module ActiveRecord::ConnectionAdapters::MySQL::DatabaseStatements

def analyze_without_explain?
  mariadb? && database_version >= "10.1.0"
end

def build_explain_clause(options = [])
  return "EXPLAIN" if options.empty?
  explain_clause = "EXPLAIN #{options.join(" ").upcase}"
  if analyze_without_explain? && explain_clause.include?("ANALYZE")
    explain_clause.sub("EXPLAIN ", "")
  else
    explain_clause
  end
end

def combine_multi_statements(total_sql)
  total_sql.each_with_object([]) do |sql, total_sql_chunks|
    previous_packet = total_sql_chunks.last
    if max_allowed_packet_reached?(sql, previous_packet)
      total_sql_chunks << +sql
    else
      previous_packet << ";\n"
      previous_packet << sql
    end
  end
end

def default_insert_value(column)
  super unless column.auto_increment?
end

def explain(arel, binds = [], options = [])
  sql     = build_explain_clause(options) + " " + to_sql(arel, binds)
  start   = Process.clock_gettime(Process::CLOCK_MONOTONIC)
  result  = internal_exec_query(sql, "EXPLAIN", binds)
  elapsed = Process.clock_gettime(Process::CLOCK_MONOTONIC) - start
  MySQL::ExplainPrettyPrinter.new.pp(result, elapsed)
end

def high_precision_current_timestamp
  HIGH_PRECISION_CURRENT_TIMESTAMP
end

def max_allowed_packet
  @max_allowed_packet ||= show_variable("max_allowed_packet")
end

def max_allowed_packet_reached?(current_packet, previous_packet)
  if current_packet.bytesize > max_allowed_packet
    raise ActiveRecordError,
      "Fixtures set is too large #{current_packet.bytesize}. Consider increasing the max_allowed_packet variable."
  elsif previous_packet.nil?
    true
  else
    (current_packet.bytesize + previous_packet.bytesize + 2) > max_allowed_packet
  end
end

def returning_column_values(result)
  if supports_insert_returning?
    result.rows.first
  else
    super
  end
end

def write_query?(sql) # :nodoc:
  !READ_QUERY.match?(sql)
rescue ArgumentError # Invalid encoding
  !READ_QUERY.match?(sql.b)
end