Delta-v/Content.Client/_DV/Mail/MailJobVisualizerSystem.cs

using Content.Shared._DV.Mail;
using Content.Shared.StatusIcon;
using Robust.Client.GameObjects;
using Robust.Shared.Prototypes;

namespace Content.Client._DV.Mail;

/// <summary>
///     Display a cool stamp on the parcel based on the job of the recipient.
/// </summary>
/// <remarks>
///     GenericVisualizer is not powerful enough to handle setting a string on
///     visual data then directly relaying that string to a layer's state.
///     I.e. there is nothing like a regex capture group for visual data.
///     Hence why this system exists.
///     To do this with GenericVisualizer would require a separate condition
///     for every job value, which would be extra mess to maintain.
///     It would look something like this, multipled a couple dozen times.
///     enum.MailVisuals.JobIcon:
///     enum.MailVisualLayers.JobStamp:
///     StationEngineer:
///     state: StationEngineer
///     SecurityOfficer:
///     state: SecurityOfficer
/// </remarks>
public sealed class MailJobVisualizerSystem : VisualizerSystem<MailComponent>
{
    [Dependency] private readonly SharedAppearanceSystem _appearance = default!;
    [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
    [Dependency] private readonly SpriteSystem _spriteSystem = default!;

    private static readonly ProtoId<JobIconPrototype> UnknownJobIcon = "JobIconUnknown";

    protected override void OnAppearanceChange(EntityUid uid, MailComponent component, ref AppearanceChangeEvent args)
    {
        if (args.Sprite == null)
            return;

        _appearance.TryGetData(uid, MailVisuals.JobIcon, out string job, args.Component);

        ProtoId<JobIconPrototype> jobProtoId = string.IsNullOrEmpty(job) ? UnknownJobIcon : job;

        if (!_prototypeManager.TryIndex(jobProtoId, out var icon))
        {
            _spriteSystem.LayerSetTexture((uid, args.Sprite), MailVisualLayers.JobStamp, _spriteSystem.Frame0(_prototypeManager.Index(UnknownJobIcon).Icon));
            return;
        }

        _spriteSystem.LayerSetTexture((uid, args.Sprite), MailVisualLayers.JobStamp, _spriteSystem.Frame0(icon.Icon));
    }
}

public enum MailVisualLayers : byte
{
    Icon,
    Lock,
    FragileStamp,
    JobStamp,
    PriorityTape,
    Breakage
}