# 建树批量并行入口（Spec-2）Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use subagent-driven-development to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** 新增多视频批量并行建树入口（视频级 16 并发 + 全局共享 API 信号量 16），单视频建树行为零变化。

**Architecture:** `VideoTreeBuilder` 公开 `build_async()`（消除事件循环嵌套）并支持外部注入 API Semaphore；`tools/build_trees.py` 复刻 `repair_trees.py` 的编排惯例（视频级 Semaphore + gather + progress.json 断点续跑 + 熔断阈值缩放）；`scripts/build_trees.sh` 自包含实验入口。设计文档：`research-wiki/designs/2026-07-11-batch-tree-build-design.md`。

**Tech Stack:** Python 3.11 asyncio / pytest + pytest-asyncio / loguru / PyYAML。

**验证策略说明**：仓库 data/ 下当前无视频文件（`find data -name "*.mp4"` 为空），设计 §6 的"3-4 短视频小批量集成"改为**桩编排集成测试**（monkeypatch VideoTreeBuilder，验证并发上限、进度跳过、信号量共享、中断恢复），真实视频烟测流程写入 sh 脚本头部注释，首次实际建树时执行。

---

### Task 1: VideoTreeBuilder 异步入口公开 + API Semaphore 注入

**Files:**
- Modify: `app/tree/video_builder.py`（`__init__` 172-192 行；`build()` 284-299 行；`_build_async` 改名 `build_async` 305 行起；`vlm_sem = asyncio.Semaphore(...)` 357 行）
- Test: `tests/unit/test_video_builder.py`（追加测试类）

- [ ] **Step 1: 写失败测试**

`tests/unit/test_video_builder.py` 末尾追加（fixture `mock_vlm`/`mock_llm`/`tree_config` 已存在于该文件 159-191 行）：

```python
# ── Semaphore 注入与异步入口（Spec-2）─────────────────────────


class TestApiSemaphoreInjection:
    """API Semaphore 注入与 build_async 公开入口。"""

    def test_injected_semaphore_stored(
        self,
        mock_vlm: MockVLMProvider,
        mock_llm: MockLLMProvider,
        tree_config: TreeConfig,
    ) -> None:
        """构造器注入的 Semaphore 应被保存供 build_async 使用。"""
        sem = asyncio.Semaphore(3)
        builder = VideoTreeBuilder(
            vlm=mock_vlm, llm=mock_llm, config=tree_config, api_semaphore=sem
        )
        assert builder._api_semaphore is sem

    def test_default_no_injection(
        self,
        mock_vlm: MockVLMProvider,
        mock_llm: MockLLMProvider,
        tree_config: TreeConfig,
    ) -> None:
        """未注入时属性为 None（build_async 内部自建，单视频行为零变化）。"""
        builder = VideoTreeBuilder(vlm=mock_vlm, llm=mock_llm, config=tree_config)
        assert builder._api_semaphore is None

    def test_build_async_is_public(
        self,
        mock_vlm: MockVLMProvider,
        mock_llm: MockLLMProvider,
        tree_config: TreeConfig,
    ) -> None:
        """build_async 必须是公开协程方法（供批量编排在事件循环内调用）。"""
        builder = VideoTreeBuilder(vlm=mock_vlm, llm=mock_llm, config=tree_config)
        assert hasattr(builder, "build_async")
        assert asyncio.iscoroutinefunction(builder.build_async)
```

（文件顶部如无 `import asyncio` 则补上。）

- [ ] **Step 2: 运行测试确认失败**

Run: `conda run -n Video-Tree-TRM pytest tests/unit/test_video_builder.py::TestApiSemaphoreInjection -v`
Expected: FAIL——`api_semaphore` 是未知构造参数（TypeError），`build_async` 不存在。

- [ ] **Step 3: 实现**

三处修改：

其一，`__init__` 增加 keyword-only 可选参数（docstring 同步补充）：

```python
    def __init__(
        self,
        vlm: VLMProvider,
        llm: LLMProvider,
        config: TreeConfig,
        *,
        api_semaphore: asyncio.Semaphore | None = None,
    ) -> None:
```

赋值区追加：

```python
        self._api_semaphore = api_semaphore
```

docstring 参数段追加一行：`api_semaphore: 外部注入的全局 VLM/LLM 并发信号量（批量建树时跨视频共享）；None 时 build_async 内部按 config.concurrency 自建，单视频行为零变化。`

