using System;
using System.IO;
using Serilog;
using SyncEngine.Configuration;
using SyncEngine.Sync;

namespace SyncEngine
{
    internal static class Program
    {
        private static int Main(string[] args)
        {
            var envLoad = EnvSettings.LoadFromStandardLocations();
            var exeDir = EnvSettings.ExeDirectory();
            var logDir = Path.Combine(exeDir, "logs");
            Directory.CreateDirectory(logDir);

            Log.Logger = new LoggerConfiguration()
                .MinimumLevel.Information()
                .WriteTo.Console()
                .WriteTo.File(Path.Combine(logDir, "sync-.log"), rollingInterval: RollingInterval.Day)
                .CreateLogger();

            try
            {
                using (var instanceLock = SyncInstanceLock.TryAcquire())
                {
                    if (instanceLock == null)
                    {
                        Log.Warning("Another SyncEngine instance is already running; exiting.");
                        return 3;
                    }

                    var mode = args.Length > 0 ? args[0] : "all";

                    if (!envLoad.Found)
                    {
                        Log.Error("No .env file found beside {ExeDir} or at the repo root.", exeDir);
                        Log.Error("Copy config\\.env.example to .env in the repo root, then build (copies .env to output) or place .env beside SyncEngine.exe.");
                        return 2;
                    }

                    Log.Information("Loaded configuration from: {Paths}", string.Join("; ", envLoad.LoadedPaths));

                    var options = SyncOptions.LoadFromEnvironment();
                    SyncOptionsValidator.Validate(options, mode, envLoad.Found);

                    Log.Information("SyncEngine starting mode={Mode} dryRun={DryRun}", mode, options.DryRun);
                    var orchestrator = new SyncOrchestrator(options, Log.Logger);
                    return orchestrator.Run(mode);
                }
            }
            catch (ConfigurationException ex)
            {
                Log.Error("Configuration error:\n{Message}", ex.Message);
                Log.Error("Edit your .env file (see .env.example) and try again.");
                return 2;
            }
            catch (Exception ex)
            {
                Log.Fatal("{Message}", SyncErrorFormatter.Describe(ex));
                Log.Debug(ex, "Unhandled exception");
                return 1;
            }
            finally
            {
                Log.CloseAndFlush();
            }
        }
    }
}