const DISCORD_WEBHOOK_HOSTS = new Set([
  "discord.com",
  "canary.discord.com",
  "ptb.discord.com",
]);

export function isValidDiscordWebhookUrl(value: string) {
  try {
    const url = new URL(value);
    return (
      url.protocol === "https:" &&
      DISCORD_WEBHOOK_HOSTS.has(url.hostname) &&
      /^\/api\/webhooks\/[^/]+\/[^/]+\/?$/.test(url.pathname)
    );
  } catch {
    return false;
  }
}

export function previewWebhookTemplate(
  template: string,
  options: { update?: boolean } = {}
) {
  const source =
    template.trim() ||
    (options.update
      ? "Submission updated by {username} ({id}).\n{update}"
      : "New submission from {username} ({id}).");
  return source.replace(/\{([^}]+)\}/g, (_match, variable: string) => {
    const key = variable.toLowerCase();
    if (key === "username" || key === "displayname") return "Example User";
    if (key === "id") return "123456789";
    if (key === "link") {
      return "https://erika.sudloh.com/admin/form/example-form/result/example-submission";
    }
    if (key === "update") return "Question 1: Previous answer → Example answer";
    if (/^\d+$/.test(key)) return `Example answer ${key}`;
    return `{${variable}}`;
  });
}