module Adr
  # Renders templates/adr.md by substituting {{key}} placeholders.
  # Arrays render as YAML flow sequences; missing keys render empty.
  class Template
    def initialize(path:)
      @path = path
    end

    def render(values)
      File.read(@path).gsub(/\{\{(\w+)\}\}/) do
        format_value(values[Regexp.last_match(1).to_sym])
      end.gsub(/ +$/, "")
    end

    private

    def format_value(value)
      case value
      when nil   then ""
      when Array then "[#{value.join(', ')}]"
      else value.to_s
      end
    end
  end
end