"""Live alerts across all pages: polls the API every few seconds, toasts new alerts, pins open acute ones on top.

Uses the built-in `st.fragment(run_every=...)`: only this fragment re-runs on the timer, the page is untouched
unless a new alert arrives on a doctor page (then the whole app reruns so the list and the card pick it up).
"""

from __future__ import annotations

from html import escape

import streamlit as st

from app.api.schemas import AlertOut
from dashboard import theme
from dashboard.api_client import ApiError
from dashboard.components import helpers as h
from dashboard.components import state, ui

POLL_SECONDS = 2.5
MAX_BANNER = 3


def _toast(a: AlertOut) -> None:
    icon = theme.TONES[h.level_tone(a.level)].icon
    st.toast(f"**{a.patient_name}** — {a.reason}", icon=icon, duration="long" if a.level == "acute" else "short")


def flush_pending_toasts() -> None:
    """Toasts queued right before a full-app rerun are shown on the next run (a rerun drops pending deltas)."""
    for a in st.session_state.pop("pending_toasts", []):
        _toast(a)


def _banner(acute: list[AlertOut]) -> None:
    for a in acute[:MAX_BANNER]:
        left, right = st.columns([8, 1.6], vertical_alignment="center")
        with left:
            st.html(
                ui.banner(
                    f"<b>Кризисный сигнал · {escape(a.patient_name)}</b> — {escape(a.reason)}"
                    f'<div style="font-size:.8rem;margin-top:2px">{escape(h.when_label(a.ts))} · '
                    "по протоколу — связаться с пациентом сегодня</div>",
                    tone="red",
                    pulse=True,
                )
            )
        with right:
            if st.button(
                "Карточка", key=f"acute-open-{a.id}", type="primary", icon=":material/arrow_forward:", width="stretch"
            ):
                st.switch_page(state.PATIENTS_PAGE, query_params={"patient": a.token})
    if len(acute) > MAX_BANNER:
        st.caption(f"Ещё кризисных сигналов: {len(acute) - MAX_BANNER}")


def render(*, rerun_app_on_new: bool = True) -> None:
    """Place once per run (app.py does it above every page)."""

    @st.fragment(run_every=POLL_SECONDS)
    def _poll() -> None:
        ss = st.session_state
        try:
            alerts = state.client().alerts(open_only=True)
        except ApiError:
            return  # pages show their own "API недоступен" banner; the poller just retries next tick
        acked = state.local_acks()
        alerts = [a for a in alerts if a.acked_at is None and a.id not in acked]

        seen: set[int] | None = ss.get("seen_alert_ids")
        if seen is None:
            # First poll of the session: what is already open is not "new" — no toast storm on page load.
            ss["seen_alert_ids"] = {a.id for a in alerts}
            new: list[AlertOut] = []
        else:
            new = h.split_new(alerts, seen)
            seen.update(a.id for a in new)

        if new and rerun_app_on_new:
            ss["pending_toasts"] = ss.get("pending_toasts", []) + new
            st.rerun(scope="app")
        for a in new:
            _toast(a)
        _banner(h.sort_alerts(a for a in alerts if a.level == "acute"))

    _poll()