其二，`_build_async` 改名为公开 `build_async`（方法体不动，docstring 首行相应更新），`build()` 同步壳改为：

```python
        return asyncio.run(self.build_async(video_path, srt_entries))
```

同时更新模块 docstring（16-21 行）与类 docstring（158-163 行）中的 `_build_async` 字样为 `build_async`。

其三，`build_async` 内 357 行的信号量创建改为：

```python
        # 创建 VLM/LLM 并发控制信号量（外部注入时跨视频全局共享，Spec-2）
        vlm_sem = (
            self._api_semaphore
            if self._api_semaphore is not None
            else asyncio.Semaphore(self._config.concurrency)
        )
```

- [ ] **Step 4: 运行测试确认通过**

Run: `conda run -n Video-Tree-TRM pytest tests/unit/test_video_builder.py -v`
Expected: 全部 PASS（既有测试 + 新增 3 个，确认改名无回归——若有既有测试直接引用 `_build_async`，同步改为 `build_async`）。

- [ ] **Step 5: Commit**

```bash
git add app/tree/video_builder.py tests/unit/test_video_builder.py
git commit -m "feat(tree): expose build_async and accept injected API semaphore"
```

（commit body 标注：核心算法 #1/#2/#3 不变——仅入口封装与信号量来源切换，构建逻辑零改动。）

---

### Task 2: tools/build_trees.py 辅助纯函数

**Files:**
- Create: `tools/build_trees.py`（本任务只写模块骨架 + 纯函数；编排在 Task 3）
- Test: `tests/unit/test_build_trees.py`（新建）

- [ ] **Step 1: 写失败测试**

新建 `tests/unit/test_build_trees.py`：

```python
"""tools/build_trees.py 单元测试。

覆盖纯函数（完整性校验、待建清单发现、SRT 查找）与编排集成（Task 3 追加）。
"""

from __future__ import annotations

import json
import sys
from pathlib import Path

import pytest

PROJECT_ROOT = Path(__file__).resolve().parent.parent.parent
if str(PROJECT_ROOT) not in sys.path:
    sys.path.insert(0, str(PROJECT_ROOT))

from app.tree.index import IndexMeta, L1Card, L1Node, TreeIndex
from tools.build_trees import _discover_pending, _find_srt_entries, _tree_is_complete


def _write_valid_tree(tree_path: Path) -> None:
    """写入一棵最小合法树。"""
    l1 = L1Node(
        id="vid_L1_000",
        card=L1Card("场景", "室内", ["实体"], ["动作"], ["关键词"], [], "线性"),
        time_range=(0.0, 10.0),
        children=[],
    )
    index = TreeIndex(metadata=IndexMeta("/v.mp4", "video"), roots=[l1])
    tree_path.parent.mkdir(parents=True, exist_ok=True)
    index.save_json(str(tree_path))


class TestTreeIsComplete:
    """_tree_is_complete 测试。"""

    def test_valid_tree(self, tmp_path: Path) -> None:
        """合法 tree.json 判定完整。"""
        tree_path = tmp_path / "vid" / "tree.json"
        _write_valid_tree(tree_path)
        assert _tree_is_complete(tree_path) is True

    def test_missing_file(self, tmp_path: Path) -> None:
        """文件不存在判定不完整。"""
        assert _tree_is_complete(tmp_path / "nope" / "tree.json") is False

    def test_corrupt_json(self, tmp_path: Path) -> None:
        """损坏 JSON 判定不完整（不抛异常）。"""
        p = tmp_path / "vid" / "tree.json"
        p.parent.mkdir(parents=True)
        p.write_text("{broken", encoding="utf-8")
        assert _tree_is_complete(p) is False


class TestDiscoverPending:
    """_discover_pending 测试。"""

    def _touch_videos(self, videos_dir: Path, names: list[str]) -> None:
        videos_dir.mkdir(parents=True, exist_ok=True)
        for n in names:
            (videos_dir / n).write_bytes(b"")

    def test_all_pending_when_fresh(self, tmp_path: Path) -> None:
        """无进度无产物时全部待建，按名排序。"""
        videos = tmp_path / "videos"
        self._touch_videos(videos, ["b.mp4", "a.mkv", "c.txt"])
        pending = _discover_pending(videos, tmp_path / "out", set())
        assert [p.name for p in pending] == ["a.mkv", "b.mp4"]  # 非视频扩展名被忽略

    def test_skips_finished_and_complete(self, tmp_path: Path) -> None:
        """progress 已记录或 tree.json 完整的视频被跳过。"""
        videos = tmp_path / "videos"
        out = tmp_path / "out"
        self._touch_videos(videos, ["a.mp4", "b.mp4", "c.mp4"])
        _write_valid_tree(out / "b" / "tree.json")  # b 已有完整树
        pending = _discover_pending(videos, out, {"a"})  # a 在 progress 中
        assert [p.name for p in pending] == ["c.mp4"]

    def test_incomplete_tree_not_skipped(self, tmp_path: Path) -> None:
        """tree.json 损坏的视频仍待建（重建覆盖）。"""
        videos = tmp_path / "videos"
        out = tmp_path / "out"
        self._touch_videos(videos, ["a.mp4"])
        (out / "a").mkdir(parents=True)
        (out / "a" / "tree.json").write_text("{broken", encoding="utf-8")
        pending = _discover_pending(videos, out, set())
        assert [p.name for p in pending] == ["a.mp4"]


class TestFindSrtEntries:
    """_find_srt_entries 测试。"""

    def test_found(self, tmp_path: Path) -> None:
        """同名 .srt 存在时解析返回条目。"""
        srt = tmp_path / "vid.srt"
        srt.write_text(
            "1\n00:00:01,000 --> 00:00:03,000\nhello world\n\n",
            encoding="utf-8",
        )
        entries = _find_srt_entries(tmp_path / "vid.mp4", tmp_path)
        assert entries is not None
        assert len(entries) == 1

    def test_missing_returns_none(self, tmp_path: Path) -> None:
        """无同名 .srt 返回 None。"""
        assert _find_srt_entries(tmp_path / "vid.mp4", tmp_path) is None
```

