using System.Text.RegularExpressions;

using Npgsql;

using NpgsqlRest;

using Serilog;

using Serilog.Configuration;

using Serilog.Core;

using Serilog.Events;

namespace NpgsqlRestClient;

public class PostgresSink(

string command,

LogEventLevel restrictedToMinimumLevel,

int paramCount,

string? connectionString,

RetryStrategy? cmdRetryStrategy) : ILogEventSink

{

public void Emit(LogEvent logEvent)

{

if (string.IsNullOrEmpty(connectionString) is true)

{

return;

}

if (logEvent.Level < restrictedToMinimumLevel)

{

return;

}

try

{

using var connection = new NpgsqlConnection(connectionString);

using var command1 = new NpgsqlCommand(command, connection);

if (paramCount > 0)

{

command1.Parameters.Add(new NpgsqlParameter() { Value = logEvent.Level.ToString() }); // $1

}

if (paramCount > 1)

{

command1.Parameters.Add(new NpgsqlParameter() { Value = logEvent.RenderMessage() }); // $2

}

if (paramCount > 2)

{

command1.Parameters.Add(new NpgsqlParameter() { Value = logEvent.Timestamp.UtcDateTime }); // $3

}

if (paramCount > 3)

{

command1.Parameters.Add(new NpgsqlParameter() { Value = logEvent.Exception?.ToString() ?? (object)DBNull.Value }); // $4

}

if (paramCount > 4)

{

command1.Parameters.Add(new NpgsqlParameter() { Value = logEvent.Properties["SourceContext"]?.ToString()?.Trim('"') ?? (object)DBNull.Value }); // $5

}

connection.Open();

command1.ExecuteNonQueryWithRetry(cmdRetryStrategy, null);

}

catch (Exception ex)

{

Console.ForegroundColor = ConsoleColor.Red;

Console.WriteLine("Error writing to Postgres Log Sink:");

Console.WriteLine(ex);

Console.ResetColor();

}

}

}

public static partial class PostgresSinkSinkExtensions

{

public static LoggerConfiguration Postgres(

this LoggerSinkConfiguration loggerConfiguration,

string command,

LogEventLevel restrictedToMinimumLevel,

string? connectionString,

RetryStrategy? cmdRetryStrategy)

{

var matches = ParameterRegex().Matches(command).ToArray();

if (matches.Length < 1 || matches.Length > 5)

{

throw new ArgumentException("Command should have at least one parameter and maximum five parameters.");

}

for(int i = 0; i < matches.Length; i++)

{

if (matches[i].Value != $"${i + 1}")

{

throw new ArgumentException($"Parameter ${i + 1} is missing in the command.");

}

}

return loggerConfiguration.Sink(new PostgresSink(command, restrictedToMinimumLevel, matches.Length, connectionString, cmdRetryStrategy));

}

[GeneratedRegex(@"\$\d+")]

public static partial Regex ParameterRegex();

}