#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""split_skill.py — 技能重组：把千行级技能的 SKILL.md 拆成「主干 + references/ 详情档」。

用法：
    <python> split_skill.py --spec <spec.json> [--dry-run]

设计（照 `dsh-knowledge-upkeep` §10）：
  · **纯机械搬运** —— 只按行号区间搬移，逐行未改；不重写、不润色、不删字。
  · **可重复跑（幂等）** —— 永远以 `<backup_dir>/<skill>-SKILL.md` 为拆前基准；
    首次运行自动生成该备份。⚠️ 绝不以「活文件」为基准（否则第二次跑会二次切割）。
  · **四项自校验**：① 行数守恒 ② 逐行包含 0 丢失 ③ 节可寻址 ④ frontmatter 唯一。

spec.json：
{
  "skills_dir": "E:/ProgramData/.workbuddy/skills",
  "backup_dir": "…/tmp/_keep-YYYYMMDD/split-bak",
  "skill": "dsh-change-workflow",
  "main_desc": "§1 … · §2 …",                 // 写进详情档头的「主文件」说明
  "moves": [
    {"ranges": [[14,92]], "ref": "00-平台速查.md",
     "title": "平台速查（硬编码事实，勿猜）",
     "covers": ["平台速查（硬编码事实，勿猜）"],   // 用于主干索引表的「覆盖的原章节」列
     "pointer": "> 📂 **…已下沉** → `references/00-平台速查.md`"}
  ]
}
ranges = 1-based 闭区间，可多段，**不得重叠**；pointer 支持 \n 多行。
"""
import argparse
import hashlib
import json
import os
import re
import sys
from collections import Counter

HDR = ("# {title}\n\n"
       "> **归属**：技能 `{skill}` 的详情档（**按需读**，不是每次都要读）。\n"
       "> **本档覆盖**：{covers}（原行 {rng}）。\n"
       "> **主文件 / 判据与流程主干** = `../SKILL.md`（{main}）。\n"
       "> **来源**：技能重组把 `../SKILL.md` 的 {rng} 段**逐行原样**下沉到本文件，未改一字。\n"
       "> **跨档引用**：正文里的「§N / 见 §8 坑 N / 见下表」等编号，用 `../SKILL.md` 末节「详情索引」的原章节列定位。\n\n---\n")

md5 = lambda b: hashlib.md5(b).hexdigest()


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--spec", required=True)
    ap.add_argument("--dry-run", action="store_true")
    a = ap.parse_args()

    cfg = json.load(open(a.spec, encoding="utf-8"))
    skill = cfg["skill"]
    d = os.path.join(cfg["skills_dir"], skill)
    src = os.path.join(d, "SKILL.md")
    os.makedirs(cfg["backup_dir"], exist_ok=True)
    bak = os.path.join(cfg["backup_dir"], "%s-SKILL.md" % skill)

    if not os.path.exists(bak):                       # 首次：以活文件为基准建备份
        open(bak, "wb").write(open(src, "rb").read())
    orig_bytes = open(bak, "rb").read()               # 之后永远以备份为基准（幂等）
    orig = orig_bytes.decode("utf-8").split("\n")
    if orig and orig[-1] == "":
        orig = orig[:-1]
    n = len(orig)

    # ── 区间校验
    moved, starts = {}, {}
    for mv in cfg["moves"]:
        for rng in mv["ranges"]:
            lo, hi = rng
            assert 1 <= lo <= hi <= n, "区间越界 %s（原文件 %d 行）" % (rng, n)
            for i in range(lo, hi + 1):
                assert i not in moved, "区间重叠于第 %d 行" % i
                moved[i] = mv["ref"]
        starts[min(r[0] for r in mv["ranges"])] = mv

    # ── 生成主干
    out, ptrs = [], []
    for i in range(1, n + 1):
        if i in starts:
            out.append(starts[i]["pointer"])
            out.append("")
            ptrs.append(starts[i]["pointer"])
        if i not in moved:
            out.append(orig[i - 1])
    main_len = len(out)

