using Nonemm.Core;

namespace Nonemm.Session;

/// One field the statistics window can put down the rows or across the columns.
/// `Headings` holds two entries for the fields that print two label columns.
public sealed class StatisticsField
{
    private readonly Func<Qso, DateTime, PivotKey> read;

    internal StatisticsField(string name, Func<Qso, DateTime, PivotKey> read, params string[] headings)
    {
        Name = name;
        this.read = read;
        Headings = headings.Length > 0 ? headings : [name];
    }

    public string Name { get; }

    public IReadOnlyList<string> Headings { get; }

    /// `startUtc` is when the contest started: the five, ten and fifteen minute
    /// fields count from it.
    public PivotKey KeyOf(Qso qso, DateTime startUtc) => read(qso, startUtc);

    public override string ToString() => Name;
}