"use client";

import * as React from "react";
import type { ColineJobRun } from "@colineapp/sdk/v2";
import { useColine } from "../provider";

const FINISHED = new Set(["succeeded", "failed", "cancelled", "dead"]);

/**
 * Watch a background job run until it finishes. Updates arrive through
 * the install's realtime hints (`coline.jobs.changed`) when the app has
 * `realtime.subscribe`, with polling as the fallback either way.
 */
export function useJob(jobId: string | null, options: { pollMs?: number } = {}) {
  const coline = useColine();
  const [latest, setRun] = React.useState<ColineJobRun | null>(null);
  const [error, setError] = React.useState<string | null>(null);
  const pollMs = options.pollMs ?? 1500;
  // A stale run from a previous jobId never shows for the new one.
  const run = jobId && latest?.id === jobId ? latest : null;

  React.useEffect(() => {
    if (!jobId) return;
    let cancelled = false;
    let timer: ReturnType<typeof setTimeout> | null = null;
    let unsubscribe: (() => void) | null = null;

    const load = async () => {
      try {
        const next = await coline.jobs.get(jobId);
        if (cancelled) return;
        setRun(next);
        setError(null);
        if (!next || FINISHED.has(next.status)) return;
      } catch (cause) {
        if (cancelled) return;
        setError(cause instanceof Error ? cause.message : String(cause));
      }
      if (timer) clearTimeout(timer);
      timer = setTimeout(() => void load(), pollMs);
    };

    void load();
    void coline.realtime
      .subscribe("coline.jobs.changed", (message) => {
        const data = message.data as { id?: string } | null;
        if (data?.id === jobId) void load();
      })
      .then((subscription) => {
        if (cancelled) subscription.unsubscribe();
        else unsubscribe = subscription.unsubscribe;
      })
      .catch(() => {
        // Without realtime permission, polling alone keeps the run current.
      });

    return () => {
      cancelled = true;
      if (timer) clearTimeout(timer);
      unsubscribe?.();
    };
  }, [coline, jobId, pollMs]);

  return {
    run,
    error,
    isRunning: run ? !FINISHED.has(run.status) : false,
    progress: run?.progress?.value ?? (run?.status === "succeeded" ? 1 : 0),
  };
}