using System;
using System.Diagnostics;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using Inventory.Core;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace Inventory.Agent
{
    public class Worker : BackgroundService
    {
        private readonly ILogger<Worker> _logger;
        private readonly IServiceProvider _serviceProvider;
        private readonly IHostApplicationLifetime _hostApplicationLifetime;

        public Worker(ILogger<Worker> logger, IServiceProvider serviceProvider, IHostApplicationLifetime hostApplicationLifetime)
        {
            _logger = logger;
            _serviceProvider = serviceProvider;
            _hostApplicationLifetime = hostApplicationLifetime;
        }

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            _logger.LogInformation("Checking for agent updates...");
            const string manifestPath = @"\\192.168.0.9\ihomp\InventoryAgent\Agent\version.json";

            if (UpdateChecker.CheckForUpdate(manifestPath, out string newMsiPath))
            {
                _logger.LogInformation("New version found. Starting silent update from {Path}", newMsiPath);
                try
                {
                    // Copy MSI locally to avoid file lock on the share
                    string tempMsi = Path.Combine(Path.GetTempPath(), Path.GetFileName(newMsiPath));
                    File.Copy(newMsiPath, tempMsi, true);

                    Process.Start(new ProcessStartInfo
                    {
                        FileName = "msiexec.exe",
                        Arguments = $"/i \"{tempMsi}\" /quiet /norestart",
                        UseShellExecute = true,
                        Verb = "runas"
                    });

                    _logger.LogInformation("Update process started. Stopping current service...");
                    _hostApplicationLifetime.StopApplication();
                    return;
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "Failed to start update process.");
                }
            }
            _logger.LogInformation("Agent is up-to-date.");

            _logger.LogInformation("Inventory Agent starting.");

            // Perform an initial run on startup
            await DoWork(stoppingToken);

            var updateIntervalMinutes = Core.Secrets.UpdateIntervalMinutes;
            _logger.LogInformation("Update interval set to {Minutes} minutes.", updateIntervalMinutes);
            using var timer = new PeriodicTimer(TimeSpan.FromMinutes(updateIntervalMinutes));

            while (await timer.WaitForNextTickAsync(stoppingToken))
            {
                await DoWork(stoppingToken);
            }
        }

        private async Task DoWork(CancellationToken stoppingToken)
        {
            _logger.LogInformation("Starting inventory update workflow.");
            try
            {
                using var scope = _serviceProvider.CreateScope();
                var updateWorkflow = scope.ServiceProvider.GetRequiredService<UpdateWorkflow>();
                await updateWorkflow.Run();
                _logger.LogInformation("Inventory update completed successfully.");
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "An error occurred during the inventory update.");
            }
        }
    }
}