export const DEFAULT_PARTY_BUFF_POLICY = Object.freeze({ schemaVersion: 1, rules: Object.freeze([]) });

export function normalizePartyBuffPolicy(value) {
  if (!value || typeof value !== "object" || Array.isArray(value) || value.schemaVersion !== 1
    || !Array.isArray(value.rules) || value.rules.length > 500) {
    throw new Error("Party buff policy must have schemaVersion 1 and at most 500 rules.");
  }
  const seen = new Set();
  const rules = value.rules.map((rule, index) => {
    if (!rule || typeof rule !== "object" || Array.isArray(rule)
      || typeof rule.abilityId !== "string" || !/^[a-z0-9][a-z0-9:._-]{0,127}$/i.test(rule.abilityId)
      || !["party", "tank", "healer"].includes(rule.scope)) {
      throw new Error(`Party buff rule ${index} must have a valid abilityId and scope.`);
    }
    if (seen.has(rule.abilityId)) throw new Error(`Duplicate party buff rule: ${rule.abilityId}.`);
    seen.add(rule.abilityId);
    return { abilityId: rule.abilityId, scope: rule.scope };
  });
  return { schemaVersion: 1, rules };
}