// EXT_materials_bump für @gltf-transform (docs/superpowers/specs/2026-09-14-hood-yard-design.md).
// @gltf-transform 4.5.0 kennt die Erweiterung nicht und verwirft sie beim Einlesen. Das Wellblech der
// Container aus three-d-stage steckt aber allein darin, die Container selbst sind flache Kästen.
// Aufgebaut wie KHR_materials_transmission in @gltf-transform/extensions: bumpTexture ist eine echte
// Texturreferenz, damit dedup, prune und compressTexture sie sehen. Ihre TextureInfo läuft über
// setTextureInfo/createTextureInfoDef, so kommt KHR_texture_transform (die Wellenteilung, etwa
// scale [3.2, 1]) mit. three.js liest die Erweiterung selbst (GLTFLoader: bumpFactor -> bumpScale,
// bumpTexture -> bumpMap).
import { Extension, ExtensionProperty, PropertyType, TextureChannel, TextureInfo } from "@gltf-transform/core";

export const EXT_MATERIALS_BUMP = "EXT_materials_bump";

export class Bump extends ExtensionProperty {
    static EXTENSION_NAME = EXT_MATERIALS_BUMP;

    init() {
        this.extensionName = EXT_MATERIALS_BUMP;
        this.propertyType = "Bump";
        this.parentTypes = [PropertyType.MATERIAL];
    }

    getDefaults() {
        return Object.assign(super.getDefaults(), {
            bumpFactor: 1,
            bumpTexture: null,
            bumpTextureInfo: new TextureInfo(this.graph, "bumpTextureInfo"),
        });
    }

    getBumpFactor() {
        return this.get("bumpFactor");
    }

    setBumpFactor(factor) {
        return this.set("bumpFactor", factor);
    }

    getBumpTexture() {
        return this.getRef("bumpTexture");
    }

    getBumpTextureInfo() {
        return this.getRef("bumpTexture") ? this.getRef("bumpTextureInfo") : null;
    }

    setBumpTexture(texture) {
        return this.setRef("bumpTexture", texture, { channels: TextureChannel.R });
    }
}

export class EXTMaterialsBump extends Extension {
    static EXTENSION_NAME = EXT_MATERIALS_BUMP;
    extensionName = EXT_MATERIALS_BUMP;
    prereadTypes = [PropertyType.MESH];
    prewriteTypes = [PropertyType.MESH];

    createBump() {
        return new Bump(this.document.getGraph());
    }

    read() {
        return this;
    }

    write() {
        return this;
    }

    preread(context) {
        const materialDefs = context.jsonDoc.json.materials ?? [];
        const textureDefs = context.jsonDoc.json.textures ?? [];
        materialDefs.forEach((materialDef, index) => {
            const def = materialDef.extensions?.[EXT_MATERIALS_BUMP];
            if (!def) return;
            const bump = this.createBump();
            context.materials[index].setExtension(EXT_MATERIALS_BUMP, bump);
            if (def.extras) bump.setExtras(def.extras);
            if (def.bumpFactor !== undefined) bump.setBumpFactor(def.bumpFactor);
            if (def.bumpTexture !== undefined) {
                bump.setBumpTexture(context.textures[textureDefs[def.bumpTexture.index].source]);
                context.setTextureInfo(bump.getBumpTextureInfo(), def.bumpTexture);
            }
        });
        return this;
    }

    prewrite(context) {
        for (const material of this.document.getRoot().listMaterials()) {
            const bump = material.getExtension(EXT_MATERIALS_BUMP);
            if (!bump) continue;
            const materialDef = context.jsonDoc.json.materials[context.materialIndexMap.get(material)];
            const def = context.createPropertyDef(bump);
            def.bumpFactor = bump.getBumpFactor();
            const texture = bump.getBumpTexture();
            if (texture) def.bumpTexture = context.createTextureInfoDef(texture, bump.getBumpTextureInfo());
            materialDef.extensions = materialDef.extensions ?? {};
            materialDef.extensions[EXT_MATERIALS_BUMP] = def;
        }
        return this;
    }
}