import { readBody, getQuery, getHeader } from "h3";
import { prisma } from "../../utils/prisma";

function teamIdFromWebhook(event: any) {
  const q = getQuery(event);
  const fromQuery = typeof q.teamId === "string" ? q.teamId : null;
  return fromQuery || process.env.TELEGRAM_DEFAULT_TEAM_ID || "demo-team";
}

function assertSecret(event: any) {
  const expected = process.env.TELEGRAM_WEBHOOK_SECRET;
  if (!expected) return;

  const got = getHeader(event, "x-telegram-bot-api-secret-token");
  if (!got || got !== expected) {
    throw createError({ statusCode: 401, statusMessage: "invalid telegram secret token" });
  }
}

function displayNameFromTelegram(obj: any) {
  const first = obj?.first_name || "";
  const last = obj?.last_name || "";
  const u = obj?.username ? `@${obj.username}` : "";
  const full = `${first} ${last}`.trim();
  return (full || u || "Telegram user").trim();
}

async function upsertBusinessConnection(teamId: string, bc: any) {
  if (!bc?.id) return;
  const businessConnectionId = String(bc.id);

  await prisma.telegramBusinessConnection.upsert({
    where: { teamId_businessConnectionId: { teamId, businessConnectionId } },
    update: {
      isEnabled: typeof bc.is_enabled === "boolean" ? bc.is_enabled : undefined,
      canReply: typeof bc.can_reply === "boolean" ? bc.can_reply : undefined,
      rawJson: bc,
    },
    create: {
      teamId,
      businessConnectionId,
      isEnabled: typeof bc.is_enabled === "boolean" ? bc.is_enabled : null,
      canReply: typeof bc.can_reply === "boolean" ? bc.can_reply : null,
      rawJson: bc,
    },
  });
}

async function ensureContactForTelegramChat(teamId: string, externalChatId: string, tgUser: any) {
  const existing = await prisma.omniContactIdentity.findUnique({
    where: { teamId_channel_externalId: { teamId, channel: "TELEGRAM", externalId: externalChatId } },
    include: { contact: true },
  });
  if (existing) return existing.contact;

  const contact = await prisma.contact.create({
    data: {
      teamId,
      name: displayNameFromTelegram(tgUser),
    },
  });

  await prisma.omniContactIdentity.create({
    data: {
      teamId,
      contactId: contact.id,
      channel: "TELEGRAM",
      externalId: externalChatId,
    },
  });

  return contact;
}

async function ensureThread(input: {
  teamId: string;
  contactId: string;
  externalChatId: string;
  businessConnectionId?: string | null;
  title?: string | null;
}) {
  return prisma.omniThread.upsert({
    where: {
      teamId_channel_externalChatId_businessConnectionId: {
        teamId: input.teamId,
        channel: "TELEGRAM",
        externalChatId: input.externalChatId,
        businessConnectionId: input.businessConnectionId ?? null,
      },
    },
    update: {
      contactId: input.contactId,
      title: input.title ?? undefined,
    },
    create: {
      teamId: input.teamId,
      contactId: input.contactId,
      channel: "TELEGRAM",
      externalChatId: input.externalChatId,
      businessConnectionId: input.businessConnectionId ?? null,
      title: input.title ?? null,
    },
  });
}

export default defineEventHandler(async (event) => {
  assertSecret(event);
  const teamId = teamIdFromWebhook(event);

  const update = (await readBody<any>(event)) || {};

  // business_connection updates (user connected/disconnected bot)
  if (update.business_connection) {
    await upsertBusinessConnection(teamId, update.business_connection);
    return { ok: true };
  }

  const msg = update.business_message || update.edited_business_message;
  if (!msg) return { ok: true };

  const businessConnectionId = msg.business_connection_id ? String(msg.business_connection_id) : null;
  const chatId = msg.chat?.id != null ? String(msg.chat.id) : null;
  const providerMessageId = msg.message_id != null ? String(msg.message_id) : null;

  if (!chatId || !providerMessageId) return { ok: true };

  const text = typeof msg.text === "string" ? msg.text : typeof msg.caption === "string" ? msg.caption : "";
  const occurredAt = msg.date ? new Date(Number(msg.date) * 1000) : new Date();

  const contact = await ensureContactForTelegramChat(teamId, chatId, msg.from || msg.chat);
  const thread = await ensureThread({
    teamId,
    contactId: contact.id,
    externalChatId: chatId,
    businessConnectionId,
    title: msg.chat?.title ? String(msg.chat.title) : null,
  });

  // Dedupe on (threadId, providerMessageId). If duplicate, ignore.
  try {
    await prisma.omniMessage.create({
      data: {
        teamId,
        contactId: contact.id,
        threadId: thread.id,
        direction: "IN",
        channel: "TELEGRAM",
        status: "DELIVERED",
        text: text || "",
        providerMessageId,
        providerUpdateId: update.update_id != null ? String(update.update_id) : null,
        rawJson: update,
        occurredAt,
      },
    });
  } catch (e: any) {
    // Prisma unique constraint violation => duplicate delivery
    if (e?.code !== "P2002") throw e;
  }

  return { ok: true };
});