- [ ] **Step 2: 运行确认失败**

Run: `conda run -n Video-Tree-TRM pytest tests/unit/test_build_trees.py -v`
Expected: FAIL（ModuleNotFoundError: tools.build_trees）。

- [ ] **Step 3: 实现模块骨架 + 纯函数**

新建 `tools/build_trees.py`：

```python
#!/usr/bin/env python3
"""批量并行建树入口：多视频并发构建三层 TreeIndex。

并发模型（Spec-2）:
    视频级 Semaphore(video_concurrency) + gather —— 复刻 repair_trees.py 惯例；
    全局共享一个 API Semaphore(api_concurrency) 注入所有 VideoTreeBuilder，
    端点压力与单视频建树完全一致，吞吐提升来自非 API 阶段跨视频重叠。

用法:
    conda activate Video-Tree-TRM
    python tools/build_trees.py --videos-dir <dir> [--out-dir store/videos]
        [--srt-dir <dir>] [--video-concurrency 16] [--limit 0]

api_concurrency 为工程配置，从 .env 读取 TREE_BUILD_API_CONCURRENCY（默认 16）。
app/core/adapters 不 import 此脚本。
"""

from __future__ import annotations

import argparse
import asyncio
import json
import os
import sys
import time
from pathlib import Path

PROJECT_ROOT = Path(__file__).resolve().parent.parent
sys.path.insert(0, str(PROJECT_ROOT))

from dotenv import load_dotenv
from loguru import logger

load_dotenv(PROJECT_ROOT / ".env")

import yaml

from app.tree.config import TreeConfig
from app.tree.index import TreeIndex
from app.tree.subtitle import parse_srt
from app.tree.video_builder import VideoTreeBuilder

# ---------------------------------------------------------------------------
# 日志配置：不缓存，立即输出
# ---------------------------------------------------------------------------

logger.remove()
logger.add(
    sys.stderr,
    format="{time:HH:mm:ss} | {level:<7} | {message}",
    level="DEBUG",
    colorize=True,
)
logger.add(
    PROJECT_ROOT / "logs" / "build_trees.log",
    format="{time:YYYY-MM-DD HH:mm:ss} | {level:<7} | {message}",
    level="DEBUG",
    rotation="50 MB",
)

# ---------------------------------------------------------------------------
# 断点续跑 — progress 文件管理（复刻 repair_trees.py 惯例）
# ---------------------------------------------------------------------------

PROGRESS_FILE = "build_progress.json"

_VIDEO_SUFFIXES = frozenset({".mp4", ".mkv", ".avi", ".webm"})


def load_progress(path: Path) -> set[str]:
    """读取 progress 文件，返回已完成视频 ID 集合。

    参数:
        path: progress JSON 文件路径。

    返回:
        已完成视频 ID 集合。文件不存在或损坏时返回空集。
    """
    if not path.exists():
        return set()
    try:
        data = json.loads(path.read_text(encoding="utf-8"))
        return set(data.get("finished_video_ids", []))
    except (json.JSONDecodeError, KeyError, TypeError, AttributeError):
        logger.warning("progress 文件损坏，忽略: {}", path)
        return set()


async def save_progress(path: Path, lock: asyncio.Lock, vid: str) -> None:
