/**
 * Small manual validators for admin API inputs (zod is intentionally not a
 * dependency). Each returns a discriminated result.
 */

const UUID_RE =
  /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;

export function isUuid(v: unknown): v is string {
  return typeof v === 'string' && UUID_RE.test(v);
}

export function parseBoolean(v: unknown): boolean | null {
  if (typeof v === 'boolean') return v;
  return null;
}

export function parsePositiveInt(
  v: unknown,
  max: number,
): { ok: true; value: number } | { ok: false; error: string } {
  if (typeof v !== 'number' || !Number.isFinite(v) || !Number.isInteger(v)) {
    return { ok: false, error: 'must be an integer' };
  }
  if (v <= 0) return { ok: false, error: 'must be positive' };
  if (v > max) return { ok: false, error: `must be <= ${max}` };
  return { ok: true, value: v };
}

export function parsePageParam(v: string | null, fallback = 1): number {
  const n = v ? Number(v) : NaN;
  if (!Number.isFinite(n) || n < 1) return fallback;
  return Math.floor(n);
}

export function parsePerPageParam(
  v: string | null,
  fallback = 25,
  max = 100,
): number {
  const n = v ? Number(v) : NaN;
  if (!Number.isFinite(n) || n < 1) return fallback;
  return Math.min(max, Math.floor(n));
}