refactor(scrapers): centralize cookie storage into shared file

Problem: each platform scraper managed its own cookie file path and
load/save/clear logic, duplicating boilerplate across kattis, usaco,
codeforces, and codechef.

Solution: add \`load_platform_cookies\`, \`save_platform_cookies\`, and
\`clear_platform_cookies\` to \`base.py\` backed by a single
\`~/.cache/cp-nvim/cookies.json\` keyed by platform name. Update all
scrapers to use these helpers.

scrapers/base.py

@@ -4,6 +4,38 @@ import os
 import re
 import sys
 from abc import ABC, abstractmethod
+from pathlib import Path
+from typing import Any
+
+_COOKIE_FILE = Path.home() / ".cache" / "cp-nvim" / "cookies.json"
+
+
+def load_platform_cookies(platform: str) -> Any | None:
+    try:
+        data = json.loads(_COOKIE_FILE.read_text())
+        return data.get(platform)
+    except Exception:
+        return None
+
+
+def save_platform_cookies(platform: str, data: Any) -> None:
+    _COOKIE_FILE.parent.mkdir(parents=True, exist_ok=True)
+    try:
+        existing = json.loads(_COOKIE_FILE.read_text())
+    except Exception:
+        existing = {}
+    existing[platform] = data
+    _COOKIE_FILE.write_text(json.dumps(existing))
+
+
+def clear_platform_cookies(platform: str) -> None:
+    try:
+        existing = json.loads(_COOKIE_FILE.read_text())
+        existing.pop(platform, None)
+        _COOKIE_FILE.write_text(json.dumps(existing))
+    except Exception:
+        pass
+
 
 from .language_ids import get_language_id
 from .models import (

scrapers/codeforces.py

@@ -8,7 +8,7 @@ from typing import Any
 import requests
 from bs4 import BeautifulSoup, Tag
 
-from .base import BaseScraper, extract_precision
+from .base import BaseScraper, clear_platform_cookies, extract_precision, load_platform_cookies, save_platform_cookies
 from .models import (
     ContestListResult,
     ContestSummary,
@@ -332,8 +332,6 @@ class CodeforcesScraper(BaseScraper):
 
 
 def _login_headless_cf(credentials: dict[str, str]) -> LoginResult:
-    from pathlib import Path
-
     try:
         from scrapling.fetchers import StealthySession  # type: ignore[import-untyped,unresolved-import]
     except ImportError:
@@ -346,9 +344,6 @@ def _login_headless_cf(credentials: dict[str, str]) -> LoginResult:
 
     _ensure_browser()
 
-    cookie_cache = Path.home() / ".cache" / "cp-nvim" / "codeforces-cookies.json"
-    cookie_cache.parent.mkdir(parents=True, exist_ok=True)
-
     logged_in = False
     login_error: str | None = None
 
@@ -405,7 +400,7 @@ def _login_headless_cf(credentials: dict[str, str]) -> LoginResult:
             try:
                 browser_cookies = session.context.cookies()
                 if any(c.get("name") == "X-User-Handle" for c in browser_cookies):
-                    cookie_cache.write_text(json.dumps(browser_cookies))
+                    save_platform_cookies("codeforces", browser_cookies)
             except Exception:
                 pass
 
@@ -426,6 +421,7 @@ def _submit_headless(
 
     source_code = Path(file_path).read_text()
 
+
     try:
         from scrapling.fetchers import StealthySession  # type: ignore[import-untyped,unresolved-import]
     except ImportError:
@@ -438,16 +434,11 @@ def _submit_headless(
 
     _ensure_browser()
 
-    cookie_cache = Path.home() / ".cache" / "cp-nvim" / "codeforces-cookies.json"
-    cookie_cache.parent.mkdir(parents=True, exist_ok=True)
     saved_cookies: list[dict[str, Any]] = []
-    if cookie_cache.exists():
+    if not _retried:
-        try:
+        saved_cookies = load_platform_cookies("codeforces") or []
-            saved_cookies = json.loads(cookie_cache.read_text())
-        except Exception:
-            pass
 