    """原子追加一个视频 ID 到 progress 文件。

    参数:
        path: progress JSON 文件路径。
        lock: asyncio.Lock，防并发读改写丢更新。
        vid: 要追加的视频 ID。
    """
    async with lock:
        finished = load_progress(path)
        finished.add(vid)
        tmp = path.with_suffix(".tmp")
        tmp.write_text(
            json.dumps({"finished_video_ids": sorted(finished)}, ensure_ascii=False, indent=2),
            encoding="utf-8",
        )
        os.replace(str(tmp), str(path))


# ---------------------------------------------------------------------------
# 待建发现与完整性校验
# ---------------------------------------------------------------------------


def _tree_is_complete(tree_path: Path) -> bool:
    """判断 tree.json 是否存在且可加载为非空树。

    参数:
        tree_path: tree.json 路径。

    返回:
        True 表示完整（跳过重建）；文件缺失/损坏/空树返回 False。
    """
    if not tree_path.exists():
        return False
    try:
        index = TreeIndex.load_json(str(tree_path))
    except (json.JSONDecodeError, KeyError, TypeError, ValueError, AssertionError) as exc:
        logger.warning("tree.json 无法加载，视为不完整: {} ({})", tree_path, exc)
        return False
    return len(index.roots) > 0


def _discover_pending(
    videos_dir: Path,
    out_dir: Path,
    finished: set[str],
) -> list[Path]:
    """扫描视频目录，返回待建视频文件列表（按文件名排序）。

    跳过条件：video_id 在 progress 中，或 out_dir/<video_id>/tree.json 完整。

    参数:
        videos_dir: 视频文件目录。
        out_dir: 树输出根目录。
        finished: progress 中已完成的视频 ID 集合。

    返回:
        待建视频文件路径列表。
    """
    pending: list[Path] = []
    for f in sorted(videos_dir.iterdir()):
        if not f.is_file() or f.suffix.lower() not in _VIDEO_SUFFIXES:
            continue
        vid = f.stem
        if vid in finished:
            continue
        if _tree_is_complete(out_dir / vid / "tree.json"):
            continue
        pending.append(f)
    return pending


def _find_srt_entries(video_path: Path, srt_dir: Path):
    """按视频同名规则查找并解析 SRT 字幕。

    参数:
        video_path: 视频文件路径。
        srt_dir: SRT 目录。

    返回:
        SRTEntry 列表；无同名 .srt 时返回 None。
    """
    srt_path = srt_dir / f"{video_path.stem}.srt"
    if not srt_path.exists():
        return None
    return parse_srt(str(srt_path))
```

（编排函数与 main 在 Task 3 追加；本步模块以纯函数收尾即可运行测试。）

- [ ] **Step 4: 运行确认通过**

Run: `conda run -n Video-Tree-TRM pytest tests/unit/test_build_trees.py -v`
Expected: 全部 PASS。

- [ ] **Step 5: Commit**

```bash
git add tools/build_trees.py tests/unit/test_build_trees.py
git commit -m "feat(tools): add build_trees skeleton with discovery helpers"
```

