using Nonemm.Core;
using Nonemm.Core.Country;

namespace Nonemm.Contests.Rules;

/// OK/OM DX. An OK or OM station sends a county code and everyone else a
/// serial number, and which side the operator is on decides what a contact
/// scores.
///
/// The received exchange lands in the section column for an OK or OM station
/// and in the exchange column for everyone else, which is where N1MM keeps
/// each of them.
public sealed class OkOmDx : Contest
{
    private readonly ModeCategory mode;

    public OkOmDx(ModeCategory mode) => this.mode = mode;

    public string Name => "OKOMDX";

    public string DisplayName => "Czech and Slovak Republics DX";

    public string CabrilloName => "OK-OM-DX";

    public IReadOnlyList<ExchangeField> ExchangeFieldsFor(StationInfo me) =>
    [
        new ExchangeField("RST", ExchangeSlot.ReceivedReport, ExchangeFieldKind.Report),
        new ExchangeField("County", ExchangeSlot.Section, ExchangeFieldKind.Text) { Width = 4 },
        new ExchangeField("Nr", ExchangeSlot.Exchange1, ExchangeFieldKind.Number),
    ];

    /// An OK or OM station sends a county and no serial; everyone else the
    /// other way round, so one of the two boxes is stepped over.
    public bool SkipsField(ExchangeField field, CountryLookup? their) =>
        field.Slot switch
        {
            ExchangeSlot.Section => their is not null && !IsOkOm(their.Entity.PrimaryPrefix),
            ExchangeSlot.Exchange1 => their is not null && IsOkOm(their.Entity.PrimaryPrefix),
            _ => false,
        };

    public IReadOnlyList<string> MultiplierNames => ["Countries", "Counties"];

    public DupeScope DupeScope => DupeScope.PerBand;

    public bool HasSerialNumbers => true;

    public IReadOnlyList<ModeCategory> Modes => [mode];

    public string SentExchangeFor(StationInfo me) => IsOkOm(me.CountryPrefix) ? me.County : "001";

    /// A maritime mobile is 5 points to either side. An OK or OM operator gets
    /// 2 points at home, 3 elsewhere on the continent and 5 from another —
    /// Czechia and Slovakia are two countries, so they are 3 points to each
    /// other. Everyone else gets 10 points for an OK or OM station, 1 at home,
    /// 3 on their own continent and 5 from another.
    public int PointsFor(QsoContext qso)
    {
        if (qso.Qso.Call.IsMaritimeMobile)
        {
            return 5;
        }
        if (!IsOkOm(qso.Me.CountryPrefix) && IsOkOm(qso.CountryPrefix))
        {
            return 10;
        }
        int home = IsOkOm(qso.Me.CountryPrefix) ? 2 : 1;
        return qso.IsSameCountry ? home : qso.IsSameContinent ? 3 : 5;
    }

    /// Both sides count the same two, once per band each: every country, and
    /// every OK or OM county. N1MM's own class counts prefixes for an OK or OM
    /// operator, which was the rule before the counties came in.
    public IReadOnlyList<Multiplier> MultipliersFor(QsoContext qso)
    {
        string band = qso.Band?.Name ?? "";
        List<Multiplier> found = [];
        if (qso.CountryPrefix.Length > 0)
        {
            found.Add(new Multiplier(1, qso.CountryPrefix, band));
        }
        string county = County(qso.Qso);
        if (IsOkOm(qso.CountryPrefix) && county.Length > 0)
        {
            found.Add(new Multiplier(2, county, band));
        }
        return found;
    }

    public int TotalScore(ScoreTally tally, ContestEntry entry) =>
        tally.Points * tally.TotalMultipliers;

    public CabrilloExchange CabrilloExchange(Qso qso, StationInfo me, ContestEntry entry) =>
        new(
            [
                new CabrilloField(me.Callsign, 13),
                new CabrilloField(qso.SentReport, 3),
                new CabrilloField(IsOkOm(me.CountryPrefix) ? me.County : $"{qso.SentNumber:000}", 6),
            ],
            [
                new CabrilloField(qso.Call.Text, 13),
                new CabrilloField(qso.ReceivedReport, 3),
                new CabrilloField(County(qso).Length > 0 ? County(qso) : qso.Exchange1, 6),
            ]);

    private static string County(Qso qso) => qso.Section.Trim().ToUpperInvariant();

    private static bool IsOkOm(string countryPrefix) => countryPrefix is "OK" or "OM";
}