"""Paginate API to fetch every server-side SerialNumber, write to file."""
import json
import time
import urllib.request
import urllib.parse

import os, sys
TOKEN_URL = os.environ.get("CF_TOKEN_URL", "https://login.dataforth.com/connect/token")
API_BASE = os.environ.get("CF_API_BASE", "https://www.dataforth.com") + "/api/v1"
CLIENT_ID = os.environ.get("CF_CLIENT_ID", "")
CLIENT_SECRET = os.environ.get("CF_CLIENT_SECRET", "")
SCOPE = os.environ.get("CF_SCOPE", "dataforth.web")
if not CLIENT_ID or not CLIENT_SECRET:
    sys.exit("set CF_CLIENT_ID + CF_CLIENT_SECRET (vault: clients/dataforth/api-oauth.sops.yaml)")

OUTFILE = r"C:\Users\guru\AppData\Local\Temp\server_inventory.txt"
PAGE_SIZE = 1000  # try 1000 first; smaller if server complains


def get_token():
    data = urllib.parse.urlencode({
        "grant_type": "client_credentials",
        "client_id": CLIENT_ID,
        "client_secret": CLIENT_SECRET,
        "scope": SCOPE,
    }).encode()
    with urllib.request.urlopen(urllib.request.Request(TOKEN_URL, data=data)) as r:
        return json.loads(r.read())["access_token"]


def main():
    token = get_token()
    headers = {"Authorization": f"Bearer {token}"}

    total = 0
    page = 1
    cursor = None
    t_start = time.time()

    with open(OUTFILE, "w") as f:
        while True:
            params = {"page": page, "pageSize": PAGE_SIZE}
            if cursor:
                params["afterSerialNumber"] = cursor
            url = f"{API_BASE}/TestReportDataFiles?" + urllib.parse.urlencode(params)
            req = urllib.request.Request(url, headers=headers)
            try:
                with urllib.request.urlopen(req, timeout=30) as r:
                    obj = json.loads(r.read())
            except Exception as e:
                print(f"  ERROR at page {page}: {e}")
                # Refresh token and retry once
                token = get_token()
                headers = {"Authorization": f"Bearer {token}"}
                with urllib.request.urlopen(urllib.request.Request(url, headers=headers), timeout=30) as r:
                    obj = json.loads(r.read())

            items = obj.get("Items", [])
            if not items:
                break

            for it in items:
                f.write(it["SerialNumber"] + "\n")
            total += len(items)
            cursor = obj.get("NextCursor")

            if page % 50 == 0 or page == 1:
                rate = total / max(1, time.time() - t_start)
                print(f"  page {page}: total={total} rate={rate:.0f}/s cursor={cursor!r}")

            if not cursor:
                break
            page += 1

    elapsed = time.time() - t_start
    print(f"\nDONE: {total} serials written to {OUTFILE} in {elapsed:.1f}s")


if __name__ == "__main__":
    main()