require 'date'

module DuckDB
  if defined?(DuckDB::Appender)
    # The DuckDB::Appender encapsulates DuckDB Appender.
    #
    #   require 'duckdb'
    #   db = DuckDB::Database.open
    #   con = db.connect
    #   con.query('CREATE TABLE users (id INTEGER, name VARCHAR)')
    #   appender = con.appender('users')
    #   appender.append_row(1, 'Alice')
    #
    class Appender
      RANGE_INT16 = -32_768..32_767
      RANGE_INT32 = -2_147_483_648..2_147_483_647
      RANGE_INT64 = -9_223_372_036_854_775_808..9_223_372_036_854_775_807

      def append_hugeint(value)
        case value
        when Integer
          append_varchar(value.to_s)
        else
          rb_raise(ArgumentError, "2nd argument `#{value}` must be Integer.")
        end
      end

      #
      # appends value.
      #
      #   require 'duckdb'
      #   db = DuckDB::Database.open
      #   con = db.connect
      #   con.query('CREATE TABLE users (id INTEGER, name VARCHAR)')
      #   appender = con.appender('users')
      #   appender.begin_row
      #   appender.append(1)
      #   appender.append('Alice')
      #   appender.end_row
      #
      def append(value)
        case value
        when NilClass
          append_null
        when Float
          append_double(value)
        when Integer
          case value
          when RANGE_INT16
            append_int16(value)
          when RANGE_INT32
            append_int32(value)
          when RANGE_INT64
            append_int64(value)
          else
            append_hugeint(value)
          end
        when String
          if defined?(DuckDB::Blob)
            blob?(value) ? append_blob(value) : append_varchar(value)
          else
            append_varchar(value)
          end
        when TrueClass, FalseClass
          append_bool(value)
        when Time
          append_varchar(value.strftime('%Y-%m-%d %H:%M:%S.%N'))
        when Date
          append_varchar(value.strftime('%Y-%m-%d'))
        else
          rb_raise(DuckDB::Error, "not supported type #{value} (value.class)")
        end
      end

      #
      # append a row.
      #
      #   appender.append_row(1, 'Alice')
      #
      # is same as:
      #
      #   appender.begin_row
      #   appender.append(1)
      #   appender.append('Alice')
      #   appender.end_row
      #
      def append_row(*args)
        begin_row
        args.each do |arg|
          append(arg)
        end
        end_row
      end

      private

      def blob?(value)
        value.instance_of?(DuckDB::Blob) || value.encoding == Encoding::BINARY
      end
    end
  end
end