module ActiveRecord::Explain

def build_explain_clause(connection, options = [])
  if connection.respond_to?(:build_explain_clause, true)
    connection.build_explain_clause(options)
  else
    "EXPLAIN for:"
  end
end

def collecting_queries_for_explain # :nodoc:
  ExplainRegistry.collect = true
  yield
  ExplainRegistry.queries
ensure
  ExplainRegistry.reset
end

def exec_explain(queries, options = []) # :nodoc:
  str = with_connection do |c|
    queries.map do |sql, binds|
      msg = +"#{build_explain_clause(c, options)} #{sql}"
      unless binds.empty?
        msg << " "
        msg << binds.map { |attr| render_bind(c, attr) }.inspect
      end
      msg << "\n"
      msg << c.explain(sql, binds, options)
    end.join("\n")
  end
  # Overriding inspect to be more human readable, especially in the console.
  def str.inspect
    self
  end
  str
end

def render_bind(connection, attr)
  if ActiveModel::Attribute === attr
    value = if attr.type.binary? && attr.value
      "<#{attr.value_for_database.to_s.bytesize} bytes of binary data>"
    else
      connection.type_cast(attr.value_for_database)
    end
  else
    value = connection.type_cast(attr)
    attr  = nil
  end
  [attr&.name, value]
end