/**
 * WHMCS Custom Field Utilities (domain-internal)
 */

const isObject = (value: unknown): value is Record<string, unknown> =>
  typeof value === "object" && value !== null;

const normalizeCustomFieldEntries = (value: unknown): Array<Record<string, unknown>> => {
  if (Array.isArray(value)) return value.filter(isObject);
  if (isObject(value) && "customfield" in value) {
    const custom = (value as { customfield?: unknown }).customfield;
    if (Array.isArray(custom)) return custom.filter(isObject);
    if (isObject(custom)) return [custom];
    return [];
  }
  return [];
};

/**
 * Build a lightweight map of WHMCS custom field identifiers to values.
 * Accepts the documented WHMCS response shapes (array or { customfield }).
 */
export function getCustomFieldsMap(customFields: unknown): Record<string, string> {
  if (!customFields) return {};

  if (isObject(customFields) && !Array.isArray(customFields) && !("customfield" in customFields)) {
    return Object.entries(customFields).reduce<Record<string, string>>((acc, [key, value]) => {
      if (typeof value === "string") {
        const trimmedKey = key.trim();
        if (trimmedKey) acc[trimmedKey] = value;
      }
      return acc;
    }, {});
  }

  const map: Record<string, string> = {};
  for (const entry of normalizeCustomFieldEntries(customFields)) {
    const idRaw = "id" in entry ? entry["id"] : undefined;
    const id =
      typeof idRaw === "string"
        ? idRaw.trim()
        : typeof idRaw === "number"
          ? String(idRaw)
          : undefined;
    const nameRaw = "name" in entry ? entry["name"] : undefined;
    const name = typeof nameRaw === "string" ? nameRaw.trim() : undefined;
    const rawValue = "value" in entry ? entry["value"] : undefined;
    if (rawValue === undefined || rawValue === null) continue;
    const value =
      typeof rawValue === "string"
        ? rawValue
        : typeof rawValue === "number" || typeof rawValue === "boolean"
          ? String(rawValue)
          : undefined;
    if (!value) continue;

    if (id) map[id] = value;
    if (name) map[name] = value;
  }

  return map;
}

/**
 * Retrieve a custom field value by numeric id or name.
 */
export function getCustomFieldValue(
  customFields: unknown,
  key: string | number
): string | undefined {
  if (key === undefined || key === null) return undefined;
  const map = getCustomFieldsMap(customFields);
  const primary = map[String(key)];
  if (primary !== undefined) return primary;

  if (typeof key === "string") {
    const numeric = Number.parseInt(key, 10);
    if (!Number.isNaN(numeric)) {
      const numericValue = map[String(numeric)];
      if (numericValue !== undefined) return numericValue;
    }
  }

  return undefined;
}