/**
 * `useDiscovery` — discovered projects + live health. Posts the known cwds to
 * `/__nwire/projects/status` on a TanStack poll, merged with the local catalog
 * so a project shows even when its process is down.
 */
import { computed } from "vue";
import { useQuery } from "@tanstack/vue-query";
import { loadCatalog, getActiveProjectCwd, type ProjectSnapshot } from "../lib/project-catalog";

const STATUS_URL = "/__nwire/projects/status";

/** Per-project live status from the server (process up? port? pid?). Shape is server-owned. */
export interface ProjectStatus {
  readonly running?: boolean;
  readonly port?: number;
  readonly pid?: number;
  readonly [k: string]: unknown;
}
export type StatusMap = Record<string, ProjectStatus>;

/** A discovered project: its catalog snapshot + (best-effort) live status. */
export interface DiscoveredProject {
  readonly cwd: string;
  readonly snapshot: ProjectSnapshot;
  readonly status?: ProjectStatus;
  readonly active: boolean;
}

export function useDiscovery(options: { intervalMs?: number } = {}) {
  const query = useQuery({
    queryKey: ["discovery"],
    queryFn: async (): Promise<StatusMap> => {
      const cwds = Object.keys(loadCatalog());
      if (cwds.length === 0) return {};
      const res = await fetch(STATUS_URL, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ cwds }),
      });
      if (!res.ok) return {};
      return (await res.json()) as StatusMap;
    },
    refetchInterval: options.intervalMs ?? 5_000,
    placeholderData: (prev) => prev,
  });

  const projects = computed<DiscoveredProject[]>(() => {
    const catalog = loadCatalog();
    const active = getActiveProjectCwd();
    const statuses = query.data.value ?? {};
    return Object.values(catalog)
      .map((snapshot) => ({
        cwd: snapshot.cwd,
        snapshot,
        status: statuses[snapshot.cwd],
        active: snapshot.cwd === active,
      }))
      .sort(
        (a, b) =>
          Number(b.active) - Number(a.active) || a.snapshot.name.localeCompare(b.snapshot.name),
      );
  });

  const runningCount = computed(() => projects.value.filter((p) => p.status?.running).length);

  return {
    projects,
    runningCount,
    isLoading: query.isLoading,
    isError: query.isError,
    refetch: query.refetch,
  };
}