using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using NLog.Web;
using NLog.Targets;
using NLog.Config;
using AyaNova.Util;
//using StackExchange.Profiling;

namespace AyaNova
{

    public class Program
    {

        public static void Main(string[] args)
        {

            //Boot lock for generator
            ServerGlobalOpsSettingsCache.BOOTING = true;
            
            //Get config
            var config = new ConfigurationBuilder().AddEnvironmentVariables().AddCommandLine(args).Build();
            ServerBootConfig.SetConfiguration(config);



            #region Initialize Logging                     
            //NOTE: there is a logging issue that breaks all this with .net 3.1 hostbuilder vs webhostbuilder but webhostbuilder will be deprecated so we need to work around it
            //the discussion about that is here: https://github.com/aspnet/AspNetCore/issues/9337
            //I think I worked around it

            //NLOG OFFICIAL GUIDELINES FOR .net core 3.x  https://github.com/NLog/NLog/wiki/Getting-started-with-ASP.NET-Core-3

            //default log level
            NLog.LogLevel NLogLevel = NLog.LogLevel.Info;
            bool logLevelIsInfoOrHigher = true;

            switch (ServerBootConfig.AYANOVA_LOG_LEVEL.ToLowerInvariant())
            {
                case "fatal":
                    NLogLevel = NLog.LogLevel.Fatal;
                    break;
                case "error":
                    NLogLevel = NLog.LogLevel.Error;
                    break;
                case "warn":
                    NLogLevel = NLog.LogLevel.Warn;
                    break;
                case "info":
                    NLogLevel = NLog.LogLevel.Info;
                    break;
                case "debug":
                    NLogLevel = NLog.LogLevel.Debug;
                    logLevelIsInfoOrHigher = false;
                    break;
                case "trace":
                    NLogLevel = NLog.LogLevel.Trace;
                    logLevelIsInfoOrHigher = false;
                    break;
                default:
                    NLogLevel = NLog.LogLevel.Info;
                    break;
            }


            // Step 1. Create configuration object 
            var logConfig = new LoggingConfiguration();

            // Step 2. Create targets and add them to the configuration 
            var fileTarget = new FileTarget();
            logConfig.AddTarget("file", fileTarget);

            //console target for really serious errors only
            var consoleTarget = new ConsoleTarget();
            logConfig.AddTarget("console", consoleTarget);

            var nullTarget = new NLog.Targets.NullTarget();
            logConfig.AddTarget("blackhole", nullTarget);

            // Step 3. Set target properties 

            fileTarget.FileName = Path.Combine(ServerBootConfig.AYANOVA_LOG_PATH, "log-ayanova.txt");
            fileTarget.Layout = "${longdate}|${uppercase:${level}}|${logger}|${message:exceptionSeparator==>:withException=true}";
            fileTarget.ArchiveFileName = Path.Combine(ServerBootConfig.AYANOVA_LOG_PATH, "log-ayanova-{#}.txt");
            fileTarget.ArchiveNumbering = ArchiveNumberingMode.Date;
            fileTarget.ArchiveEvery = FileArchivePeriod.Wednesday;
            fileTarget.MaxArchiveFiles = 3;

            // Step 4. Define rules

            //filter out all Microsoft INFO level logs as they are too much
            var logRuleFilterOutMicrosoft = new LoggingRule("Microsoft.*", NLog.LogLevel.Trace, NLog.LogLevel.Info, nullTarget);
            logRuleFilterOutMicrosoft.Final = true;

            //filter out httpclient logs at INFO level
            //2020-01-28 11:19:12.8767|INFO|System.Net.Http.HttpClient.Default.LogicalHandler|Start processing HTTP request GET https://rockfish.ayanova.com/rvf/a6d18a8a-5613-4979-99da-80d07641a2fe
            var logRuleFilterOutHttpClient = new LoggingRule("System.Net.Http.HttpClient.Default.*", NLog.LogLevel.Trace, NLog.LogLevel.Info, nullTarget);
            logRuleFilterOutHttpClient.Final = true;


            //filter out all Microsoft EF CORE concurrency exceptions, it's a nuisance unless debugging or something
            //This is what I have to filter because it's the top exception: Microsoft.EntityFrameworkCore.Update
            //But this is what I'm actually trying to filter: Microsoft.EntityFrameworkCore.DbUpdateConcurrencyException
            //however there doesn't appear to be a way to filter out based on content so...

            var logRuleFilterOutMicrosoftEfCoreConcurrencyExceptions = new LoggingRule("Microsoft.EntityFrameworkCore.Update", NLog.LogLevel.Trace, NLog.LogLevel.Error, nullTarget);
            logRuleFilterOutMicrosoftEfCoreConcurrencyExceptions.Final = true;

            var logRuleFilterOutMicrosoftEfCoreCommandExceptions = new LoggingRule("Microsoft.EntityFrameworkCore.Database.Command", NLog.LogLevel.Trace, NLog.LogLevel.Error, nullTarget);
            logRuleFilterOutMicrosoftEfCoreCommandExceptions.Final = true;

            var logRuleFilterOutMicrosoftEfCoreDbUpdateExceptions = new LoggingRule("Microsoft.EntityFrameworkCore.DbUpdateException", NLog.LogLevel.Trace, NLog.LogLevel.Error, nullTarget);
            logRuleFilterOutMicrosoftEfCoreDbUpdateExceptions.Final = true;