---

### Task 3: 编排 main_async + CLI + 桩编排集成测试

**Files:**
- Modify: `tools/build_trees.py`（追加客户端构建、编排、CLI）
- Test: `tests/unit/test_build_trees.py`（追加编排测试）

- [ ] **Step 1: 写失败测试（桩 builder 编排集成）**

`tests/unit/test_build_trees.py` 追加：

```python
# ── 编排集成（桩 builder，无真实视频/LLM）──────────────────────

import asyncio

from tools.build_trees import main_async


class _StubBuilder:
    """记录并发与注入信号量的桩 builder。"""

    instances: list["_StubBuilder"] = []
    inflight = 0
    max_inflight = 0

    def __init__(self, vlm, llm, config, *, api_semaphore=None) -> None:
        self.api_semaphore = api_semaphore
        _StubBuilder.instances.append(self)

    async def build_async(self, video_path: str, srt_entries=None):
        _StubBuilder.inflight += 1
        _StubBuilder.max_inflight = max(_StubBuilder.max_inflight, _StubBuilder.inflight)
        await asyncio.sleep(0.02)
        _StubBuilder.inflight -= 1
        from app.tree.index import IndexMeta, L1Card, L1Node, TreeIndex

        l1 = L1Node(
            id="x_L1_000",
            card=L1Card("s", "室内", [], [], [], [], "线性"),
            time_range=(0.0, 1.0),
            children=[],
        )
        return TreeIndex(metadata=IndexMeta(video_path, "video"), roots=[l1])


@pytest.fixture()
def batch_env(tmp_path: Path, monkeypatch: pytest.MonkeyPatch):
    """5 个假视频 + 桩 builder + 隔离的 progress 路径。"""
    import tools.build_trees as bt

    _StubBuilder.instances = []
    _StubBuilder.inflight = 0
    _StubBuilder.max_inflight = 0
    monkeypatch.setattr(bt, "VideoTreeBuilder", _StubBuilder)
    monkeypatch.setattr(bt, "_build_clients", lambda api_concurrency: (None, None))

    videos = tmp_path / "videos"
    videos.mkdir()
    for i in range(5):
        (videos / f"v{i}.mp4").write_bytes(b"")

    return {
        "videos": videos,
        "out": tmp_path / "out",
        "progress": tmp_path / "build_progress.json",
    }


def _make_args(env: dict, video_concurrency: int = 2, limit: int = 0) -> "argparse.Namespace":
    import argparse

    return argparse.Namespace(
        videos_dir=str(env["videos"]),
        out_dir=str(env["out"]),
        srt_dir=str(env["videos"]),
        video_concurrency=video_concurrency,
        limit=limit,
        progress_path=str(env["progress"]),
    )


class TestOrchestration:
    """main_async 编排行为（桩 builder）。"""

    @pytest.mark.asyncio
    async def test_video_concurrency_capped(self, batch_env: dict) -> None:
        """同时在建视频数不得超过 video_concurrency。"""
        await main_async(_make_args(batch_env, video_concurrency=2))
        assert _StubBuilder.max_inflight <= 2
        assert len(_StubBuilder.instances) == 5

    @pytest.mark.asyncio
    async def test_shared_api_semaphore(self, batch_env: dict) -> None:
        """全部 builder 实例共享同一个 API Semaphore 对象。"""
        await main_async(_make_args(batch_env))
        sems = {id(b.api_semaphore) for b in _StubBuilder.instances}
        assert len(sems) == 1
        assert _StubBuilder.instances[0].api_semaphore is not None

    @pytest.mark.asyncio
    async def test_trees_saved_and_progress_recorded(self, batch_env: dict) -> None:
        """每个视频产出 tree.json 且 progress 记录全部完成。"""
        await main_async(_make_args(batch_env))
        for i in range(5):
            assert (batch_env["out"] / f"v{i}" / "tree.json").exists()
        from tools.build_trees import load_progress

        assert load_progress(batch_env["progress"]) == {f"v{i}" for i in range(5)}

    @pytest.mark.asyncio
    async def test_resume_skips_finished(self, batch_env: dict) -> None:
        """第二次运行跳过全部已完成视频。"""
        await main_async(_make_args(batch_env))
        n_first = len(_StubBuilder.instances)
        await main_async(_make_args(batch_env))
        assert len(_StubBuilder.instances) == n_first  # 无新建

    @pytest.mark.asyncio
    async def test_partial_completion_resume(self, batch_env: dict) -> None:
        """部分完成后重跑只建剩余视频（模拟中断后恢复）。"""
        batch_env["progress"].write_text(
            json.dumps({"finished_video_ids": ["v0", "v1"]}),
            encoding="utf-8",
        )
        await main_async(_make_args(batch_env))
        assert len(_StubBuilder.instances) == 3  # 仅 v2/v3/v4

    @pytest.mark.asyncio
    async def test_limit(self, batch_env: dict) -> None:
        """--limit 2 只建前两个（烟测入口）。"""
        await main_async(_make_args(batch_env, limit=2))
        assert len(_StubBuilder.instances) == 2
```

- [ ] **Step 2: 运行确认失败**

Run: `conda run -n Video-Tree-TRM pytest tests/unit/test_build_trees.py::TestOrchestration -v`
Expected: FAIL（ImportError: main_async 不存在）。

