import { prisma } from "../../utils/prisma";

function mapChannel(channel: string) {
  if (channel === "TELEGRAM") return "Telegram";
  if (channel === "WHATSAPP") return "WhatsApp";
  if (channel === "INSTAGRAM") return "Instagram";
  if (channel === "EMAIL") return "Email";
  return "Phone";
}

const COOKIE_USER = "cf_user";
const COOKIE_TEAM = "cf_team";
const COOKIE_CONV = "cf_conv";

const TEAM_POLL_INTERVAL_MS = 2000;

const peersByTeam = new Map<string, Set<any>>();
const peerTeamById = new Map<string, string>();
const lastSignatureByTeam = new Map<string, string>();
const lastMsgCreatedAtByTeam = new Map<string, Date>();

let pollTimer: ReturnType<typeof setInterval> | null = null;

function parseCookies(raw: string | null) {
  const out = new Map<string, string>();
  for (const part of String(raw ?? "").split(";")) {
    const [key, ...rest] = part.trim().split("=");
    if (!key) continue;
    const value = rest.join("=");
    try {
      out.set(key, decodeURIComponent(value));
    } catch {
      out.set(key, value);
    }
  }
  return out;
}

function attachPeerToTeam(peer: any, teamId: string) {
  if (!peersByTeam.has(teamId)) peersByTeam.set(teamId, new Set());
  peersByTeam.get(teamId)?.add(peer);
  peerTeamById.set(String(peer.id), teamId);
}

function detachPeer(peer: any) {
  const key = String(peer.id);
  const teamId = peerTeamById.get(key);
  if (!teamId) return;
  peerTeamById.delete(key);

  const peers = peersByTeam.get(teamId);
  if (!peers) return;
  peers.delete(peer);
  if (peers.size === 0) {
    peersByTeam.delete(teamId);
    lastSignatureByTeam.delete(teamId);
    lastMsgCreatedAtByTeam.delete(teamId);
  }
}

function stopPollIfIdle() {
  if (peersByTeam.size > 0 || !pollTimer) return;
  clearInterval(pollTimer);
  pollTimer = null;
}

async function validateSessionFromPeer(peer: any) {
  const cookieHeader = peer?.request?.headers?.get?.("cookie") ?? null;
  const cookies = parseCookies(cookieHeader);

  const userId = String(cookies.get(COOKIE_USER) ?? "").trim();
  const teamId = String(cookies.get(COOKIE_TEAM) ?? "").trim();
  const conversationId = String(cookies.get(COOKIE_CONV) ?? "").trim();
  if (!userId || !teamId || !conversationId) return null;

  const [user, team, conv] = await Promise.all([
    prisma.user.findUnique({ where: { id: userId }, select: { id: true } }),
    prisma.team.findUnique({ where: { id: teamId }, select: { id: true } }),
    prisma.aiConversation.findFirst({
      where: { id: conversationId, teamId, createdByUserId: userId },
      select: { id: true },
    }),
  ]);

  if (!user || !team || !conv) return null;
  return { teamId };
}

async function computeTeamSignature(teamId: string) {
  const [
    omniMessageMax,
    contactMax,
    contactMessageMax,
    telegramConnectionMax,
    contactInboxMax,
    inboxPrefMax,
    clientTimelineEntryMax,
  ] = await Promise.all([
    prisma.omniMessage.aggregate({
      where: { teamId },
      _max: { updatedAt: true },
    }),
    prisma.contact.aggregate({
      where: { teamId },
      _max: { updatedAt: true },
    }),
    prisma.contactMessage.aggregate({
      where: { contact: { teamId } },
      _max: { createdAt: true },
    }),
    prisma.telegramBusinessConnection.aggregate({
      where: { teamId },
      _max: { updatedAt: true },
    }),
    prisma.contactInbox.aggregate({
      where: { teamId },
      _max: { updatedAt: true },
    }),
    prisma.contactInboxPreference.aggregate({
      where: { teamId },
      _max: { updatedAt: true },
    }),
    prisma.clientTimelineEntry.aggregate({
      where: { teamId },
      _max: { updatedAt: true },
    }),
  ]);

  return [
    omniMessageMax._max.updatedAt?.toISOString() ?? "",
    contactMax._max.updatedAt?.toISOString() ?? "",
    contactMessageMax._max.createdAt?.toISOString() ?? "",
    telegramConnectionMax._max.updatedAt?.toISOString() ?? "",
    contactInboxMax._max.updatedAt?.toISOString() ?? "",
    inboxPrefMax._max.updatedAt?.toISOString() ?? "",
    clientTimelineEntryMax._max.updatedAt?.toISOString() ?? "",
  ].join("|");
}

function sendJson(peer: any, payload: Record<string, unknown>) {
  try {
    peer.send(JSON.stringify(payload));
  } catch {
    // ignore socket write errors
  }
}

async function checkNewMessages(teamId: string) {
  const lastTs = lastMsgCreatedAtByTeam.get(teamId) ?? new Date(0);
  try {
    const msgs = await prisma.contactMessage.findMany({
      where: { contact: { teamId }, createdAt: { gt: lastTs } },
      include: { contact: { select: { id: true, name: true } } },
      orderBy: { createdAt: "asc" },
      take: 50,
    });
    if (msgs.length) {
      lastMsgCreatedAtByTeam.set(teamId, msgs[msgs.length - 1]!.createdAt);
    }
    return msgs;
  } catch {
    return [];
  }
}

async function pollAndBroadcast() {
  for (const [teamId, peers] of peersByTeam.entries()) {
    if (!peers.size) continue;

    // Check for new messages → send granular events
    const newMessages = await checkNewMessages(teamId);
    for (const msg of newMessages) {
      const payload = {
        type: "message.new",
        contactId: msg.contact.id,
        contactName: msg.contact.name,
        text: msg.content ?? "",
        channel: mapChannel(msg.channel),
        direction: msg.direction === "OUTBOUND" ? "out" : "in",
        at: msg.occurredAt?.toISOString() ?? msg.createdAt.toISOString(),
      };
      for (const peer of peers) {
        sendJson(peer, payload);
      }
    }

    // Check for other dashboard changes (contacts, calendar, deals, etc.)
    const signature = await computeTeamSignature(teamId);
    const previous = lastSignatureByTeam.get(teamId);
    if (signature === previous) continue;

    lastSignatureByTeam.set(teamId, signature);
    const payload = {
      type: "dashboard.changed",
      teamId,
      at: new Date().toISOString(),
    };

    for (const peer of peers) {
      sendJson(peer, payload);
    }
  }
}

function ensurePoll() {
  if (pollTimer) return;
  pollTimer = setInterval(() => {
    void pollAndBroadcast();
  }, TEAM_POLL_INTERVAL_MS);
}

export default defineWebSocketHandler({
  async open(peer) {
    const session = await validateSessionFromPeer(peer);
    if (!session) {
      peer.close(4401, "Unauthorized");
      return;
    }

    attachPeerToTeam(peer, session.teamId);
    ensurePoll();
    sendJson(peer, { type: "realtime.connected", at: new Date().toISOString() });
    void pollAndBroadcast();
  },

  close(peer) {
    detachPeer(peer);
    stopPollIfIdle();
  },

  error(peer) {
    detachPeer(peer);
    stopPollIfIdle();
  },
});