import { afterEach, describe, expect, it, vi } from "vitest";
import { renderHook } from "@testing-library/react";
import { useScanner } from "./use-scanner.js";

// The global hardware-scanner hook: a fast keystroke burst ended by Enter fires onScan,
// regardless of focus, WITHOUT hijacking human typing or editable fields, and pauses
// while a modal is open. This pins the 2026-06-21 focus-independent scan behaviour
// (otherwise only verifiable in Playwright).

afterEach(() => vi.restoreAllMocks());

/** Dispatch a keydown on the document with a controllable timeStamp (the hook measures
 *  inter-key gaps off e.timeStamp). jsdom sets timeStamp to 0, so we override it. */
function key(char: string, timeStamp: number, target: EventTarget = document.body) {
  const e = new KeyboardEvent("keydown", { key: char, bubbles: true, cancelable: true });
  Object.defineProperty(e, "timeStamp", { value: timeStamp });
  Object.defineProperty(e, "target", { value: target });
  document.dispatchEvent(e);
}

/** Type a code as a fast burst (5ms apart) ending in Enter, from a start time. */
function scan(code: string, start = 1000, gap = 5) {
  let t = start;
  for (const ch of code) { key(ch, t); t += gap; }
  key("Enter", t);
  return t;
}

describe("useScanner", () => {
  it("fires onScan with the code on a fast burst + Enter (focus on body)", () => {
    const onScan = vi.fn();
    renderHook(() => useScanner({ onScan }));
    scan("12345678901");
    expect(onScan).toHaveBeenCalledTimes(1);
    expect(onScan).toHaveBeenCalledWith("12345678901");
  });

  it("ignores slow, human-paced typing (gap > 50ms resets the buffer)", () => {
    const onScan = vi.fn();
    renderHook(() => useScanner({ onScan }));
    // 120ms between keys — a person, not a scanner. Each gap resets the buffer, so by
    // Enter only the last char remains (< MIN_LENGTH) → no scan.
    scan("123", 1000, 120);
    expect(onScan).not.toHaveBeenCalled();
  });

  it("does not fire while paused (a modal is open)", () => {
    const onScan = vi.fn();
    renderHook(() => useScanner({ onScan, paused: true }));
    scan("12345678901");
    expect(onScan).not.toHaveBeenCalled();
  });

  it("ignores keystrokes into an editable field (manual typing unaffected)", () => {
    const onScan = vi.fn();
    renderHook(() => useScanner({ onScan }));
    const input = document.createElement("input");
    document.body.appendChild(input);
    scanInto("12345678901", input);
    expect(onScan).not.toHaveBeenCalled();
    input.remove();
  });

  it("ignores a lone Enter / too-short burst", () => {
    const onScan = vi.fn();
    renderHook(() => useScanner({ onScan }));
    key("Enter", 1000);
    expect(onScan).not.toHaveBeenCalled();
    scan("ab"); // length 2 < MIN_LENGTH 3
    expect(onScan).not.toHaveBeenCalled();
  });
});

/** Burst with the event target set to an editable element. */
function scanInto(code: string, target: EventTarget, start = 1000, gap = 5) {
  let t = start;
  for (const ch of code) { key(ch, t, target); t += gap; }
  key("Enter", t, target);
}