/**
 * usage-log.test.ts
 *
 * parseOpenAiUsage is the single point where every non-Ollama provider's token counts get
 * picked up (openai-compat serves Gemini/LM Studio/OpenAI, openai-codex serves Codex). It
 * returning null silently means a provider vanishes from the cost-comparison log entirely —
 * which is exactly the bug this module was extracted to fix on 2026-07-29, and the kind that
 * produces no error, just a quietly wrong conclusion months later.
 */

import { test, describe } from 'node:test';
import assert from 'node:assert/strict';
import { parseOpenAiUsage } from '../src/providers/usage-log';

describe('parseOpenAiUsage', () => {
  test('표준 OpenAI usage 필드를 읽는다', () => {
    assert.deepEqual(
      parseOpenAiUsage({ prompt_tokens: 137, completion_tokens: 42 }),
      { promptTokens: 137, completionTokens: 42 },
    );
  });

  test('camelCase 변형도 받는다', () => {
    assert.deepEqual(
      parseOpenAiUsage({ promptTokens: 10, completionTokens: 20 }),
      { promptTokens: 10, completionTokens: 20 },
    );
  });

  test('한쪽만 있어도 기록한다 — 절반이라도 남기는 게 0건보다 낫다', () => {
    assert.deepEqual(parseOpenAiUsage({ prompt_tokens: 500 }), { promptTokens: 500, completionTokens: 0 });
    assert.deepEqual(parseOpenAiUsage({ completion_tokens: 7 }), { promptTokens: 0, completionTokens: 7 });
  });

  test('usage가 없거나 값이 없으면 null — 0/0짜리 가짜 행을 남기지 않는다', () => {
    assert.equal(parseOpenAiUsage(undefined), null);
    assert.equal(parseOpenAiUsage(null), null);
    assert.equal(parseOpenAiUsage({}), null);
    assert.equal(parseOpenAiUsage({ prompt_tokens: 0, completion_tokens: 0 }), null);
    assert.equal(parseOpenAiUsage('nope' as any), null);
  });

  test('숫자가 아닌 값은 0으로 떨어뜨린다 (NaN이 로그에 새지 않게)', () => {
    assert.equal(parseOpenAiUsage({ prompt_tokens: 'abc', completion_tokens: 'def' }), null);
    assert.deepEqual(
      parseOpenAiUsage({ prompt_tokens: 'abc', completion_tokens: 5 }),
      { promptTokens: 0, completionTokens: 5 },
    );
  });
});