#306

backend/app/services/material_sync_export_path.rb

@@ -0,0 +1,56 @@
+class MaterialSyncExportPath
+  class << self
+    def build prefix: nil, relative_path: nil, filename: nil, source_file_id: nil
+      path = normalize_path(relative_path)
+      path = fallback_filename(filename, source_file_id) if path.blank?
+
+      normalized_prefix = normalize_path(prefix)
+      return path if normalized_prefix.blank?
+      return normalized_prefix if path.blank?
+
+      [normalized_prefix, path].join('/')
+    end
+
+    def normalize_path path
+      raw = path.to_s.delete("\0").tr('\\', '/').strip
+      raw = raw.sub(%r{\A[A-Za-z]:/+}, '')
+      raw = raw.sub(%r{\A/+}, '')
+      return nil if raw.blank?
+
+      segments = raw.split('/').filter_map do |segment|
+        normalized = normalize_segment(segment)
+        normalized.presence
+      end
+      return nil if segments.empty?
+
+      segments.join('/')
+    end
+
+    def uniquify path, source_file_id
+      normalized = normalize_path(path)
+      return normalized if normalized.blank? || source_file_id.blank?
+
+      ext = File.extname(normalized)
+      base = ext.present? ? normalized.delete_suffix(ext) : normalized
+      "#{ base }--#{ source_file_id }#{ ext }"
+    end
+
+    private
+
+    def fallback_filename filename, source_file_id
+      name = normalize_path(filename)
+      return name if name.present?
+      return nil if source_file_id.blank?
+
+      source_file_id.to_s
+    end
+
+    def normalize_segment segment
+      cleaned = segment.to_s.delete("\0").tr('\\/', '_').strip
+      return nil if cleaned.blank? || cleaned == '.'
+      return '__' if cleaned == '..'
+
+      cleaned
+    end
+  end
+end