using JournalBot.Shared;

namespace JournalBot.Service;

public sealed class Worker : BackgroundService
{
    private readonly ILogger<Worker> _log;
    private readonly BotRunner _runner;
    private readonly TimeSpan _interval;
    private readonly string _serviceLogPath;

    public Worker(ILogger<Worker> log, IConfiguration config)
    {
        _log = log;
        var py = config["JournalBot:PythonExe"]!;
        var workingDir = config["JournalBot:WorkingDir"]!;
        var minutes = config.GetValue("JournalBot:IntervalMinutes", 15);
        _runner = new BotRunner(py, workingDir);
        _interval = TimeSpan.FromMinutes(minutes);
        _serviceLogPath = Path.Combine(workingDir, "runtime", "logs", "service.log");
        Directory.CreateDirectory(Path.GetDirectoryName(_serviceLogPath)!);
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        // Run once at startup, then every interval.
        await RunIngestAsync(stoppingToken);
        using var timer = new PeriodicTimer(_interval);
        while (await timer.WaitForNextTickAsync(stoppingToken))
            await RunIngestAsync(stoppingToken);
    }

    private async Task RunIngestAsync(CancellationToken ct)
    {
        try
        {
            var result = await _runner.RunAsync("ingest", ct);
            var line = $"[{DateTimeOffset.Now:O}] ingest exit={result.ExitCode}";
            _log.LogInformation("{Line}", line);
            await AppendLogAsync(line + "\n" + result.Output);
        }
        catch (OperationCanceledException) { throw; }
        catch (Exception ex)
        {
            _log.LogError(ex, "ingest run failed");
            await AppendLogAsync($"[{DateTimeOffset.Now:O}] ingest ERROR: {ex.Message}");
        }
    }

    private async Task AppendLogAsync(string text)
    {
        try { await File.AppendAllTextAsync(_serviceLogPath, text + "\n", System.Text.Encoding.UTF8); }
        catch { /* logging must never crash the service */ }
    }
}