# -*- coding: utf-8 -*-
"""/download 端点 json 同步模式的契约测试（沙箱，不触真实上游）。

test_download_billing.py 覆盖参数校验与退费口径；本文件钉住 format=json
的同步下载分支——它此前零覆盖，却是 40 行内嵌「取信息 → 下载 → 组响应 →
结算」的完整事务：
- 任一步失败：退回预扣（无 open 账本行）+ 专属文案
- 成功：settle(1, 'delivered')，余额恰好 -1

替身边界：monkeypatch ``services.api_service.api_service.downloader``
（路由内延迟导入取的就是这个实例属性），MusicInfo/DownloadResult 用
真实 dataclass 构造。
"""
import asyncio

import pytest
from fastapi.testclient import TestClient

import auth_system as auth
import core.db as db
from music_downloader.models import MusicInfo

SECRET = 'download-sync-test-secret'
PW = 'Passw0rd12'


async def _fake_secret_key() -> str:
    return SECRET


def _info() -> MusicInfo:
    return MusicInfo(id=347230, name='晴天', artists='周杰伦', album='叶惠美',
                     pic_url='', duration=269, track_number=1,
                     download_url='', file_type='mp3', file_size=1024,
                     quality='lossless')


def _dl(success: bool = True, msg: str = ''):
    from music_downloader.models import DownloadResult
    return DownloadResult(success=success, file_path='/tmp/x.mp3',
                          error_message=msg)


@pytest.fixture()
def env(tmp_path, monkeypatch):
    db_path = tmp_path / 'site.db'
    monkeypatch.setattr(auth.db, 'DATA_DIR', tmp_path)
    monkeypatch.setattr(auth.db, 'DB_PATH', db_path)
    monkeypatch.setattr(auth.db, 'BACKUP_DIR', tmp_path / 'backups')
    monkeypatch.setattr(auth.db, 'SECRET_KEY_PATH', tmp_path / 'secret.key')
    monkeypatch.setattr(db, 'DATA_DIR', tmp_path)
    monkeypatch.setattr(db, 'DB_PATH', db_path)
    asyncio.run(auth.init_db())
    monkeypatch.setattr('web.deps.secret_key', _fake_secret_key)
    asyncio.run(auth.create_user('payer', PW, email='p@example.com', credits=3))

    state: dict = {'info_exc': None, 'dl_result': _dl(), 'dl_exc': None}

    class _FakeDownloader:
        async def get_music_info(self, music_id, quality, cookies):
            if state['info_exc'] is not None:
                raise state['info_exc']
            return state['info']

        async def download_music_file(self, music_id, quality, **kw):
            if state['dl_exc'] is not None:
                raise state['dl_exc']
            return state['dl_result']

    state['info'] = _info()
    from services.api_service import api_service
    monkeypatch.setattr(api_service, 'downloader', _FakeDownloader())

    from web.app import create_app
    client = TestClient(create_app())

    r = client.post('/auth/login', json={'username': 'payer', 'password': PW})
    raw = r.headers.get('set-cookie', '')
    cookie = ''
    for part in raw.split(';'):
        if part.strip().startswith('session='):
            cookie = part.strip()[len('session='):]
            break
    state['headers'] = {'Cookie': f'session={cookie}'}
    state['client'] = client
    return state


def _balance(username: str = 'payer') -> int:
    u = asyncio.run(auth.get_user_by_name(username))
    assert u is not None, f'用户 {username} 不存在'
    return int(u['duration_seconds'] or 0)


def _open_rows() -> list[dict]:
    rows = asyncio.run(auth._q(
        "SELECT task_id, status FROM billing_ledger WHERE status='open'"))
    return [dict(r) for r in rows]


def _post(env, **payload):
    return env['client'].post('/download', json={'id': '347230', 'format': 'json',
                                                 **payload}, headers=env['headers'])


def test_json_success_settles_one_credit(env):
    r = _post(env)
    assert r.status_code == 200
    body = r.json()
    assert body is not None and body['success'] is True
    assert body['data']['name'] == '晴天'
    assert body['data']['artist'] == '周杰伦'
    assert body['data']['filename'] == '周杰伦 - 晴天.mp3'  # 默认 filename_format=artist_song
    assert body['data']['duration'] == 269 * 1000
    assert _balance() == 2  # 预扣 1，交付结算
    assert _open_rows() == []


def test_json_info_failure_refunds(env):
    env['info_exc'] = RuntimeError('song gone')
    r = _post(env)
    assert r.status_code == 404
    assert r.json()['message'] == '获取失败：歌曲不存在或暂无版权'
    assert _balance() == 3
    assert _open_rows() == []


def test_json_download_failure_refunds(env):
    env['dl_result'] = _dl(success=False, msg='size mismatch')
    r = _post(env)
    assert r.status_code == 500
    assert r.json()['message'] == '下载失败，请稍后重试或更换音质'
    assert _balance() == 3
    assert _open_rows() == []


def test_json_download_exception_refunds(env):
    env['dl_exc'] = RuntimeError('disk full')
    r = _post(env)
    assert r.status_code == 500
    assert r.json()['message'] == '服务暂时不可用，请稍后再试'
    assert _balance() == 3
    assert _open_rows() == []


def test_empty_id_refunds_with_specific_message(env):
    r = env['client'].post('/download', json={'id': '', 'format': 'json'},
                           headers=env['headers'])
    assert r.json()['message'] == "参数 'music_id' 不能为空"
    assert _balance() == 3
    assert _open_rows() == []