using NLog;
using System.Net;
using System.Reflection;
using System.Text.Json.Serialization;

namespace ChatRoom;

public class Server
{
    /// <summary>
	/// Logger for this class.
	/// </summary>
	Logger log = LogManager.GetCurrentClassLogger();

    /// <summary>
	/// Program entry point.
	/// </summary>
	/// <param name="args">Command line arguments.</param>
    public static void Main(string[] args)
    {
        var self = new Server();
        self.Run(args);
    }

    /// <summary>
	/// Program body.
	/// </summary>
	/// <param name="args">Command line arguments.</param>
	private void Run(string[] args)
    {
        //configure logging
        ConfigureLogging();

        //indicate server is about to start
        log.Info("Server is about to start");

        //start the server
        StartServer(args);
    }

    /// <summary>
    /// Configure loggin subsystem.
    /// </summary>
    private void ConfigureLogging()
    {
        var config = new NLog.Config.LoggingConfiguration();

        var console =
            new NLog.Targets.ConsoleTarget("console")
            {
                Layout = @"${date:format=HH\:mm\:ss}|${level}| ${message} ${exception}"
            };
        config.AddTarget(console);
        config.AddRuleForAllLevels(console);

        LogManager.Configuration = config;
    }

    /// <summary>
	/// Starts integrated server.
	/// </summary>
	/// <param name="args">Command line arguments.</param>
    public void StartServer(string[] args)
    {
        //create web app builder
        var builder = WebApplication.CreateBuilder(args);
        
        //configure integrated server
        builder.WebHost.ConfigureKestrel(opts => {
            opts.Listen(IPAddress.Loopback, 5000);
        });

        //add and configure swagger documentation generator (http://127.0.0.1:5000/swagger/)
        builder.Services.AddSwaggerGen(opts => {
            //include code comments in swagger documentation
            var xmlFilename = $"{Assembly.GetExecutingAssembly().GetName().Name}.xml";
            opts.IncludeXmlComments(Path.Combine(AppContext.BaseDirectory, xmlFilename));
        });

        //turn on support for web api controllers
        builder.Services
            .AddControllers()
            .AddJsonOptions(opts => {
                //this makes enumeration values to be strings instead of integers in opeanapi doc
                opts.JsonSerializerOptions.Converters.Add(new JsonStringEnumConverter());
            });

        //add CORS policies
        builder.Services.AddCors(cr => {
            //allow everything from everywhere
            cr.AddPolicy("allowAll", cp => {
                cp.AllowAnyOrigin();
                cp.AllowAnyMethod();
                cp.AllowAnyHeader();
            });
        });

        //publish the background logic as (an internal) service through dependency injection, 
        //otherwise it will not start until the first client calls into controller
        builder.Services.AddSingleton(new ChatRoomLogic());

        //build the server
        var app = builder.Build();

        //turn CORS policy on
        app.UseCors("allowAll");

        //turn on support for swagger doc web page
        app.UseSwagger();
        app.UseSwaggerUI();

        //turn on request routing
        app.UseRouting();

        //configure routes
        app.MapControllerRoute(
            name: "default",
            pattern: "{controller}/{action=Index}/{id?}"
        );

        //run the server
        app.Run();
        // app.RunAsync(); //use this if you need to implement background processing in the main thread
    }
}