<?php
namespace services;

class XmlFeedImporter
{
  const BATCH_SIZE = 200;
  const HTTP_TIMEOUT = 300;
  const GMC_NS = 'http://base.google.com/ns/1.0';

  /**
   * Importuje feed XML (Google Merchant) dla klienta i wzbogaca tabele products.
   * Strumieniowy parser (XMLReader) odporny na feedy z kilkoma tysiacami pozycji.
   *
   * Aktualizuje pola: title, description, custom_label_1, price (zrodlowe dane z feedu).
   * NIE nadpisuje pol edytowanych przez skrypty/AI: title_gmc, description_gmc (sluza do supplemental feed -> GMC).
   * Dla pozycji nieobecnej w products tworzy nowy rekord.
   *
   * @param int $client_id
   * @return array raport z polami: feed_url, fetched, updated, inserted, skipped, errors, peak_memory_mb, duration_ms
   */
  static public function import_for_client( $client_id, array $options = [] )
  {
    global $mdb;

    $client_id = (int) $client_id;
    $debug_offer_id = trim( (string) ( $options['debug_offer_id'] ?? '' ) );
    $report = [
      'feed_url'       => '',
      'fetched'        => 0,
      'updated'        => 0,
      'inserted'       => 0,
      'skipped'        => 0,
      'errors'         => [],
      'peak_memory_mb' => 0,
      'duration_ms'    => 0,
    ];
    if ( $debug_offer_id !== '' )
    {
      $report['debug_offer'] = [
        'offer_id' => $debug_offer_id,
        'found_in_feed' => false,
        'custom_label_1_raw_present' => false,
        'custom_label_1_value' => '',
        'title_present' => false,
        'matched_existing_rows' => 0,
        'updated_rows' => 0,
      ];
    }

    if ( $client_id <= 0 )
    {
      $report['errors'][] = 'Nieprawidlowy client_id';
      return $report;
    }

    $client = $mdb -> get( 'clients', [ 'id', 'xml_feed_url' ], [ 'id' => $client_id ] );
    $feed_url = trim( (string) ( $client['xml_feed_url'] ?? '' ) );
    if ( $feed_url === '' )
    {
      $report['skipped_reason'] = 'no_feed';
      return $report;
    }
    $report['feed_url'] = $feed_url;

    $started_at = microtime( true );
    @set_time_limit( 600 );
    @ini_set( 'memory_limit', '512M' );

    $tmp_file = tempnam( sys_get_temp_dir(), 'xmlfeed_' );
    if ( $tmp_file === false )
    {
      $report['errors'][] = 'Nie mozna utworzyc pliku tymczasowego';
      return $report;
    }

    $download_ok = self::download_feed( $feed_url, $tmp_file, $report );
    if ( !$download_ok )
    {
      @unlink( $tmp_file );
      return $report;
    }

    $reader = new \XMLReader();
    if ( !$reader -> open( $tmp_file ) )
    {
      $report['errors'][] = 'Nie mozna otworzyc feedu XML do parsowania';
      @unlink( $tmp_file );
      return $report;
    }

    $batch = [];
    while ( $reader -> read() )
    {
      if ( $reader -> nodeType !== \XMLReader::ELEMENT )
      {
        continue;
      }

      $local = $reader -> localName;
      if ( $local !== 'item' && $local !== 'entry' )
      {
        continue;
      }

      try
      {
        $node = $reader -> expand();
        if ( !$node )
        {
          $report['skipped']++;
          continue;
        }

        $item = self::extract_item_fields( $node );
        if ( $item === null || $item['offer_id'] === '' )
        {
          $report['skipped']++;
          continue;
        }

        if ( $debug_offer_id !== '' && (string) $item['offer_id'] === $debug_offer_id )
        {
          $report['debug_offer']['found_in_feed'] = true;
          $report['debug_offer']['custom_label_1_raw_present'] = !empty( $item['custom_label_1_raw_present'] );
          $report['debug_offer']['custom_label_1_value'] = (string) ( $item['custom_label_1'] ?? '' );
          $report['debug_offer']['title_present'] = trim( (string) ( $item['title'] ?? '' ) ) !== '';
          if ( !$report['debug_offer']['custom_label_1_raw_present'] )
          {
            $report['debug_offer']['missing_reason'] = 'custom_label_1_missing_in_feed';
          }
          else if ( trim( (string) $item['custom_label_1'] ) === '' )
          {
            $report['debug_offer']['missing_reason'] = 'custom_label_1_empty_in_feed';
          }
        }

        $report['fetched']++;
        $batch[] = $item;

        if ( count( $batch ) >= self::BATCH_SIZE )
        {
          self::flush_batch( $client_id, $batch, $report );
          $batch = [];
          gc_collect_cycles();
        }
      }
      catch ( \Throwable $e )
      {
        $report['skipped']++;
        if ( count( $report['errors'] ) < 20 )
        {
          $report['errors'][] = 'Item parse error: ' . $e -> getMessage();
        }
      }
    }

    if ( !empty( $batch ) )
    {
      self::flush_batch( $client_id, $batch, $report );
      $batch = [];
    }

