import { ref } from "vue";

export type RealtimeNewMessage = {
  contactId: string;
  contactName: string;
  text: string;
  channel: string;
  direction: string;
  at: string;
};

export type RealtimePilotTrace = { text: string; at: string };

export function useCrmRealtime(opts: {
  isAuthenticated: () => boolean;
  onDashboardChanged: () => Promise<void>;
  onNewMessage?: (msg: RealtimeNewMessage) => void;
  onPilotTrace?: (log: RealtimePilotTrace) => void;
  onPilotFinished?: () => void;
}) {
  const crmRealtimeState = ref<"idle" | "connecting" | "open" | "error">("idle");
  let crmRealtimeSocket: WebSocket | null = null;
  let crmRealtimeReconnectTimer: ReturnType<typeof setTimeout> | null = null;
  let crmRealtimeRefreshTimer: ReturnType<typeof setTimeout> | null = null;
  let crmRealtimeRefreshInFlight = false;
  let crmRealtimeReconnectAttempt = 0;

  function clearCrmRealtimeReconnectTimer() {
    if (!crmRealtimeReconnectTimer) return;
    clearTimeout(crmRealtimeReconnectTimer);
    crmRealtimeReconnectTimer = null;
  }

  function clearCrmRealtimeRefreshTimer() {
    if (!crmRealtimeRefreshTimer) return;
    clearTimeout(crmRealtimeRefreshTimer);
    crmRealtimeRefreshTimer = null;
  }

  async function runCrmRealtimeRefresh() {
    if (!opts.isAuthenticated() || crmRealtimeRefreshInFlight) return;
    crmRealtimeRefreshInFlight = true;
    try {
      await opts.onDashboardChanged();
    } catch {
      // ignore transient realtime refresh errors
    } finally {
      crmRealtimeRefreshInFlight = false;
    }
  }

  function scheduleCrmRealtimeRefresh(delayMs = 250) {
    clearCrmRealtimeRefreshTimer();
    crmRealtimeRefreshTimer = setTimeout(() => {
      crmRealtimeRefreshTimer = null;
      void runCrmRealtimeRefresh();
    }, delayMs);
  }

  function scheduleCrmRealtimeReconnect() {
    clearCrmRealtimeReconnectTimer();
    const attempt = Math.min(crmRealtimeReconnectAttempt + 1, 8);
    crmRealtimeReconnectAttempt = attempt;
    const delayMs = Math.min(1000 * 2 ** (attempt - 1), 15000);
    crmRealtimeReconnectTimer = setTimeout(() => {
      crmRealtimeReconnectTimer = null;
      startCrmRealtime();
    }, delayMs);
  }

  function stopCrmRealtime() {
    clearCrmRealtimeReconnectTimer();
    clearCrmRealtimeRefreshTimer();

    if (crmRealtimeSocket) {
      const socket = crmRealtimeSocket;
      crmRealtimeSocket = null;
      socket.onopen = null;
      socket.onmessage = null;
      socket.onerror = null;
      socket.onclose = null;
      try {
        socket.close(1000, "client stop");
      } catch {
        // ignore socket close errors
      }
    }

    crmRealtimeState.value = "idle";
  }

  function startCrmRealtime() {
    if (process.server || !opts.isAuthenticated()) return;
    if (crmRealtimeSocket) {
      const state = crmRealtimeSocket.readyState;
      if (state === WebSocket.OPEN || state === WebSocket.CONNECTING) return;
    }

    clearCrmRealtimeReconnectTimer();
    const protocol = window.location.protocol === "https:" ? "wss:" : "ws:";
    const url = `${protocol}//${window.location.host}/ws/crm-updates`;

    const socket = new WebSocket(url);
    crmRealtimeSocket = socket;
    crmRealtimeState.value = "connecting";

    socket.onopen = () => {
      crmRealtimeState.value = "open";
      crmRealtimeReconnectAttempt = 0;
    };

    socket.onmessage = (event) => {
      const raw = typeof event.data === "string" ? event.data : "";
      if (!raw) return;
      try {
        const payload = JSON.parse(raw) as { type?: string; [key: string]: any };
        if (payload.type === "dashboard.changed") {
          scheduleCrmRealtimeRefresh();
        }
        if (payload.type === "message.new" && opts.onNewMessage) {
          opts.onNewMessage(payload as unknown as RealtimeNewMessage);
        }
        if (payload.type === "pilot.trace" && opts.onPilotTrace) {
          opts.onPilotTrace({ text: String(payload.text ?? ""), at: String(payload.at ?? "") });
        }
        if (payload.type === "pilot.catchup" && opts.onPilotTrace && Array.isArray(payload.logs)) {
          for (const log of payload.logs) {
            opts.onPilotTrace({ text: String((log as any).text ?? ""), at: String((log as any).at ?? "") });
          }
        }
        if (payload.type === "pilot.finished" && opts.onPilotFinished) {
          opts.onPilotFinished();
        }
      } catch {
        // ignore malformed realtime payloads
      }
    };

    socket.onerror = () => {
      crmRealtimeState.value = "error";
    };

    socket.onclose = () => {
      const wasActive = crmRealtimeSocket === socket;
      if (wasActive) {
        crmRealtimeSocket = null;
      }
      if (!opts.isAuthenticated()) {
        crmRealtimeState.value = "idle";
        return;
      }
      crmRealtimeState.value = "error";
      scheduleCrmRealtimeReconnect();
    };
  }

  return { crmRealtimeState, startCrmRealtime, stopCrmRealtime };
}