/**
 * Token Estimator 单元测试（P1-14 测试基线）
 */

import { describe, it, expect } from 'vitest';
import { estimateStringTokens, estimateMessagesTokens } from '../token-estimator';

describe('estimateStringTokens', () => {
  it('空值返回 0', () => {
    expect(estimateStringTokens('')).toBe(0);
    expect(estimateStringTokens(null)).toBe(0);
    expect(estimateStringTokens(undefined)).toBe(0);
  });

  it('纯 ASCII：4 字符 ≈ 1 token', () => {
    // 16 个 ASCII 字符 → 16 * 0.25 = 4 tokens
    expect(estimateStringTokens('abcdefghijklmnop')).toBe(4);
  });

  it('纯中文：1 字符 ≈ 1 token', () => {
    expect(estimateStringTokens('你好世界')).toBe(4);
  });

  it('混合文本按系数分别计算', () => {
    // 4 ASCII (1 token) + 2 中文 (2 tokens) = 3 tokens
    expect(estimateStringTokens('abcd你好')).toBe(3);
  });

  it('Emoji 计为 1 token/字符', () => {
    expect(estimateStringTokens('🎉🎊')).toBe(2);
  });

  it('结果向上取整', () => {
    // 1 个 ASCII = 0.25 → ceil 为 1
    expect(estimateStringTokens('a')).toBe(1);
  });
});

describe('estimateMessagesTokens', () => {
  it('每条消息计入结构性开销（4 tokens）', () => {
    const msgs = [{ content: '' }, { content: '' }];
    expect(estimateMessagesTokens(msgs)).toBe(8); // 2 * 4 overhead
  });

  it('content 为 null 时只计开销（tool_calls 消息场景）', () => {
    expect(estimateMessagesTokens([{ content: null }])).toBe(4);
  });

  it('toolCalls 计入 id/name/args 开销', () => {
    const withToolCall = [
      {
        content: null,
        toolCalls: [{ id: 'tc_12345678', name: 'read_file', args: { file_path: '/a/b.ts' } }],
      },
    ];
    const withoutToolCall = [{ content: null }];
    const diff = estimateMessagesTokens(withToolCall) - estimateMessagesTokens(withoutToolCall);
    // id(9 chars→3) + name(9→3) + args(~18→5) + overhead(8) ≈ 19 tokens
    expect(diff).toBeGreaterThanOrEqual(15);
    expect(diff).toBeLessThanOrEqual(30);
  });

  it('reasoningContent 计入 token', () => {
    const withReasoning = [{ content: '', reasoningContent: 'abcd' }];
    const without = [{ content: '' }];
    expect(estimateMessagesTokens(withReasoning) - estimateMessagesTokens(without)).toBe(1);
  });
});