when testing against a different PostgreSQL instance

private const string Host = "localhost";

private const string Port = "5432";

private const string Username = "postgres";

private const string Password = "postgres";

private const string InitialConnectionString = $"Host={Host};Port={Port};Database=postgres;Username={Username};Password={Password}";

private static readonly StringBuilder script = new();

private static readonly object _createLock = new();

private static volatile bool _created = false;

static Database()

{

foreach (var method in typeof(Database).GetMethods(BindingFlags.Static | BindingFlags.Public))

{

if (method.GetParameters().Length == 0 && !string.Equals(method.Name, "Create", StringComparison.OrdinalIgnoreCase))

{

method.Invoke(null, []);

}

}

}

public static string GetIinitialConnectionString() => InitialConnectionString;

public static NpgsqlConnection CreateConnection()

{

var builder = new NpgsqlConnectionStringBuilder(InitialConnectionString)

{

Database = Dbname

};

return new NpgsqlConnection(builder.ConnectionString);

}

public static string Create()

{

// Thread-safe singleton pattern - only create database once per test run

if (_created)

{

var builder = new NpgsqlConnectionStringBuilder(InitialConnectionString)

{

Database = Dbname

};

return builder.ConnectionString;

}

lock (_createLock)

{

if (_created)

{

var builder = new NpgsqlConnectionStringBuilder(InitialConnectionString)

{

Database = Dbname

};

return builder.ConnectionString;

}

DropIfExists();

var connBuilder = new NpgsqlConnectionStringBuilder(InitialConnectionString)

{

Database = Dbname

};

using NpgsqlConnection test = new(connBuilder.ConnectionString);

test.Open();

using var command = test.CreateCommand();

command.CommandText = script.ToString();

command.ExecuteNonQuery();

_created = true;

return connBuilder.ConnectionString;

}

}

public static string CreateAdditional(string appName)

{

var builder = new NpgsqlConnectionStringBuilder(InitialConnectionString)

{

Database = Dbname,

ApplicationName = appName

};

return builder.ConnectionString;

}

/// <summary>

/// Creates a connection string for the test_user with minimal privileges (PoLP testing).

/// </summary>

public static string CreatePolpConnection()

{

var builder = new NpgsqlConnectionStringBuilder(InitialConnectionString)

{

Database = Dbname,

Username = "test_user",

Password = "test_pass"

};

return builder.ConnectionString;

}

public static void DropIfExists()

{

using NpgsqlConnection connection = new(InitialConnectionString);

connection.Open();

void Exec(string sql)

{

using var command = connection.CreateCommand();

command.CommandText = sql;

command.ExecuteNonQuery();

}

bool Any(string sql)

{

using var command = connection.CreateCommand();

command.CommandText = sql;

using var reader = command.ExecuteReader();

if (reader.Read())

{

return true;

}

return false;

}

if (Any($"select 1 from pg_database where datname = '{Dbname}'"))

{

Exec($"revoke connect on database {Dbname} from public");

Exec($"select pg_terminate_backend(pid) from pg_stat_activity where datname = '{Dbname}' and pid <> pg_backend_pid()");

Exec($"drop database {Dbname}");

}

Exec($"create database {Dbname}");

Exec($"alter database {Dbname} set timezone to 'UTC'");

}

}