from typing import Any

from fastapi import APIRouter, Request
from fastapi.responses import HTMLResponse

from app import journal
from app.render import render

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


@router.get("/journal")
async def journal_view(
    _request: Request,
    level: str = "all",
    unit: str = "",
    search: str = "",
    cursor: str = "",
    hide_sudo: str = "",
):
    """Render the Journal tab fragment: a page of journal entries.

    Without a cursor it fetches 100 lines; with one (continuing a scroll)
    200, then keeps the newest 400 for the template. level is validated
    against journal.LEVELS, and failures (RuntimeError/OSError from
    journalctl) are rendered as an error banner instead of a 500.

    Args:
        _request: FastAPI request (unused).
        level: "all" / "warn" / "err".
        unit: unit name filter, empty for none.
        search: free-text filter, empty for none.
        cursor: journal cursor to continue after, empty for none.
        hide_sudo: "on" to hide sudo's own log entries.

    Returns:
        The rendered journal.html as an HTMLResponse.
    """
    if level not in journal.LEVELS:
        level = "all"
    lines = 200 if cursor else 100
    error = None
    entries: list[dict[str, Any]] = []
    next_cursor = ""
    try:
        entries, nc = await journal.tail(
            cursor or None,
            level,
            unit or None,
            search or None,
            lines,
            hide_sudo=(hide_sudo == "on"),
        )
        next_cursor = nc or ""
        entries = entries[-400:]
    except (RuntimeError, OSError) as e:
        error = str(e)[:300]
    return HTMLResponse(
        render(
            "journal.html",
            entries=entries,
            next_cursor=next_cursor,
            level=level,
            unit=unit,
            search=search,
            error=error,
        )
    )