class ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaDumper

def default_primary_key?(column)
  schema_type(column) == :bigserial
end

def exclusion_constraints_in_create(table, stream)
  if (exclusion_constraints = @connection.exclusion_constraints(table)).any?
    add_exclusion_constraint_statements = exclusion_constraints.map do |exclusion_constraint|
      parts = [
        "t.exclusion_constraint #{exclusion_constraint.expression.inspect}"
      ]
      parts << "where: #{exclusion_constraint.where.inspect}" if exclusion_constraint.where
      parts << "using: #{exclusion_constraint.using.inspect}" if exclusion_constraint.using
      parts << "deferrable: #{exclusion_constraint.deferrable.inspect}" if exclusion_constraint.deferrable
      if exclusion_constraint.export_name_on_schema_dump?
        parts << "name: #{exclusion_constraint.name.inspect}"
      end
      "    #{parts.join(', ')}"
    end
    stream.puts add_exclusion_constraint_statements.sort.join("\n")
  end
end

def explicit_primary_key_default?(column)
  column.type == :uuid || (column.type == :integer && !column.serial?)
end

def extensions(stream)
  extensions = @connection.extensions
  if extensions.any?
    stream.puts "  # These are extensions that must be enabled in order to support this database"
    extensions.sort.each do |extension|
      stream.puts "  enable_extension #{extension.inspect}"
    end
    stream.puts
  end
end

def extract_expression_for_virtual_column(column)
  column.default_function.inspect
end

def prepare_column_options(column)
  spec = super
  spec[:array] = "true" if column.array?
  if @connection.supports_virtual_columns? && column.virtual?
    spec[:as] = extract_expression_for_virtual_column(column)
    spec[:stored] = true
    spec = { type: schema_type(column).inspect }.merge!(spec)
  end
  spec[:enum_type] = column.sql_type.inspect if column.enum?
  spec
end

def schema_expression(column)
  super unless column.serial?
end

def schema_type(column)
  return super unless column.serial?
  if column.bigint?
    :bigserial
  else
    :serial
  end
end

def schemas(stream)
  schema_names = @connection.schema_names - ["public"]
  if schema_names.any?
    schema_names.sort.each do |name|
      stream.puts "  create_schema #{name.inspect}"
    end
    stream.puts
  end
end

def types(stream)
  types = @connection.enum_types
  if types.any?
    stream.puts "  # Custom types defined in this database."
    stream.puts "  # Note that some types may not work with other database engines. Be careful if changing database."
    types.sort.each do |name, values|
      stream.puts "  create_enum #{name.inspect}, #{values.inspect}"
    end
    stream.puts
  end
end

def unique_constraints_in_create(table, stream)
  if (unique_constraints = @connection.unique_constraints(table)).any?
    add_unique_constraint_statements = unique_constraints.map do |unique_constraint|
      parts = [
        "t.unique_constraint #{unique_constraint.column.inspect}"
      ]
      parts << "nulls_not_distinct: #{unique_constraint.nulls_not_distinct.inspect}" if unique_constraint.nulls_not_distinct
      parts << "deferrable: #{unique_constraint.deferrable.inspect}" if unique_constraint.deferrable
      if unique_constraint.export_name_on_schema_dump?
        parts << "name: #{unique_constraint.name.inspect}"
      end
      "    #{parts.join(', ')}"
    end
    stream.puts add_unique_constraint_statements.sort.join("\n")
  end
end