import type { BrandingShell } from '@/lib/email/shell';

import { consumePendingWelcome } from './pending-welcome';

interface AuthBranding {
  appName?: string | null;
  logoUrl?: string | null;
  backgroundUrl?: string | null;
}

/**
 * Builds the email body for better-auth's `sendResetPassword` callback,
 * choosing between two framings of the same set-password link:
 *
 *   - a unique **welcome** email when the recipient was flagged by the admin
 *     "create user" flow (a brand-new user has nothing to reset), or
 *   - the standard **password-reset** email for genuine self-service resets.
 *
 * Pure aside from rendering — no SMTP, no DB — so the welcome-vs-reset routing
 * is directly unit-testable.
 */
export async function buildAccountPasswordEmail(opts: {
  email: string;
  name?: string | null;
  url: string;
  appName: string;
  authBranding: AuthBranding | null;
}): Promise<{ subject: string; html: string; text: string }> {
  const emailBranding: BrandingShell | null = opts.authBranding
    ? {
        logoUrl: opts.authBranding.logoUrl ?? null,
        backgroundUrl: opts.authBranding.backgroundUrl ?? null,
        primaryColor: null,
        emailHeaderHtml: null,
        emailFooterHtml: null,
      }
    : null;

  if (consumePendingWelcome(opts.email)) {
    const { crmWelcomeEmail } = await import('@/lib/email/templates/crm-welcome');
    return crmWelcomeEmail(
      { link: opts.url, recipientName: opts.name ?? undefined, appName: opts.appName },
      { branding: emailBranding },
    );
  }

  const { renderShell, safeUrl } = await import('@/lib/email/shell');
  const subject = `Reset your ${opts.appName} password`;
  const safeName = (opts.name || 'there').replace(/[<>&]/g, '');
  const body = `
    <p style="margin-bottom:16px;">Hi ${safeName},</p>
    <p style="margin-bottom:16px;">You requested a password reset for your ${opts.appName} account.</p>
    <p style="margin-bottom:16px;">
      <a href="${safeUrl(opts.url)}" style="color:#2563eb;font-weight:600;">Click here to set a new password</a>
      - the link expires in 1 hour.
    </p>
    <p style="color:#64748b;">If you didn't request this, you can safely ignore this email.</p>
  `;
  const html = renderShell({ title: subject, body, branding: emailBranding });
  const text = `Reset your password: ${opts.url}`;
  return { subject, html, text };
}