/**
 * ابزار بارگذاری و اعمال تم White-label.
 * برند از theme.config.json یا API تنظیمات خوانده می‌شود.
 */

export interface ThemeConfig {
  site_name: string;
  primary_color: string;
  secondary_color: string;
  logo_url: string;
  support_email: string;
}

export const DEFAULT_THEME: ThemeConfig = {
  site_name: "SuperApp",
  primary_color: "#0284c7",
  secondary_color: "#0f172a",
  logo_url: "/assets/logo.png",
  support_email: "support@example.com",
};

export function applyTheme(
  theme: ThemeConfig,
  root: HTMLElement = document.documentElement
): void {
  root.style.setProperty("--color-primary", theme.primary_color);
  root.style.setProperty("--color-secondary", theme.secondary_color);
  root.style.setProperty("--color-primary-muted", hexWithAlpha(theme.primary_color, 0.12));
  root.style.setProperty("--color-primary-soft", hexWithAlpha(theme.primary_color, 0.08));
  root.style.setProperty("--color-secondary-muted", hexWithAlpha(theme.secondary_color, 0.06));
}

function hexWithAlpha(hex: string, alpha: number): string {
  const normalized = hex.replace("#", "");
  if (normalized.length !== 6) return hex;
  const r = parseInt(normalized.slice(0, 2), 16);
  const g = parseInt(normalized.slice(2, 4), 16);
  const b = parseInt(normalized.slice(4, 6), 16);
  return `rgba(${r}, ${g}, ${b}, ${alpha})`;
}

export async function loadTheme(url = "/theme.config.json"): Promise<ThemeConfig> {
  try {
    const res = await fetch(url);
    if (!res.ok) return DEFAULT_THEME;
    return { ...DEFAULT_THEME, ...(await res.json()) };
  } catch {
    return DEFAULT_THEME;
  }
}