kandev/apps/web/hooks/use-workflow-snapshot.ts

import { useEffect, useRef } from "react";
import { fetchWorkflowSnapshot } from "@/lib/api";
import { snapshotToState } from "@/lib/ssr/mapper";
import { useAppStore, useAppStoreApi } from "@/components/state-provider";
import { isCurrentWorkspaceContext } from "@/lib/state/workspace-context";

export function useWorkflowSnapshot(workflowId: string | null) {
  const store = useAppStoreApi();
  const connectionStatus = useAppStore((state) => state.connection.status);
  const skippedInitialHydratedRef = useRef(false);

  useEffect(() => {
    if (!workflowId) return;
    let cancelled = false;
    const requestState = store.getState();
    const requestedWorkspaceId = requestState.workspaces.activeId;
    const requestedGeneration = requestState.workspaceContextGeneration;
    const existing = requestState.kanban;
    if (
      !skippedInitialHydratedRef.current &&
      existing.workflowId === workflowId &&
      (existing.steps.length > 0 || existing.tasks.length > 0)
    ) {
      skippedInitialHydratedRef.current = true;
      return;
    }
    const setLoading = store.getState().kanban.workflowId !== workflowId;
    if (setLoading) {
      store.setState((state) => ({ ...state, kanban: { ...state.kanban, isLoading: true } }));
    }
    fetchWorkflowSnapshot(workflowId, { cache: "no-store" })
      .then((snapshot) => {
        if (
          cancelled ||
          !isCurrentWorkspaceContext(store.getState(), requestedWorkspaceId, requestedGeneration)
        ) {
          return;
        }
        store.getState().hydrate(snapshotToState(snapshot));
      })
      .catch((error) => {
        // Suppress superseded-fetch noise; retry happens on WS reconnect.
        if (
          cancelled ||
          !isCurrentWorkspaceContext(store.getState(), requestedWorkspaceId, requestedGeneration)
        ) {
          return;
        }
        console.warn("[useWorkflowSnapshot] failed to load snapshot:", error);
      })
      .finally(() => {
        // Only clear the flag this effect raised; skip when cancelled or when a concurrent caller owns it.
        if (
          cancelled ||
          !setLoading ||
          !isCurrentWorkspaceContext(store.getState(), requestedWorkspaceId, requestedGeneration)
        ) {
          return;
        }
        store.setState((state) => ({ ...state, kanban: { ...state.kanban, isLoading: false } }));
      });
    return () => {
      cancelled = true;
    };
  }, [workflowId, store, connectionStatus]);
}