class Rack::Session::Abstract::SessionHash

def self.find(req)
  req.get_header RACK_SESSION
end

def self.set(req, session)
  req.set_header RACK_SESSION, session
end

def self.set_options(req, options)
  req.set_header RACK_SESSION_OPTIONS, options.dup
end

def [](key)
  load_for_read!
  @data[key.to_s]
end

def []=(key, value)
  load_for_write!
  @data[key.to_s] = value
end

def clear
  load_for_write!
  @data.clear
end

def delete(key)
  load_for_write!
  @data.delete(key.to_s)
end

def destroy
  clear
  @id = @store.send(:delete_session, @req, id, options)
end

def dig(key, *keys)
  load_for_read!
  @data.dig(key.to_s, *keys)
end

def each(&block)
  load_for_read!
  @data.each(&block)
end

def empty?
  load_for_read!
  @data.empty?
end

def exists?
  return @exists if instance_variable_defined?(:@exists)
  @data = {}
  @exists = @store.send(:session_exists?, @req)
end

def fetch(key, default = Unspecified, &block)
  load_for_read!
  if default == Unspecified
    @data.fetch(key.to_s, &block)
  else
    @data.fetch(key.to_s, default, &block)
  end
end

def has_key?(key)
  load_for_read!
  @data.has_key?(key.to_s)
end

def id
  return @id if @loaded or instance_variable_defined?(:@id)
  @id = @store.send(:extract_session_id, @req)
end

def initialize(store, req)
  @store = store
  @req = req
  @loaded = false
end

def inspect
  if loaded?
    @data.inspect
  else
    "#<#{self.class}:0x#{self.object_id.to_s(16)} not yet loaded>"
  end
end

def keys
  load_for_read!
  @data.keys
end

def load!
  @id, session = @store.send(:load_session, @req)
  @data = stringify_keys(session)
  @loaded = true
end

def load_for_read!
  load! if !loaded? && exists?
end

def load_for_write!
  load! unless loaded?
end

def loaded?
  @loaded
end

def options
  @req.session_options
end

def replace(hash)
  load_for_write!
  @data.replace(stringify_keys(hash))
end

def stringify_keys(other)
  # Use transform_keys after dropping Ruby 2.4 support
  hash = {}
  other.to_hash.each do |key, value|
    hash[key.to_s] = value
  end
  hash
end

def to_hash
  load_for_read!
  @data.dup
end

def update(hash)
  load_for_write!
  @data.update(stringify_keys(hash))
end

def values
  load_for_read!
  @data.values
end