import asyncio,json,os
from pathlib import Path
from core.threads import run_blocking
def _read(p):
    if not p.exists():p.write_text("[]")
    return p.stat().st_mtime_ns,frozenset(int(x) for x in json.loads(p.read_text()))
def _write(p,ids):
    t=p.with_suffix(".tmp");t.write_text(json.dumps(sorted(ids),indent=2));os.replace(t,p);return p.stat().st_mtime_ns
class Whitelist:
    def __init__(s,path,hook):
        s.path=Path(path);s.hook=hook;s.ids=frozenset();s.m=None;s.lock=asyncio.Lock();s.task=None
    def __contains__(s,i):return i in s.ids
    async def load(s):
        try:m,ids=await run_blocking(_read,s.path)
        except Exception as e:
            s.hook.put(f"whitelist unreadable: {e!r}, keeping previous list")
            try:s.m=(await run_blocking(s.path.stat)).st_mtime_ns
            except OSError:pass
            return
        if s.m is not None and ids!=s.ids:s.hook.put(f"whitelist reloaded ({len(ids)} ids)")
        s.ids=ids;s.m=m
    async def watch(s):
        while True:
            await asyncio.sleep(1)
            try:m=(await run_blocking(s.path.stat)).st_mtime_ns
            except OSError:m=None
            if m!=s.m:await s.load()
    async def start(s):
        await s.load();s.task=asyncio.create_task(s.watch())
    async def mutate(s,i,add):
        async with s.lock:
            n=set(s.ids)
            if add:n.add(i)
            else:n.discard(i)
            s.m=await run_blocking(_write,s.path,n);s.ids=frozenset(n)