/**
 * 外观同步的行为判据（2026-09-14）。
 *
 * 背景：用户质问「为什么背景是保存在本地而不是服务器！」⇒ 主题与壁纸搬到服务端
 * （账号级），本地只做缓存。这一层出错**不会抛异常**，只会表现为"设置看起来保存了，
 * 换设备却是别的样子"或"改动没存上却显示已同步" —— 所以必须逐条钉住：
 *
 *   1. 拉取以服务端为准（换设备能拿回来）
 *   2. ★ 拉取**不会**再推回去（否则自己触发自己：一次拉取顺带一次 PUT，
 *      服务端 updated_at 被无意义刷新，还会掩盖真实的本地改动）
 *   3. 本地改动会推上去（payload 形状要对）
 *   4. 推不上去要变成 pending，未登录/不可达是 local-only —— **降级可见**
 *   5. 壁纸只在换图时上传一次（几 MB 的东西不该每次 PUT 都跟着走）
 */
import { beforeEach, describe, expect, it, vi } from 'vitest';

import { setActiveAuth } from '../../src/api/config';
import { useAppearanceSync } from '../../src/stores/appearanceSync';
import { useBackgroundStore } from '../../src/stores/backgroundStore';
import { useThemeStore } from '../../src/stores/themeStore';
import { payloadFromLocal, snapshotFromResponse } from '../../src/lib/appearance';

type Call = { url: string; method: string; body?: any };

function fakeFetch(handler: (call: Call) => Response | Promise<Response>) {
  const calls: Call[] = [];
  globalThis.fetch = (async (input: any, init: any = {}) => {
    const url = String(input);
    const call: Call = { url, method: init.method || 'GET', body: init.body };
    calls.push(call);
    return handler(call);
  }) as any;
  return calls;
}

const json = (body: unknown, status = 200) =>
  new Response(JSON.stringify(body), { status, headers: { 'Content-Type': 'application/json' } });

const REMOTE = {
  theme: 'dark',
  bg_kind: 'preset',
  bg_preset_id: 'dusk',
  bg_dim: 33,
  bg_blur: 7,
  has_image: false
};

beforeEach(() => {
  localStorage.clear();
  setActiveAuth({ base: 'http://gw', token: 'tok' });
  useAppearanceSync.setState({ status: 'idle', lastSyncedAt: 0, applyingRemote: false });
  useThemeStore.getState().setPref('system');
  useBackgroundStore.setState({ kind: 'none', presetId: 'aurora', imageDataUrl: '', dim: 12, blur: 4 });
});

describe('快照换算（纯函数）', () => {
  it('服务端的值能灌进本地形状，认不出的退回默认', () => {
    expect(snapshotFromResponse(REMOTE)).toEqual({
      theme: 'dark',
      bgKind: 'preset',
      bgPresetId: 'dusk',
      bgDim: 33,
      bgBlur: 7
    });
    expect(snapshotFromResponse({ theme: 'neon', bg_kind: 'video' } as any)).toMatchObject({
      theme: 'system',
      bgKind: 'none'
    });
  });

  it('★ image 档但没图 → 退回 none（免得服务端存成"有图却没有"）', () => {
    const p = payloadFromLocal({ theme: 'dark', kind: 'image', presetId: 'aurora', imageDataUrl: '', dim: 12, blur: 4 });
    expect(p.bg_kind).toBe('none');
    const q = payloadFromLocal({ theme: 'dark', kind: 'image', presetId: 'aurora', imageDataUrl: 'data:image/png;base64,AA', dim: 12, blur: 4 });
    expect(q.bg_kind).toBe('image');
  });

  it('越界的 dim/blur 被夹住（服务端也会夹，但本地不该先送出脏值）', () => {
    const p = payloadFromLocal({ theme: 'light', kind: 'preset', presetId: 'aurora', imageDataUrl: '', dim: 999, blur: -3 });
    expect(p.bg_dim).toBe(90);
    expect(p.bg_blur).toBe(0);
  });
});

describe('拉取与推送', () => {
  it('拉取以服务端为准（换设备能拿回来）', async () => {
    fakeFetch(() => json(REMOTE));
    await useAppearanceSync.getState().pull();
    expect(useThemeStore.getState().pref).toBe('dark');
    const bg = useBackgroundStore.getState();
    expect(bg.kind).toBe('preset');
    expect(bg.presetId).toBe('dusk');
    expect(bg.dim).toBe(33);
    expect(useAppearanceSync.getState().status).toBe('synced');
  });

  it('★ 拉取不会再推回去（否则是自触发回环）', async () => {
    const calls = fakeFetch(() => json(REMOTE));
    await useAppearanceSync.getState().pull();
    const writes = calls.filter(c => c.method !== 'GET');
    expect(writes, `拉取期间不该有任何写请求：${JSON.stringify(writes)}`).toEqual([]);
  });

  it('本地改动推上去，且 payload 形状对', async () => {
    const calls = fakeFetch(() => json({ saved: true }));
    useThemeStore.getState().setPref('light');
    useBackgroundStore.getState().setPreset('mint');
    await useAppearanceSync.getState().push();

    const put = calls.find(c => c.method === 'PUT');
    expect(put, '应当发出 PUT').toBeTruthy();
    const body = JSON.parse(String(put!.body));
    expect(body).toMatchObject({ theme: 'light', bg_kind: 'preset', bg_preset_id: 'mint' });
    expect(useAppearanceSync.getState().status).toBe('synced');
  });

  it('未登录 → local-only（降级必须可见）', async () => {
    setActiveAuth({ base: '', token: '' });
    fakeFetch(() => json(REMOTE));
    await useAppearanceSync.getState().pull();
    expect(useAppearanceSync.getState().status).toBe('local-only');
  });

  it('服务端不可达 → local-only，不是"已同步"', async () => {
    fakeFetch(() => json({}, 500));
    await useAppearanceSync.getState().pull();
    expect(useAppearanceSync.getState().status).toBe('local-only');
  });

  it('推送失败 → pending（稍后重试，而不是假装成功）', async () => {
    fakeFetch(() => json({}, 503));
    await useAppearanceSync.getState().push();
    expect(useAppearanceSync.getState().status).toBe('pending');
  });

  it('★ 壁纸只在换图时上传一次（几 MB 不该每次 PUT 都跟着走）', async () => {
    const calls = fakeFetch(() => json({ has_image: true }));
    useBackgroundStore.getState().setImage('data:image/png;base64,AAAB');
    await useAppearanceSync.getState().push();
    const posts = () => calls.filter(c => c.method === 'POST').length;
    expect(posts(), '第一次推送应上传图片').toBe(1);

    // 只改参数、不换图 → 不该再上传
    useBackgroundStore.getState().setDim(40);
    await useAppearanceSync.getState().push();
    expect(posts(), '没换图时不该重复上传').toBe(1);
  });
});