    # ── 生成详情档
    refs = {}
    for mv in cfg["moves"]:
        refs.setdefault(mv["ref"], []).append(mv)
    index, ref_body = [], {}
    for refname, mvs in sorted(refs.items()):
        rngs = sorted(r for mv in mvs for r in mv["ranges"])
        body = [l for (lo, hi) in rngs for l in orig[lo - 1:hi]]
        rng_txt = " + ".join("L%d–L%d" % (lo, hi) for (lo, hi) in rngs)
        covers = " · ".join(dict.fromkeys(c for mv in mvs for c in mv.get("covers", [])))
        head = HDR.format(title=mvs[0]["title"], skill=skill, covers=covers,
                          rng=rng_txt, main=cfg.get("main_desc", ""))
        ref_body[refname] = body
        index.append((refname, covers, len(body), rng_txt))
        if not a.dry_run:
            rd = os.path.join(d, "references")
            os.makedirs(rd, exist_ok=True)
            with open(os.path.join(rd, refname), "w", encoding="utf-8", newline="\n") as f:
                f.write(head + "\n".join(body) + "\n")

    # ── 主干末节：详情索引（= 跨档引用的定位表）
    out += ["", "## 详情索引（references/）", "",
            "> 本技能 = **主干（本文件）+ 详情档**。主干只留判据 / 流程主干 / 命令骨架；长表、案例、实测记录、历史细节在下面各档。",
            ">", "> **跨档引用怎么查**：正文里的「§N」「见 §8 坑 N」「见下表」等编号，按本表「覆盖的原章节」列定位。",
            "", "| 详情档 | 覆盖的原章节 | 原行段 | 行数 |", "|---|---|---|---|"]
    for refname, covers, ln, rng_txt in index:
        out.append("| `references/%s` | %s | %s | %d |" % (refname, covers.replace("|", "/"), rng_txt, ln))
    out.append("")
    idx_block = len(out) - main_len
    text = "\n".join(out).rstrip("\n") + "\n"
    new_lines = text.split("\n")[:-1]

    # ── 四项自校验
    core = main_len - 2 * len(cfg["moves"])
    det = sum(len(v) for v in ref_body.values())
    A = Counter(orig)
    B = Counter([l for l in new_lines if l not in ptrs]
                + [l for rn in ref_body for l in ref_body[rn]])
    lost = [k for k in A if A[k] > B[k]]
    heads = [re.sub(r"^#+\s*", "", l).strip() for l in orig if re.match(r"^#{1,3} ", l)]
    blob = text + "".join("\n".join(v) for v in ref_body.values())
    miss = [h for h in heads if h and h not in blob]
    fm = [l for l in new_lines[:14] if l.startswith("version:")]

    checks = [
        ("① 行数守恒", core + det == n, "主干内容 %d + 详情 %d = %d（原 %d）" % (core, det, core + det, n)),
        ("② 逐行包含", not lost, "丢失 %d 行；新增（指针 %d + 索引 %d）" % (len(lost), 2 * len(cfg["moves"]), idx_block)),
        ("③ 节可寻址", not miss, "标题 %d 个，未命中 %d%s" % (len(heads), len(miss), (" " + repr(miss[:3])) if miss else "")),
        ("④ frontmatter", len(fm) == 1, "version 行 = %s" % (fm or "缺失/重复")),
    ]
    print("=" * 68)
    print("技能 %s：原 %d 行  md5=%s" % (skill, n, md5(orig_bytes)))
    for name, ok, info in checks:
        print("  %s %s ── %s" % ("OK  " if ok else "FAIL", name, info))
    print("  主干 SKILL.md = %d 行  %s" % (len(new_lines), "(dry-run，未落盘)" if a.dry_run else "md5=%s" % md5(text.encode("utf-8"))))
    for refname, covers, ln, rng_txt in index:
        print("    - %-40s %4d 行  %s" % (refname, ln, rng_txt))
    if not a.dry_run:
        with open(src, "w", encoding="utf-8", newline="\n") as f:
            f.write(text)
    bad = [c[0] for c in checks if not c[1]]
    if bad:
        print("⛔ 未通过：%s ⇒ 停下来看，别硬推" % "、".join(bad))
        return 1
    print("✅ 四项校验全绿" + ("（dry-run）" if a.dry_run else "；记得三处同步 + 三方 md5 对账"))
    return 0


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