"use strict";

const fs = require("fs");
const path = require("path");

const VEHICLE_IDS = [
  "car_a01_002",
  "car_a02_002",
  "car_a03_001",
  "truck_a01_001",
  "truck_a02_001",
  "truck_a03_001",
];
const LIBRARY_ROOT = path.resolve(__dirname, "..", "..", "assets", "models", "custom", "lowpoly_cars");
const TEXTURE_NAME = "color_512x512.jpg";
const REVERSED_MODEL_IDS = new Set(["truck_a03_001"]);

function writePreviewVehicleLibrary(outDir, fileStem) {
  const textureOutput = `${fileStem}-vehicle-texture.jpg`;
  fs.mkdirSync(outDir, { recursive: true });
  fs.copyFileSync(path.join(LIBRARY_ROOT, "textures", TEXTURE_NAME), path.join(outDir, textureOutput));
  return VEHICLE_IDS.map((id) => {
    const modelName = `${fileStem}-vehicle-${id}.gltf`;
    const binName = `${fileStem}-vehicle-${id}.bin`;
    const sourceDir = path.join(LIBRARY_ROOT, id);
    const gltf = JSON.parse(fs.readFileSync(path.join(sourceDir, "model.gltf"), "utf8"));
    for (const image of gltf.images || []) image.uri = textureOutput;
    for (const buffer of gltf.buffers || []) buffer.uri = binName;
    if (REVERSED_MODEL_IDS.has(id)) {
      // The source's longitudinal PCA axis points rearward for this truck.
      for (const node of gltf.nodes || []) node.rotation = [0, 1, 0, 0];
    }
    for (const material of gltf.materials || []) {
      const pbr = material.pbrMetallicRoughness || (material.pbrMetallicRoughness = {});
      // Match the Cesium foliage profile: lift albedo first, then use the
      // texture itself as a modest shadow-side floor.
      pbr.baseColorFactor = [2.1, 2.1, 2.1, 1];
      if (pbr.baseColorTexture) {
        material.emissiveTexture = { ...pbr.baseColorTexture };
        material.emissiveFactor = [0.25, 0.25, 0.25];
      }
    }
    fs.writeFileSync(path.join(outDir, modelName), `${JSON.stringify(gltf, null, 2)}\n`);
    fs.copyFileSync(path.join(sourceDir, "model.bin"), path.join(outDir, binName));
    return modelName;
  });
}

module.exports = { VEHICLE_IDS, REVERSED_MODEL_IDS, writePreviewVehicleLibrary };