    $reader -> close();
    @unlink( $tmp_file );

    if ( $debug_offer_id !== '' && empty( $report['debug_offer']['found_in_feed'] ) )
    {
      $report['debug_offer']['missing_reason'] = 'offer_id_missing_in_feed';
    }

    $mdb -> update( 'clients', [ 'xml_feed_last_sync_at' => date( 'Y-m-d H:i:s' ) ], [ 'id' => $client_id ] );

    $report['peak_memory_mb'] = round( memory_get_peak_usage( true ) / 1024 / 1024, 1 );
    $report['duration_ms'] = (int) round( ( microtime( true ) - $started_at ) * 1000 );

    return $report;
  }

  static private function download_feed( $url, $tmp_file, &$report )
  {
    $fp = fopen( $tmp_file, 'wb' );
    if ( $fp === false )
    {
      $report['errors'][] = 'Nie mozna otworzyc pliku tymczasowego do zapisu';
      return false;
    }

    $ch = curl_init( $url );
    curl_setopt_array( $ch, [
      CURLOPT_FILE           => $fp,
      CURLOPT_FOLLOWLOCATION => true,
      CURLOPT_MAXREDIRS      => 5,
      CURLOPT_TIMEOUT        => self::HTTP_TIMEOUT,
      CURLOPT_CONNECTTIMEOUT => 30,
      CURLOPT_FAILONERROR    => true,
      CURLOPT_USERAGENT      => 'adsPRO XML Feed Importer/1.0',
      CURLOPT_SSL_VERIFYPEER => true,
      CURLOPT_ENCODING       => '',
    ] );

    $ok = curl_exec( $ch );
    $http_code = (int) curl_getinfo( $ch, CURLINFO_HTTP_CODE );
    $err = curl_error( $ch );
    curl_close( $ch );
    fclose( $fp );

    if ( !$ok || ( $http_code >= 400 ) )
    {
      $report['errors'][] = 'Pobieranie feedu nieudane (HTTP ' . $http_code . '): ' . $err;
      return false;
    }

    if ( filesize( $tmp_file ) === 0 )
    {
      $report['errors'][] = 'Feed jest pusty';
      return false;
    }

    return true;
  }

  static private function extract_item_fields( \DOMNode $node )
  {
    $doc = new \DOMDocument();
    $imported = $doc -> importNode( $node, true );
    $doc -> appendChild( $imported );

    $sxe = simplexml_import_dom( $doc -> documentElement );
    if ( $sxe === false )
    {
      return null;
    }

    $g = $sxe -> children( self::GMC_NS );

    $offer_id = '';
    if ( isset( $g -> id ) )
    {
      $offer_id = trim( (string) $g -> id );
    }
    if ( $offer_id === '' && isset( $sxe -> id ) )
    {
      $offer_id = trim( (string) $sxe -> id );
    }
    if ( $offer_id === '' )
    {
      return null;
    }

    $title = '';
    if ( isset( $g -> title ) )
    {
      $title = trim( (string) $g -> title );
    }
    if ( $title === '' && isset( $sxe -> title ) )
    {
      $title = trim( (string) $sxe -> title );
    }

    $description = '';
    if ( isset( $g -> description ) )
    {
      $description = trim( (string) $g -> description );
    }
    if ( $description === '' && isset( $sxe -> description ) )
    {
      $description = trim( (string) $sxe -> description );
    }

    $custom_label_1_raw_present = isset( $g -> custom_label_1 );
    $custom_label_1 = $custom_label_1_raw_present ? trim( (string) $g -> custom_label_1 ) : '';
    if ( !$custom_label_1_raw_present && isset( $sxe -> custom_label_1 ) )
    {
      $custom_label_1_raw_present = true;
      $custom_label_1 = trim( (string) $sxe -> custom_label_1 );
    }
    if ( !$custom_label_1_raw_present )
    {
      $custom_label_1_fallback = self::get_text_by_local_name( $doc, 'custom_label_1' );
      if ( $custom_label_1_fallback !== null )
      {
        $custom_label_1_raw_present = true;
        $custom_label_1 = trim( (string) $custom_label_1_fallback );
      }
    }

