'use client';

import type { ErrorCorrectionLevel } from '@/types/qrcode';

export interface QRShareableState {
  text?: string;
  errorCorrection?: ErrorCorrectionLevel;
  foregroundColor?: string;
  backgroundColor?: string;
  margin?: number;
}

const DEFAULTS = {
  errorCorrection: 'M' as ErrorCorrectionLevel,
  foregroundColor: '#000000',
  backgroundColor: '#ffffff',
  margin: 4,
};

export function decodeQRFromUrl(): QRShareableState | null {
  if (typeof window === 'undefined') return null;

  const params = new URLSearchParams(window.location.search);
  const text = params.get('text');
  const ec = params.get('ec') as ErrorCorrectionLevel | null;
  const fg = params.get('fg');
  const bg = params.get('bg');
  const margin = params.get('margin');

  if (!text && !ec && !fg && !bg && !margin) return null;

  return {
    text: text || undefined,
    errorCorrection: ec || undefined,
    foregroundColor: fg ? `#${fg}` : undefined,
    backgroundColor: bg ? `#${bg}` : undefined,
    margin: margin ? parseInt(margin, 10) : undefined,
  };
}

export function updateQRUrl(
  text: string,
  errorCorrection: ErrorCorrectionLevel,
  foregroundColor: string,
  backgroundColor: string,
  margin: number,
): void {
  if (typeof window === 'undefined') return;

  const params = new URLSearchParams();

  if (text) params.set('text', text);
  if (errorCorrection !== DEFAULTS.errorCorrection) params.set('ec', errorCorrection);
  if (foregroundColor !== DEFAULTS.foregroundColor) params.set('fg', foregroundColor.replace('#', ''));
  if (backgroundColor !== DEFAULTS.backgroundColor) params.set('bg', backgroundColor.replace('#', ''));
  if (margin !== DEFAULTS.margin) params.set('margin', String(margin));

  const query = params.toString();
  const newUrl = query
    ? `${window.location.pathname}?${query}`
    : window.location.pathname;

  window.history.replaceState({}, '', newUrl);
}

export function getQRShareableUrl(
  text: string,
  errorCorrection: ErrorCorrectionLevel,
  foregroundColor: string,
  backgroundColor: string,
  margin: number,
): string {
  if (typeof window === 'undefined') return '';

  const params = new URLSearchParams();

  if (text) params.set('text', text);
  if (errorCorrection !== DEFAULTS.errorCorrection) params.set('ec', errorCorrection);
  if (foregroundColor !== DEFAULTS.foregroundColor) params.set('fg', foregroundColor.replace('#', ''));
  if (backgroundColor !== DEFAULTS.backgroundColor) params.set('bg', backgroundColor.replace('#', ''));
  if (margin !== DEFAULTS.margin) params.set('margin', String(margin));

  const query = params.toString();
  return `${window.location.origin}${window.location.pathname}${query ? `?${query}` : ''}`;
}