using KonSoft.Shared.Hosting.AspNetCore;
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using System;
using System.Linq;
using Volo.Abp;
using Yarp.ReverseProxy.Configuration;

namespace KonSoft.Shared.Hosting.Gateways
{
    public static class YarpSwaggerUIBuilderExtensions
    {
        public static IApplicationBuilder UseSwaggerUIWithYarp(this IApplicationBuilder app,
        ApplicationInitializationContext context)
        {
            app.UseSwagger();
            app.UseAbpSwaggerWithCustomScriptUI(options =>
            {
                var configuration = context.ServiceProvider.GetRequiredService<IConfiguration>();
                var logger = context.ServiceProvider.GetRequiredService<ILogger<ApplicationInitializationContext>>();
                var proxyConfigProvider = context.ServiceProvider.GetRequiredService<IProxyConfigProvider>();
                var yarpConfig = proxyConfigProvider.GetConfig();

                var routedClusters = yarpConfig.Clusters
                    .SelectMany(t => t.Destinations,
                        (clusterId, destination) => new { clusterId.ClusterId, destination.Value });

                var groupedClusters = routedClusters
                    .GroupBy(q => q.Value.Address)
                    .Select(t => t.First())
                    .Distinct()
                    .ToList();

                foreach (var clusterGroup in groupedClusters)
                {
                    var routeConfig = yarpConfig.Routes.FirstOrDefault(q =>
                        q.ClusterId == clusterGroup.ClusterId);
                    if (routeConfig == null)
                    {
                        logger.LogWarning($"Swagger UI: Couldn't find route configuration for {clusterGroup.ClusterId}...");
                        continue;
                    }

                    var baseUrl = clusterGroup.Value.Address;

                    if (Convert.ToBoolean(configuration["App:IsOnK8s"])) // If the application is running on K8s, the swagger.json should be reached from public dns.
                    {
                        baseUrl = clusterGroup.Value.Metadata?["PublicAddress"];
                    }

                    options.SwaggerEndpoint($"{baseUrl}/swagger/v1/swagger.json", $"{routeConfig.RouteId} API");
                    options.OAuthClientId(configuration["AuthServer:SwaggerClientId"]);
                }
            });

            return app;
        }
    }
}