import {
  DEFAULT_MASK_FIELD_KEYWORDS,
  NEVER_EXPORT_FIELD_EXACT_NAMES,
  type ExportMaskPolicy,
} from "../constants/export";

function hitKeyword(field: string, keywords: readonly string[]): boolean {
  const name = field.toLowerCase();
  return keywords.some((k) => name.includes(k.toLowerCase()));
}

function normalizeFieldName(field: string): string {
  return field.toLowerCase().replace(/[_-]/g, "");
}

function shouldNeverExportField(field: string): boolean {
  const normalizedField = normalizeFieldName(field);
  return NEVER_EXPORT_FIELD_EXACT_NAMES.includes(
    normalizedField as (typeof NEVER_EXPORT_FIELD_EXACT_NAMES)[number],
  );
}

function shouldMaskField(field: string): boolean {
  return hitKeyword(field, DEFAULT_MASK_FIELD_KEYWORDS);
}

function maskValue(value: unknown): unknown {
  if (value === null || value === undefined) {
    return value;
  }
  if (typeof value === "string") {
    return "***";
  }
  if (typeof value === "number") {
    return 0;
  }
  if (typeof value === "boolean") {
    return false;
  }
  return "[masked]";
}

export function sanitizeUserForExport(
  row: Record<string, unknown>,
  maskPolicy: ExportMaskPolicy,
): Record<string, unknown> {
  const out: Record<string, unknown> = {};
  for (const [field, value] of Object.entries(row)) {
    if (shouldNeverExportField(field)) {
      continue;
    }
    if (maskPolicy === "masked" && shouldMaskField(field)) {
      out[field] = maskValue(value);
      continue;
    }
    out[field] = value;
  }
  return out;
}

// Backward-compatible alias used by current tests/callers.
export const applyExportMask = sanitizeUserForExport;