    $price = null;
    if ( isset( $g -> price ) )
    {
      $price_raw = trim( (string) $g -> price );
      $price = self::parse_price( $price_raw );
    }
    if ( $price === null && isset( $g -> sale_price ) )
    {
      $price = self::parse_price( trim( (string) $g -> sale_price ) );
    }

    return [
      'offer_id'       => self::truncate( $offer_id, 255 ),
      'title'          => self::truncate( $title, 255 ),
      'description'    => $description,
      'custom_label_1' => self::truncate( $custom_label_1, 255 ),
      'custom_label_1_raw_present' => $custom_label_1_raw_present,
      'price'          => $price,
    ];
  }

  static private function get_text_by_local_name( \DOMDocument $doc, $local_name )
  {
    $local_name = (string) $local_name;
    foreach ( $doc -> getElementsByTagName( '*' ) as $node )
    {
      if ( $node -> localName === $local_name )
      {
        return $node -> textContent;
      }
    }

    return null;
  }

  static private function parse_price( $raw )
  {
    if ( $raw === '' )
    {
      return null;
    }
    if ( preg_match( '/([0-9]+(?:[.,][0-9]+)?)/', $raw, $m ) )
    {
      $value = (float) str_replace( ',', '.', $m[1] );
      if ( $value > 0 )
      {
        return round( $value, 2 );
      }
    }
    return null;
  }

  static private function truncate( $value, $max )
  {
    if ( function_exists( 'mb_substr' ) )
    {
      return mb_substr( (string) $value, 0, $max, 'UTF-8' );
    }
    return substr( (string) $value, 0, $max );
  }

  static private function flush_batch( $client_id, array $batch, array &$report )
  {
    global $mdb;

    if ( empty( $batch ) )
    {
      return;
    }

    $pdo = $mdb -> pdo;

    try
    {
      $pdo -> beginTransaction();

      $offer_ids = [];
      foreach ( $batch as $item )
      {
        $offer_ids[ $item['offer_id'] ] = true;
      }
      $offer_ids = array_keys( $offer_ids );

      $existing = [];
      if ( !empty( $offer_ids ) )
      {
        $placeholders = [];
        $select_params = [ ':client_id' => $client_id ];
        foreach ( $offer_ids as $idx => $oid )
        {
          $key = ':oid_' . $idx;
          $placeholders[] = $key;
          $select_params[ $key ] = $oid;
        }
        $sel_sql = 'SELECT id, offer_id FROM products WHERE client_id = :client_id AND offer_id IN (' . implode( ', ', $placeholders ) . ')';
        $sel_stmt = $pdo -> prepare( $sel_sql );
        $sel_stmt -> execute( $select_params );
        while ( $row = $sel_stmt -> fetch( \PDO::FETCH_ASSOC ) )
        {
          // jeden offer_id moze miec wiele wierszy (legacy duplikaty) - zbieramy wszystkie id
          $existing[ (string) $row['offer_id'] ][] = (int) $row['id'];
        }
      }

      $update_stmt = $pdo -> prepare(
        'UPDATE products SET
            title = :title,
            description = :description,
            custom_label_1 = COALESCE(:custom_label_1, custom_label_1),
            price = COALESCE(:price, price)
          WHERE id = :id'
      );

      $insert_stmt = $pdo -> prepare(
        'INSERT INTO products (client_id, offer_id, title, description, custom_label_1, price)
         VALUES (:client_id, :offer_id, :title, :description, :custom_label_1, :price)'
      );

      $updated_count = 0;
      $inserted_count = 0;

      $debug_offer_id = (string) ( $report['debug_offer']['offer_id'] ?? '' );

      foreach ( $batch as $item )
      {
        $title = $item['title'] !== '' ? $item['title'] : null;
        $desc  = $item['description'] !== '' ? $item['description'] : null;
        $cl1   = $item['custom_label_1'] !== '' ? $item['custom_label_1'] : null;
        $price = $item['price'];
        $is_debug_offer = $debug_offer_id !== '' && (string) $item['offer_id'] === $debug_offer_id;

        if ( !empty( $existing[ $item['offer_id'] ] ) )
        {
          if ( $is_debug_offer )
          {
            $report['debug_offer']['matched_existing_rows'] = count( $existing[ $item['offer_id'] ] );
          }
          // aktualizujemy WSZYSTKIE legacy duplikaty (utrzymujemy spojnosc danych)
          foreach ( $existing[ $item['offer_id'] ] as $row_id )
          {
            $update_stmt -> execute( [
              ':title'          => $title,
              ':description'    => $desc,
              ':custom_label_1' => $cl1,
              ':price'          => $price,
              ':id'             => $row_id,
            ] );
            $updated_count++;
            if ( $is_debug_offer )
            {
              $report['debug_offer']['updated_rows']++;
            }
          }
        }
        else
        {
          $insert_stmt -> execute( [
            ':client_id'      => $client_id,
            ':offer_id'       => $item['offer_id'],
            ':title'          => $title,
            ':description'    => $desc,
            ':custom_label_1' => $cl1,
            ':price'          => $price,
          ] );
          $inserted_count++;
          if ( $is_debug_offer )
          {
            $report['debug_offer']['inserted'] = true;
          }
        }
      }

      $pdo -> commit();

      $report['updated']  += $updated_count;
      $report['inserted'] += $inserted_count;
    }
    catch ( \Throwable $e )
    {
      if ( $pdo -> inTransaction() )
      {
        $pdo -> rollBack();
      }
      if ( count( $report['errors'] ) < 20 )
      {
        $report['errors'][] = 'Batch flush error: ' . $e -> getMessage();
      }
      $report['skipped'] += count( $batch );
    }
  }
}