import asyncio
import time
from collections import deque
from typing import Awaitable, Callable, Any


_queue: asyncio.Queue = asyncio.Queue()
_current_label: str | None = None
_current_meta: dict[str, Any] | None = None
_pending: deque[tuple[str, float]] = deque()


async def enqueue(label: str, job: Callable[[], Awaitable[None]]) -> int:
    enqueued_at = time.time()
    await _queue.put((label, job, enqueued_at))
    _pending.append((label, enqueued_at))
    return len(_pending)


async def worker():
    global _current_label, _current_meta
    while True:
        label, job, enqueued_at = await _queue.get()
        if _pending:
            if _pending[0] == (label, enqueued_at):
                _pending.popleft()
            else:
                try:
                    _pending.remove((label, enqueued_at))
                except ValueError:
                    pass
        _current_label = label
        _current_meta = {"enqueued_at": enqueued_at, "started_at": time.time()}
        try:
            await job()
        finally:
            _current_label = None
            _current_meta = None
            _queue.task_done()


def format_status() -> str:
    pending = list(_pending)
    lines = ["🧾 Queue"]
    lines.append(f"🔄 Running: {_current_label or 'idle'}")
    lines.append(f"⏳ Pending: {len(pending)}")
    if pending:
        preview = ", ".join([p[0] for p in pending[:5]])
        lines.append(f"➡️ Next: {preview}")
    return "\n".join(lines)


def format_details(limit: int = 10) -> str:
    now = time.time()
    lines = ["🧾 Queue details"]
    if _current_label:
        started_at = _current_meta.get("started_at") if _current_meta else None
        runtime = f"{int(now - started_at)}s" if started_at else "n/a"
        lines.append(f"🔄 Running: {_current_label} ({runtime})")
    else:
        lines.append("🔄 Running: idle")

    pending = list(_pending)
    lines.append(f"⏳ Pending: {len(pending)}")
    if pending:
        lines.append("🔢 Position | Label | Wait")
        for i, (label, enqueued_at) in enumerate(pending[:limit], start=1):
            wait = int(now - enqueued_at)
            lines.append(f"{i:>3} | {label} | {wait}s")
    return "\n".join(lines)