import test from 'node:test';
import assert from 'node:assert/strict';

import {
  mergeConversationSnapshot,
  mergeSessionMessagesAfterFinish,
} from './chat-finish-sync.mjs';

const msg = (id, role, text) => ({
  id,
  role,
  metadata: { userVisible: true },
  content: [{ type: 'text', text }],
});

test('mergeConversationSnapshot keeps local-only messages when server snapshot is shorter', () => {
  const local = [
    msg('u1', 'user', '生成一个页面'),
    msg('a1', 'assistant', '正在写入 public/demo.html…'),
    msg('a2', 'assistant', '页面已生成'),
  ];
  const server = [msg('u1', 'user', '生成一个页面')];
  const merged = mergeConversationSnapshot(local, server);
  assert.equal(merged.length, 3);
  assert.deepEqual(
    merged.map((message) => message.id),
    ['u1', 'a1', 'a2'],
  );
});

test('mergeConversationSnapshot prefers server content for shared message ids', () => {
  const local = [msg('u1', 'user', '旧文案')];
  const server = [msg('u1', 'user', '新文案')];
  const merged = mergeConversationSnapshot(local, server);
  assert.equal(merged.length, 1);
  assert.equal(merged[0].content[0].text, '新文案');
});

test('mergeConversationSnapshot returns current when incoming is empty', () => {
  const local = [msg('u1', 'user', 'hello')];
  assert.deepEqual(mergeConversationSnapshot(local, []), local);
});

test('mergeSessionMessagesAfterFinish matches Finish sync merge semantics', () => {
  const local = [
    msg('u1', 'user', '根据图片做主题页'),
    msg('a1', 'assistant', '已完成'),
  ];
  const server = [msg('u1', 'user', '根据图片做主题页')];
  assert.deepEqual(
    mergeSessionMessagesAfterFinish(local, server).map((message) => message.id),
    ['u1', 'a1'],
  );
});