import { describe, expect, test } from "bun:test";

import {
  getSystemPrefersDark,
  parseThemePreference,
  readThemePreference,
  resolveEffectiveTheme,
  THEME_MEDIA_QUERY,
  THEME_PREFERENCE_STORAGE_KEY,
  writeThemePreference,
} from "../../../src/web/shared/hooks/use-theme-preference";

function createStorage(initial?: string): Storage {
  const values = new Map<string, string>();
  if (initial !== undefined) values.set(THEME_PREFERENCE_STORAGE_KEY, initial);
  return {
    clear: () => values.clear(),
    getItem: (key) => values.get(key) ?? null,
    key: (index) => Array.from(values.keys())[index] ?? null,
    get length() {
      return values.size;
    },
    removeItem: (key) => values.delete(key),
    setItem: (key, value) => values.set(key, value),
  };
}

describe("theme preference 纯逻辑", () => {
  test("解析合法和非法主题偏好", () => {
    expect(parseThemePreference("dark")).toBe("dark");
    expect(parseThemePreference("light")).toBe("light");
    expect(parseThemePreference("system")).toBe("system");
    expect(parseThemePreference("unknown")).toBe("system");
  });

  test("读取和写入 localStorage", () => {
    const storage = createStorage("dark");
    expect(readThemePreference(storage)).toBe("dark");

    writeThemePreference("light", storage);
    expect(storage.getItem(THEME_PREFERENCE_STORAGE_KEY)).toBe("light");
  });

  test("storage 异常时回退且不抛错", () => {
    const brokenStorage = {
      getItem: () => {
        throw new Error("blocked");
      },
      setItem: () => {
        throw new Error("blocked");
      },
    } as unknown as Storage;

    expect(readThemePreference(brokenStorage)).toBe("system");
    expect(() => writeThemePreference("dark", brokenStorage)).not.toThrow();
  });

  test("解析系统主题和异常回退", () => {
    const matchMedia = ((query: string) => {
      expect(query).toBe(THEME_MEDIA_QUERY);
      return { matches: true };
    }) as Window["matchMedia"];
    const brokenMatchMedia = (() => {
      throw new Error("blocked");
    }) as Window["matchMedia"];

    expect(getSystemPrefersDark(matchMedia)).toBe(true);
    expect(getSystemPrefersDark(brokenMatchMedia)).toBe(false);
  });

  test("根据系统主题解析实际主题", () => {
    expect(resolveEffectiveTheme("dark", false)).toBe("dark");
    expect(resolveEffectiveTheme("light", true)).toBe("light");
    expect(resolveEffectiveTheme("system", true)).toBe("dark");
    expect(resolveEffectiveTheme("system", false)).toBe("light");
  });
});