import asyncio

from fastapi import APIRouter
from fastapi.responses import HTMLResponse

from app.collect import procs as proc_col
from app.render import render

router = APIRouter(prefix="/api", tags=["processes"])

SORT_KEYS = ("pid", "name", "cpu", "rss", "mem_pct", "io_read", "io_write", "gpu")


@router.get("/processes")
async def processes(q: str = "", sort: str = "cpu", order: str = "desc"):
    """Render the Processes tab fragment: filterable, sortable process table.

    The full sample is taken in a worker thread, then optionally filtered
    by substring match on name or exact match on pid. Sorting is done with
    None values last (the tuple key trick); at most 300 rows are rendered.
    Invalid sort/order values fall back to cpu/desc.

    Args:
        q: search filter, empty for all.
        sort: column to sort by, one of SORT_KEYS.
        order: "asc" or "desc".

    Returns:
        The rendered processes.html as an HTMLResponse.
    """
    if sort not in SORT_KEYS:
        sort = "cpu"
    if order not in ("asc", "desc"):
        order = "desc"
    procs = await asyncio.to_thread(proc_col.sample)
    if q:
        ql = q.lower()
        procs = [p for p in procs if ql in p["name"].lower() or str(p["pid"]) == ql]
    reverse = order == "desc"
    try:
        procs.sort(key=lambda p: (p[sort] is None, p[sort]), reverse=reverse)
    except (KeyError, TypeError):
        pass
    return HTMLResponse(
        render(
            "processes.html",
            procs=procs[:300],
            total=len(procs),
            q=q,
            sort=sort,
            order=order,
        )
    )