"""
从 raw_cases/case_*.json 中提取 source_url / 帖子链接，
解析 channel_content_id，再从 .cache/content_search 中查找对应的原始帖子数据。

主函数：extract_sources_to_json(raw_cases_dir)
  - 扫描该目录下所有 case_{platform}.json
  - 解析每个 "工序发现[].帖子链接"（新格式）或 "cases[].source_url"（旧格式）
  - 从项目根的 .cache/content_search/*.json 中匹配 channel_content_id
  - 把匹配到的完整 post 写入 {raw_cases_dir}/source.json
"""

import json
import re
from pathlib import Path
from typing import Any, Dict, List, Optional, Tuple


# ── URL → (platform, content_id) 解析 ────────────────────────────────

_URL_PATTERNS = [
    # B站: https://www.bilibili.com/video/BV1xxx
    ("bili", re.compile(r"bilibili\.com/video/(BV[\w]+)")),
    # 小红书: https://www.xiaohongshu.com/explore/{id} 或 /discovery/item/{id}
    ("xhs", re.compile(r"xiaohongshu\.com/(?:explore|discovery/item)/([a-f0-9]+)")),
    # YouTube: https://www.youtube.com/watch?v={id} 或 https://youtu.be/{id}
    ("youtube", re.compile(r"(?:youtube\.com/watch\?v=|youtu\.be/)([\w-]+)")),
    # X/Twitter: https://x.com/{user}/status/{id} 或 twitter.com
    ("x", re.compile(r"(?:x\.com|twitter\.com)/[^/]+/status/(\d+)")),
    # 知乎: https://zhuanlan.zhihu.com/p/{id} 或 zhihu.com/question/{qid}/answer/{aid}
    ("zhihu", re.compile(r"zhuanlan\.zhihu\.com/p/(\d+)")),
    ("zhihu", re.compile(r"zhihu\.com/question/\d+/answer/(\d+)")),
    # 公众号: 通过 __biz 或整个 URL 作为 id（后备）
    ("gzh", re.compile(r"mp\.weixin\.qq\.com/s[/?]([^\s\"']+)")),
]


def parse_url(url: str) -> Optional[Tuple[str, str]]:
    """从 URL 解析出 (platform, content_id)。返回 None 表示无法解析。"""
    if not url or not isinstance(url, str):
        return None
    for platform, pat in _URL_PATTERNS:
        m = pat.search(url)
        if m:
            return platform, m.group(1)
    return None


# ── 从 case 文件中抽取所有链接 ────────────────────────────────

def extract_urls_from_case(case_data: Any) -> List[str]:
    """兼容新旧两种格式，返回 case 文件里出现的所有 URL。"""
    urls: List[str] = []

    if not isinstance(case_data, dict):
        return urls

    # 新格式：工序发现[].帖子链接
    for item in case_data.get("工序发现", []) or []:
        if isinstance(item, dict):
            link = item.get("帖子链接") or item.get("source_url")
            if link:
                urls.append(link)

    # 旧格式：cases[].source_url
    for item in case_data.get("cases", []) or []:
        if isinstance(item, dict):
            link = item.get("source_url") or item.get("帖子链接")
            if link:
                urls.append(link)

    return urls


# ── 从 cache 中构建 (platform, content_id) → post 索引 ────────────────────────────────

def build_cache_index(cache_dir: Path, trace_ids: Optional[List[str]] = None) -> Dict[Tuple[str, str], Dict[str, Any]]:
    """
    构建 (platform, channel_content_id) -> post 映射。

    Args:
        cache_dir: cache 目录路径
        trace_ids: 可选的 trace_id 列表。如果提供，只加载这些特定的 cache 文件；
                   否则扫描所有 cache 文件

    Returns:
        (platform, content_id) -> post 的映射字典
    """
    index: Dict[Tuple[str, str], Dict[str, Any]] = {}
    if not cache_dir.exists():
        return index

    # 如果提供了 trace_ids，只加载这些特定文件
    if trace_ids:
        cache_files = [cache_dir / f"{tid}.json" for tid in trace_ids if tid]
        cache_files = [f for f in cache_files if f.exists()]
    else:
        # 否则扫描所有 cache 文件
        cache_files = list(cache_dir.glob("*.json"))

    for cache_file in cache_files:
        try:
            with open(cache_file, "r", encoding="utf-8") as f:
                data = json.load(f)
        except Exception:
            continue

        for key, entry in data.items():
            if not key.startswith("search:"):
                continue
            platform = key.split(":", 1)[1]

