import { mkdirSync, readFileSync } from 'node:fs';
import { join } from 'node:path';

import {
  buildChunkId,
  chunkText,
  createEmbedder,
  extractTitle,
  hasFlag,
  listSourceFiles,
  loadRagRuntime,
  parseLimitFiles,
  readConfig,
  repoRoot,
} from './rag-utils.mjs';

const config = readConfig();
const limitFiles = parseLimitFiles(process.argv);
const dryRun = hasFlag(process.argv, '--dry-run');

const files = listSourceFiles(config, limitFiles);
const rows = [];

for (const file of files) {
  const text = readFileSync(file.path, 'utf8');
  const title = extractTitle(text, file.rel);
  for (const chunk of chunkText(text, config.chunk ?? {})) {
    rows.push({
      id: buildChunkId(file.rel, chunk.index),
      path: file.rel,
      title,
      chunk_index: chunk.index,
      source_weight: file.weight,
      text: chunk.text,
    });
  }
}

console.log(`[rag:index] source files=${files.length}, chunks=${rows.length}`);

if (dryRun) {
  for (const row of rows.slice(0, 10)) {
    console.log(`- ${row.id} ${row.title}`);
  }
  process.exit(0);
}

if (rows.length === 0) {
  throw new Error('No RAG chunks found.');
}

const { lancedb, transformers } = await loadRagRuntime(config);
const embed = await createEmbedder(transformers, config.model);

for (let index = 0; index < rows.length; index += 1) {
  rows[index].vector = await embed(rows[index].text, 'passage');
  if ((index + 1) % 25 === 0 || index + 1 === rows.length) {
    console.log(`[rag:index] embedded ${index + 1}/${rows.length}`);
  }
}

mkdirSync(join(repoRoot, config.databaseDir), { recursive: true });
const db = await lancedb.connect(join(repoRoot, config.databaseDir));
await db.createTable(config.tableName, rows, { mode: 'overwrite' });

console.log(
  `[rag:index] wrote table=${config.tableName}, db=${config.databaseDir}, model=${config.model}`,
);