import { spawn } from "node:child_process";
import { stat } from "node:fs/promises";
import path from "node:path";
import { exists, loadRecipe, projectRoot, readJson, workRoot, writeJson } from "./lib.mjs";

function runCli(args) {
  const cli = path.join(projectRoot, "node_modules/@gltf-transform/cli/bin/cli.js");
  return new Promise((resolve, reject) => {
    const child = spawn(process.execPath, [cli, ...args], { cwd: projectRoot, stdio: "inherit", windowsHide: true });
    child.once("error", reject);
    child.once("exit", (code) => code === 0 ? resolve() : reject(new Error(`gltf-transform exited with code ${code}.`)));
  });
}

function compressKtx2(file) {
  const compressor = path.join(projectRoot, "scripts/asset-pipeline/compress-ktx2.mjs");
  return new Promise((resolve, reject) => {
    const child = spawn(process.execPath, [
      compressor,
      file,
      "--concurrency",
      "1",
      "--jobs",
      "2",
    ], { cwd: projectRoot, stdio: "inherit", windowsHide: true });
    child.once("error", reject);
    child.once("exit", (code) => code === 0
      ? resolve()
      : reject(new Error(`KTX2 compression exited with code ${code}.`)));
  });
}

export async function optimizeDungeonEnvironment(slug) {
  await loadRecipe(slug);
  const directory = path.join(workRoot, slug, "staging", "environment");
  const conversionFile = path.join(directory, "conversion-report.json");
  if (!await exists(conversionFile)) return { status: "blocked", dungeonId: slug, blockers: ["Run dungeon:convert first."] };
  const conversion = await readJson(conversionFile);
  const source = path.join(directory, conversion.visual.file);
  if (!await exists(source)) return { status: "blocked", dungeonId: slug, blockers: ["The lossless visual GLB is missing."] };
  const optimized = path.join(directory, `${slug}-visual.optimized.glb`);
  await runCli([
    "optimize",
    source,
    optimized,
    "--compress",
    "meshopt",
    "--meshopt-level",
    "high",
    "--instance",
    "true",
    "--instance-min",
    "3",
    "--texture-size",
    "2048",
  ]);
  await compressKtx2(optimized);
  const report = {
    schemaVersion: 1,
    dungeonId: slug,
    status: "review-required",
    source: { file: path.basename(source), size: (await stat(source)).size },
    optimized: { file: path.basename(optimized), size: (await stat(optimized)).size },
    compression: "meshopt+ktx2",
    commands: [
      "gltf-transform optimize --compress meshopt --meshopt-level high --instance true --instance-min 3 --texture-size 2048",
      "node scripts/asset-pipeline/compress-ktx2.mjs <optimized.glb> --concurrency 1 --jobs 2",
    ],
  };
  await writeJson(path.join(directory, "optimization-report.json"), report);
  return report;
}