            # 新格式：entry = {"history": [...], "latest_index": n}
            # 旧格式：entry = {"keyword": ..., "posts": [...]}
            if isinstance(entry, dict) and "history" in entry:
                post_lists = [h.get("posts", []) for h in entry.get("history", [])]
            elif isinstance(entry, dict) and "posts" in entry:
                post_lists = [entry.get("posts", [])]
            else:
                continue

            for posts in post_lists:
                for post in posts or []:
                    if not isinstance(post, dict):
                        continue
                    cid = post.get("channel_content_id")
                    if cid:
                        # 直接用 (platform, content_id) 作为索引键
                        index[(platform, str(cid))] = post

    return index


# ── 主入口 ────────────────────────────────

def extract_sources_to_json(
    raw_cases_dir: Path,
    cache_dir: Optional[Path] = None,
    output_name: str = "source.json",
    trace_ids: Optional[List[str]] = None,
) -> Dict[str, Any]:
    """
    扫描 raw_cases_dir 下的 case_*.json，
    从 cache 中找出原始帖子，输出到 {raw_cases_dir}/{output_name}。

    返回统计信息 dict。
    """
    raw_cases_dir = Path(raw_cases_dir)
    if cache_dir is None:
        # 项目根目录：script 文件往上三级
        project_root = Path(__file__).resolve().parent.parent.parent.parent
        cache_dir = project_root / ".cache" / "content_search"
    cache_dir = Path(cache_dir)

    # 1. 构建 cache 索引
    cache_index = build_cache_index(cache_dir, trace_ids=trace_ids)

    # 2. 加载已有的 source.json（如果存在）
    output_file = raw_cases_dir / output_name
    existing_sources = []
    existing_ids = set()  # (platform, channel_content_id) 集合用于去重

    if output_file.exists():
        try:
            with open(output_file, "r", encoding="utf-8") as f:
                existing_data = json.load(f)
                existing_sources = existing_data.get("sources", [])
                # 构建已有的 ID 集合
                for src in existing_sources:
                    key = (src.get("platform"), src.get("channel_content_id"))
                    existing_ids.add(key)
        except Exception as e:
            print(f"Warning: Failed to load existing source.json: {e}")

    # 3. 扫描所有 case 文件
    matched: List[Dict[str, Any]] = []
    unmatched: List[Dict[str, Any]] = []
    seen_keys: set = set(existing_ids)  # 从已有的 ID 开始

    for case_file in sorted(raw_cases_dir.glob("case_*.json")):
        # 跳过自己（如果 source.json 误被命名成 case_*）
        if case_file.name == output_name:
            continue
        try:
            with open(case_file, "r", encoding="utf-8") as f:
                case_data = json.load(f)
        except Exception as e:
            unmatched.append({"case_file": case_file.name, "error": str(e)})
            continue

        urls = extract_urls_from_case(case_data)
        for url in urls:
            # 解析 URL 得到 platform 和 content_id
            parsed = parse_url(url)
            if not parsed:
                unmatched.append({
                    "case_file": case_file.name,
                    "url": url,
                    "reason": "url_parse_failed",
                })
                continue

            platform, cid = parsed
            key = (platform, cid)
            if key in seen_keys:
                continue
            seen_keys.add(key)

            # 直接用 (platform, content_id) 在 cache 索引中查找
            post = cache_index.get(key)
            if post:
                matched.append({
                    "case_file": case_file.name,
                    "platform": platform,
                    "channel_content_id": cid,
                    "source_url": url,
                    "post": post,
                })
            else:
                unmatched.append({
                    "case_file": case_file.name,
                    "platform": platform,
                    "channel_content_id": cid,
                    "source_url": url,
                    "reason": "not_in_cache",
                })

    # 4. 合并已有数据和新匹配的数据
    all_sources = existing_sources + matched

    # 5. 写输出
    output = {
        "total": len(all_sources),
        "cache_dir": str(cache_dir),
        "sources": all_sources,
    }

    output_file.parent.mkdir(parents=True, exist_ok=True)
    with open(output_file, "w", encoding="utf-8") as f:
        json.dump(output, f, ensure_ascii=False, indent=2)

    # 返回统计信息（包含 unmatched 用于日志输出）
    return {
        "total_matched": len(matched),
        "total_existing": len(existing_sources),
        "total_unmatched": len(unmatched),
        "output_file": str(output_file),
    }


if __name__ == "__main__":
    # CLI：python extract_sources.py <raw_cases_dir> [cache_dir]
    import sys
    if len(sys.argv) < 2:
        print("Usage: python extract_sources.py <raw_cases_dir> [cache_dir]")
        sys.exit(1)

    raw_cases_dir = Path(sys.argv[1])
    cache_dir = Path(sys.argv[2]) if len(sys.argv) > 2 else None

    result = extract_sources_to_json(raw_cases_dir, cache_dir=cache_dir)
    print(f"[OK] Matched: {result['total_matched']}, Unmatched: {result['total_unmatched']}")
    print(f"     Output: {raw_cases_dir / 'source.json'}")