- [ ] **Step 3: 实现客户端构建 + 编排 + CLI**

`tools/build_trees.py` 追加：

```python
# ---------------------------------------------------------------------------
# LLM/VLM 客户端构建（复刻 repair_trees.py 惯例）
# ---------------------------------------------------------------------------


def _build_clients(api_concurrency: int):
    """构建 GovernedLLMClient（LLM + VLM），熔断阈值随 API 并发缩放。

    参数:
        api_concurrency: 全局 API 并发上限（熔断阈值取 max(cfg, api_concurrency*2)）。

    返回:
        (llm_client, vlm_client) 元组。
    """
    from adapters.breaker import CircuitBreaker
    from adapters.llm import GovernedLLMClient
    from adapters.telemetry import SQLiteTelemetryRecorder
    from adapters.vlm import GovernedVLMClient

    (PROJECT_ROOT / "logs").mkdir(exist_ok=True)
    telemetry = SQLiteTelemetryRecorder(str(PROJECT_ROOT / "logs" / "build_trees_telemetry.db"))

    breaker_threshold = int(os.getenv("LLM_CIRCUIT_BREAKER_THRESHOLD", "5"))
    breaker_threshold = max(breaker_threshold, api_concurrency * 2)
    breaker_cooldown = int(os.getenv("LLM_CIRCUIT_BREAKER_COOLDOWN", "60"))
    timeout_s = float(os.getenv("LLM_TIMEOUT", "120"))
    max_retries = int(os.getenv("LLM_MAX_RETRIES", "3"))
    base_delay = float(os.getenv("LLM_RETRY_BASE_DELAY", "2.0"))
    max_delay = float(os.getenv("LLM_RETRY_MAX_DELAY", "30.0"))
    ttft = float(os.getenv("LLM_TTFT_TIMEOUT", "30"))
    inter_token = float(os.getenv("LLM_INTER_TOKEN_TIMEOUT", "15"))

    llm = GovernedLLMClient(
        model=os.environ["SEARCH_LLM_MODEL"],
        base_url=os.environ["SEARCH_LLM_BASE_URL"],
        api_key=os.environ["SEARCH_LLM_API_KEY"],
        provider="deepseek",
        thinking=False,
        breaker=CircuitBreaker(fail_threshold=breaker_threshold, cooldown_s=breaker_cooldown),
        cache=None,
        telemetry=telemetry,
        timeout_s=timeout_s,
        ttft_timeout_s=ttft,
        inter_token_timeout_s=inter_token,
        max_retries=max_retries,
        retry_base_delay_s=base_delay,
        retry_max_delay_s=max_delay,
    )
    vlm_base = GovernedLLMClient(
        model=os.environ["VL_LLM_MODEL"],
        base_url=os.environ["VL_LLM_BASE_URL"],
        api_key=os.environ["VL_LLM_API_KEY"],
        provider="qwen",
        thinking=False,
        breaker=CircuitBreaker(fail_threshold=breaker_threshold, cooldown_s=breaker_cooldown),
        cache=None,
        telemetry=telemetry,
        timeout_s=timeout_s,
        ttft_timeout_s=ttft,
        inter_token_timeout_s=inter_token,
        max_retries=max_retries,
        retry_base_delay_s=base_delay,
        retry_max_delay_s=max_delay,
    )
    return llm, GovernedVLMClient(vlm_base)


# ---------------------------------------------------------------------------
# 主编排
# ---------------------------------------------------------------------------


async def main_async(args: argparse.Namespace) -> None:
    """异步主流程：视频级并发建树 + 全局共享 API 信号量。

    参数:
        args: CLI 参数（videos_dir/out_dir/srt_dir/video_concurrency/limit/progress_path）。
    """
    videos_dir = Path(args.videos_dir)
    out_dir = Path(args.out_dir)
    srt_dir = Path(args.srt_dir)
    assert videos_dir.is_dir(), f"视频目录不存在: {videos_dir}"

    api_concurrency = int(os.getenv("TREE_BUILD_API_CONCURRENCY", "16"))

    # Phase 1: 待建发现（progress + 完整性双重跳过）
