using EnvelopeGenerator.WorkerService.Configuration;
using EnvelopeGenerator.WorkerService.Services;
using Microsoft.Data.SqlClient;
using Microsoft.Extensions.Options;

namespace EnvelopeGenerator.WorkerService;

public class Worker : BackgroundService
{
    private readonly ILogger<Worker> _logger;
    private readonly WorkerSettings _settings;
    private readonly TempFileManager _tempFiles;

    public Worker(
        ILogger<Worker> logger,
        IOptions<WorkerSettings> settings,
        TempFileManager tempFiles)
    {
        _logger = logger;
        _settings = settings.Value;
        _tempFiles = tempFiles;
    }

    public override async Task StartAsync(CancellationToken cancellationToken)
    {
        _logger.LogInformation("Starting EnvelopeGenerator worker...");
        _logger.LogInformation("Debug mode: {Debug}", _settings.Debug);

        ValidateConfiguration();
        await EnsureDatabaseConnectionAsync(cancellationToken);
        await _tempFiles.CreateAsync(cancellationToken);

        await base.StartAsync(cancellationToken);
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        _logger.LogInformation("EnvelopeGenerator worker is running. Jobs are scheduled every {Interval} minute(s).", Math.Max(1, _settings.IntervalMinutes));
        await Task.Delay(Timeout.Infinite, stoppingToken);
    }

    public override async Task StopAsync(CancellationToken cancellationToken)
    {
        _logger.LogInformation("Stopping EnvelopeGenerator worker...");
        await _tempFiles.CleanupAsync(cancellationToken);
        await base.StopAsync(cancellationToken);
    }

    private void ValidateConfiguration()
    {
        if (string.IsNullOrWhiteSpace(_settings.ConnectionString))
        {
            throw new InvalidOperationException("Connection string cannot be empty. Configure 'WorkerSettings:ConnectionString'.");
        }
    }

    private async Task EnsureDatabaseConnectionAsync(CancellationToken cancellationToken)
    {
        try
        {
            await using var connection = new SqlConnection(_settings.ConnectionString);
            await connection.OpenAsync(cancellationToken);
            _logger.LogInformation("Database connection established successfully.");
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Database connection could not be established.");
            throw;
        }
    }
}