import { NextResponse } from "next/server";
import { buildInviteEmail } from "@/lib/invite-email";

// Sends a team-invitation email via the Twilio Emails API. Server-only: the Twilio
// Account SID + Auth Token come from Vercel env (TWILIO_ACCOUNT_SID / TWILIO_AUTH_TOKEN)
// and never reach the browser. From EMAIL_FROM_ADDRESS (default support@lynkedup.dev).
//
// POST /api/email/invite  { to, token, roleNames?[] }  → { ok }
// The email body is a fixed invite template (only `to` + `token` + role names are
// caller-supplied), so this can't be used to send arbitrary content.

export const runtime = "nodejs";

const TWILIO_EMAILS_URL = "https://comms.twilio.com/v1/Emails";
const EMAIL_RE = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
const SESSION_COOKIE = "__Host-insignia_session";

export async function POST(request: Request) {
  // Light guard: only a signed-in session (which the invite UI has) may trigger sends,
  // so this isn't an open email relay. Presence check — the cookie is HttpOnly + __Host-.
  const cookies = request.headers.get("cookie") ?? "";
  if (!cookies.includes(`${SESSION_COOKIE}=`)) {
    return NextResponse.json({ ok: false, error: "unauthorized" }, { status: 401 });
  }

  const sid = process.env.TWILIO_ACCOUNT_SID ?? "";
  const authToken = process.env.TWILIO_AUTH_TOKEN ?? "";
  const from = process.env.EMAIL_FROM_ADDRESS ?? "support@lynkedup.dev";
  const fromName = process.env.EMAIL_FROM_NAME ?? "LynkedUp Pro";
  if (!sid || !authToken) {
    return NextResponse.json({ ok: false, error: "email_not_configured" }, { status: 503 });
  }

  let body: { to?: string; token?: string; roleNames?: string[] };
  try {
    body = await request.json();
  } catch {
    return NextResponse.json({ ok: false, error: "invalid_json" }, { status: 400 });
  }

  const to = (body.to ?? "").trim().toLowerCase();
  const token = (body.token ?? "").trim();
  const roleNames = Array.isArray(body.roleNames) ? body.roleNames.filter((r) => typeof r === "string").slice(0, 10) : [];
  if (!EMAIL_RE.test(to)) return NextResponse.json({ ok: false, error: "invalid_email" }, { status: 400 });
  if (token.length < 16 || token.length > 256) return NextResponse.json({ ok: false, error: "invalid_token" }, { status: 400 });

  const origin = (process.env.PORTAL_BASE_URL || new URL(request.url).origin).replace(/\/$/, "");
  const inviteUrl = `${origin}/portal/invite?token=${encodeURIComponent(token)}`;
  const { subject, html, text } = buildInviteEmail({ inviteUrl, roleNames });

  const payload = {
    from: { address: from, name: fromName },
    to: [{ address: to }],
    content: { subject, html, text },
  };

  try {
    const res = await fetch(TWILIO_EMAILS_URL, {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        Authorization: `Basic ${Buffer.from(`${sid}:${authToken}`).toString("base64")}`,
      },
      body: JSON.stringify(payload),
    });
    if (!res.ok) {
      const detail = await res.text().catch(() => "");
      return NextResponse.json({ ok: false, error: "send_failed", status: res.status, detail: detail.slice(0, 300) }, { status: 502 });
    }
    return NextResponse.json({ ok: true });
  } catch (e) {
    return NextResponse.json({ ok: false, error: "send_error", detail: (e as Error).message }, { status: 502 });
  }
}