require "../prompt"

class StringParser
  def parse(current : String) : Prompt
    prompt = Prompt.new
    remaining = read_string(prompt.zones, current)
    prompt.prelude_zone.content << remaining
    
    prompt.system_zone.content.reverse!
    prompt.past_zone.content.reverse!
    prompt.present_zone.content.reverse!
    prompt.future_zone.content.reverse!

    return prompt
  end

  def read_string(zone_list : Array(Zone), current : String)
    # puts "== read_string(current=#{current})"

    pos = current.index("@@")

    ## If there is no remaining @@, then return current
    if pos.nil?
      # puts "-- no remaining @@, returning"
      return current
    end

    ## If @@ is not at position 0, then parse its content first and return remains
    if pos > 0
      return current[0..(pos-1)] + read_string(zone_list, current[pos..])
    end

    ## If @@ is at position 0, try detecting tag
    zone = zone_list.find { |zone| current.starts_with?("@@" + zone.tag) }

    ## When there is not recognizable tag, skip fake tag and parse
    if zone.nil? 
      # puts "-- no recognizable tag, returning as is"
      return "@@" + read_string(zone_list, current[2..])
    end

    ## Handle recognized tag, skip tag & parse & add remains
    # puts "-- found tag #{zone.tag}"
    remaining = read_string(zone_list, current[(2+zone.tag.size)..])
    zone.content << remaining
    return ""
  end
end