#!/usr/bin/env python3
r"""doc_link_audit.py — design 文档链接健康检查

扫 design/gdd/、design/registry/、design/ux/ 下的 .md 与 .yaml，校验两类引用：
  (a) markdown 链接  [文字](路径[#锚点])   —— 一律相对"链接所在文件自身目录"解析（标准
      markdown 语义），跨目录用 ../。排除图片 ![...]；目标里混入全角标点（偶发把全角括号
      写进目标）时在首个全角标点处截断再校验。
  (b) 反引号路径引用  `路径.扩展名`（扩展名限 md/yaml/yml/tres/gd/py/json/csv）——
      只校验"路径形"（含 / 且不含空格、通配符）的引用；裸文件名（如表格里的
      `reward.tres`、文档树里的 `棋盘生成.md`）是简称提及不是链接，跳过不校验。
      解析顺序：所在文件目录 → 仓库根 → design/ → prototypes/dungeon-sweeper-vertical-slice/
      （data/tables/*.tres 类指路代码侧的惯用写法实际落在 slice 下；带 ./ ../ 前缀的只按
      所在文件目录解析，不做多基猜测）。
锚点校验：目标为 .md 时，把其标题行转成 GFM 中文锚（去空格、去冒号等标点、小写英文，
仅保留字母/数字/汉字），链接 #锚点 与之精确匹配即命中。

用法:
  python tools/doc_link_audit.py                  # 扫默认范围，报告模式（exit 0）
  python tools/doc_link_audit.py --strict         # 有非已知死链 exit 1（供门禁/CI）
  python tools/doc_link_audit.py --known tools/doc_link_known.txt
                                                  # 已知死链清单，每行 <文件相对路径>|<目标>，
                                                  # 命中的归"已知"类不算失败
  python tools/doc_link_audit.py <file.md> ...    # 只扫指定文件
  python tools/doc_link_audit.py --json           # 机器可读

口径：只扫 design/gdd/ design/registry/ design/ux/——design/art、design/research
（历史素材/提案）不在扫描域，但作为链接目标被校验。排除 ``` 围栏代码块与 ; 开头注释行。
"""
import argparse
import json
import re
import sys
from pathlib import Path

DEFAULT_DIRS = ["design/gdd", "design/registry", "design/ux"]
PROTO_PREFIX = "prototypes/dungeon-sweeper-vertical-slice"

ALLOWED_EXTS = ("md", "yaml", "yml", "tres", "gd", "py", "json", "csv")
MD_LINK_RE = re.compile(r"(?<!!)\[[^\]]*\]\(([^)\s]+)\)")   # (?<!!) 排除图片
BACKTICK_RE = re.compile(r"`([^`\n]+)`")
HEADING_RE = re.compile(r"^#{1,6}\s+(.*?)\s*$")
EXT_RE = re.compile(r"\.(" + "|".join(ALLOWED_EXTS) + r")$", re.IGNORECASE)
SCHEME_RE = re.compile(r"^[a-z][a-z0-9+.-]*:", re.IGNORECASE)   # http:/mailto: 等外链
# 链接目标里不该出现的全角标点/强调符——出现即在此截断（源文偶发把全角括号写进目标）
DEST_CUT_RE = re.compile(r"[（）【】，、；：“”‘’·…—*]")


def anchor_slug(heading):
    """GFM 中文锚：仅保留字母/数字/汉字，小写英文。"""
    return "".join(ch.lower() for ch in heading if ch.isalnum())


def readable_lines(text):
    """逐行产出，跳过 ``` 围栏代码块；不做行过滤，交由调用方按需排除注释行。"""
    fenced = False
    for lineno, line in enumerate(text.split("\n"), 1):
        if line.strip().startswith("```"):
            fenced = not fenced
            continue
        if fenced:
            continue
        yield lineno, line


class Repo:
    def __init__(self, root):
        self.root = root
        self._heads = {}   # Path(resolve) -> set(slug)

    def headings(self, path):
        key = path.resolve()
        if key not in self._heads:
            slugs = set()
            try:
                text = key.read_text(encoding="utf-8").replace("\r\n", "\n")
            except OSError:
                text = ""
            for _, line in readable_lines(text):
                m = HEADING_RE.match(line)
                if m:
                    slugs.add(anchor_slug(m.group(1)))
            self._heads[key] = slugs
        return self._heads[key]

    def resolve_markdown(self, src, target):
        """markdown 链接目标：一律相对所在文件目录，不做多基猜测。"""
        return src.parent / target

    def resolve_backtick(self, src, target):
        """反引号路径引用：带 ./ ../ 前缀只按所在文件目录；否则按序试多基目录。"""
        norm = target.replace("\\", "/")
        if norm.startswith(("./", "../")):
            bases = [src.parent]
        else:
            bases = [src.parent, self.root, self.root / "design", self.root / PROTO_PREFIX]
        for base in bases:
            p = base / norm
            if p.exists():
                return p
        return None


