/**
 * Settings API client — SMTP configuration.
 * Consumes the SettingsController built in 07-03.
 * All calls use credentials: 'include' for cookie-based auth.
 *
 * T-07-17: SmtpConfig exposes only hasPassword, never the secret.
 * The password field is never pre-filled from server data.
 */

const API_URL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:3001';

// --- Types mirroring the 07-03 backend contract ---

/**
 * SMTP configuration as returned by GET /settings/smtp.
 * encryptedPassword is NEVER returned (T-07-17).
 */
export interface SmtpConfig {
  host: string;
  port: number;
  encryption: 'none' | 'starttls' | 'ssl-tls';
  username?: string;
  fromAddress: string;
  /** True when an encrypted password is stored; the password value is never exposed. */
  hasPassword: boolean;
}

/**
 * Payload for PUT /settings/smtp and POST /settings/smtp/test.
 * password is optional — omit to preserve the existing stored password.
 */
export interface SaveSmtpPayload {
  host: string;
  port: number;
  encryption: 'none' | 'starttls' | 'ssl-tls';
  username?: string;
  /** Only include when the user has typed a new password. */
  password?: string;
  fromAddress: string;
  /** If set, backend sends a real test email to this address instead of just verify(). */
  testTo?: string;
}

// --- API functions ---

/**
 * Fetch the SMTP configuration for the current tenant.
 * GET /settings/smtp
 * Returns null when no configuration has been saved yet (404).
 */
export async function fetchSmtp(): Promise<SmtpConfig | null> {
  const res = await fetch(`${API_URL}/settings/smtp`, {
    credentials: 'include',
  });
  if (res.status === 404) return null;
  if (!res.ok) throw new Error('Failed to fetch SMTP config');
  return res.json();
}

/**
 * Save the SMTP configuration.
 * PUT /settings/smtp
 */
export async function saveSmtp(payload: SaveSmtpPayload): Promise<SmtpConfig> {
  const res = await fetch(`${API_URL}/settings/smtp`, {
    method: 'PUT',
    headers: { 'Content-Type': 'application/json' },
    credentials: 'include',
    body: JSON.stringify(payload),
  });
  if (!res.ok) throw new Error('Failed to save SMTP config');
  return res.json();
}

/**
 * Test the SMTP connection with the given settings.
 * POST /settings/smtp/test
 * Returns { success: boolean } — backend runs nodemailer.verify().
 */
export async function testSmtp(
  payload: SaveSmtpPayload,
): Promise<{ success: boolean; warning?: string }> {
  const res = await fetch(`${API_URL}/settings/smtp/test`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    credentials: 'include',
    body: JSON.stringify(payload),
  });
  if (!res.ok) throw new Error('Failed to test SMTP config');
  return res.json();
}