#!/usr/bin/env python3
"""MGU Scientific Library (nbmgu.ru) catalog search — server-rendered, curl-able.

Discovered 2026-07-15 from the advanced-search page JS (functions.js
CreateClientRequest): the "JS" search is a plain GET:

    https://nbmgu.ru/search/?adv=1&q1=<query>&f1=<FIELD>&v1=0&cat=BOOK[&p=<page>]

Fields (f1..f3, AND-combined):
    Fields (f1..f3, AND-combined between rows):
    ANY  все · AUT  автор · COA  колл. автор · TIT  заглавие · KEY  ключ. слова
    RUB  рубрики · YEA  год · PLA  место · PUB  изд-во · SER  серия
    ISB  ISBN · ISS  ISSN · NBM  индексы НБ МГУ
Method (v1..v3, per row): 0=Слова (stemming, default) · 1=Словосочетание (phrase)
    · 2=Начинается с · 3=Дословно (exact).
Results: "Всего: N", 20 rows/page (p=0-based). Row = GOST description text
(title / authors; notes - [edition]) + "City : Publisher, Year" + shelf code.
Detail page /order/storing.aspx?uid=... is holdings/order only (no full record).
**ISB field NOT populated** (0 hits for 3 formats x 2 control ISBNs) — search by
AUT/TIT/SER/PUB instead; ISBN validation stays with РГБ/Google/OL (tools/isbnval.py).

Usage:
    tools/mgu.py "query" [FIELD=ANY] [pages=1] [method=0]
    tools/mgu.py --multi "AUT:Франц" "TIT:Число" ["TIT:точное:3"]   (AND rows)
"""
import re, subprocess, sys, time

UA = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"
BASE = "https://nbmgu.ru/search/"


def search_url(pairs, p=0, cat="BOOK"):
    for attempt in range(3):
        args = ["curl", "-s", "-G", "-A", UA, "--max-time", "90", "-e", BASE]
        args += ["--data-urlencode", "adv=1"]
        # mirror the browser: always send slots 1..N (empties included)
        for i, pr in enumerate(pairs, 1):
            f, q = pr[0], pr[1]
            v = str(pr[2]) if len(pr) > 2 else "0"
            args += ["--data-urlencode", f"q{i}={q}",
                     "--data-urlencode", f"f{i}={f}",
                     "--data-urlencode", f"v{i}={v}"]
        if p:
            args += ["--data-urlencode", f"p={p}"]
        args += ["--data-urlencode", f"cat={cat}", BASE]
        try:
            out = subprocess.run(args, capture_output=True, timeout=120)
            if out.returncode != 0 or len(out.stdout) < 5000:
                print(f"  (curl rc={out.returncode} size={len(out.stdout)} err={out.stderr[:120]!r})",
                      file=sys.stderr)
            body = out.stdout.decode("utf-8", "replace")
        except Exception as e:
            print(f"  (subprocess error: {e})", file=sys.stderr)
            body = ""
        if len(body) > 5000:
            return body
        time.sleep(4 * (attempt + 1))
    return body


def parse(html):
    total = ""
    m = re.search(r"Всего:\s*(\d+)", html)
    if m:
        total = m.group(1)
    rows = []
    # NOTE: anchor title attr contains a raw '>' ("<br/>"), so plain [^>]+ fails;
    # split on row start and rely on href being the LAST attribute of the anchor.
    for chunk in html.split('<li class="result">')[1:]:
        cm = re.search(r'<h2>\s*(\d+)\.\s*<a\b.*?href="(/order/storing\.aspx\?[^\"]+)"\s*>(.*?)</a>',
                       chunk, re.S)
        pm = re.search(r"</h2>\s*<p>(.*?)</p>", chunk, re.S)
        sm = re.search(r"Шифр:\s*([^<]+)", chunk)
        if not (cm and pm):
            continue
        clean = lambda s: re.sub(r"\s+", " ", re.sub(r"<[^>]+>", " ", s)).strip()
        rows.append({
            "n": cm.group(1),
            "desc": clean(cm.group(3)),
            "pubyear": clean(pm.group(1)),
            "shelf": clean(sm.group(1)) if sm else "",
            "url": "https://nbmgu.ru" + cm.group(2),
        })
    return total, rows


def main():
    argv = sys.argv[1:]
    if not argv:
        sys.exit(__doc__)
    if argv[0] == "--multi":
        pairs = []
        for spec in argv[1:]:
            parts = spec.split(":")
            f = parts[0].upper()
            q = parts[1] if len(parts) > 1 else ""
            v = int(parts[2]) if len(parts) > 2 else 0
            pairs.append((f, q, v) if v else (f, q))
        pmax = 1
    else:
        q = argv[0]
        f = argv[1].upper() if len(argv) > 1 else "ANY"
        v = int(argv[3]) if len(argv) > 3 else 0
        pairs = [(f, q, v) if v else (f, q)]
        pmax = int(argv[2]) if len(argv) > 2 else 1
    all_rows = []
    total = ""
    seen = set()
    for p in range(pmax):
        html = search_url(pairs, p=p)
        total, rows = parse(html)
        # out-of-range p falls back to page 0 on the server side — dedupe by url
        new = [r for r in rows if r["url"] not in seen]
        if not new:
            break
        seen.update(r["url"] for r in new)
        all_rows += new
        if total and len(all_rows) >= int(total):
            break
        time.sleep(3)
    print(f"### MGU: {pairs} — total: {total} (fetched {len(all_rows)})")
    for r in all_rows:
        print(f"{r['n']:>3}. {r['desc']}")
        print(f"      {r['pubyear']} | шифр: {r['shelf']} | {r['url']}")


if __name__ == "__main__":
    main()