import { getLegalSettingsValues } from '../routes/legal-settings.js';

/**
 * Strict whitelist of supported placeholders.
 * Only these placeholders will be replaced in legal page content.
 * Unknown placeholders remain unchanged.
 */
const SUPPORTED_PLACEHOLDERS = new Set([
  'COMPANY_NAME',
  'LEGAL_ENTITY_NAME',
  'RUC_NUMBER',
  'COMPANY_ADDRESS',
  'COMPANY_CITY',
  'COMPANY_COUNTRY',
  'SUPPORT_EMAIL',
  'LEGAL_EMAIL',
  'GOVERNING_LAW',
  'JURISDICTION_CITY',
  'CURRENT_YEAR',
  'LAST_UPDATED_DATE',
]);

/**
 * Replace legal placeholders in content using strict whitelist mapping.
 *
 * Rules:
 * - Only supported placeholders are replaced
 * - Unknown placeholders remain unchanged
 * - Missing values are replaced with empty string
 * - No code execution or dynamic evaluation
 * - Replacement is pure string substitution
 *
 * @param content - The markdown/text content containing {{PLACEHOLDER}} tokens
 * @param updatedAt - The page's updated_at timestamp (for LAST_UPDATED_DATE)
 * @returns Content with placeholders replaced
 */
export async function replaceLegalPlaceholders(
  content: string,
  updatedAt?: string
): Promise<string> {
  if (!content) return content;

  // Fetch legal settings values from DB
  const settingsValues = await getLegalSettingsValues();

  // Build the full replacement map
  const replacements: Record<string, string> = { ...settingsValues };

  // Dynamic values
  replacements['CURRENT_YEAR'] = new Date().getFullYear().toString();

  if (updatedAt) {
    try {
      const date = new Date(updatedAt);
      if (!isNaN(date.getTime())) {
        replacements['LAST_UPDATED_DATE'] = date.toLocaleDateString('en-US', {
          year: 'numeric',
          month: 'long',
          day: 'numeric',
        });
      } else {
        replacements['LAST_UPDATED_DATE'] = updatedAt;
      }
    } catch {
      replacements['LAST_UPDATED_DATE'] = updatedAt;
    }
  }

  // Replace only whitelisted placeholders using a single regex pass
  // Matches {{PLACEHOLDER_NAME}} where PLACEHOLDER_NAME is uppercase letters and underscores
  return content.replace(/\{\{([A-Z_]+)\}\}/g, (match, placeholderName) => {
    // Only replace if the placeholder is in the whitelist
    if (!SUPPORTED_PLACEHOLDERS.has(placeholderName)) {
      return match; // Unknown placeholder - leave unchanged
    }

    // Return the value or empty string if missing
    return replacements[placeholderName] ?? '';
  });
}