/**
 * Noise Filter
 * Filters out low-quality memories (meta-questions, agent denials, session boilerplate)
 * Inspired by openclaw-plugin-continuity's noise filtering approach.
 */

// Agent-side denial patterns
const DENIAL_PATTERNS = [
  /i don'?t have (any )?(information|data|memory|record)/i,
  /i'?m not sure about/i,
  /i don'?t recall/i,
  /i don'?t remember/i,
  /it looks like i don'?t/i,
  /i wasn'?t able to find/i,
  /no (relevant )?memories found/i,
  /i don'?t have access to/i,
];

// User-side meta-question patterns (about memory itself, not content)
const META_QUESTION_PATTERNS = [
  /\bdo you (remember|recall|know about)\b/i,
  /\bcan you (remember|recall)\b/i,
  /\bdid i (tell|mention|say|share)\b/i,
  /\bhave i (told|mentioned|said)\b/i,
  /\bwhat did i (tell|say|mention)\b/i,
];

// Session boilerplate
const BOILERPLATE_PATTERNS = [
  /^(hi|hello|hey|good morning|good evening|greetings)/i,
  /^fresh session/i,
  /^new session/i,
  /^HEARTBEAT/i,
];

export interface NoiseFilterOptions {
  /** Filter agent denial responses (default: true) */
  filterDenials?: boolean;
  /** Filter meta-questions about memory (default: true) */
  filterMetaQuestions?: boolean;
  /** Filter session boilerplate (default: true) */
  filterBoilerplate?: boolean;
}

const DEFAULT_OPTIONS: Required<NoiseFilterOptions> = {
  filterDenials: true,
  filterMetaQuestions: true,
  filterBoilerplate: true,
};

/**
 * Check if a memory text is noise that should be filtered out.
 * Returns true if the text is noise.
 */
export function isNoise(text: string, options: NoiseFilterOptions = {}): boolean {
  const opts = { ...DEFAULT_OPTIONS, ...options };
  const trimmed = text.trim();

  if (trimmed.length < 5) return true;

  if (opts.filterDenials && DENIAL_PATTERNS.some(p => p.test(trimmed))) return true;
  if (opts.filterMetaQuestions && META_QUESTION_PATTERNS.some(p => p.test(trimmed))) return true;
  if (opts.filterBoilerplate && BOILERPLATE_PATTERNS.some(p => p.test(trimmed))) return true;

  return false;
}

/**
 * Filter an array of items, removing noise entries.
 */
export function filterNoise<T>(
  items: T[],
  getText: (item: T) => string,
  options?: NoiseFilterOptions
): T[] {
  const opts = { ...DEFAULT_OPTIONS, ...options };
  return items.filter(item => !isNoise(getText(item), opts));
}