import { useState } from "react";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { qk } from "../lib/queryKeys";
import { useTranslation } from "react-i18next";
import { CheckCircle2, Clock, Database, History, Loader2, Pause, Play } from "lucide-react";
import { api, type MyStatus } from "../lib/api";
import { formatViews } from "../lib/format";
import { PopoverSurface, useAnchoredPopover } from "./AnchoredPopover";

// Per-user status (not the global catalog): shows the number of videos available to *this*
// user, how many of *their* channels are still being fetched, and how many lack full
// history (clickable -> channel manager filtered to those). The pause control is admin-only.
export default function SyncStatus({
  isAdmin,
  onGoToFullHistory,
}: {
  isAdmin: boolean;
  onGoToFullHistory: () => void;
}) {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const [open, setOpen] = useState(false);
  // A read-out with a couple of controls rather than a list of choices, so it is a `dialog`
  // popover. It portals out of the header, whose glass backdrop-filter would otherwise trap its
  // stacking and positioning.
  const pop = useAnchoredPopover({
    open,
    onOpenChange: setOpen,
    mode: "dialog",
    role: "dialog",
    placement: "bottom-end",
    offset: 8,
  });
  const { data } = useQuery({
    queryKey: qk.myStatus(),
    queryFn: api.myStatus,
    // Track the scheduler near-real-time: poll even when the tab is backgrounded, and
    // refresh immediately on tab focus (the global default disables focus refetch), so the
    // "N without full history" count keeps ticking down without a manual reload. Poll faster
    // while a job is running or work is pending — so the live "syncing" state is actually
    // caught — and ease back to a slow idle tick once everything's settled.
    refetchInterval: (query) => {
      const d = query.state.data as MyStatus | undefined;
      const busy =
        !!d && (d.sync_active || d.channels_recent_pending > 0 || d.channels_deep_pending > 0);
      return busy ? 8_000 : 30_000;
    },
    refetchIntervalInBackground: true,
    refetchOnWindowFocus: true,
    staleTime: 5_000,
  });

  const toggle = useMutation({
    mutationFn: () => (data?.paused ? api.resumeSync() : api.pauseSync()),
    onSuccess: () => qc.invalidateQueries({ queryKey: qk.myStatus() }),
  });

  if (!data) return null;

  const syncing = data.channels_recent_pending;
  const notFull = data.channels_deep_pending; // your channels without full history yet
  // Spin only while a sync job is actually running; otherwise pending work shows as a calm,
  // static state (or, for deep history, just the "N without full history" link below).
  const active = data.sync_active;
  const showMain = data.paused || active || syncing > 0 || notFull === 0;

  // Calm one-liner describing the current sync state.
  const stateNode = data.paused ? (
    <span className="text-accent font-medium">{t("header.sync.paused")}</span>
  ) : active ? (
    <span className="flex items-center gap-1">
      <Loader2 className="w-3.5 h-3.5 animate-spin" />
      {syncing > 0
        ? t("header.sync.syncing", { count: syncing })
        : notFull > 0
          ? t("header.sync.backfillingHistory")
          : t("header.sync.working")}
    </span>
  ) : syncing > 0 ? (
    <span className="flex items-center gap-1">
      <Clock className="w-3.5 h-3.5" />
      {t("header.sync.recentQueued", { count: syncing })}
    </span>
  ) : (
    // A small check anchors the "all synced" state so it doesn't read as orphaned text.
    <span className="flex items-center gap-1 text-emerald-500">
      <CheckCircle2 className="w-3.5 h-3.5" />
      <span className="text-muted">{t("header.sync.allSynced")}</span>
    </span>
  );

  const pauseBtn = isAdmin && (data.paused || syncing > 0 || notFull > 0) && (
    <button
      onClick={() => toggle.mutate()}
      disabled={toggle.isPending}
      title={data.paused ? t("header.sync.resume") : t("header.sync.pause")}
      className="p-1 rounded-md hover:bg-card hover:text-fg transition"
    >
      {data.paused ? <Play className="w-3.5 h-3.5" /> : <Pause className="w-3.5 h-3.5" />}
    </button>
  );

  // Chip: the headline count rides in the header; the state, the history link and pause live in a
  // popover. An accent dot flags the only two things worth interrupting you for (paused / missing
  // history) so the collapsed chip still tells you when to look.
  const needsAttention = data.paused || notFull > 0;
  const countsText = `${formatViews(data.my_videos)} ${t("header.sync.yours")} / ${formatViews(
    data.total_videos,
  )} ${t("header.sync.total")}`;
  return (
    <div className="pointer-events-auto shrink-0">
      <button
        ref={pop.refs.setReference}
        {...pop.getReferenceProps()}
        // Short label only: the popover already explains the numbers, and the long one overflowed
        // the viewport edge from here.
        title={countsText}
        className="glass glass-hover relative flex items-center gap-1.5 px-2.5 py-1.5 rounded-xl text-xs text-muted"
      >
        {active ? (
          <Loader2 className="w-3.5 h-3.5 shrink-0 animate-spin text-accent" />
        ) : (
          <Database className="w-3.5 h-3.5 shrink-0" />
        )}
        <span className="text-fg font-medium tabular-nums">{formatViews(data.my_videos)}</span>
        {needsAttention && (
          <span className="absolute -top-0.5 -right-0.5 w-2 h-2 rounded-full bg-accent ring-2 ring-bg" />
        )}
      </button>

      <PopoverSurface
        popover={pop}
        ariaLabel={countsText}
        className="glass-menu w-64 rounded-xl p-3 text-xs text-muted animate-[popIn_0.16s_ease]"
      >
        <div
          title={t("header.sync.countTooltip")}
          className="flex items-center gap-1.5 pb-2 border-b border-border/60"
        >
          <Database className="w-3.5 h-3.5 shrink-0" />
          <span>
            <span className="text-fg font-medium">{formatViews(data.my_videos)}</span>{" "}
            {t("header.sync.yours")}
            <span className="opacity-40"> / </span>
            {formatViews(data.total_videos)} {t("header.sync.total")}
          </span>
        </div>
        {showMain && (
          <div className="flex items-center justify-between gap-1.5 pt-2">
            <span className="flex items-center gap-1.5 min-w-0">{stateNode}</span>
            {pauseBtn}
          </div>
        )}
        {notFull > 0 && (
          <div className="flex items-center justify-between gap-1.5 pt-2">
            <button
              onClick={() => {
                setOpen(false);
                onGoToFullHistory();
              }}
              title={t("header.sync.fullHistoryTooltip")}
              className="flex items-center gap-1 hover:text-fg underline decoration-dotted decoration-muted/40 underline-offset-4 transition cursor-pointer"
            >
              <History className="w-3.5 h-3.5" />
              {t("header.sync.withoutFullHistory", { count: notFull })}
            </button>
            {!showMain && pauseBtn}
          </div>
        )}
      </PopoverSurface>
    </div>
  );
}
