import type { FederatedPointerEvent } from 'pixi.js';

/** Longest gap between two presses that still reads as one double-click. */
const DOUBLE_MS = 400;
/** How far the pointer may travel between them. */
const SLOP = 6;

interface LastPress {
  key: unknown;
  button: number;
  time: number;
  x: number;
  y: number;
  count: number;
}

let last: LastPress = { key: null, button: -1, time: 0, x: 0, y: 0, count: 0 };

/**
 * How often `key` was pressed in a row with the same button – 2 on a double-click. Pixi counts
 * clicks only for the `click`/`pointertap` it synthesises and leaves `detail` at 0 on
 * `pointerdown`, so a press handler reading `e.detail` never sees a second click.
 *
 * `key` identifies what was hit and should survive a rebuild of the widget it belongs to: list
 * rows are thrown away and recreated whenever the list refreshes, which a selection – the first
 * click – can trigger.
 */
export function pressCount(e: FederatedPointerEvent, key: unknown): number {
  const gap = e.timeStamp - last.time;
  const repeat =
    key === last.key &&
    e.button === last.button &&
    gap >= 0 &&
    gap <= DOUBLE_MS &&
    Math.hypot(e.global.x - last.x, e.global.y - last.y) <= SLOP;
  const count = repeat ? last.count + 1 : 1;
  last = {
    key,
    button: e.button,
    time: e.timeStamp,
    x: e.global.x,
    y: e.global.y,
    // A finished double-click ends the run: folding a row open and shut again is two
    // double-clicks, and the second must count as one rather than as clicks three and four.
    count: count === 2 ? 0 : count,
  };
  return count;
}