using System.Text.RegularExpressions;
using FictionArchive.Service.Shared.Services.Filters;
using MassTransit;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace FictionArchive.Service.Shared.Extensions;

public static class MassTransitExtensions
{
    public static IServiceCollection AddFictionArchiveMassTransit(
        this IServiceCollection services,
        IConfiguration configuration,
        Action<IBusRegistrationConfigurator>? configureConsumers = null)
    {
        services.AddMassTransit(x =>
        {
            configureConsumers?.Invoke(x);

            x.UsingRabbitMq((context, cfg) =>
            {
                var (host, username, password) = ParseRabbitMqConfiguration(configuration);

                cfg.Host(host, h =>
                {
                    h.Username(username);
                    h.Password(password);
                });

                cfg.UseMessageRetry(r => r.Exponential(
                    retryLimit: 5,
                    minInterval: TimeSpan.FromSeconds(1),
                    maxInterval: TimeSpan.FromMinutes(1),
                    intervalDelta: TimeSpan.FromSeconds(2)));

                cfg.UseConsumeFilter(typeof(LoggingConsumeFilter<>), context);

                // Process one message at a time per consumer (matches old EventBus behavior)
                cfg.PrefetchCount = 1;

                cfg.ConfigureEndpoints(context);
            });
        });

        return services;
    }

    /// <summary>
    /// Parses RabbitMQ configuration from either ConnectionString format or separate Host/Username/Password keys.
    /// ConnectionString format: amqp://[username:password@]host[:port]
    /// </summary>
    private static (string Host, string Username, string Password) ParseRabbitMqConfiguration(IConfiguration configuration)
    {
        var connectionString = configuration["RabbitMQ:ConnectionString"];

        if (!string.IsNullOrEmpty(connectionString))
        {
            return ParseConnectionString(connectionString);
        }

        // Fallback to separate configuration keys
        var host = configuration["RabbitMQ:Host"] ?? "localhost";
        var username = configuration["RabbitMQ:Username"] ?? "guest";
        var password = configuration["RabbitMQ:Password"] ?? "guest";

        return (host, username, password);
    }

    /// <summary>
    /// Parses an AMQP connection string into host, username, and password components.
    /// Supports formats:
    /// - amqp://host
    /// - amqp://host:port
    /// - amqp://username:password@host
    /// - amqp://username:password@host:port
    /// </summary>
    private static (string Host, string Username, string Password) ParseConnectionString(string connectionString)
    {
        var username = "guest";
        var password = "guest";
        var host = "localhost";

        // Try to parse as URI first
        if (Uri.TryCreate(connectionString, UriKind.Absolute, out var uri))
        {
            host = uri.Host;

            if (!string.IsNullOrEmpty(uri.UserInfo))
            {
                var userInfoParts = uri.UserInfo.Split(':', 2);
                username = Uri.UnescapeDataString(userInfoParts[0]);
                if (userInfoParts.Length > 1)
                {
                    password = Uri.UnescapeDataString(userInfoParts[1]);
                }
            }
        }
        else
        {
            // Fallback regex parsing for edge cases
            var match = Regex.Match(connectionString, @"amqp://(?:([^:]+):([^@]+)@)?([^:/]+)");
            if (match.Success)
            {
                if (match.Groups[1].Success && match.Groups[2].Success)
                {
                    username = match.Groups[1].Value;
                    password = match.Groups[2].Value;
                }
                if (match.Groups[3].Success)
                {
                    host = match.Groups[3].Value;
                }
            }
        }

        return (host, username, password);
    }
}