import express from 'express';
import cors from 'cors';
import { warmUp } from './embed.js';
import { INTENTS_COLLECTION, DOCS_COLLECTION, query, health } from './collections.js';
import { classify } from './confidence.js';

// ==============================|| Doormile AI — retrieval sidecar ||============================== //
//
// Two jobs, and neither of them is "produce a number":
//
//   POST /route  text -> which intent is this? (+ how sure)
//   POST /ask    text -> which documentation passages answer this?
//
// The console then runs its OWN deterministic intent code to produce every
// figure. Nothing this service returns is ever read by an operator as data.

const app = express();
app.use(cors());
app.use(express.json({ limit: '64kb' }));

app.get('/health', async (_req, res) => {
  try {
    const model = await warmUp();
    const store = await health();
    res.json({ ok: true, model, ...store });
  } catch (err) {
    res.status(503).json({ ok: false, error: err.message });
  }
});

app.post('/route', async (req, res) => {
  const text = String(req.body?.text || '').trim();
  if (!text) return res.status(400).json({ error: 'text is required' });

  try {
    const hits = await query(INTENTS_COLLECTION, text, 5);
    const { confidence, score, margin } = classify(hits);

    // Distinct intents only — five phrasings of the same intent in the top-5
    // is a strong signal, not five alternatives to offer the operator.
    const seen = new Set();
    const alternatives = [];
    for (const h of hits) {
      const id = h.metadata?.intentId;
      if (!id || seen.has(id)) continue;
      seen.add(id);
      alternatives.push({ intentId: id, score: h.score, example: h.document });
    }

    return res.json({
      intentId: alternatives[0]?.intentId ?? null,
      isWrite: Boolean(hits[0]?.metadata?.isWrite),
      confidence,
      score: Number(score.toFixed(4)),
      margin: Number(margin.toFixed(4)),
      matchedExample: hits[0]?.document ?? null,
      // Only meaningful when confidence is low — that is when the panel should
      // offer these as buttons instead of picking one.
      alternatives: alternatives.slice(1, 3)
    });
  } catch (err) {
    return res.status(503).json({ error: err.message });
  }
});

app.post('/ask', async (req, res) => {
  const text = String(req.body?.text || '').trim();
  if (!text) return res.status(400).json({ error: 'text is required' });

  try {
    const hits = await query(DOCS_COLLECTION, text, 4);
    // Passages are returned verbatim with attribution. There is no generation
    // step: summarising would need a hosted model (CLAUDE.md §2) and would let
    // a paraphrase drift from what the document actually says.
    res.json({
      chunks: hits
        .filter((h) => h.score > 0.35)
        .map((h) => ({
          text: h.document,
          source: h.metadata?.source,
          heading: h.metadata?.heading,
          score: Number(h.score.toFixed(4))
        }))
    });
  } catch (err) {
    res.status(503).json({ error: err.message });
  }
});

const port = Number(process.env.PORT) || 8787;
app.listen(port, () => {
  console.log(`[doormile-ai] listening on :${port}`);
  // Pay the model load at boot rather than on an operator's first question.
  warmUp()
    .then((m) => console.log(`[doormile-ai] model ready: ${m.model} (${m.dimensions}d)`))
    .catch((e) => console.error('[doormile-ai] model failed to load:', e.message));
});