class RubyXL::OOXMLRelationshipsFile

def self.get_class_by_rel_type(rel_type)
  unless defined?(@@rel_hash)
    @@rel_hash = {}
    RubyXL.constants.each { |c|
      klass = RubyXL.const_get(c)
      if klass.is_a?(Class) && klass.const_defined?(:REL_TYPE) then
        @@rel_hash[klass::REL_TYPE] = klass
      end
    }
  end
  @@rel_hash[rel_type]
end

def self.load_relationship_file(zipdir_path, base_file_path)
  rel_file_path = rel_file_path(base_file_path)
  puts "--> DEBUG:  #{'  ' * @@debug_indent}Loading .rel file: #{rel_file_path}" if @@debug_indent
  parse_file(zipdir_path, rel_file_path)
end

def self.rel_file_path(base_file_path)
  basename = base_file_path.root? ? '' : base_file_path.basename
  base_file_path.dirname.join('_rels', "#{basename}.rels").cleanpath
end

def add_relationship(obj)
  return if obj.nil? || !defined?(obj.class::REL_TYPE) || (obj.respond_to?(:empty?) && obj.empty?)
  relationships << RubyXL::Relationship.new(:id     => "rId#{relationships.size + 1}",
                                            :type   => obj.class::REL_TYPE,
                                            :target => obj.xlsx_path.relative_path_from(owner.xlsx_path.dirname))
end

def before_write_xml
  case owner
  when RubyXL::WorkbookRoot, RubyXL::Workbook then
    # Fully implemented objects with no generic (unhandled) relationships -
    #   (re)generating relationships from scratch.
    related_objects = owner.related_objects
    related_objects += owner.generic_storage if owner.generic_storage
    self.relationships = []
    related_objects.compact.each { |f| add_relationship(f) }
  end
  super
end

def find_by_rid(r_id)
  relationships.find { |r| r.id == r_id }
end

def find_by_target(target)
  relationships.find { |r|
    (r.target == target) || (r.target == target.relative_path_from(owner.xlsx_path.dirname))
  }
end

def load_related_files(zipdir_path, base_file_name)
  self.related_files = {}
  @@debug_indent += 2 if @@debug_indent
  self.relationships.each { |rel|
    next if rel.target_mode == 'External'
    file_path = ::Pathname.new(rel.target)
    file_path = (base_file_name.dirname + file_path).cleanpath if file_path.relative?
    klass = RubyXL::OOXMLRelationshipsFile.get_class_by_rel_type(rel.type)
    if klass.nil? then
      if !RubyXL.class_variable_get(:@@suppress_warnings) then
        puts "*** WARNING: storage class not found for #{rel.target} (#{rel.type})"
      end
      klass = GenericStorageObject
    end
    puts "--> DEBUG:#{'  ' * @@debug_indent}Loading #{klass} (#{rel.id}): #{file_path}" if @@debug_indent
    obj = klass.parse_file(zipdir_path, file_path)
    obj.load_relationships(zipdir_path, file_path) if obj.respond_to?(:load_relationships)
    self.related_files[rel.id] = obj
  }
  @@debug_indent -=2 if @@debug_indent
  related_files
end

def new_relationship(target, type)
  RubyXL::Relationship.new(:id     => "rId#{relationships.size + 1}",
                           :type   => type,
                           :target => target)
end

def xlsx_path
  self.class.rel_file_path(owner.xlsx_path)
end