/**
 * Turning results into the text the model reads.
 *
 * Twenty results with 600-character snippets is roughly 15KB, comfortably under
 * pi's 50KB / 2000-line budget — but the truncation is applied anyway rather
 * than argued about, because a pathological page could blow past it and an
 * overflowing tool result costs the whole session, not just this call.
 */

import type { SearchResult } from "./extract.ts";

export type FormatInput = {
  query: string;
  searchUrl: string;
  finalUrl: string;
  endpoint: string;
  /** Engine display name, e.g. "DuckDuckGo". */
  engine: string;
  /** Where the engine choice came from, e.g. "/search-engine". */
  engineSource: string;
  results: SearchResult[];
};

export const formatResults = (input: FormatInput): string => {
  const lines: string[] = [
    // Naming the engine on every result set matters more than it looks: the
    // agent may have switched engines mid-conversation to get around a block,
    // and results from different indexes are not interchangeable evidence.
    `Search results for "${input.query}" — ${input.results.length} hits from ${input.engine} ` +
      `(${input.engineSource}), via Chrome at ${input.endpoint}`,
    `Query URL: ${input.searchUrl}`,
  ];
  if (input.finalUrl !== input.searchUrl) lines.push(`Landed on: ${input.finalUrl}`);
  lines.push("");

  input.results.forEach((result, index) => {
    lines.push(`${index + 1}. ${result.title}`);
    lines.push(`   ${result.url}`);
    if (result.snippet) lines.push(`   ${result.snippet}`);
    lines.push("");
  });

  return lines.join("\n").trimEnd();
};

/**
 * The note appended when pi's truncation utilities cut the output. Says what was
 * lost and what to do about it — a bare "[truncated]" tells the model nothing it
 * can act on, and there is no temp file to point at because the full text only
 * ever existed in memory.
 */
export const truncationNote = (shown: number, total: number, bytesShown: string, bytesTotal: string): string =>
  `\n\n[Output truncated: ${shown} of ${total} lines (${bytesShown} of ${bytesTotal}). ` +
  `Re-run castle_cdp_search with a smaller numResults to see the rest.]`;