using Infineon.Monitoring.MonA;
using System.Diagnostics;
using System.Globalization;
using WinLog.Models;

namespace WinLog;

public class Worker : BackgroundService
{

    private int? _LastValue;
    private bool? _Heartbeat;
    private DateTime? _LastUpload;
    private readonly Calendar _Calendar;
    private readonly ILogger<Worker> _Logger;
    private readonly AppSettings _AppSettings;

    public Worker(ILogger<Worker> logger, AppSettings appSettings)
    {
        _Logger = logger;
        _Heartbeat = null;
        _AppSettings = appSettings;
        _Calendar = new CultureInfo("en-US").Calendar;
        if (!Directory.Exists(_AppSettings.Directory))
            _ = Directory.CreateDirectory(_AppSettings.Directory);
    }

#pragma warning disable CA1416

    private static List<EventLogEntry> GetOracleEventLogEntries(AppSettings appSettings, DateTime dateTime)
    {
        List<EventLogEntry> results = [];
        EventLog[] eventLogs = EventLog.GetEventLogs();
        long ticks = dateTime.AddMinutes(-appSettings.RollingMinutes).Ticks;
        foreach (EventLog eventLog in eventLogs)
        {
            if (!eventLog.Log.Contains(appSettings.LogFilter))
                continue;
            foreach (object? item in eventLog.Entries)
            {
                if (item is not EventLogEntry eventLogEntry)
                    continue;
                if (eventLogEntry.TimeGenerated.Ticks < ticks)
                    continue;
                if (!appSettings.MessageFilters.Any(l => eventLogEntry.Message.Contains(l)))
                    continue;
                results.Add(eventLogEntry);
            }
        }
        return results;
    }

    private static List<(DateTime, string)> GetOracleEventLogEntryMessages(AppSettings appSettings, DateTime dateTime)
    {
        List<(DateTime, string)> results = [];
        List<EventLogEntry> collection = GetOracleEventLogEntries(appSettings, dateTime);
        foreach (EventLogEntry eventLogEntry in collection)
            results.Add(new(eventLogEntry.TimeGenerated, eventLogEntry.Message));
        return results;
    }

#pragma warning restore CA1416

    public override Task StartAsync(CancellationToken cancellationToken)
    {
        MonIn monIn = MonIn.GetInstance();
        string result = monIn.SendStatus(_AppSettings.MonitorApplicationSite, _AppSettings.MonitorApplicationResource, "Heartbeat", State.Ok);
        _Heartbeat = !string.IsNullOrEmpty(result);
        return base.StartAsync(cancellationToken);
    }

    public override Task StopAsync(CancellationToken cancellationToken)
    {
        MonIn monIn = MonIn.GetInstance();
        string result = monIn.SendStatus(_AppSettings.MonitorApplicationSite, _AppSettings.MonitorApplicationResource, "Heartbeat", State.Down);
        _Heartbeat = !string.IsNullOrEmpty(result);
        return base.StopAsync(cancellationToken);
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        string directory;
        DateTime dateTime;
        string weekOfYear;
        string weekDirectory;
        string formattedDateTime;
        List<string> lines = [];
        MonIn monIn = MonIn.GetInstance();
        string performanceName = string.Concat(_AppSettings.MonitorApplicationResource, "_Count");
        while (!stoppingToken.IsCancellationRequested)
        {
            lines.Clear();
            dateTime = DateTime.Now;
            weekOfYear = _Calendar.GetWeekOfYear(dateTime, CalendarWeekRule.FirstDay, DayOfWeek.Sunday).ToString("00");
            weekDirectory = $"{dateTime:yyyy}_Week_{weekOfYear}{@"\"}{dateTime:yyyy-MM-dd}";
            directory = Path.Combine(_AppSettings.Directory, weekDirectory);
            if (!Directory.Exists(directory))
                _ = Directory.CreateDirectory(directory);
            _Logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);
            List<(DateTime, string)> collection = GetOracleEventLogEntryMessages(_AppSettings, dateTime);
            foreach ((DateTime timeGenerated, string message) in collection)
            {
                formattedDateTime = timeGenerated.ToString(_AppSettings.DateFormat);
                lines.Add($"{formattedDateTime}\t{message}");
            }
            File.WriteAllLines(Path.Combine(directory, $"{dateTime.Ticks}.tsv"), lines);
            if (_LastValue is null || _LastUpload is null || _LastValue.Value != lines.Count || new TimeSpan(dateTime.Ticks - _LastUpload.Value.Ticks).TotalMinutes > 5)
            {
                _ = monIn.SendPerformanceMessage(_AppSettings.MonitorApplicationSite, _AppSettings.MonitorApplicationResource, performanceName, value: lines.Count, description: string.Empty);
                _LastUpload = DateTime.Now;
                _LastValue = lines.Count;
            }
            await Task.Delay(_AppSettings.MillisecondsDelay, stoppingToken);
        }
    }

}