import type { CapabilityProvider, CapabilityRequest, ProviderResult } from '@insignia/iios-contracts';

interface EmailPayload {
  subject?: string;
  text?: string;
  html?: string;
  inReplyTo?: string;
}

/**
 * Email egress provider: shapes the outbound command into an email envelope
 * ({to, subject, text, html, inReplyTo}) and POSTs it to a configured send endpoint
 * (a vendor mail API / SMTP relay behind a URL). Activated only when
 * IIOS_PROVIDER_URL_EMAIL is set; a transport failure is surfaced as FAILED, never thrown.
 */
export class EmailProvider implements CapabilityProvider {
  readonly name = 'email-http';
  readonly channelTypes = ['EMAIL'];
  readonly capabilities = { canSend: true };

  constructor(private readonly url: string) {}

  async send(req: CapabilityRequest): Promise<ProviderResult> {
    const started = Date.now();
    const p = (req.payload ?? {}) as EmailPayload;
    const email = { to: req.target, subject: p.subject ?? '(no subject)', text: p.text, html: p.html, inReplyTo: p.inReplyTo };
    try {
      const res = await fetch(this.url, {
        method: 'POST',
        headers: { 'content-type': 'application/json', 'idempotency-key': req.idempotencyKey },
        body: JSON.stringify(email),
      });
      const latencyMs = Date.now() - started;
      if (!res.ok) return { providerRef: `email-${res.status}`, outcome: 'FAILED', errorCode: `HTTP_${res.status}`, latencyMs };
      return { providerRef: `email-${req.idempotencyKey}`, outcome: 'SENT', latencyMs };
    } catch (err) {
      return { providerRef: 'email-error', outcome: 'FAILED', errorCode: (err as Error).message.slice(0, 60), latencyMs: Date.now() - started };
    }
  }
}