def scan(repo, paths, comment_re=re.compile(r"^\s*;")):
    findings = []          # 死链/锚点未命中
    counts = {"markdown": 0, "anchor": 0, "backtick": 0}
    for p in paths:
        text = p.read_text(encoding="utf-8").replace("\r\n", "\n")
        for lineno, line in readable_lines(text):
            if comment_re.match(line):
                continue
            # (a) markdown 链接
            for m in MD_LINK_RE.finditer(line):
                raw = m.group(1)
                target = DEST_CUT_RE.split(raw, 1)[0]
                if not target or SCHEME_RE.match(target):
                    continue
                path, sep, frag = target.partition("#")
                if not path:   # 同页锚点
                    counts["anchor"] += 1
                    if frag not in repo.headings(p):
                        findings.append(_f(p, lineno, "anchor", target, "锚点未命中", line))
                    continue
                counts["markdown"] += 1
                tp = repo.resolve_markdown(p, path)
                if not tp.exists():
                    findings.append(_f(p, lineno, "markdown", target, "目标不存在", line))
                elif frag:
                    counts["anchor"] += 1
                    if tp.suffix.lower() == ".md" and frag not in repo.headings(tp):
                        findings.append(_f(p, lineno, "anchor", target, "锚点未命中", line))
            # (b) 反引号路径引用（只校验路径形）
            for m in BACKTICK_RE.finditer(line):
                raw = m.group(1).strip()
                if "/" not in raw or " " in raw or "*" in raw or "?" in raw:
                    continue
                if not EXT_RE.search(raw) or SCHEME_RE.match(raw):
                    continue
                counts["backtick"] += 1
                if repo.resolve_backtick(p, raw) is None:
                    findings.append(_f(p, lineno, "backtick", raw, "目标不存在", line))
    findings.sort(key=lambda f: (f["file"], f["line"]))
    return findings, counts


def _f(p, lineno, kind, target, problem, line):
    return {
        "file": p.as_posix(),
        "line": lineno,
        "kind": kind,
        "target": target,
        "problem": problem,
        "text": line.strip()[:160],
    }


def load_known(path):
    """已知死链清单：每行 <文件相对路径>|<目标>；# 与空行忽略。"""
    known = set()
    if not path:
        return known
    for line in Path(path).read_text(encoding="utf-8").replace("\r\n", "\n").split("\n"):
        line = line.strip()
        if not line or line.startswith("#"):
            continue
        file, sep, target = line.partition("|")
        if sep:
            known.add((file.strip().replace("\\", "/").lstrip("./"), target.strip()))
    return known


def main():
    ap = argparse.ArgumentParser(description="design 文档链接健康检查")
    ap.add_argument("files", nargs="*", help="指定文件；缺省扫默认目录")
    ap.add_argument("--strict", action="store_true", help="有非已知死链时 exit 1")
    ap.add_argument("--known", help="已知死链清单（每行 <文件相对路径>|<目标>）")
    ap.add_argument("--json", action="store_true")
    args = ap.parse_args()

    if args.files:
        paths = [Path(f) for f in args.files]
    else:
        paths = []
        for d in DEFAULT_DIRS:
            paths += sorted(Path(d).rglob("*.md"))
            paths += sorted(Path(d).rglob("*.yaml"))
    paths = [p for p in paths if p.is_file()]
    if not paths:
        print("扫描域为空（未找到任何 .md/.yaml）", file=sys.stderr)
        return 2

    repo = Repo(Path("."))
    findings, counts = scan(repo, paths)
    known = load_known(args.known)
    dead = [f for f in findings if (f["file"], f["target"]) not in known]
    known_dead = [f for f in findings if (f["file"], f["target"]) in known]

    if args.json:
        print(json.dumps({
            "scanned": len(paths),
            "counts": {"markdown": counts["markdown"], "backtick": counts["backtick"],
                       "anchor": counts["anchor"], "total": sum(counts.values())},
            "dead": dead,
            "known_dead": known_dead,
            "dead_count": len(dead),
            "known_count": len(known_dead),
        }, ensure_ascii=False, indent=1))
    else:
        total = sum(counts.values())
        print(f"扫描 {len(paths)} 个文件 · 链接 {total} 处"
              f"（markdown {counts['markdown']} + 反引号路径 {counts['backtick']}"
              f" + 锚点 {counts['anchor']}）· 死链 {len(dead)} 处 · 已知死链 {len(known_dead)} 处")
        for title, items in (("死链", dead), ("已知死链（不算失败）", known_dead)):
            if not items:
                continue
            print(f"\n【{title}】×{len(items)}")
            by_file = {}
            for f in items:
                by_file.setdefault(f["file"], []).append(f)
            for file, fs in sorted(by_file.items()):
                for f in fs:
                    print(f"  {file}:{f['line']}  [{f['kind']}] {f['target']}（{f['problem']}）")
    return 1 if (args.strict and dead) else 0


if __name__ == "__main__":
    sys.exit(main())