import { NextResponse } from "next/server";
import { getPayload } from "payload";
import config from "@payload-config";

export const dynamic = "force-dynamic";

type InboundBody = {
  from?: unknown;
  sender?: unknown;
  email?: unknown;
  name?: unknown;
  subject?: unknown;
  text?: unknown;
  body?: unknown;
  html?: unknown;
  messageId?: unknown;
  inReplyTo?: unknown;
};

function stringValue(value: unknown): string {
  return typeof value === "string" ? value.trim() : "";
}

function extractEmail(value: unknown): string {
  if (value && typeof value === "object" && "email" in value) return extractEmail((value as { email?: unknown }).email);
  const raw = stringValue(value);
  const match = raw.match(/<([^>]+)>/) || raw.match(/([\w.+-]+@[\w.-]+\.[A-Za-z]{2,})/);
  return (match?.[1] || raw).trim().toLowerCase();
}

function stripHtml(value: string): string {
  return value.replace(/<style[\s\S]*?<\/style>/gi, "").replace(/<script[\s\S]*?<\/script>/gi, "").replace(/<[^>]+>/g, " ").replace(/\s+/g, " ").trim();
}

function findThreadKey(subject: string): string | null {
  return subject.match(/\[ANOUMA-([^\]]+)\]/i)?.[1] || null;
}

export async function POST(request: Request) {
  const secret = process.env.INBOUND_EMAIL_SECRET;
  const supplied = request.headers.get("x-inbound-secret") || request.headers.get("authorization")?.replace(/^Bearer\s+/i, "");
  if (!secret || supplied !== secret) return NextResponse.json({ error: "Unauthorized" }, { status: 401 });

  let body: InboundBody;
  try {
    body = await request.json();
  } catch {
    return NextResponse.json({ error: "JSON erwartet." }, { status: 400 });
  }

  const fromRaw = body.from ?? body.sender ?? body.email;
  const email = extractEmail(fromRaw);
  const fromName = fromRaw && typeof fromRaw === "object" && "name" in fromRaw ? stringValue((fromRaw as { name?: unknown }).name) : "";
  const name = stringValue(body.name) || fromName || stringValue(fromRaw).replace(/<[^>]+>/, "").trim() || email;
  const subject = stringValue(body.subject) || "Antwort auf deine Anfrage";
  const messageId = stringValue(body.messageId);
  const text = stringValue(body.text) || stringValue(body.body) || stripHtml(stringValue(body.html));
  if (!email || !messageId || !text) return NextResponse.json({ error: "Absender, messageId und Inhalt sind erforderlich." }, { status: 400 });

  try {
    const payload = await getPayload({ config });
    if (messageId) {
      const existing = await payload.find({ collection: "conversation-messages", where: { externalMessageId: { equals: messageId } }, limit: 1, overrideAccess: true });
      if (existing.docs[0]) return NextResponse.json({ ok: true, duplicate: true });
    }

    const threadKey = findThreadKey(subject);
    let conversation = threadKey
      ? (await payload.find({ collection: "conversations", where: { threadKey: { equals: threadKey } }, limit: 1, overrideAccess: true })).docs[0]
      : undefined;
    if (!conversation) {
      conversation = (await payload.find({ collection: "conversations", where: { email: { equals: email }, status: { not_equals: "closed" } }, sort: "-lastMessageAt", limit: 1, overrideAccess: true })).docs[0];
    }
    if (!conversation) return NextResponse.json({ error: "Keine passende Konversation gefunden." }, { status: 404 });

    await payload.create({
      collection: "conversation-messages",
      overrideAccess: true,
      data: {
        conversation: conversation.id,
        senderType: "visitor",
        senderName: name,
        senderEmail: email,
        body: text.slice(0, 10000),
        externalMessageId: messageId,
      },
    });
    await payload.update({ collection: "conversations", id: conversation.id, overrideAccess: true, data: { status: "open", lastMessageAt: new Date().toISOString() } });
    return NextResponse.json({ ok: true });
  } catch (error) {
    console.error("inbound email failed", error);
    return NextResponse.json({ error: "E-Mail konnte nicht übernommen werden." }, { status: 500 });
  }
}