const CREATE_FIELDS = ["name", "description", "default_treatment", "active"];
const UPDATE_FIELDS = ["description", "default_treatment", "active"];

const hasOwn = (value, key) => Object.prototype.hasOwnProperty.call(value, key);

/**
 * Trims stable feature flag identity fields while leaving free-form text unchanged.
 */
const normalizeStringField = (key, value) => {
  if (value == null) return value;
  if (key !== "name" && key !== "default_treatment") return value;
  return typeof value === "string" ? value.trim() : value;
};

/**
 * Whitelists fields accepted by feature flag definition create/update admin endpoints.
 */
const pickFeatureFlagFields = (input, allowedFields) => {
  if (!input || typeof input !== "object" || Array.isArray(input)) {
    return {};
  }

  return allowedFields.reduce((payload, field) => {
    if (hasOwn(input, field)) {
      payload[field] = normalizeStringField(field, input[field]);
    }
    return payload;
  }, {});
};

/**
 * Builds a safe payload for creating a feature flag definition.
 */
const sanitizeFeatureFlagCreatePayload = (input) => pickFeatureFlagFields(input, CREATE_FIELDS);

/**
 * Builds a safe payload for updating editable feature flag definition fields.
 */
const sanitizeFeatureFlagUpdatePayload = (input) => pickFeatureFlagFields(input, UPDATE_FIELDS);

module.exports = {
  sanitizeFeatureFlagCreatePayload,
  sanitizeFeatureFlagUpdatePayload
};