import { beforeEach, describe, expect, it } from "vitest";
import {
	DEFAULT_THEME,
	THEME_KEY,
	isTheme,
	resetTheme,
	setTheme,
	toggleTheme,
	useTheme,
} from "./theme";

describe("theme store", () => {
	beforeEach(() => {
		localStorage.clear();
		resetTheme();
	});

	it("starts light and stamps the document", () => {
		expect(useTheme.getState().theme).toBe(DEFAULT_THEME);
		expect(document.documentElement.dataset.theme).toBe("light");
	});

	it("setTheme applies, stamps and remembers the theme", () => {
		setTheme("dark");
		expect(useTheme.getState().theme).toBe("dark");
		expect(document.documentElement.dataset.theme).toBe("dark");
		expect(localStorage.getItem(THEME_KEY)).toBe("dark");
	});

	it("toggleTheme alternates between light and dark", () => {
		toggleTheme();
		expect(useTheme.getState().theme).toBe("dark");
		toggleTheme();
		expect(useTheme.getState().theme).toBe("light");
		expect(document.documentElement.dataset.theme).toBe("light");
	});

	it("resetTheme goes back to light", () => {
		setTheme("dark");
		resetTheme();
		expect(useTheme.getState().theme).toBe("light");
		expect(localStorage.getItem(THEME_KEY)).toBe("light");
	});
});

describe("isTheme", () => {
	it("accepts the two themes and rejects anything else", () => {
		expect(isTheme("light")).toBe(true);
		expect(isTheme("dark")).toBe(true);
		expect(isTheme("system")).toBe(false);
		expect(isTheme(null)).toBe(false);
		expect(isTheme(42)).toBe(false);
	});
});