from fastapi import APIRouter, Depends, Query
from sqlalchemy import func, select
from sqlalchemy.orm import Session

from app.auth.jwt_auth import get_current_user
from app.config import get_settings
from app.database import get_db
from app.models import Event, Host
from app.schemas.list_models import HostListResponse, HostSummary
from app.services.host_health import (
    DAILY_REPORT_SSH,
    HEARTBEAT_TYPE,
    agent_status,
    max_event_time_by_host,
)

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


@router.get("", response_model=HostListResponse)
def list_hosts(
    page: int = Query(1, ge=1),
    page_size: int = Query(50, ge=1, le=200),
    product: str | None = None,
    hostname: str | None = None,
    db: Session = Depends(get_db),
    _user: str = Depends(get_current_user),
) -> HostListResponse:
    stmt = select(Host)
    count_stmt = select(func.count()).select_from(Host)

    if product:
        stmt = stmt.where(Host.product == product)
        count_stmt = count_stmt.where(Host.product == product)
    if hostname:
        like = f"%{hostname}%"
        host_match = Host.hostname.ilike(like) | Host.display_name.ilike(like)
        stmt = stmt.where(host_match)
        count_stmt = count_stmt.where(host_match)

    total = db.scalar(count_stmt) or 0
    rows = db.scalars(
        stmt.order_by(Host.last_seen_at.desc())
        .offset((page - 1) * page_size)
        .limit(page_size)
    ).all()

    settings = get_settings()
    hb_map = max_event_time_by_host(db, HEARTBEAT_TYPE)
    report_map = max_event_time_by_host(db, DAILY_REPORT_SSH)

    items: list[HostSummary] = []
    for host in rows:
        event_count = db.scalar(
            select(func.count()).select_from(Event).where(Event.host_id == host.id)
        )
        last_hb = hb_map.get(host.id)
        items.append(
            HostSummary(
                id=host.id,
                hostname=host.hostname,
                display_name=host.display_name,
                os_family=host.os_family,
                product=host.product,
                product_version=host.product_version,
                ipv4=host.ipv4,
                last_seen_at=host.last_seen_at,
                event_count=int(event_count or 0),
                last_heartbeat_at=last_hb,
                last_daily_report_at=report_map.get(host.id),
                agent_status=agent_status(
                    last_hb, stale_minutes=settings.sac_heartbeat_stale_minutes
                ),
            )
        )

    return HostListResponse(items=items, total=total, page=page, page_size=page_size)