// EmptyState — unit tests (#352).
//
// No jsdom / testing-library in this project (see FilterPanel.test.tsx): the
// component is pure (no hook), so it is called as a plain function and its
// React-element tree is walked directly. `Link` is react-router's real
// component: creating the element never needs a router, only rendering would.
import { describe, it, expect, vi } from "vitest";
import { isValidElement, type ReactElement, type ReactNode } from "react";
import { Link } from "react-router-dom";

import EmptyState from "./EmptyState";

function find(node: ReactNode, pred: (el: ReactElement) => boolean): ReactElement[] {
  if (Array.isArray(node)) return node.flatMap((n) => find(n, pred));
  if (!isValidElement(node)) return [];
  const el = node as ReactElement<{ children?: ReactNode }>;
  return [...(pred(el) ? [el] : []), ...find(el.props.children, pred)];
}

function texts(node: ReactNode): string[] {
  if (Array.isArray(node)) return node.flatMap(texts);
  if (typeof node === "string") return [node];
  if (!isValidElement(node)) return [];
  return texts((node as ReactElement<{ children?: ReactNode }>).props.children);
}

const ICON = "ICON_MARKER";

describe("EmptyState", () => {
  it("renders the icon, the title and the description", () => {
    const el = EmptyState({ icon: ICON, title: "Title", description: "Desc" });
    const text = texts(el);
    expect(text).toContain(ICON);
    expect(text).toContain("Title");
    expect(text).toContain("Desc");
  });

  it("renders no action container when no action is given", () => {
    const el = EmptyState({ icon: ICON, title: "Title" });
    expect(find(el, (e) => e.type === Link)).toHaveLength(0);
    expect(find(el, (e) => e.type === "button")).toHaveLength(0);
  });

  it("renders a `to` action as a react-router Link, never a button", () => {
    const el = EmptyState({
      icon: ICON,
      title: "Title",
      primaryAction: { label: "Go", to: "/import" },
    });
    const links = find(el, (e) => e.type === Link) as ReactElement<{ to: string; children: ReactNode }>[];
    expect(links).toHaveLength(1);
    expect(links[0].props.to).toBe("/import");
    expect(texts(links[0].props.children)).toContain("Go");
    expect(find(el, (e) => e.type === "button")).toHaveLength(0);
  });

  it("renders an `onClick` action as a type=button that calls the handler", () => {
    const onClick = vi.fn();
    const el = EmptyState({
      icon: ICON,
      title: "Title",
      primaryAction: { label: "Do", onClick },
    });
    const buttons = find(el, (e) => e.type === "button") as ReactElement<{
      type: string;
      disabled: boolean;
      onClick: () => void;
    }>[];
    expect(buttons).toHaveLength(1);
    expect(buttons[0].props.type).toBe("button");
    expect(buttons[0].props.disabled).toBe(false);
    buttons[0].props.onClick();
    expect(onClick).toHaveBeenCalledTimes(1);
  });

  it("propagates `disabled` on the button variant", () => {
    const el = EmptyState({
      icon: ICON,
      title: "Title",
      primaryAction: { label: "Do", onClick: vi.fn(), disabled: true },
    });
    const [button] = find(el, (e) => e.type === "button") as ReactElement<{ disabled: boolean }>[];
    expect(button.props.disabled).toBe(true);
  });

  it("renders both actions, primary first", () => {
    const el = EmptyState({
      icon: ICON,
      title: "Title",
      primaryAction: { label: "Primary", to: "/a" },
      secondaryAction: { label: "Secondary", onClick: vi.fn() },
    });
    const actions = find(el, (e) => e.type === Link || e.type === "button");
    expect(actions).toHaveLength(2);
    expect(actions[0].type).toBe(Link);
    expect(actions[1].type).toBe("button");
  });

  it("renders children between the description and the actions", () => {
    const el = EmptyState({
      icon: ICON,
      title: "Title",
      description: "Desc",
      primaryAction: { label: "Go", to: "/a" },
      children: "CHILD_MARKER",
    });
    const text = texts(el);
    expect(text.indexOf("Desc")).toBeLessThan(text.indexOf("CHILD_MARKER"));
    expect(text.indexOf("CHILD_MARKER")).toBeLessThan(text.indexOf("Go"));
  });
});