module SingaiPrompt

# File lib/singai_prompt.rb, line 20
def build_agent_prompt(artist:, title:, original_lines:, channel_lines:, fandom_lines:, asker:, channel:)
  artist_text = artist.to_s.strip
  title_text = title.to_s.strip
  return AiGuard.rejection_message if AiGuard.system_request?(artist_text)
  return AiGuard.rejection_message if AiGuard.system_request?(title_text)

  originals = Array(original_lines).map(&:to_s).map(&:strip).reject(&:empty?)
  parts = [INSTRUCTION, ""]

  if channel_lines.any?
    parts << "Recent messages in #{channel} (oldest to newest):"
    parts.concat(channel_lines)
    parts << ""
  end

  if fandom_lines.any?
    parts << "Fandom / bot personas in this channel (use if relevant):"
    parts.concat(fandom_lines)
    parts << ""
  end

  parts << "Original song: #{artist_text} — #{title_text}"
  parts << "Original lyrics (#{originals.length} lines):"
  parts.concat(originals)
  parts << ""
  parts << "Write exactly #{originals.length} themed lyric lines for #{asker} in #{channel}."

  AiGuard.guard_prompt(parts.join("\n"))
end