Gigas002/GTiff2Tiles

using NetVips;

// ReSharper disable MemberCanBePrivate.Global

namespace GTiff2Tiles.Core.Images;

/// <summary>
/// Represents image's band
/// </summary>
public class Band
{
    #region Properties

    /// <summary>
    /// Default <see cref="Band"/> value
    /// </summary>
    public const int DefaultValue = 255;

    /// <summary>
    /// Current value
    /// </summary>
    public int Value { get; }

    #endregion

    #region Constructors

    /// <summary>
    /// Creates new <see cref="Band"/>
    /// </summary>
    /// <param name="value"><see cref="int"/> in range
    /// from 0 to 255</param>
    /// <exception cref="ArgumentOutOfRangeException"/>
    public Band(int value = DefaultValue)
    {
        #region Preconditions checks

        if (value < 0 || value > 255) throw new ArgumentOutOfRangeException(nameof(value));

        #endregion

        Value = value;
    }

    #endregion

    #region Methods

    /// <summary>
    /// Add <see cref="Band"/>s to <see cref="Image"/>
    /// </summary>
    /// <param name="image">Reference on <see cref="Image"/>
    /// to add <see cref="Band"/>s to</param>
    /// <param name="bands">Collection of <see cref="Band"/>s to add</param>
    /// <exception cref="ArgumentNullException"/>
    public static void AddBands(ref Image image, IEnumerable<Band> bands)
    {
        #region Preconditions checks

        if (image == null) throw new ArgumentNullException(nameof(image));
        if (bands == null) throw new ArgumentNullException(nameof(bands));

        #endregion

        image = bands.Aggregate(image, (current, band) => current.Bandjoin(band.Value));
    }

    /// <summary>
    /// Add default <see cref="Band"/>s to <see cref="Image"/> until
    /// bands count is lesser than <see cref="Image"/>'s current bands count
    /// </summary>
    /// <param name="image">Reference on <see cref="Image"/>
    /// to add <see cref="Band"/>s to</param>
    /// <param name="bandsCount">Count of desired <see cref="Band"/>s
    /// in <see cref="Image"/>;
    /// <remarks><para/>NOT the count of <see cref="Band"/>s to add</remarks></param>
    /// <exception cref="ArgumentNullException"/>
    public static void AddDefaultBands(ref Image image, int bandsCount)
    {
        #region Preconditions checks

        if (image == null) throw new ArgumentNullException(nameof(image));

        #endregion

        // Don't use HashSet
        List<Band> bandsToAdd = new();
        for (int i = bandsCount; i > image.Bands; i--) bandsToAdd.Add(new Band());
        AddBands(ref image, bandsToAdd);
    }

    #endregion
}