import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
import { ThemeCache, type CachedPolicy, type CachedTheme } from "../theme-cache.js";

const TTL_MS = 5 * 60 * 1000; // 5 minutes

const MOCK_POLICY: CachedPolicy = {
  defaultLightThemeUri: "at://did:plc:forum/space.atbb.forum.theme/3lbllight",
  defaultDarkThemeUri: "at://did:plc:forum/space.atbb.forum.theme/3lbldark",
  allowUserChoice: true,
  availableThemes: [
    { uri: "at://did:plc:forum/space.atbb.forum.theme/3lbllight", cid: "bafylight" },
    { uri: "at://did:plc:forum/space.atbb.forum.theme/3lbldark", cid: "bafydark" },
  ],
};

const MOCK_THEME: CachedTheme = {
  cid: "bafylight",
  tokens: { "color-bg": "#fff" },
  cssOverrides: null,
  fontUrls: null,
};

describe("ThemeCache — policy", () => {
  let cache: ThemeCache;

  beforeEach(() => {
    vi.useFakeTimers();
    cache = new ThemeCache(TTL_MS);
  });

  afterEach(() => {
    vi.useRealTimers();
  });

  it("returns null when policy has not been set", () => {
    expect(cache.getPolicy()).toBeNull();
  });

  it("returns policy immediately after setting", () => {
    cache.setPolicy(MOCK_POLICY);
    expect(cache.getPolicy()).toEqual(MOCK_POLICY);
  });

  it("returns null after TTL expires", () => {
    cache.setPolicy(MOCK_POLICY);
    vi.advanceTimersByTime(TTL_MS + 1);
    expect(cache.getPolicy()).toBeNull();
  });

  it("returns policy just before TTL expires", () => {
    cache.setPolicy(MOCK_POLICY);
    vi.advanceTimersByTime(TTL_MS - 1);
    expect(cache.getPolicy()).toEqual(MOCK_POLICY);
  });

  it("can be refreshed before expiry (re-set resets TTL)", () => {
    cache.setPolicy(MOCK_POLICY);
    vi.advanceTimersByTime(TTL_MS - 1);
    cache.setPolicy({ ...MOCK_POLICY, allowUserChoice: false });
    vi.advanceTimersByTime(TTL_MS - 1);
    // Total elapsed: (TTL-1) + (TTL-1) = 2*TTL - 2ms, but the re-set happened at TTL-1
    // so the new entry expires at (TTL-1) + TTL = 2*TTL - 1ms from start
    const result = cache.getPolicy();
    expect(result).not.toBeNull();
    expect(result!.allowUserChoice).toBe(false);
  });
});

describe("ThemeCache — themes", () => {
  let cache: ThemeCache;

  beforeEach(() => {
    vi.useFakeTimers();
    cache = new ThemeCache(TTL_MS);
  });

  afterEach(() => {
    vi.useRealTimers();
  });

  it("returns null on cache miss", () => {
    expect(
      cache.getTheme("at://did:plc:forum/space.atbb.forum.theme/3lbllight", "light")
    ).toBeNull();
  });

  it("returns theme immediately after setting", () => {
    const uri = "at://did:plc:forum/space.atbb.forum.theme/3lbllight";
    cache.setTheme(uri, "light", MOCK_THEME);
    expect(cache.getTheme(uri, "light")).toEqual(MOCK_THEME);
  });

  it("returns null after TTL expires", () => {
    const uri = "at://did:plc:forum/space.atbb.forum.theme/3lbllight";
    cache.setTheme(uri, "light", MOCK_THEME);
    vi.advanceTimersByTime(TTL_MS + 1);
    expect(cache.getTheme(uri, "light")).toBeNull();
  });

  it("treats light and dark as separate cache entries", () => {
    const uri = "at://did:plc:forum/space.atbb.forum.theme/shared";
    const lightTheme: CachedTheme = { cid: "bafylight", tokens: { "color-bg": "#fff" }, cssOverrides: null, fontUrls: null };
    const darkTheme: CachedTheme = { cid: "bafydark", tokens: { "color-bg": "#111" }, cssOverrides: null, fontUrls: null };

    cache.setTheme(uri, "light", lightTheme);
    cache.setTheme(uri, "dark", darkTheme);

    expect(cache.getTheme(uri, "light")).toEqual(lightTheme);
    expect(cache.getTheme(uri, "dark")).toEqual(darkTheme);
  });

  it("different URIs are stored independently", () => {
    const lightUri = "at://did/col/light";
    const darkUri = "at://did/col/dark";
    const lightTheme: CachedTheme = { cid: "bafylight", tokens: { "color-bg": "#fff" }, cssOverrides: null, fontUrls: null };
    const darkTheme: CachedTheme = { cid: "bafydark", tokens: { "color-bg": "#111" }, cssOverrides: null, fontUrls: null };

    cache.setTheme(lightUri, "light", lightTheme);
    cache.setTheme(darkUri, "dark", darkTheme);

    expect(cache.getTheme(lightUri, "light")).toEqual(lightTheme);
    expect(cache.getTheme(darkUri, "dark")).toEqual(darkTheme);
    expect(cache.getTheme(lightUri, "dark")).toBeNull();
    expect(cache.getTheme(darkUri, "light")).toBeNull();
  });

  it("deleteTheme removes a specific entry before TTL", () => {
    const uri = "at://did/col/theme";
    cache.setTheme(uri, "light", MOCK_THEME);
    cache.deleteTheme(uri, "light");
    expect(cache.getTheme(uri, "light")).toBeNull();
  });

  it("deleteTheme only removes the targeted uri:colorScheme entry", () => {
    const uri = "at://did/col/theme";
    const darkTheme: CachedTheme = { cid: "bafydark", tokens: { "color-bg": "#111" }, cssOverrides: null, fontUrls: null };
    cache.setTheme(uri, "light", MOCK_THEME);
    cache.setTheme(uri, "dark", darkTheme);
    cache.deleteTheme(uri, "light");
    expect(cache.getTheme(uri, "light")).toBeNull();
    expect(cache.getTheme(uri, "dark")).toEqual(darkTheme);
  });

  it("evicts stale entry from the map on expired access", () => {
    const uri = "at://did/col/theme";
    cache.setTheme(uri, "light", MOCK_THEME);
    vi.advanceTimersByTime(TTL_MS + 1);
    // Access after expiry
    expect(cache.getTheme(uri, "light")).toBeNull();
    // After eviction, setting a new entry works correctly
    const newTheme = { ...MOCK_THEME, cid: "bafynew" };
    cache.setTheme(uri, "light", newTheme);
    expect(cache.getTheme(uri, "light")).toEqual(newTheme);
  });
});