// What each model asks for, and what you have on hand.
//
// A Bambu Studio / OrcaSlicer 3MF names the filaments its plates use. Reading
// that means shelling out to Python, so it is done once per model in the
// background — like thumbnails and fingerprints — and kept in models.filaments.
// With that stored, "what can I print right now" is a plain query rather than
// hundreds of subprocesses.
const db = require('./db');
const converter = require('./converter');

const BATCH = 25;

// Models that have never been looked at, paired with their first loose 3MF.
// A model whose only 3MF sits inside an archive is left for a later pass rather
// than paying an extraction for each one.
const PENDING = `
  FROM models m
  LEFT JOIN LATERAL (
    SELECT f.file_path FROM files f
    WHERE f.model_id = m.id AND f.format = '3mf'
    ORDER BY f.id LIMIT 1
  ) f3 ON true
  WHERE m.deleted_at IS NULL AND m.filaments_status IS NULL`;

// "PLA Basic" and "pla basic" are the same filament; "PLA-CF" is not.
const normalise = (s) => String(s || '').trim().toUpperCase().replace(/\s+/g, ' ');

// The materials a model needs that nothing on hand provides. Colour is ignored
// on purpose: matching a project's exact colours would make almost nothing
// printable, and a different colour still prints.
function missingMaterials(filaments, spools) {
  const onHand = new Set(spools
    .filter((s) => s.remaining_g === null || s.remaining_g === undefined || Number(s.remaining_g) > 0)
    .map((s) => normalise(s.material)));
  const needed = [...new Set((filaments || []).map((f) => normalise(f.type)).filter(Boolean))];
  return needed.filter((type) => !onHand.has(type));
}

// True when every filament the model names is on a spool you still have.
// A model we know nothing about is not claimed to be printable.
function isPrintable(filaments, spools) {
  if (!filaments || !filaments.length) return false;
  return missingMaterials(filaments, spools).length === 0;
}

// One pass. Returns whether it did any work, so it fits the background worker
// loop in fingerprint.js.
async function run() {
  const { rows } = await db.query(
    `SELECT m.id, f3.file_path ${PENDING} ORDER BY m.id LIMIT ${BATCH}`);
  if (!rows.length) return false;

  for (const row of rows) {
    if (!row.file_path) {
      await mark(row.id, 'none', null);
      continue;
    }
    try {
      const filaments = await converter.readFilaments(row.file_path);
      // A plain 3MF mesh names no filaments — that is an answer, not a failure.
      await mark(row.id, filaments.length ? 'done' : 'none', filaments.length ? filaments : null);
    } catch (err) {
      console.warn(`Could not read filaments for model ${row.id}:`, err.message);
      await mark(row.id, 'error', null);
    }
  }
  return true;
}

async function mark(modelId, status, filaments) {
  await db.query('UPDATE models SET filaments = $2, filaments_status = $3 WHERE id = $1',
    [modelId, filaments ? JSON.stringify(filaments) : null, status]);
}

async function pendingCount() {
  const { rows } = await db.query(`SELECT COUNT(*)::int AS n ${PENDING}`);
  return rows[0].n;
}

// Look at every model again — after adding files, say.
async function reread() {
  await db.query('UPDATE models SET filaments_status = NULL');
}

module.exports = { run, pendingCount, reread, missingMaterials, isPrintable, normalise };