import type { ShaderGraphIR, ShaderSocketIR } from "./shader-graph";

const input = (id: string, name: string, dataType: ShaderSocketIR["dataType"], defaultValue?: ShaderSocketIR["defaultValue"]): ShaderSocketIR => ({ id, name, direction: "INPUT", dataType, ...(defaultValue === undefined ? {} : { defaultValue }) });
const output = (id: string, name: string, dataType: ShaderSocketIR["dataType"]): ShaderSocketIR => ({ id, name, direction: "OUTPUT", dataType });

/** Build a valid bounded graph for the source-backed Principled writer. */
export const shaderGraphCommands = Object.freeze({
  setPrincipledGraph(materialId: string, baseColor: readonly number[], roughness: number, metallic: number): ShaderGraphIR {
    const principled = "shader:principled";
    const materialOutput = "shader:material-output";
    return {
      schemaVersion: 1,
      id: `shader-graph:${materialId}`,
      materialId,
      nodes: [
        { id: principled, type: "PRINCIPLED", name: "Principled BSDF", sockets: [
          input("Base Color", "Base Color", "COLOR", [...baseColor].slice(0, 4)),
          input("Metallic", "Metallic", "VALUE", metallic),
          input("Roughness", "Roughness", "VALUE", roughness),
          output("BSDF", "BSDF", "SHADER"),
        ] },
        { id: materialOutput, type: "MATERIAL_OUTPUT", name: "Material Output", sockets: [input("Surface", "Surface", "SHADER")] },
      ],
      links: [{ fromNodeId: principled, fromSocketId: "BSDF", toNodeId: materialOutput, toSocketId: "Surface" }],
      outputNodeId: materialOutput,
    };
  },
} as const);