    progress_path = Path(args.progress_path)
    finished = load_progress(progress_path)
    if finished:
        logger.info("progress 已记录 {} 个完成视频", len(finished))
    pending = _discover_pending(videos_dir, out_dir, finished)
    if args.limit > 0:
        pending = pending[: args.limit]
    logger.info(
        "待建 {} 个视频, video_concurrency={}, api_concurrency={}",
        len(pending), args.video_concurrency, api_concurrency,
    )
    if not pending:
        return

    # Phase 2: 客户端与共享信号量
    llm, vlm = _build_clients(api_concurrency)
    with open(PROJECT_ROOT / "config" / "default.yaml", encoding="utf-8") as f:
        tree_cfg = TreeConfig.from_dict(yaml.safe_load(f)["tree"])
    api_sem = asyncio.Semaphore(api_concurrency)
    video_sem = asyncio.Semaphore(args.video_concurrency)
    progress_lock = asyncio.Lock()
    start_time = time.time()
    completed = 0
    failed: list[str] = []

    # Phase 3: 视频级并发编排（复刻 repair_trees 模式）
    async def _build_one(video_path: Path) -> None:
        nonlocal completed
        async with video_sem:
            vid = video_path.stem
            logger.info("开始建树 {}", vid)
            builder = VideoTreeBuilder(vlm=vlm, llm=llm, config=tree_cfg, api_semaphore=api_sem)
            srt_entries = _find_srt_entries(video_path, srt_dir)
            try:
                index = await builder.build_async(str(video_path), srt_entries)
            except Exception as exc:
                logger.error("建树失败 {} ({}): {}", vid, type(exc).__name__, exc)
                failed.append(vid)
                return
            tree_path = out_dir / vid / "tree.json"
            tree_path.parent.mkdir(parents=True, exist_ok=True)
            index.save_json(str(tree_path))
            await save_progress(progress_path, progress_lock, vid)
            completed += 1
            if completed % 5 == 0:
                elapsed = time.time() - start_time
                rate = completed / elapsed * 60 if elapsed > 0 else 0
                logger.info(
                    "进度: {}/{}, 已用 {:.0f}s, 速率 {:.2f} 视频/分钟",
                    completed, len(pending), elapsed, rate,
                )

    await asyncio.gather(*[asyncio.create_task(_build_one(p)) for p in pending])

    # Phase 4: 汇总
    elapsed = time.time() - start_time
    logger.info(
        "批量建树完成: 成功 {}, 失败 {}, 总耗时 {:.0f}s{}",
        completed, len(failed), elapsed,
        f", 失败清单: {failed}" if failed else "",
    )


def main() -> None:
    """同步入口。"""
    parser = argparse.ArgumentParser(description="批量并行建树")
    parser.add_argument("--videos-dir", type=str, required=True, help="视频文件目录")
    parser.add_argument("--out-dir", type=str, default="store/videos", help="树输出根目录")
    parser.add_argument("--srt-dir", type=str, default="", help="SRT 目录（默认同 videos-dir）")
    parser.add_argument("--video-concurrency", type=int, default=16, help="同时在建视频数")
    parser.add_argument("--limit", type=int, default=0, help="只建前 N 个（0=全部，烟测用）")
    parser.add_argument(
        "--progress-path",
        type=str,
        default=str(PROJECT_ROOT / "logs" / PROGRESS_FILE),
        dest="progress_path",
        help="progress 文件路径",
    )
    args = parser.parse_args()
    if not args.srt_dir:
        args.srt_dir = args.videos_dir
    asyncio.run(main_async(args))


if __name__ == "__main__":
    main()
```

