#!/usr/bin/env node
// SHRINKGOD CLI — same pipeline as the web UI, headless.
//   shrinkgod model.glb                        -> model.opt.glb (balanced)
//   shrinkgod --preset crunch *.glb --outdir out/
//   shrinkgod model.glb --ratio 0.15 --max-tex 512 --webp -o small.glb
import { parseArgs } from 'node:util';
import { readFile, writeFile, mkdir } from 'node:fs/promises';
import path from 'node:path';
import { NodeIO } from '@gltf-transform/core';
import { ALL_EXTENSIONS } from '@gltf-transform/extensions';
import { listTextureSlots } from '@gltf-transform/functions';
import { MeshoptDecoder, MeshoptEncoder } from 'meshoptimizer';
import draco3d from 'draco3dgltf';
import { runPipeline, reportDoc, isColorSlot, PRESETS } from '../src/pipeline.js';

const HELP = `SHRINKGOD — local GLB optimizer (CLI)

Usage: shrinkgod [options] <input.glb> [more.glb ...]

Options:
  --preset <light|balanced|crunch>  base settings (default: balanced)
  --ratio <0..1>       fraction of geometry to keep (overrides preset)
  --error <0..1>       simplify error tolerance, fraction of mesh radius
  --max-tex <px>       longest texture side (0 = leave textures alone)
  --webp / --no-webp   convert color maps to WebP
  --quality <0..100>   lossy texture quality (default 85)
  --no-join            don't merge static meshes
  --no-quantize        skip vertex quantization
  --meshopt            EXT_meshopt_compression (web loaders only; Blender can't read it)
  -o, --out <file>     output path (single input only)
  --outdir <dir>       output directory for batch runs
  --suffix <s>         output suffix (default ".opt")
  -h, --help

Rig protection is automatic: skinned meshes keep >=50% geometry, morph-target
meshes are untouched, joining is disabled for animated models.`;

function fmtBytes(n) {
  if (n >= 1024 * 1024) return (n / 1024 / 1024).toFixed(1) + 'MB';
  if (n >= 1024) return (n / 1024).toFixed(0) + 'KB';
  return n + 'B';
}

async function nodeTextureStep(doc, opts, notes) {
  const textures = doc.getRoot().listTextures();
  if (!textures.length) return;
  let sharp;
  try {
    sharp = (await import('sharp')).default;
  } catch {
    notes.push('sharp not installed — textures left untouched (npm install sharp)');
    return;
  }
  for (const tex of textures) {
    const image = tex.getImage();
    if (!image) continue;
    const mime = tex.getMimeType();
    if (!/^image\/(png|jpeg|webp)$/.test(mime)) continue;

    let img, meta;
    try {
      img = sharp(Buffer.from(image.buffer, image.byteOffset, image.byteLength));
      meta = await img.metadata();
    } catch {
      notes.push(`could not decode texture "${tex.getName() || mime}" — left as-is`);
      continue;
    }
    const longest = Math.max(meta.width, meta.height);
    const scale = opts.maxTex > 0 ? Math.min(1, opts.maxTex / longest) : 1;
    const needsResize = scale < 1;

    const slots = listTextureSlots(tex);
    const color = slots.length === 0 || slots.some(isColorSlot);
    let target; // sharp format name
    if (!color) target = 'png';
    else if (opts.webp) target = 'webp';
    else target = mime === 'image/webp' ? 'webp' : mime.slice(6); // png|jpeg

    if (!needsResize && target === 'png' && mime === 'image/png') continue;

    if (needsResize) {
      img = img.resize(
        Math.max(1, Math.round(meta.width * scale)),
        Math.max(1, Math.round(meta.height * scale)),
        { fit: 'fill' }
      );
    }
    const q = Math.round(opts.texQuality * 100);
    if (target === 'webp') img = img.webp({ quality: q });
    else if (target === 'jpeg') img = img.jpeg({ quality: q });
    else img = img.png();

