export const runtime = "nodejs";

import { NextResponse } from "next/server";
import { z } from "zod";
import { and, eq } from "drizzle-orm";
import { getCurrentSession } from "@/lib/auth/session";
import { db } from "@/lib/db/client";
import { emails, emailDrafts } from "@/lib/db/schema";
import { generateDraftReply } from "@/lib/ai/draftReply";
import { BRIEFING_MODEL } from "@/lib/ai/client";

const bodySchema = z.object({ emailId: z.string().min(1) });

export async function POST(request: Request) {
  const session = await getCurrentSession();
  if (!session) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  const parsed = bodySchema.safeParse(await request.json().catch(() => null));
  if (!parsed.success) {
    return NextResponse.json({ error: "Invalid input" }, { status: 400 });
  }

  const email = await db.query.emails.findFirst({
    where: and(eq(emails.id, parsed.data.emailId), eq(emails.userId, session.user.id)),
  });
  if (!email) {
    return NextResponse.json({ error: "Email not found" }, { status: 404 });
  }

  try {
    const draft = await generateDraftReply({
      from: email.fromAddress,
      subject: email.subject,
      bodyText: email.bodyText ?? email.snippet ?? "",
    });

    const [row] = await db
      .insert(emailDrafts)
      .values({
        userId: session.user.id,
        sourceEmailId: email.id,
        generatedSubject: draft.subject,
        generatedBody: draft.body,
        modelUsed: BRIEFING_MODEL,
      })
      .returning();

    return NextResponse.json({ draft: row });
  } catch (err) {
    const message = err instanceof Error ? err.message : String(err);
    return NextResponse.json({ error: message }, { status: 500 });
  }
}