            //this rule is only intended to filter out this incorrect exception:
            //2019-01-16 16:13:03.4808|WARN|Microsoft.EntityFrameworkCore.Query|Query: '(from Widget <generated>_4 in DbSet<Widget> select [<generated>_4]).Skip(__p_1).Take(__p_2)' uses a row limiting operation (Skip/Take) without OrderBy which may lead to unpredictable results.
            var logRuleFilterOutMicrosoftEfCoreQueryExceptions = new LoggingRule("Microsoft.EntityFrameworkCore.Query", NLog.LogLevel.Trace, NLog.LogLevel.Error, nullTarget);
            logRuleFilterOutMicrosoftEfCoreQueryExceptions.Final = true;


            //Log all other regular items at selected level
            var logRuleAyaNovaItems = new LoggingRule("*", NLogLevel, fileTarget);

            //Log error or above to console
            var logRuleForConsole = new LoggingRule("*", NLog.LogLevel.Error, consoleTarget);

            //add console serious error only log rule
            logConfig.LoggingRules.Add(logRuleForConsole);

            //only log microsoft stuff it log is debug level or lower
            if (logLevelIsInfoOrHigher)
            {
                //filter OUT microsoft stuff
                logConfig.LoggingRules.Add(logRuleFilterOutMicrosoft);
                logConfig.LoggingRules.Add(logRuleFilterOutMicrosoftEfCoreConcurrencyExceptions);
                logConfig.LoggingRules.Add(logRuleFilterOutMicrosoftEfCoreCommandExceptions);
                logConfig.LoggingRules.Add(logRuleFilterOutMicrosoftEfCoreDbUpdateExceptions);
                logConfig.LoggingRules.Add(logRuleFilterOutMicrosoftEfCoreQueryExceptions);
                //also httpclient stuff
                logConfig.LoggingRules.Add(logRuleFilterOutHttpClient);
            }

            logConfig.LoggingRules.Add(logRuleAyaNovaItems);


            //Turn on internal logging:
            if (ServerBootConfig.AYANOVA_LOG_ENABLE_LOGGER_DIAGNOSTIC_LOG)
            {
                NLog.Common.InternalLogger.LogFile = "log-ayanova-logger.txt";
                NLog.Common.InternalLogger.LogLevel = NLog.LogLevel.Debug;
            }

            // NLog: setup the logger first to catch all errors         
            var logger = NLogBuilder.ConfigureNLog(logConfig).GetLogger("BOOT");

            //This is the first log entry
            logger.Info($"AYANOVA SERVER {AyaNovaVersion.VersionString} BOOTING");

            //log configuration
            try
            {
                var AyaNovaConfig = config.AsEnumerable().Where(z => z.Key.StartsWith("AYANOVA") && z.Key != "AYANOVA_JWT_SECRET"&& z.Key != "AYANOVA_SET_SUPERUSER_PW").Select(z => z.Key + "=" + z.Value).ToList();
                var DiagConfig = string.Join(",", AyaNovaConfig);
                DiagConfig = DbUtil.PasswordRedactedConnectionString(DiagConfig);
                logger.Info($"Config {DiagConfig}");
            }
            catch (Exception ex)
            {
                logger.Error(ex, "Error fetching configuration");
            }
            logger.Debug($"Full configuration is {config.GetDebugView()}");

            if (ServerBootConfig.AYANOVA_LOG_ENABLE_LOGGER_DIAGNOSTIC_LOG)
                logger.Warn("AYANOVA_LOG_ENABLE_LOGGER_DIAGNOSTIC_LOG is enabled, this will cause the server to run very slowly");


            //Log environmental settings
            logger.Info("OS - {0}", Environment.OSVersion.ToString());
            logger.Debug("Machine - {0}", Environment.MachineName);
            logger.Debug("User - {0}", Environment.UserName);
            logger.Debug(".Net Version - {0}", Environment.Version.ToString());
            logger.Debug("CPU count - {0}", Environment.ProcessorCount);


            #endregion


            //Ensure we are in the correct folder
            string startFolder = Directory.GetCurrentDirectory();
            var wwwRootFolder = Path.Combine(startFolder, "wwwroot");


            //Test for web root path
            //If user starts AyaNova from folder that is not the contentRoot then 
            //AyaNova won't be able to serve static files
            if (!Directory.Exists(wwwRootFolder))
            {
                var err = string.Format("E1010 - AyaNova was not started in the correct folder.  AyaNova must be started from the folder that contains the \"wwwroot\" folder but was started instead from this folder: \"{0}\" which does not contain the wwwroot folder.", startFolder);
                logger.Fatal(err);
                throw new System.ApplicationException(err);
            }

            try
            {
                //BuildWebHost(args, logger).Run();
                BuildHost(args, logger).Build().Run();
            }
            catch (Exception e)
            {
                logger.Fatal(e, "E1090 - AyaNova server can't start due to unexpected exception during initialization");
                throw;
            }
            finally
            {
                // Ensure to flush and stop internal timers/threads before application-exit (Avoid segmentation fault on Linux)
                logger.Info("AyaNova server shutting down");
                NLog.LogManager.Shutdown();
            }

        }






        public static IHostBuilder BuildHost(string[] args, NLog.Logger logger)
        {
            logger.Debug("Building host");
            var configuration = new ConfigurationBuilder().AddCommandLine(args).Build();

            return Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder
                .UseSetting("detailedErrors", "true")
                .UseUrls(ServerBootConfig.AYANOVA_USE_URLS)//default port and urls, set first can be overridden by any later setting here                              
                .UseConfiguration(configuration)//support command line override of port (dotnet run urls=http://*:8081)
                .UseIISIntegration()//support IIS integration just in case, it appears here to override prior settings if necessary (port) 
                .UseStartup<Startup>()
                .ConfigureLogging((context, logging) =>
                {
                    // clear all previously registered providers
                    //https://stackoverflow.com/a/46336988/8939
                    logging.ClearProviders();
                })
                .UseNLog(); // NLog: setup NLog for Dependency injection   
            });
        }

    }//eoc

}//eons