module ActiveRecord::ConnectionAdapters::PostgreSQL::DatabaseStatements

def begin_db_transaction # :nodoc:
  internal_execute("BEGIN", "TRANSACTION", allow_retry: true, materialize_transactions: false)
end

def begin_isolated_db_transaction(isolation) # :nodoc:
  internal_execute("BEGIN ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}", "TRANSACTION", allow_retry: true, materialize_transactions: false)
end

def build_explain_clause(options = [])
  return "EXPLAIN" if options.empty?
  "EXPLAIN (#{options.join(", ").upcase})"
end

def build_truncate_statements(table_names)
  ["TRUNCATE TABLE #{table_names.map(&method(:quote_table_name)).join(", ")}"]
end

def cancel_any_running_query
  return if @raw_connection.nil? || IDLE_TRANSACTION_STATUSES.include?(@raw_connection.transaction_status)
  @raw_connection.cancel
  @raw_connection.block
rescue PG::Error
end

def commit_db_transaction # :nodoc:
  internal_execute("COMMIT", "TRANSACTION", allow_retry: false, materialize_transactions: true)
end

def exec_delete(sql, name = nil, binds = []) # :nodoc:
  execute_and_clear(sql, name, binds) { |result| result.cmd_tuples }
end

def exec_insert(sql, name = nil, binds = [], pk = nil, sequence_name = nil, returning: nil) # :nodoc:
  if use_insert_returning? || pk == false
    super
  else
    result = internal_exec_query(sql, name, binds)
    unless sequence_name
      table_ref = extract_table_ref_from_insert_sql(sql)
      if table_ref
        pk = primary_key(table_ref) if pk.nil?
        pk = suppress_composite_primary_key(pk)
        sequence_name = default_sequence_name(table_ref, pk)
      end
      return result unless sequence_name
    end
    last_insert_id_result(sequence_name)
  end
end

def exec_restart_db_transaction # :nodoc:
  cancel_any_running_query
  internal_execute("ROLLBACK AND CHAIN", "TRANSACTION", allow_retry: false, materialize_transactions: true)
end

def exec_rollback_db_transaction # :nodoc:
  cancel_any_running_query
  internal_execute("ROLLBACK", "TRANSACTION", allow_retry: false, materialize_transactions: true)
end

def execute(...) # :nodoc:
  super
ensure
  @notice_receiver_sql_warnings = []
end

def execute_batch(statements, name = nil)
  execute(combine_multi_statements(statements))
end

def explain(arel, binds = [], options = [])
  sql    = build_explain_clause(options) + " " + to_sql(arel, binds)
  result = internal_exec_query(sql, "EXPLAIN", binds)
  PostgreSQL::ExplainPrettyPrinter.new.pp(result)
end

def handle_warnings(sql)
  @notice_receiver_sql_warnings.each do |warning|
    next if warning_ignored?(warning)
    warning.sql = sql
    ActiveRecord.db_warnings_action.call(warning)
  end
end

def high_precision_current_timestamp
  HIGH_PRECISION_CURRENT_TIMESTAMP
end

def internal_exec_query(sql, name = "SQL", binds = [], prepare: false, async: false, allow_retry: false, materialize_transactions: true) # :nodoc:
  execute_and_clear(sql, name, binds, prepare: prepare, async: async, allow_retry: allow_retry, materialize_transactions: materialize_transactions) do |result|
    types = {}
    fields = result.fields
    fields.each_with_index do |fname, i|
      ftype = result.ftype i
      fmod  = result.fmod i
      types[fname] = types[i] = get_oid_type(ftype, fmod, fname)
    end
    build_result(columns: fields, rows: result.values, column_types: types)
  end
end

def last_insert_id_result(sequence_name)
  internal_exec_query("SELECT currval(#{quote(sequence_name)})", "SQL")
end

def query(sql, name = nil) # :nodoc:
  mark_transaction_written_if_write(sql)
  log(sql, name) do
    with_raw_connection do |conn|
      result = conn.async_exec(sql).map_types!(@type_map_for_results).values
      verified!
      result
    end
  end
end

def raw_execute(sql, name, async: false, allow_retry: false, materialize_transactions: true)
  log(sql, name, async: async) do
    with_raw_connection(allow_retry: allow_retry, materialize_transactions: materialize_transactions) do |conn|
      result = conn.async_exec(sql)
      verified!
      handle_warnings(result)
      result
    end
  end
end

def returning_column_values(result)
  result.rows.first
end

def suppress_composite_primary_key(pk)
  pk unless pk.is_a?(Array)
end

def warning_ignored?(warning)
  ["WARNING", "ERROR", "FATAL", "PANIC"].exclude?(warning.level) || super
end

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