#!/usr/bin/env python3
"""Batch-validate ISBNs via isbnsearch.org (user-provided source, 2026-07-15).

Response shapes (calibrated):
  200 + "ISBN-13:"/"ISBN-10:" fields -> book found; parse title/author/publisher/year
  200 + "Please Verify to Continue"  -> rate-limit wall; cooldown 150s, retry
  404 "Page Not Found"               -> ISBN not in their DB

Usage:
    tools/isbncheck.py <items.tsv> <out.tsv>
items.tsv rows: item\tlang\tisbn   (whitespace-separated, # comments)
Resume: rows already OK in out.tsv are skipped.
Politeness: random pause 8-18s between requests (curl engine).
"""
import random, 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"


def fetch(isbn):
    url = f"https://isbnsearch.org/isbn/{isbn}"
    p = subprocess.run(["curl", "-s", "-A", UA, "--max-time", "60",
                        "-w", "\nHTTP_CODE:%{http_code}", url],
                       capture_output=True, timeout=90)
    body, _, code = p.stdout.decode("utf-8", "replace").rpartition("HTTP_CODE:")
    return code.strip(), body


def parse(body):
    def field(label):
        m = re.search(r"<td[^>]*>\s*" + re.escape(label) + r"\s*</td>\s*<td[^>]*>(.*?)</td>",
                      body, re.S)
        if not m:
            return ""
        return re.sub(r"<[^>]+>", " ", m.group(1)).strip()
    tm = re.search(r"<title>ISBN\s+\S+\s*-\s*(.*?)</title>", body, re.S)
    title = re.sub(r"<[^>]+>", " ", tm.group(1)).strip() if tm else ""
    pm = re.search(r"Published:?\s*</td>\s*<td[^>]*>\s*([\d]{4})", body)
    year = pm.group(1) if pm else ""
    return title, field("Author:") or field("Authors:"), field("Publisher:"), year


def main():
    items_file, out_file = sys.argv[1], sys.argv[2]
    rows = []
    for line in open(items_file):
        line = line.strip()
        if not line or line.startswith("#"):
            continue
        rows.append(line.split("\t"))
    # resume: load existing OK rows (stale non-OK rows from wall-hits are dropped)
    done = set()
    if __import__("os").path.exists(out_file):
        for line in open(out_file):
            parts = line.rstrip("\n").split("\t")
            if len(parts) >= 4 and parts[3] == "OK":
                done.add((parts[0], parts[1], parts[2]))
    out = open(out_file, "w")
    out.write("item\tlang\tisbn\tstatus\ttitle\tauthor\tpublisher\tyear\n")
    if __import__("os").path.exists(out_file):
        for line in open(out_file):
            if line.startswith("item\t"):
                continue
            parts = line.rstrip("\n").split("\t")
            if len(parts) >= 4 and parts[3] == "OK":
                out.write(line)
    total = len(rows)
    n = 0
    for i, (item, lang, isbn) in enumerate(rows):
        if (item, lang, isbn) in done:
            print(f"[{i+1}/{total}] {item}/{lang} {isbn} skip (OK)", flush=True)
            continue
        n += 1
        status, fields = None, None
        for attempt in range(4):
            try:
                code, body = fetch(isbn)
            except Exception as e:
                print(f"  {isbn}: fetch error ({e}), backoff", flush=True)
                time.sleep(15)
                continue
            if code == "200" and ("ISBN-13:" in body or "ISBN-10:" in body):
                status = "OK"
                fields = parse(body)
                break
            if code == "200" and "Please Verify to Continue" in body:
                print(f"  {isbn}: VERIFY wall, cooldown 150s (attempt {attempt+1})", flush=True)
                time.sleep(150)
                continue
            status = code  # 404 etc.
            break
        if status == "OK":
            title, author, pub, year = fields
            out.write(f"{item}\t{lang}\t{isbn}\tOK\t{title}\t{author}\t{pub}\t{year}\n")
            print(f"[{i+1}/{total}] {item}/{lang} {isbn} OK: {title[:60]}", flush=True)
        else:
            out.write(f"{item}\t{lang}\t{isbn}\t{status}\t-\t-\t-\t-\n")
            print(f"[{i+1}/{total}] {item}/{lang} {isbn} -> HTTP {status} (not found)", flush=True)
        out.flush()
        if i < total - 1:
            time.sleep(random.uniform(8, 18))
    out.close()
    print(f"done -> {out_file}")


if __name__ == "__main__":
    main()