-    logged_in = cookie_cache.exists() and not _retried
+    logged_in = bool(saved_cookies) and not _retried
     login_error: str | None = None
     submit_error: str | None = None
     needs_relogin = False
@@ -520,9 +511,9 @@ def _submit_headless(
             headless=True,
             timeout=BROWSER_SESSION_TIMEOUT,
             google_search=False,
-            cookies=saved_cookies if (cookie_cache.exists() and not _retried) else [],
+            cookies=saved_cookies if (saved_cookies and not _retried) else [],
         ) as session:
-            if not (cookie_cache.exists() and not _retried):
+            if not (saved_cookies and not _retried):
                 print(json.dumps({"status": "checking_login"}), flush=True)
                 session.fetch(
                     f"{BASE_URL}/",
@@ -552,12 +543,12 @@ def _submit_headless(
             try:
                 browser_cookies = session.context.cookies()
                 if any(c.get("name") == "X-User-Handle" for c in browser_cookies):
-                    cookie_cache.write_text(json.dumps(browser_cookies))
+                    save_platform_cookies("codeforces", browser_cookies)
             except Exception:
                 pass
 
         if needs_relogin and not _retried:
-            cookie_cache.unlink(missing_ok=True)
+            clear_platform_cookies("codeforces")
             return _submit_headless(
                 contest_id,
                 problem_id,

scrapers/kattis.py

@@ -10,7 +10,7 @@ from pathlib import Path
 
 import httpx
 
-from .base import BaseScraper, extract_precision
+from .base import BaseScraper, clear_platform_cookies, extract_precision, load_platform_cookies, save_platform_cookies
 from .timeouts import HTTP_TIMEOUT
 from .models import (
     ContestListResult,
@@ -28,8 +28,6 @@ HEADERS = {
 }
 CONNECTIONS = 8
 
-_COOKIE_PATH = Path.home() / ".cache" / "cp-nvim" / "kattis-cookies.json"
-
 TIME_RE = re.compile(
     r"CPU Time limit</span>\s*<span[^>]*>\s*(\d+)\s*seconds?\s*</span>",
     re.DOTALL,
@@ -209,20 +207,16 @@ async def _stream_single_problem(client: httpx.AsyncClient, slug: str) -> None:
 
 
 async def _load_kattis_cookies(client: httpx.AsyncClient) -> None:
-    if not _COOKIE_PATH.exists():
+    data = load_platform_cookies("kattis")
-        return
+    if isinstance(data, dict):
-    try:
+        for k, v in data.items():
-        for k, v in json.loads(_COOKIE_PATH.read_text()).items():
             client.cookies.set(k, v)
-    except Exception:
-        pass
 
 
 async def _save_kattis_cookies(client: httpx.AsyncClient) -> None:
-    cookies = {k: v for k, v in client.cookies.items()}
+    cookies = dict(client.cookies.items())
     if cookies:
-        _COOKIE_PATH.parent.mkdir(parents=True, exist_ok=True)
+        save_platform_cookies("kattis", cookies)
-        _COOKIE_PATH.write_text(json.dumps(cookies))
 
 
 async def _do_kattis_login(
@@ -368,7 +362,7 @@ class KattisScraper(BaseScraper):
                 return self._submit_error(f"Submit request failed: {e}")
 
             if r.status_code in (400, 403) or r.text == "Request validation failed":
-                _COOKIE_PATH.unlink(missing_ok=True)
+                clear_platform_cookies("kattis")
                 print(json.dumps({"status": "logging_in"}), flush=True)
                 ok = await _do_kattis_login(client, username, password)
                 if not ok:

scrapers/usaco.py

@@ -8,7 +8,7 @@ from typing import Any, cast
 
 import httpx
 
-from .base import BaseScraper, extract_precision
+from .base import BaseScraper, extract_precision, load_platform_cookies, save_platform_cookies
 from .timeouts import HTTP_TIMEOUT
 from .models import (
     ContestListResult,
@@ -27,7 +27,6 @@ HEADERS = {
 }
 CONNECTIONS = 4
 
-_COOKIE_PATH = Path.home() / ".cache" / "cp-nvim" / "usaco-cookies.json"
 _LOGIN_PATH = "/current/tpcm/login-session.php"
 _SUBMIT_PATH = "/current/tpcm/submit-solution.php"
 
@@ -202,20 +201,16 @@ def _parse_submit_form(
 
 
 async def _load_usaco_cookies(client: httpx.AsyncClient) -> None:
-    if not _COOKIE_PATH.exists():
+    data = load_platform_cookies("usaco")
-        return
+    if isinstance(data, dict):
-    try:
+        for k, v in data.items():
-        for k, v in json.loads(_COOKIE_PATH.read_text()).items():
             client.cookies.set(k, v)
-    except Exception:
-        pass
 
 
 async def _save_usaco_cookies(client: httpx.AsyncClient) -> None:
-    cookies = {k: v for k, v in client.cookies.items()}
+    cookies = dict(client.cookies.items())
     if cookies:
-        _COOKIE_PATH.parent.mkdir(parents=True, exist_ok=True)
+        save_platform_cookies("usaco", cookies)
-        _COOKIE_PATH.write_text(json.dumps(cookies))
 
 
 async def _check_usaco_login(client: httpx.AsyncClient, username: str) -> bool: