require "erubis"

module ActionView
  class Template
    module Handlers
      class ERB
        class Erubis < ::Erubis::Eruby
          # :nodoc: all
          def add_preamble(src)
            @newline_pending = 0
            src << "@output_buffer = output_buffer || ActionView::OutputBuffer.new;"
          end

          def add_text(src, text)
            return if text.empty?

            if text == "\n"
              @newline_pending += 1
            else
              src << "@output_buffer.safe_append='"
              src << "\n" * @newline_pending if @newline_pending > 0
              src << escape_text(text)
              src << "'.freeze;"

              @newline_pending = 0
            end
          end

          # Erubis toggles <%= and <%== behavior when escaping is enabled.
          # We override to always treat <%== as escaped.
          def add_expr(src, code, indicator)
            case indicator
            when "=="
              add_expr_escaped(src, code)
            else
              super
            end
          end

          BLOCK_EXPR = /\s*((\s+|\))do|\{)(\s*\|[^|]*\|)?\s*\Z/

          def add_expr_literal(src, code)
            flush_newline_if_pending(src)
            if BLOCK_EXPR.match?(code)
              src << "@output_buffer.append= " << code
            else
              src << "@output_buffer.append=(" << code << ");"
            end
          end

          def add_expr_escaped(src, code)
            flush_newline_if_pending(src)
            if BLOCK_EXPR.match?(code)
              src << "@output_buffer.safe_expr_append= " << code
            else
              src << "@output_buffer.safe_expr_append=(" << code << ");"
            end
          end

          def add_stmt(src, code)
            flush_newline_if_pending(src)
            super
          end

          def add_postamble(src)
            flush_newline_if_pending(src)
            src << "@output_buffer.to_s"
          end

          def flush_newline_if_pending(src)
            if @newline_pending > 0
              src << "@output_buffer.safe_append='#{"\n" * @newline_pending}'.freeze;"
              @newline_pending = 0
            end
          end
        end
      end
    end
  end
end