    const out = new Uint8Array(await img.toBuffer());
    if (!needsResize && out.byteLength >= image.byteLength) continue;
    tex.setImage(out).setMimeType('image/' + target);
  }
}

async function main() {
  const { values: v, positionals } = parseArgs({
    allowPositionals: true,
    options: {
      preset: { type: 'string', default: 'balanced' },
      ratio: { type: 'string' },
      error: { type: 'string' },
      'max-tex': { type: 'string' },
      webp: { type: 'boolean' },
      'no-webp': { type: 'boolean' },
      quality: { type: 'string', default: '85' },
      'no-join': { type: 'boolean' },
      'no-quantize': { type: 'boolean' },
      meshopt: { type: 'boolean' },
      out: { type: 'string', short: 'o' },
      outdir: { type: 'string' },
      suffix: { type: 'string', default: '.opt' },
      help: { type: 'boolean', short: 'h' },
    },
  });

  if (v.help || positionals.length === 0) {
    console.log(HELP);
    process.exit(v.help ? 0 : 1);
  }
  const preset = PRESETS[v.preset];
  if (!preset) {
    console.error(`unknown preset "${v.preset}" (light|balanced|crunch)`);
    process.exit(1);
  }
  if (v.out && positionals.length > 1) {
    console.error('--out only works with a single input; use --outdir for batches');
    process.exit(1);
  }

  const opts = {
    ratio: v.ratio != null ? parseFloat(v.ratio) : preset.ratio,
    error: v.error != null ? parseFloat(v.error) : preset.error,
    maxTex: v['max-tex'] != null ? parseInt(v['max-tex'], 10) : preset.maxTex,
    webp: v['no-webp'] ? false : v.webp != null ? v.webp : preset.webp,
    texQuality: parseInt(v.quality, 10) / 100,
    join: !v['no-join'],
    quantize: !v['no-quantize'],
    meshopt: !!v.meshopt,
  };

  await Promise.all([MeshoptDecoder.ready, MeshoptEncoder.ready]);
  const io = new NodeIO()
    .registerExtensions(ALL_EXTENSIONS)
    .registerDependencies({
      'meshopt.decoder': MeshoptDecoder,
      'meshopt.encoder': MeshoptEncoder,
      'draco3d.decoder': await draco3d.createDecoderModule(),
    });

  if (v.outdir) await mkdir(v.outdir, { recursive: true });

  let failed = 0;
  for (const input of positionals) {
    const t0 = performance.now();
    try {
      const inBytes = await readFile(input);
      const doc = await io.readBinary(new Uint8Array(inBytes));
      const before = reportDoc(doc, inBytes.byteLength);

      const { notes } = await runPipeline(doc, opts, { textureStep: nodeTextureStep });
      const outBytes = await io.writeBinary(doc);
      const after = reportDoc(doc, outBytes.byteLength);

      const base = path.basename(input).replace(/\.glb$/i, '');
      const outPath =
        v.out ?? path.join(v.outdir ?? path.dirname(input), `${base}${v.suffix}.glb`);
      await writeFile(outPath, outBytes);

      const secs = ((performance.now() - t0) / 1000).toFixed(1);
      const saved = (1 - after.bytes / before.bytes) * 100;
      console.log(
        `${input} -> ${outPath}\n` +
          `  ${fmtBytes(before.bytes)} -> ${fmtBytes(after.bytes)} (-${saved.toFixed(0)}%)  ` +
          `tris ${before.tris.toLocaleString()} -> ${after.tris.toLocaleString()}  ` +
          `tex ${fmtBytes(before.texBytes)} -> ${fmtBytes(after.texBytes)}  [${secs}s]`
      );
      for (const n of notes) console.log(`  · ${n}`);
    } catch (e) {
      failed++;
      console.error(`${input}: FAILED — ${e.message || e}`);
    }
  }
  process.exit(failed ? 1 : 0);
}

main();