import { act, type ReactElement, useState } from "react";
import { createRoot, type Root } from "react-dom/client";
import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
import { Dialog, Field, SelectMenu } from "../src/index.js";
import { EKKLESIA_UI_STYLESHEET } from "../src/styles.js";

declare global {
  // eslint-disable-next-line no-var
  var IS_REACT_ACT_ENVIRONMENT: boolean | undefined;
}

/**
 * SelectMenu (ADR 0065): a single choice drawn by Ekklesia — the WAI-ARIA select-only combobox —
 * rather than the browser's native menu.
 */

let container: HTMLDivElement;
let root: Root;

beforeEach(() => {
  globalThis.IS_REACT_ACT_ENVIRONMENT = true;
  container = document.createElement("div");
  document.body.appendChild(container);
  root = createRoot(container);
});

afterEach(() => {
  act(() => root.unmount());
  container.remove();
});

const OPTIONS = [
  { label: "Nothing yet", value: "" },
  { label: "Signage", value: "signage" },
  { label: "Bulletin", value: "bulletin" },
  { label: "Parent Call", value: "parent-call" },
];

function Harness(props: {
  readonly onChange?: (value: string) => void;
  readonly disabled?: boolean;
}) {
  const [value, setValue] = useState("");
  return (
    <>
      <Field label="Show on this screen">
        {(control) => (
          <SelectMenu
            {...control}
            data-testid="menu"
            disabled={props.disabled}
            onChange={(next) => {
              setValue(next);
              props.onChange?.(next);
            }}
            options={OPTIONS}
            value={value}
          />
        )}
      </Field>
      <button data-testid="elsewhere" type="button">
        Elsewhere
      </button>
    </>
  );
}

function render(node: ReactElement): void {
  act(() => root.render(node));
}

function trigger(): HTMLButtonElement {
  return container.querySelector('[data-testid="menu"]') as HTMLButtonElement;
}

function list(): HTMLElement {
  return container.querySelector('[role="listbox"]') as HTMLElement;
}

function press(key: string, init: KeyboardEventInit = {}): KeyboardEvent {
  const event = new KeyboardEvent("keydown", { bubbles: true, cancelable: true, key, ...init });
  act(() => {
    trigger().dispatchEvent(event);
  });
  return event;
}

function activeLabel(): string | undefined {
  const id = trigger().getAttribute("aria-activedescendant");
  return id === null
    ? undefined
    : (container.querySelector(`#${CSS.escape(id)}`)?.textContent ?? "");
}

describe("SelectMenu", () => {
  it("is a labelled combobox controlling a listbox of options, never a native select", () => {
    render(<Harness />);

    expect(container.querySelector("select")).toBeNull();
    const control = trigger();
    expect(control.tagName).toBe("BUTTON");
    // The shared control, so its border, height, and 16px phone size (no iOS zoom) are the field's.
    expect(control.classList.contains("ek-control")).toBe(true);
    expect(control.getAttribute("role")).toBe("combobox");
    expect(control.getAttribute("aria-haspopup")).toBe("listbox");
    expect(control.getAttribute("aria-expanded")).toBe("false");
    expect(control.getAttribute("aria-controls")).toBe(list().id);
    // The Field's label names it.
    expect(container.querySelector("label")?.getAttribute("for")).toBe(control.id);
    expect(control.textContent).toBe("Nothing yet");
    expect(list().hidden).toBe(true);
    const options = [...list().querySelectorAll('[role="option"]')];
    expect(options.map((option) => option.textContent)).toEqual(OPTIONS.map((o) => o.label));
    expect(options.map((option) => option.getAttribute("aria-selected"))).toEqual([
      "true",
      "false",
      "false",
      "false",
    ]);
  });

  it("opens, moves, and chooses from the keyboard", () => {
    const onChange = vi.fn();
    render(<Harness onChange={onChange} />);
    act(() => trigger().focus());

    expect(press("ArrowDown").defaultPrevented).toBe(true);
    expect(trigger().getAttribute("aria-expanded")).toBe("true");
    expect(list().hidden).toBe(false);
    // It opens on the current choice.
    expect(activeLabel()).toBe("Nothing yet");
    press("ArrowDown");
    press("ArrowDown");
    expect(activeLabel()).toBe("Bulletin");
    press("ArrowUp");
    expect(activeLabel()).toBe("Signage");
    press("End");
    expect(activeLabel()).toBe("Parent Call");
    press("Home");
    expect(activeLabel()).toBe("Nothing yet");
    // Typing a letter moves to the next choice that starts with it.
    press("b");
    expect(activeLabel()).toBe("Bulletin");

