// api_v1/scanner/scanFile.js
const path = require('path');
const fsp = require('fs/promises');
const { sha256 } = require('./utils');
const { SUPPORTED_EXTS } = require('../config');
const { log } = require('./logger');

/**
 * scanFile: genera informazioni su UN singolo file
 * Restituisce lo stesso formato di scanCartella, ma senza recursion.
 *
 * Parametri:
 * - userName
 * - cartella
 * - absFile (percorso assoluto del file)
 * - db (opzionale)
 */
async function scanFileEntry(userName, cartella, absFile, db) {
  const ext = path.extname(absFile).toLowerCase();
  if (!SUPPORTED_EXTS.has(ext)) {
    log(`⛔ Estensione non supportata: ${ext}`);
    return null;
  }

  const name = path.basename(absFile);
  const relPath = name; // singolo file → niente struttura ricorsiva

  let st;
  try {
    st = await fsp.stat(absFile);
  } catch {
    log(`⛔ Impossibile leggere stat per ${absFile}`);
    return null;
  }

  const id = sha256(`${userName}/${cartella}/${relPath}`);

  log(`📄 scanFile → user=${userName} cartella=${cartella} file=${name} id=${id}`);

  return {
    id,
    user: userName,
    cartella,
    name,
    relPath,
    absPath: absFile,
    ext,
    stat: st,
    path: `/photos/${userName}/original/${cartella}/${relPath}`
  };
}

async function scanFile(userName, cartella, absFile, db) {
  const f = await scanFile(user, cart, absFile);
      const fileName = f.name;
      const id = f.id;
      const st = f.stat;


      let prev = await db("photos")
        .select("id", "size_bytes", "mtimeMs", "_indexHash", "fast_hash", "path")
        .where({ id })
        .first();

      if (prev && LOG_VERBOSE) {
        log(`${prefix}   ⚪ Invariato: ${fileName}`);
      }

      const fastHash = sha256(`${st.size}-${st.mtimeMs}`);

      // ---------------------------------------------------------
      // PATH CAMBIATO = NUOVO FILE
      // ---------------------------------------------------------
      if (prev && prev.path !== f.path) {
        log(`${prefix}   🟢 Nuovo/Modificato: ${fileName}`);
        prev = null;
      }

      // ---------------------------------------------------------
      // NUOVO FILE
      // ---------------------------------------------------------
      if (!prev) {
        log(`${prefix}   🟢 Nuovo/Modificato: ${fileName}`);

        const meta = await processFile(
          user,
          cartella,
          f.relPath,
          f.absPath,
          f.ext,
          st
        );

        meta.id = id;
        meta.path = f.path;

        // INSERT CORRETTO (senza colonna gps)
        await db("photos").insert({
          id: meta.id,
          user,
          cartella,
          name: meta.name,
          path: meta.path,
          thub1: meta.thub1,
          thub2: meta.thub2,
          mime_type: meta.mime_type,
          width: meta.width,
          height: meta.height,
          rotation: meta.rotation,
          size_bytes: meta.size_bytes,
          mtimeMs: meta.mtimeMs,
          duration_ms: meta.duration_ms,
          taken_at: meta.taken_at,
          data: meta.data,
          lat: meta.gps?.lat ?? null,
          lon: meta.gps?.lng ?? null,
          alt: meta.gps?.alt ?? null,
          location: meta.location ? JSON.stringify(meta.location) : null,
          _indexHash: meta._indexHash,
          fast_hash: fastHash
        });

        await db('photo_changes').insert({
          photo_id: meta.id,
          user,
          change_type: 'added',
          timestamp: new Date().toISOString()
        });


        newFiles.push(meta);
        //log(`🟢 [PUSH newFiles] id=${meta.id} path=${meta.path}`);

        continue;
      }

      // ---------------------------------------------------------
      // FAST-SIZE-SKIP
      // ---------------------------------------------------------
      if (prev.size_bytes === st.size) {
        //log(`🔵 [FAST-SIZE-SKIP] id=${id}`);

        await db("photos")
          .where({ id })
          .update({
            path: f.path,
            size_bytes: st.size,
            mtimeMs: st.mtimeMs,
            fast_hash: fastHash
          });

        continue;
      }

      // ---------------------------------------------------------
      // FAST-HASH-SKIP
      // ---------------------------------------------------------
      if (prev.fast_hash === fastHash) {
        //log(`🔵 [FAST-HASH-SKIP] id=${id}`);

        await db("photos")
          .where({ id })
          .update({
            path: f.path,
            size_bytes: st.size,
            mtimeMs: st.mtimeMs
          });

        continue;
      }

      // ---------------------------------------------------------
      // MODIFICATO
      // ---------------------------------------------------------
      //log(`🟠 [FULL-SCAN] id=${id}`);
      log(`${prefix}   🟠 Nuovo/Modificato: ${fileName}`);
      const meta = await processFile(
        user,
        cartella,
        f.relPath,
        f.absPath,
        f.ext,
        st
      );

      meta.id = id;
      meta.path = f.path;

      await db("photos")
        .insert({
          id: meta.id,
          user,
          cartella,
          name: meta.name,
          path: meta.path,
          thub1: meta.thub1,
          thub2: meta.thub2,
          mime_type: meta.mime_type,
          width: meta.width,
          height: meta.height,
          rotation: meta.rotation,
          size_bytes: meta.size_bytes,
          mtimeMs: meta.mtimeMs,
          duration_ms: meta.duration_ms,
          taken_at: meta.taken_at,
          data: meta.data,
          lat: meta.gps?.lat ?? null,
          lon: meta.gps?.lng ?? null,
          alt: meta.gps?.alt ?? null,
          location: meta.location ? JSON.stringify(meta.location) : null,
          _indexHash: meta._indexHash,
          fast_hash: fastHash
        })
        .onConflict("id")
        .merge();

      await db('photo_changes').insert({
        photo_id: meta.id,
        user,
        change_type: 'updated',
        timestamp: new Date().toISOString()
      });

      newFiles.push(meta);
      log(`${prefix} 🟠 Nuovo/Modificato al server  ${fileName}`);
    }

  }


}

module.exports = scanFile;