Enhance bulk import scripts (#5010)

* Enhance bulk import scripts

* Fix: restore running statement of BulkImport::VBulletin

script/bulk_import/base.rb

@@ -176,7 +176,7 @@ class BulkImport::Base
 
   POST_COLUMNS ||= %i{
     id user_id last_editor_id topic_id post_number sort_order reply_to_post_number
-    raw cooked hidden word_count created_at last_version_at updated_at
+    like_count raw cooked hidden word_count created_at last_version_at updated_at
   }
 
   TOPIC_ALLOWED_USER_COLUMNS ||= %i{
@@ -306,7 +306,8 @@ class BulkImport::Base
   end
 
   def process_category(category)
-    @categories[category[:imported_id].to_s] = category[:id] = @last_category_id += 1
+    category[:id] ||= @last_category_id += 1
+    @categories[category[:imported_id].to_s] ||= category[:id]
     category[:name] = category[:name][0...50].scrub.strip
     # TODO: unique name
     category[:name_lower] = category[:name].downcase
@@ -347,6 +348,7 @@ class BulkImport::Base
     @topic_id_by_post_id[post[:id]] = post[:topic_id]
     post[:raw] = (post[:raw] || "").scrub.strip.presence || "<Empty imported post>"
     post[:raw] = process_raw post[:raw]
+    post[:like_count] ||= 0
     post[:cooked] = pre_cook post[:raw]
     post[:hidden] ||= false
     post[:word_count] = post[:raw].scan(/[[:word:]]+/).size
@@ -484,7 +486,8 @@ class BulkImport::Base
         mapped = yield(row)
         next unless mapped
         processed = send(process_method_name, mapped)
-        imported_ids << mapped[:imported_id]
+        imported_ids << mapped[:imported_id] unless mapped[:imported_id].nil?
+        imported_ids |= mapped[:imported_ids] unless mapped[:imported_ids].nil?
         @raw_connection.put_copy_data columns.map { |c| processed[c] }
         print "\r%7d - %6d/sec".freeze % [imported_ids.size, imported_ids.size.to_f / (Time.now - start)] if imported_ids.size % 5000 == 0
       end
@@ -538,7 +541,18 @@ class BulkImport::Base
   end
 
   def pre_cook(raw)
-    cooked = @markdown.render(raw).scrub.strip
+    cooked = raw
+
+    # Convert YouTube URLs to lazyYT DOMs before being transformed into links
+    cooked.gsub!(/\nhttps\:\/\/www.youtube.com\/watch\?v=(\w+)\n/) do
+      video_id = $1
+      result = <<-HTML
+        <div class="lazyYT" data-youtube-id="#{video_id}" data-width="480" data-height="270" data-parameters="feature=oembed&amp;wmode=opaque"></div>
+      HTML
+      result.strip
+    end
+
+    cooked = @markdown.render(cooked).scrub.strip
 
     cooked.gsub!(/\[QUOTE="?([^,"]+)(?:, post:(\d+), topic:(\d+))?"?\](.+?)\[\/QUOTE\]/im) do
       username, post_id, topic_id = $1, $2, $3