注意：`_build_one` 中 `except Exception` 用于**单视频错误隔离**（一个视频失败不拖垮整批，失败清单汇总上报，vid 不进 progress 可重跑）——这是编排层的错误隔离语义而非吞错，日志含异常类型与内容。

- [ ] **Step 4: 运行确认通过**

Run: `conda run -n Video-Tree-TRM pytest tests/unit/test_build_trees.py -v`
Expected: 全部 PASS（纯函数 8 个 + 编排 6 个，共 14 个）。

- [ ] **Step 5: Commit**

```bash
git add tools/build_trees.py tests/unit/test_build_trees.py
git commit -m "feat(tools): batch tree build orchestration with shared API semaphore"
```

---

### Task 4: scripts/build_trees.sh + 工程配置 + 回归收尾

**Files:**
- Create: `scripts/build_trees.sh`
- Modify: `.env.example`（追加 TREE_BUILD_API_CONCURRENCY）

- [ ] **Step 1: 写 sh 脚本**

新建 `scripts/build_trees.sh`：

```bash
#!/usr/bin/env bash
# 批量并行建树（Spec-2）
# 职责：对目录下所有视频并发构建三层 TreeIndex，断点续跑。
#
# 用法:
#   bash scripts/build_trees.sh --videos-dir <dir>                 # 全量
#   bash scripts/build_trees.sh --videos-dir <dir> --limit 2       # 真实视频烟测
#   VIDEO_CONCURRENCY=8 bash scripts/build_trees.sh --videos-dir <dir>
#
# 真实视频烟测流程（首次使用时执行）:
#   1. --limit 2 建两个视频，观察日志速率与 API 并发
#   2. 中途 Ctrl+C 后重跑，确认已完成视频被跳过、未完成视频续跑
#   3. 检查 store/videos/<vid>/tree.json 可被 TreeIndex.load_json 加载
#
# 日志输出:
#   stderr → 终端实时显示
#   logs/build_trees.log → 完整日志（自动 rotation 50MB）
#   logs/build_trees_telemetry.db → LLM/VLM 调用遥测
#   logs/build_progress.json → 断点续跑进度
#
# api_concurrency 走 .env 的 TREE_BUILD_API_CONCURRENCY（工程配置，默认 16）

set -euo pipefail

cd "$(dirname "$0")/.."

VIDEO_CONCURRENCY="${VIDEO_CONCURRENCY:-16}"

export PYTHONUNBUFFERED=1

# shellcheck source=/dev/null
source "$(conda info --base)/etc/profile.d/conda.sh"
conda activate Video-Tree-TRM

python tools/build_trees.py \
    --out-dir store/videos \
    --video-concurrency "$VIDEO_CONCURRENCY" \
    "$@"
```

```bash
chmod +x scripts/build_trees.sh
```

- [ ] **Step 2: 补 .env.example**

`.env.example` 追加（若文件不存在则跳过并在 NOTES 说明）：

```
# 建树批量并行：全局 VLM/LLM 在途调用上限（Spec-2 工程配置）
TREE_BUILD_API_CONCURRENCY=16
```

- [ ] **Step 3: 全量回归 + lint**

Run: `conda run -n Video-Tree-TRM ruff format --check tools/build_trees.py tests/unit/test_build_trees.py app/tree/video_builder.py`
Run: `conda run -n Video-Tree-TRM ruff check tools/build_trees.py tests/unit/test_build_trees.py app/tree/video_builder.py`
Run: `conda run -n Video-Tree-TRM radon cc tools/build_trees.py app/tree/video_builder.py -n C -s`（新增函数不得出现 C 级；video_builder 既有 C 级为存量）
Run: `conda run -n Video-Tree-TRM pytest tests/ -q`
Expected: 全绿。

- [ ] **Step 4: Commit**

```bash
git add scripts/build_trees.sh .env.example
git commit -m "feat(scripts): add batch tree build entry with smoke-test guide"
```

---

## Self-Review 记录

1. **Spec 覆盖**：设计 §3 全部落地——build_async 公开 + Semaphore 注入（Task 1）、两层并发参数与全局共享信号量（Task 3）、熔断阈值缩放（Task 3 `_build_clients`）、progress 断点续跑与完整性跳过（Task 2/3）、sh 入口与 D7 配置归属（Task 4）；§4 速率日志（Task 3 Phase 3）；§6 验证改为桩编排测试（头部"验证策略说明"已声明理由：仓库无视频文件），自动化覆盖"已完成跳过"（`test_resume_skips_finished`）与"部分完成后恢复"（`test_partial_completion_resume`）；**段级断点续跑**由 builder 既有 `_load_resume_state` 机制承担（算法 #3，本计划零改动）+ 真实视频烟测流程（sh 头注释步骤 2）在首次实际建树时验证。
2. **占位符扫描**：无 TBD/TODO；所有代码步骤含完整代码。
3. **类型一致性**：`_discover_pending(videos_dir, out_dir, finished)`、`_find_srt_entries(video_path, srt_dir)`、`main_async(args)`、`_build_clients(api_concurrency)` 在测试与实现间签名一致；`_make_args` 构造的 Namespace 字段与 `main_async` 读取字段一一对应（含 progress_path）。

## 核心算法保真校验

本计划涉及**算法 #1（L2 轴心建树）/#2（VLM 批量帧描述）/#3（断点续跑）**所在文件 `app/tree/video_builder.py`：改动仅为 (a) `_build_async` 改名公开（方法体零改动）、(b) 信号量来源三元切换（默认路径与现状逐字等价）、(c) 构造器加可选参数。三项算法的核心逻辑（L2→L3 链式触发、批量 VLM+fallback、progress 段级恢复）均未触碰。执行时质量门第 7 项应 diff 确认 `build_async` 方法体与原 `_build_async` 逐行一致。其余算法不涉及。