#!/usr/bin/env python3
"""Search РГБ (Russian State Library) via libgen.vg biblioservice. JSON, paginated.
Usage: rsl.py "query" [maxpages]
Polite: 3s between page requests."""
import sys, time, json, urllib.parse, urllib.request

UA = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36"

def fetch(url, tries=3):
    last = None
    for i in range(tries):
        try:
            req = urllib.request.Request(url, headers={"User-Agent": UA})
            return urllib.request.urlopen(req, timeout=90).read().decode("utf-8", "replace")
        except Exception as e:
            last = e
            time.sleep(5 + 5 * i)
    raise SystemExit(f"fetch failed: {last}")

def main():
    q = sys.argv[1]
    maxpages = int(sys.argv[2]) if len(sys.argv) > 2 else 2
    seen = set()
    for page in range(1, maxpages + 1):
        url = "https://libgen.vg/biblioservice.php?" + urllib.parse.urlencode(
            {"value": q, "type": "rsl", "format": "json", "page": page})
        try:
            d = json.loads(fetch(url))
        except SystemExit:
            print("(fetch failed)")
            break
        recs = {k: v for k, v in d.items() if k != "error"}
        if not recs:
            if page == 1:
                print("(no records)")
            break
        new = 0
        for k in sorted(recs, key=int):
            r = recs[k]
            if r["id"] in seen:
                continue
            seen.add(r["id"])
            new += 1
            title = " ".join(r.get("title", [])) + (
                (" : " + r["title_add"]) if r.get("title_add") else "")
            author = "; ".join(r.get("author", []))
            pub = " ".join(r.get("publisher", []))
            city = " ".join(r.get("city", []))
            year = " ".join(r.get("year", []))
            pages = " ".join(r.get("pages", []))
            isbn = ", ".join(r.get("505_isbn", []))
            series = " ".join(r.get("series_name", []))
            print(f"[{r['id']}] {title}")
            print(f"    {author}")
            print(f"    {city} : {pub}, {year} | {pages} | {isbn}" + (f" | серия: {series}" if series else ""))
        if new == 0:
            break
        time.sleep(3)

if __name__ == "__main__":
    main()