packages/domain/src/policies/defamation-gate.ts

/**
 * Defamation wording gate — PHASE_1 §13, CLAUDE.md safety.
 * Blocked words list matches "user reports / unresolved / alleged" only policy.
 * Never label any entity "fraud/scam/criminal".
 */

const BLOCKED_WORDS = ["fraud", "scam", "criminal", "cheater", "thief"];

const BLOCKED_RE = new RegExp(`\\b(${BLOCKED_WORDS.join("|")})\\b`, "gi");

const REPLACEMENTS: Record<string, string> = {
  fraud: "alleged issue",
  scam: "user reports",
  criminal: "user reports",
  cheater: "unresolved",
  thief: "unresolved",
};

export interface DefamationCheck {
  safe: boolean;
  flaggedTerms: string[];
  redactedBody: string;
}

export function checkDefamation(body: string): DefamationCheck {
  const flaggedTerms: string[] = [];
  const replaced = body.replace(BLOCKED_RE, (match) => {
    const lower = match.toLowerCase();
    flaggedTerms.push(match);
    return REPLACEMENTS[lower] ?? match;
  });
  return {
    safe: flaggedTerms.length === 0,
    flaggedTerms,
    redactedBody: replaced,
  };
}