    press("Enter");
    expect(onChange).toHaveBeenCalledWith("bulletin");
    expect(trigger().getAttribute("aria-expanded")).toBe("false");
    expect(trigger().textContent).toBe("Bulletin");
    // Focus never left the control.
    expect(document.activeElement).toBe(trigger());

    press(" ");
    expect(activeLabel()).toBe("Bulletin");
    press("ArrowDown");
    press(" ");
    expect(onChange).toHaveBeenLastCalledWith("parent-call");
  });

  it("closes on Escape without choosing, and without closing a dialog it sits in", () => {
    const onChange = vi.fn();
    const onDismiss = vi.fn();
    render(
      <Dialog onDismiss={onDismiss} open title="Change">
        <Harness onChange={onChange} />
      </Dialog>,
    );
    act(() => trigger().focus());
    press("ArrowDown");
    press("ArrowDown");

    const escapeKey = press("Escape");
    expect(escapeKey.defaultPrevented).toBe(true);
    expect(trigger().getAttribute("aria-expanded")).toBe("false");
    expect(onChange).not.toHaveBeenCalled();
    expect(onDismiss).not.toHaveBeenCalled();
    expect(document.activeElement).toBe(trigger());

    // Closed, Escape is the dialog's again.
    press("Escape");
    expect(onDismiss).toHaveBeenCalledTimes(1);
  });

  it("chooses the active option on Tab, as a native select does", () => {
    const onChange = vi.fn();
    render(<Harness onChange={onChange} />);
    act(() => trigger().focus());
    press("ArrowDown");
    press("ArrowDown");
    const tab = press("Tab");
    expect(tab.defaultPrevented).toBe(false);
    expect(onChange).toHaveBeenCalledWith("signage");
    expect(trigger().getAttribute("aria-expanded")).toBe("false");
  });

  it("works with a pointer: press to open, press an option to choose, press outside to close", () => {
    const onChange = vi.fn();
    render(<Harness onChange={onChange} />);

    act(() => trigger().click());
    expect(trigger().getAttribute("aria-expanded")).toBe("true");
    // Pressed, it takes focus (Safari would not), so the keyboard and Escape work from here.
    expect(document.activeElement).toBe(trigger());
    const signage = [...list().querySelectorAll<HTMLElement>('[role="option"]')][1] as HTMLElement;
    act(() => signage.click());
    expect(onChange).toHaveBeenCalledWith("signage");
    expect(trigger().getAttribute("aria-expanded")).toBe("false");

    act(() => trigger().click());
    act(() => {
      (container.querySelector('[data-testid="elsewhere"]') as HTMLElement).dispatchEvent(
        new Event("pointerdown", { bubbles: true, composed: true }),
      );
    });
    expect(trigger().getAttribute("aria-expanded")).toBe("false");
    expect(onChange).toHaveBeenCalledTimes(1);
  });

  it("does nothing while disabled", () => {
    const onChange = vi.fn();
    render(<Harness disabled onChange={onChange} />);
    expect(trigger().disabled).toBe(true);
    press("ArrowDown");
    expect(trigger().getAttribute("aria-expanded")).toBe("false");
  });

  it("is drawn from tokens: a themed list, and a chevron inside the control's own padding", () => {
    expect(EKKLESIA_UI_STYLESHEET).toContain(".ek-select-menu__chevron {");
    expect(EKKLESIA_UI_STYLESHEET).toMatch(
      /\.ek-select-menu__list \{[^}]*background: var\(--ekklesia-background-raised\)/u,
    );
    expect(EKKLESIA_UI_STYLESHEET).toMatch(
      /\.ek-select-menu__option\[aria-selected="true"\] \{[^}]*var\(--ekklesia-state-selected-background\)/u,
    );
    // The chevron's turn is a motion token, so reduced motion stills it.
    expect(EKKLESIA_UI_STYLESHEET).toMatch(
      /\.ek-select-menu__chevron \{[^}]*transition: transform var\(--ekklesia-motion-duration-short\)/u,
    );
  });
});