import { parseAttention, parseDigest, parseSessionItem, parseSessionList } from "agents-shared/contract";
import { activityByDay } from "agents-shared/timeline";
import { useQuery, useQueryClient, type QueryKey } from "@tanstack/react-query";
import { useMemo } from "react";
import { getConditional, getJSON, HttpError, Unauthorized, type Conditional, type Parser } from "./api";
import { useCalendar } from "./zone";

const MINUTE = 60_000;

export function useDigest() {
  const cal = useCalendar();
  return useQuery({
    queryKey: ["digest", cal.zone],
    queryFn: ({ signal }) => getJSON(`/api/attention/digest?tz=${encodeURIComponent(cal.zone)}`, parseDigest, signal),
    staleTime: MINUTE,
    refetchInterval: MINUTE,
  });
}

export function useAttention() {
  return useQuery({
    queryKey: ["attention"],
    queryFn: ({ signal }) => getJSON("/api/attention", parseAttention, signal),
    staleTime: MINUTE,
    refetchInterval: MINUTE,
  });
}

/** Interactions per day for the day strip. */
export function useActivity() {
  const cal = useCalendar();
  const { data } = useAttention();
  return useMemo(() => (data ? activityByDay(data, cal) : null), [data, cal]);
}

function useConditional<T>(key: QueryKey, path: string, parse: Parser<T>, interval: number | false) {
  const client = useQueryClient();
  return useQuery({
    queryKey: key,
    queryFn: ({ signal }) => getConditional(path, parse, client.getQueryData<Conditional<T>>(key), signal),
    refetchInterval: interval,
    staleTime: interval === false ? 30_000 : interval - 500,
  });
}

/** Metadata only; unchanged polls cost a 304. */
export function useSessionList(active: boolean) {
  return useConditional(["sessions"], "/api/sessions?view=list", parseSessionList, active ? 5000 : false);
}

export function useSessionItem(key: string, active: boolean) {
  return useConditional(["session", key], `/api/sessions/item?id=${encodeURIComponent(key)}`, parseSessionItem, active ? 3000 : false);
}

export function describeFailure(error: Error | null) {
  if (error instanceof Unauthorized) return "Sign in to see your history.";
  if (error instanceof HttpError && error.status === 503) return "Your Mac is busy. Showing what was already loaded.";
  return "Couldn’t reach your Mac. Showing what was already loaded.";
}