UnflattenContext.cs

using System.Collections.Generic;
using JSONstat.Models;

namespace JSONstat.Transform;

/// <summary>
/// The context handed to the <see cref="Dataset.Unflatten{T}"/> selector for
/// each cell, mirroring the JavaScript Toolkit's <c>Unflatten</c> callback
/// arguments (coordinates, datapoint, counter, accumulator).
/// </summary>
public sealed class UnflattenContext<T>
{
    private readonly List<T> _rows;

    internal UnflattenContext(
        IReadOnlyDictionary<string, string> coordinates,
        Datum datapoint,
        int n,
        List<T> rows)
    {
        Coordinates = coordinates;
        Datapoint = datapoint;
        N = n;
        _rows = rows;
    }

    /// <summary>Dimension id -> category id for the current cell.</summary>
    public IReadOnlyDictionary<string, string> Coordinates { get; }

    /// <summary>The value and status of the current cell.</summary>
    public Datum Datapoint { get; }

    /// <summary>The linear cell counter.</summary>
    public int N { get; }

    /// <summary>The rows accumulated so far.</summary>
    public IReadOnlyList<T> Row => _rows;
}