require "active_record"

module TurntableHelper
  def reload_turntable!(config_file_name = nil, env = :test)
    ActiveRecord::Base.include(ActiveRecord::Turntable)
    ActiveRecord::SchemaDumper.prepend(ActiveRecord::Turntable::ActiveRecordExt::SchemaDumper)
    ActiveRecord::Base.turntable_configuration_file = config_file_name
    configuration =
      ActiveRecord::Turntable::Configuration.load(
        ActiveRecord::Base.turntable_configuration_file,
        env
      )
    ActiveRecord::Base.reset_turntable_configuration(configuration)
    ActiveRecord::Base.logger = Logger.new("/dev/null")
    ActiveRecord::Base.establish_connection(env)
  end

  def migrate(version)
    ActiveRecord::Migrator.run(:up, MIGRATIONS_ROOT, version)
  end

  # Helper methods below come from rails test helpers
  #
  def capture_sql
    SQLCounter.clear_log
    yield
    SQLCounter.log_all.dup
  end

  class SQLCounter
    class << self
      attr_accessor :ignored_sql, :log, :log_all
      def clear_log; self.log = []; self.log_all = []; end
    end

    clear_log

    self.ignored_sql = [/^PRAGMA/, /^SELECT currval/, /^SELECT CAST/, /^SELECT @@IDENTITY/, /^SELECT @@ROWCOUNT/, /^SAVEPOINT/, /^ROLLBACK TO SAVEPOINT/, /^RELEASE SAVEPOINT/, /^SHOW max_identifier_length/, /^BEGIN/, /^COMMIT/]

    # FIXME: this needs to be refactored so specific database can add their own
    # ignored SQL, or better yet, use a different notification for the queries
    # instead examining the SQL content.
    oracle_ignored     = [/^select .*nextval/i, /^SAVEPOINT/, /^ROLLBACK TO/, /^\s*select .* from all_triggers/im, /^\s*select .* from all_constraints/im, /^\s*select .* from all_tab_cols/im]
    mysql_ignored      = [/^SHOW FULL TABLES/i, /^SHOW FULL FIELDS/, /^SHOW CREATE TABLE /i, /^SHOW VARIABLES /, /^\s*SELECT (?:column_name|table_name)\b.*\bFROM information_schema\.(?:key_column_usage|tables)\b/im]
    postgresql_ignored = [/^\s*select\b.*\bfrom\b.*pg_namespace\b/im, /^\s*select tablename\b.*from pg_tables\b/im, /^\s*select\b.*\battname\b.*\bfrom\b.*\bpg_attribute\b/im, /^SHOW search_path/i]
    sqlite3_ignored =    [/^\s*SELECT name\b.*\bFROM sqlite_master/im, /^\s*SELECT sql\b.*\bFROM sqlite_master/im]

    [oracle_ignored, mysql_ignored, postgresql_ignored, sqlite3_ignored].each do |db_ignored_sql|
      ignored_sql.concat db_ignored_sql
    end

    attr_reader :ignore

    def initialize(ignore = Regexp.union(self.class.ignored_sql))
      @ignore = ignore
    end

    def call(name, start, finish, message_id, values)
      return if values[:cached]

      sql = values[:sql]
      self.class.log_all << sql
      self.class.log << sql unless ignore =~ sql
    end
  end

  ActiveSupport::Notifications.subscribe("sql.active_record", SQLCounter.new)
end
