import { useCallback, useEffect, useRef, useState } from "react";
import { ArrowDown, ArrowUp } from "lucide-react";
import { useTranslation } from "react-i18next";
import Tooltip from "./Tooltip";

function PriorityStepButton({
  delta,
  Icon,
  label,
  onHoldStart,
  onStop,
  onTap,
}: {
  delta: number;
  Icon: typeof ArrowUp;
  label: string;
  onHoldStart: (delta: number) => void;
  onStop: () => void;
  onTap: (delta: number) => void;
}) {
  return (
    <button
      onPointerDown={(e) => {
        // Keep receiving pointer events even if the pointer drifts off the small button mid-hold.
        try {
          e.currentTarget.setPointerCapture(e.pointerId);
        } catch {
          /* invalid pointer id (e.g. synthetic events) — capture is a nicety, not required */
        }
        onHoldStart(delta);
      }}
      onPointerUp={onStop}
      onPointerCancel={onStop}
      onClick={() => onTap(delta)}
      className="text-muted hover:text-accent leading-none"
      aria-label={label}
    >
      <Icon className="w-3.5 h-3.5" />
    </button>
  );
}

/**
 * A press-and-hold-repeat priority control with an inline-editable value (negatives allowed).
 * Shared by the channel manager table (a cell) and the channel detail page (a header control), so
 * the two never drift. The caller owns persistence: `onPriority(delta)` nudges by ±1 (with hold
 * auto-repeat), `onSet(value)` writes a typed-in absolute value.
 */
export function PriorityStepper({
  priority,
  onPriority,
  onSet,
}: {
  priority: number;
  onPriority: (delta: number) => void;
  onSet: (value: number) => void;
}) {
  const { t } = useTranslation();
  const [editing, setEditing] = useState(false);
  const [draft, setDraft] = useState("");
  const holdDelay = useRef<ReturnType<typeof setTimeout> | null>(null);
  const holdRepeat = useRef<ReturnType<typeof setTimeout> | null>(null);
  const suppressClick = useRef(false);

  const stop = useCallback(() => {
    if (holdDelay.current) clearTimeout(holdDelay.current);
    if (holdRepeat.current) clearTimeout(holdRepeat.current);
    holdDelay.current = holdRepeat.current = null;
  }, []);
  useEffect(() => stop, [stop]); // clear any running timers on unmount

  // Hold past a threshold → auto-repeat at an accelerating rate, and suppress the trailing click so
  // a hold doesn't double-count its final notch. A quick tap never crosses the threshold, so it
  // falls through to onClick — which also keeps the keyboard path (Enter/Space) working.
  const start = (delta: number) => {
    suppressClick.current = false;
    holdDelay.current = setTimeout(() => {
      suppressClick.current = true;
      let rate = 140;
      const tick = () => {
        onPriority(delta);
        rate = Math.max(40, rate - 12);
        holdRepeat.current = setTimeout(tick, rate);
      };
      tick();
    }, 350);
  };
  const onTap = (delta: number) => {
    if (suppressClick.current) {
      suppressClick.current = false;
      return;
    }
    onPriority(delta);
  };

  const commitEdit = () => {
    const parsed = parseInt(draft, 10);
    if (!Number.isNaN(parsed) && parsed !== priority) onSet(parsed);
    setEditing(false);
  };
  const beginEdit = () => {
    setDraft(String(priority));
    setEditing(true);
  };

  // The value sits to the LEFT of the arrows (not between them) so the cursor — which rests on the
  // arrows while you press-and-hold — never covers the live value you're setting. Clicking the value
  // opens an inline edit to type any integer directly (negatives allowed).
  return (
    <Tooltip hint={t("channels.row.priorityHint")}>
      <div className="inline-flex items-center gap-1.5 cursor-help">
        {/* The number keeps its footprint (w-6) whether displayed or editing; the input is absolutely
          positioned OVER it (out of flow) so opening the editor never changes the row height/width —
          it just overlays, extending left for a longer number. */}
        <span className="relative inline-block w-6 h-5 text-right leading-5">
          <button
            onClick={beginEdit}
            aria-label={t("channels.row.editPriority")}
            title={t("channels.row.editPriority")}
            className={`text-sm font-medium tabular-nums hover:text-accent ${editing ? "invisible" : ""}`}
          >
            {priority}
          </button>
          {editing && (
            <input
              type="number"
              value={draft}
              autoFocus
              onFocus={(e) => e.currentTarget.select()}
              onChange={(e) => setDraft(e.target.value)}
              onBlur={commitEdit}
              onKeyDown={(e) => {
                if (e.key === "Enter") commitEdit();
                else if (e.key === "Escape") setEditing(false);
              }}
              aria-label={t("channels.row.priorityHint")}
              className="absolute top-1/2 right-0 -translate-y-1/2 w-14 h-6 text-sm font-medium tabular-nums text-right bg-card border border-accent rounded-sm px-1 outline-hidden z-popover [appearance:textfield] [&::-webkit-inner-spin-button]:appearance-none"
            />
          )}
        </span>
        <span className="inline-flex flex-col">
          <PriorityStepButton
            delta={1}
            Icon={ArrowUp}
            label={t("channels.row.raisePriority")}
            onHoldStart={start}
            onStop={stop}
            onTap={onTap}
          />
          <PriorityStepButton
            delta={-1}
            Icon={ArrowDown}
            label={t("channels.row.lowerPriority")}
            onHoldStart={start}
            onStop={stop}
            onTap={onTap}
          />
        </span>
      </div>
    </Tooltip>
  );
}