using Nonemm.Contests.Multipliers;
using Nonemm.Core;
using Nonemm.Core.Country;

namespace Nonemm.Contests.Rules;

/// CQ World Wide DX, CW, SSB and RTTY. Points by continent, multipliers are
/// zones and countries counted once per band. The country list is DXCC plus
/// WAE, which is what `wl_cty.dat` holds.
///
/// RTTY is a different contest wearing the same name: the exchange carries the
/// state or province as well as the zone, that is a third multiplier, and every
/// contact scores — a contact inside your own country counts 1 rather than 0.
public sealed class CqWorldWide : Contest
{
    private readonly ModeCategory mode;

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

    public string Name => mode switch
    {
        ModeCategory.Phone => "CQWWSSB",
        ModeCategory.Digital => "CQWWRTTY",
        _ => "CQWWCW",
    };

    public string DisplayName => $"CQ World Wide DX {ModeLabel()}";

    public string CabrilloName => mode switch
    {
        ModeCategory.Cw => "CQ-WW-CW",
        ModeCategory.Phone => "CQ-WW-SSB",
        _ => "CQ-WW-RTTY",
    };

    /// The state or province box is not required: a station outside the US and
    /// Canada sends `DX` there, and holding up the log for it would cost more
    /// than it is worth.
    public IReadOnlyList<ExchangeField> ExchangeFieldsFor(StationInfo me) => IsRtty
        ?
        [
            new ExchangeField("Snt", ExchangeSlot.SentReport, ExchangeFieldKind.Report, IsRequired: false),
            new ExchangeField("Rcv", ExchangeSlot.ReceivedReport, ExchangeFieldKind.Report),
            new ExchangeField("CQ-Zone", ExchangeSlot.Zone, ExchangeFieldKind.CqZone),
            new ExchangeField("State/RAC", ExchangeSlot.Section, ExchangeFieldKind.UsStateOrCanadianProvince, IsRequired: false),
        ]
        :
        [
            new ExchangeField("Snt", ExchangeSlot.SentReport, ExchangeFieldKind.Report, IsRequired: false),
            new ExchangeField("Rcv", ExchangeSlot.ReceivedReport, ExchangeFieldKind.Report),
            new ExchangeField("CQ-Zone", ExchangeSlot.Zone, ExchangeFieldKind.CqZone),
        ];

    /// On RTTY the exchange carries a state or province, but only from the US
    /// and Canada; the box is stepped over for everybody else. N1MM's entry
    /// window does the same, and the box is still there to type in.
    public bool SkipsField(ExchangeField field, CountryLookup? their) =>
        IsRtty
        && field.Slot == ExchangeSlot.Section
        && their is not null
        && their.Entity.PrimaryPrefix is not ("K" or "VE");

    public IReadOnlyList<string> MultiplierNames =>
        IsRtty ? ["Zones", "Countries", "States"] : ["Zones", "Countries"];

    public DupeScope DupeScope => DupeScope.PerBand;

    public bool HasSerialNumbers => false;

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

    /// The report is fixed for the whole contest, so the sent exchange is the
    /// zone alone, which is also what N1MM stores. RTTY sends the state or
    /// province after it, and `DX` from anywhere else.
    public string SentExchangeFor(StationInfo me) =>
        IsRtty ? $"{me.CqZone} {HomeOf(me)}" : me.CqZone.ToString();

    /// A maritime mobile station counts for no country, and still scores by
    /// the continent it is operating from, which is what N1MM logs.
    public int PointsFor(QsoContext qso)
    {
        if (IsRtty)
        {
            return qso.IsSameCountry && qso.Qso.Call.CountsForEntity ? 1
                : qso.IsSameContinent ? 2
                : 3;
        }
        if (qso.IsSameCountry && qso.Qso.Call.CountsForEntity)
        {
            return 0;
        }
        if (!qso.IsSameContinent)
        {
            return 3;
        }
        return qso.Continent == "NA" ? 2 : 1;
    }

    public IReadOnlyList<Multiplier> MultipliersFor(QsoContext qso)
    {
        string band = qso.Band?.Name ?? "";
        List<Multiplier> found = [];
        if (qso.Qso.Zone > 0)
        {
            found.Add(new Multiplier(1, qso.Qso.Zone.ToString(), band));
        }
        found.Add(new Multiplier(2, qso.CountryPrefix, band));
        string home = qso.Qso.Section.Trim().ToUpperInvariant();
        if (IsRtty && StatesAndProvinces.CqWwRttyAreas.Contains(home))
        {
            found.Add(new Multiplier(3, home, band));
        }
        return found;
    }

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

    public CabrilloExchange CabrilloExchange(Qso qso, StationInfo me, ContestEntry entry) => IsRtty
        ? new CabrilloExchange(
            [
                new CabrilloField(me.Callsign, 13),
                new CabrilloField(qso.SentReport, 3),
                new CabrilloField(me.CqZone.ToString(), 3),
                new CabrilloField(HomeOf(me), 6),
            ],
            [
                new CabrilloField(qso.Call.Text, 13),
                new CabrilloField(qso.ReceivedReport, 3),
                new CabrilloField(qso.Zone.ToString(), 3),
                new CabrilloField(Home(qso.Section), 6),
            ])
        : new CabrilloExchange(
            [
                new CabrilloField(me.Callsign, 13),
                new CabrilloField(qso.SentReport, 3),
                new CabrilloField(me.CqZone.ToString(), 6),
            ],
            [
                new CabrilloField(qso.Call.Text, 13),
                new CabrilloField(qso.ReceivedReport, 3),
                new CabrilloField(qso.Zone.ToString(), 6),
            ]);

    private bool IsRtty => mode == ModeCategory.Digital;

    /// What goes in the state column: the state or province, and `DX` for
    /// everywhere else, which is what the contest asks a DX station to send.
    private static string HomeOf(StationInfo me) =>
        Home(me.State.Length > 0 ? me.State : me.Province);

    private static string Home(string text)
    {
        string value = text.Trim().ToUpperInvariant();
        return StatesAndProvinces.IsStateOrProvince(value) ? value : "DX";
    }

    private string ModeLabel() => mode switch
    {
        ModeCategory.Cw => "CW",
        ModeCategory.Phone => "SSB",
        _ => "RTTY",
    };

}