using Avalonia.Controls;
using Avalonia.Controls.Documents;
using Avalonia.Media;
using Avalonia.Threading;
using Nonemm.Contests;
using Nonemm.Core;
using Nonemm.Core.Country;
using Nonemm.Session;
using Nonemm.Spotting;

namespace Nonemm.App.Windows;

/// N1MM's info window: who is operating, what is known about the station in the
/// call box, the rate graphs against the goals, and the timers contests with a
/// rest rule or a band-change rule ask the operator to watch.
public sealed partial class InfoWindow : RefreshableWindow
{
    /// How far from the radio's frequency a spot may be and still be the one
    /// the call-frame line shows.
    private static readonly Frequency SpotReach = Frequency.FromHertz(500);

    private readonly AppSession session;
    private readonly DispatcherTimer clock;
    private readonly Throttled later;
    private readonly EventHandler onNotices;
    private readonly EventHandler onSolar;
    private int ticks;

    public InfoWindow(AppSession session)
    {
        this.session = session;
        InitializeComponent();
        later = new Throttled(TimeSpan.FromSeconds(2), Refresh, holdWhileTyping: true);
        clock = new DispatcherTimer { Interval = TimeSpan.FromSeconds(1) };
        clock.Tick += (_, _) =>
        {
            ShowTimers();
            if (++ticks % GraphEveryTicks == 0)
            {
                ShowGraphs();
            }
        };
        clock.Start();
        onNotices = (_, _) => Dispatcher.UIThread.Post(ShowMessages);
        onSolar = (_, _) => Dispatcher.UIThread.Post(ShowWwv);
        session.NoticesChanged += onNotices;
        session.SolarChanged += onSolar;
        Closed += (_, _) =>
        {
            clock.Stop();
            later.Cancel();
            session.NoticesChanged -= onNotices;
            session.SolarChanged -= onSolar;
        };
        Refresh();
    }

    private ContestSession? Logging => session.Logging;

    private Configuration.StoredInfoWindow Info => session.Settings.Info;

    public override void RefreshFromSession() => later.Request();

    public override void RefreshForEntry() => ShowLines();

    public override void Refresh()
    {
        ShowHeader();
        ShowLines();
        ShowWwv();
        ShowMessages();
        ShowGraphs();
        ShowTimers();
    }

    /// N1MM's caption: `Info - DL1ABC - Exch: 599 001`, where the number is the
    /// next one to be sent in a contest that sends one.
    private void ShowHeader()
    {
        string station = session.Settings.Station.Callsign;
        if (Logging is null || session.Position is not { } position)
        {
            Title = $"Info - {station}";
            OperatorText.Text = station;
            StatusText.Text = "";
            return;
        }
        string report = position.Entry.Exchange.Any(f => f.Slot == Contests.ExchangeSlot.SentReport)
            ? position.DefaultReport()
            : "";
        string sent = Logging.Instance.SentExchange;
        string exchange = sent.Contains("001") || sent.Contains('#')
            ? position.SentNumber.ToString().PadLeft(3, '0')
            : sent;
        Title = $"Info - {station} - Exch: {report} {exchange}";
        OperatorText.Text = Logging.Operator.Length > 0
            ? Logging.Operator
            : session.Settings.CurrentOperator.Length > 0 ? session.Settings.CurrentOperator : station;
        StatusText.Text = Info.ShowGoals ? $"Contest Start Time:  {Logging.Instance.StartDate:yyyy-MM-dd HH:mm:ss}Z" : "";
    }

    /// The spot, the country with its bearing, and the sun there. They follow
    /// the call in the entry window, and the spot under the radio's frequency
    /// when no call is being typed.
    private void ShowLines()
    {
        SpotText.IsVisible = Info.CallFrameSpot;
        CountryText.IsVisible = Info.CountryInfo;
        SunText.IsVisible = Info.SunTimes;
        SpotText.Text = "";
        CountryText.Text = "";
        SunText.Text = "";
        if (session.Position is not { } position)
        {
            return;
        }
        DateTime now = DateTime.UtcNow;
        string call = position.Entry.Call.Trim();
        Spot? spot = SpotFor(position, call);
        if (spot is not null)
        {
            SpotText.Text = InfoLines.Spot(spot, now);
        }
        CountryLookup? country = call.Length >= 2
            ? position.Country()
            : spot is null ? null : session.Countries?.Find(spot.Call);
        if (country is null)
        {
            return;
        }
        StationPath? path = call.Length >= 2
            ? StationPath.For(position, now)
            : StationPath.ToCall(position, spot!.Call, now);
        string where = InfoLines.Country(country, Logging?.Contest.UsesItuZones ?? false);
        CountryText.Text = path is null ? where : $"{where}, {InfoLines.Bearing(path, position.Me.Continent == "NA")}";
        SunLine sun = InfoLines.Sun(country, now);
        SunText.Text = sun.Text;
        if (sun.IsSoon)
        {
            SunText.Foreground = Brushes.OrangeRed;
        }
        else
        {
            SunText.ClearValue(TextBlock.ForegroundProperty);
        }
    }

    private Spot? SpotFor(OperatingPosition position, string call)
    {
        if (call.Length < 2)
        {
            return session.Bandmap.Near(position.Frequency, SpotReach) is { IsStation: true } near ? near : null;
        }
        Band? band = position.Band;
        return session.Bandmap.All()
            .Where(s => s.IsStation && string.Equals(s.Call.Text, call, StringComparison.OrdinalIgnoreCase))
            .OrderByDescending(s => s.Band == band)
            .ThenByDescending(s => s.AtUtc)
            .FirstOrDefault();
    }

    private void ShowWwv()
    {
        WwvText.IsVisible = Info.Wwv;
        WwvText.Text = session.Solar?.Original ?? "";
    }

    private void ShowMessages()
    {
        MessagesScroll.IsVisible = Info.Messages;
        if (!Info.Messages)
        {
            return;
        }
        MessagesText.Inlines?.Clear();
        foreach (Notice notice in session.Notices)
        {
            Run line = new($"{notice.AtUtc:HH:mm:ss} {notice.Text}\n");
            if (notice.IsAlert)
            {
                line.FontWeight = FontWeight.Bold;
                line.Foreground = Brushes.OrangeRed;
            }
            MessagesText.Inlines?.Add(line);
        }
        MessagesScroll.ScrollToEnd();
    }
}