#!/usr/bin/env python3
"""根据 catalog.json 中每个条目的 week 字段，在 plan/weekNN-*.md 中生成“本周相关专题”一节。

- 生成内容放在 <!-- week-topics:start --> 和 <!-- week-topics:end --> 之间，重复运行会替换，不会重复插入
- 第一次插入的位置：“## 本周自查清单 / ## 本周验收”之前（代码块之外）；没有这两个标题时放在文末
- 先运行 tools/build_catalog.py 生成 catalog.json

用法：python3 tools/gen_week_topics.py [--check]   （--check 只检查是否需要更新，需要时返回 1）
"""
from __future__ import annotations

import json
import re
import sys
from collections import defaultdict
from pathlib import Path

ROOT = Path(__file__).resolve().parents[1]
START, END = "<!-- week-topics:start -->", "<!-- week-topics:end -->"
ANCHOR = re.compile(r"^## (本周自查清单|本周验收)")
FENCE = re.compile(r"^\s*(```|~~~)")
TYPE_ORDER = {"lesson": 0, "scenario": 1, "interview": 2}
TYPE_NAME = {"lesson": "课程", "scenario": "场景", "interview": "面试题"}
AI_CODING_NOTE = ("- **AI 编程练习（每周）**：本周至少一个功能用 AI 编程工具（Cursor / Claude Code / Codex 等）完成，"
                  "按 [AI 编程：工作流](../topics/ai/ai-coding/01-workflow-rules-skills.md) 写清需求和规则，"
                  "按 [验证与证据](../topics/ai/ai-coding/02-verify-evidence.md) 保存测试结果和会话记录（脱敏后），"
                  "第 15 周整理成“AI 编程 + 验证方法”的应聘案例。")


def build_section(week: int, items: list[dict], stacks: dict[str, dict]) -> str:
    by_stack: dict[str, list[dict]] = defaultdict(list)
    cross: list[dict] = []
    for it in items:
        if it["type"] == "scenario" and it["domain"] == "cross":
            cross.append(it)
        elif it["type"] in TYPE_ORDER and it.get("stack"):
            by_stack[it["path"].split("/")[2]].append(it)
    lines = [START, "", "## 本周相关专题", "",
             "> 本节由 `tools/gen_week_topics.py` 根据专题文件的 `week` 字段自动生成，请勿手改；"
             "想调整就修改对应专题文件的 frontmatter 后重新生成。", ""]
    if week <= 14:
        lines += [AI_CODING_NOTE, ""]
    if by_stack:
        lines += ["| 技术栈 | 课程 / 场景 / 面试题 |", "| --- | --- |"]
        for sid in sorted(by_stack, key=lambda s: (stacks.get(s, {}).get("domain", ""), s)):
            st = stacks.get(sid, {})
            name = f"[{st.get('title', sid)}](../{st['index']})" if st.get("index") else sid
            links = []
            for it in sorted(by_stack[sid], key=lambda x: (TYPE_ORDER[x["type"]], x.get("order") or 0, x["path"])):
                title = TYPE_NAME[it["type"]] if it["type"] == "interview" else it["title"].split("：")[0]
                links.append(f"{TYPE_NAME[it['type']]}：[{title}](../{it['path']})" if it["type"] != "interview"
                             else f"[面试题](../{it['path']})")
            lines.append(f"| {name} | {'；'.join(links)} |")
        lines.append("")
    if cross:
        lines += ["**跨技术栈场景**：" + "、".join(f"[{c['title'].split('：')[0]}](../{c['path']})" for c in sorted(cross, key=lambda c: c["path"])), ""]
    lines.append(END)
    return "\n".join(lines)


def insert(text: str, section: str) -> str:
    if START in text and END in text:
        return re.sub(re.escape(START) + r".*?" + re.escape(END), lambda _: section, text, count=1, flags=re.S)
    in_fence = False
    lines = text.split("\n")
    for i, line in enumerate(lines):
        if FENCE.match(line):
            in_fence = not in_fence
        elif not in_fence and ANCHOR.match(line):
            return "\n".join(lines[:i] + [section, ""] + lines[i:])
    return text.rstrip("\n") + "\n\n" + section + "\n"


def main() -> int:
    check = "--check" in sys.argv
    cat = json.loads((ROOT / "catalog.json").read_text(encoding="utf-8"))
    stacks = {s["stack"]: s for s in cat["stacks"]}
    per_week: dict[int, list[dict]] = defaultdict(list)
    for it in cat["items"]:
        if it["path"].startswith(("topics/", "scenarios/")):
            for w in it.get("week") or []:
                per_week[int(w)].append(it)
    stale = []
    for f in sorted((ROOT / "plan").glob("week*.md")):
        week = int(re.match(r"week(\d+)", f.name).group(1))
        old = f.read_text(encoding="utf-8")
        new = insert(old, build_section(week, per_week.get(week, []), stacks))
        if new != old:
            stale.append(f.name)
            if not check:
                f.write_text(new, encoding="utf-8")
    if check:
        if stale:
            print("需要重新生成：" + "、".join(stale))
            return 1
        print("各周“本周相关专题”已是最新")
        return 0
    print(f"已更新 {len(stale)} 个周计划文件")
    return 0


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