openscad-graph-editor

using Godot;
using JetBrains.Annotations;
using OpenScadGraphEditor.Library;
using OpenScadGraphEditor.Utils;
using OpenScadGraphEditor.Widgets;

namespace OpenScadGraphEditor.Nodes
{
    /// <summary>
    /// Utility node that does a pairwise multiplication of two arrays.
    /// </summary>
    [UsedImplicitly]
    public class PairwiseMultiply : ScadNode, IAmAnExpression, IHaveCustomWidget, IHaveNodeBackground
    {
        public override string NodeTitle => "Pairwise multiply";
        public override string NodeQuickLookup => "VPm";
        public override string NodeDescription => "Multiplies the given two vectors pairwise (each element of the first vector is multiplied with the corresponding element of the second vector).";

        public PairwiseMultiply()
        {
            InputPorts
                .Array()
                .Array();

            OutputPorts
                .Array();
        }

        public override string GetPortDocumentation(PortId portId)
        {
            switch (portId.Port)
            {
                case 0 when portId.IsInput:
                    return "The first vector. If the vectors are of different length, the shorter vector is padded with zeros.";
                case 1 when portId.IsInput:
                    return "The second vector. If the vectors are of different length, the shorter vector is padded with zeros.";
                case 0 when portId.IsOutput:
                    return "The result of the pairwise multiplication. Contains as many elements as the longer of the both input vectors.";
                default:
                    return "";
            }
        }

        public override string Render(ScadGraph context, int portIndex)
        {
            var first = RenderInput(context, 0);
            var second = RenderInput(context, 1);

            if (first.Empty() || second.Empty())
            {
                return "";
            }

            // because first and second could be expressions, we wrap all of this in a let
            // block otherwise we go crazy with the parentheses.
            
            var var1 = Id.UniqueStableVariableName(0);
            var var2 = Id.UniqueStableVariableName(1);
            
            return $"(let({var1} = {first}, {var2} = {second}) [for(i =[0:max(len({var1}), len({var2}))-1]) (i < len({var1}) ? {var1}[i] : 0) * (i < len({var2}) ? {var2}[i] : 0)])";
        }

        public ScadNodeWidget InstantiateCustomWidget()
        {
            return Prefabs.New<SmallNodeWidget>();
        }

        public Texture NodeBackground => Resources.PairwiseMultiplyIcon;
    }
}