from __future__ import annotations
from datetime import datetime, timedelta, timezone
from quart import Blueprint, render_template, request, redirect, url_for, current_app, session
from sqlalchemy import and_, case, select, func
from steward.auth.middleware import require_role
from steward.core.audit import log_audit
from steward.models.hosts import Host, ProbeType
from steward.models.monitors import PingResult, DnsResult, PingStatus
from steward.models.users import UserRole

hosts_bp = Blueprint("hosts", __name__, url_prefix="/hosts")


async def _compute_uptime(db) -> dict[str, dict]:
    """Return per-host uptime % for 24h, 7d, 30d windows.

    Returns {host_id: {"24h": float|None, "7d": float|None, "30d": float|None}}.
    """
    now = datetime.now(timezone.utc)
    cutoff_30d = now - timedelta(days=30)
    cutoff_7d  = now - timedelta(days=7)
    cutoff_24h = now - timedelta(hours=24)

    result = await db.execute(
        select(
            PingResult.host_id,
            # 30d window — all rows in query qualify
            func.count(PingResult.id).label("total_30d"),
            func.sum(case((PingResult.status == PingStatus.up, 1), else_=0)).label("up_30d"),
            # 7d sub-window
            func.sum(case((PingResult.probed_at >= cutoff_7d, 1), else_=0)).label("total_7d"),
            func.sum(case(
                (and_(PingResult.probed_at >= cutoff_7d, PingResult.status == PingStatus.up), 1),
                else_=0,
            )).label("up_7d"),
            # 24h sub-window
            func.sum(case((PingResult.probed_at >= cutoff_24h, 1), else_=0)).label("total_24h"),
            func.sum(case(
                (and_(PingResult.probed_at >= cutoff_24h, PingResult.status == PingStatus.up), 1),
                else_=0,
            )).label("up_24h"),
        )
        .where(PingResult.probed_at >= cutoff_30d)
        .group_by(PingResult.host_id)
    )

    def _pct(up, total):
        return round(float(up) / float(total) * 100, 2) if total else None

    stats: dict[str, dict] = {}
    for row in result:
        stats[row.host_id] = {
            "24h": _pct(row.up_24h, row.total_24h),
            "7d":  _pct(row.up_7d,  row.total_7d),
            "30d": _pct(row.up_30d, row.total_30d),
        }
    return stats


@hosts_bp.get("/")
@require_role(UserRole.viewer)
async def list_hosts():
    async with current_app.db_sessionmaker() as db:
        result = await db.execute(select(Host).order_by(Host.name))
        hosts = result.scalars().all()

        # Latest ping result per host
        latest_ping_subq = (
            select(PingResult.host_id, func.max(PingResult.probed_at).label("max_at"))
            .group_by(PingResult.host_id)
            .subquery()
        )
        pr = await db.execute(
            select(PingResult).join(
                latest_ping_subq,
                (PingResult.host_id == latest_ping_subq.c.host_id)
                & (PingResult.probed_at == latest_ping_subq.c.max_at),
            )
        )
        latest_pings = {r.host_id: r for r in pr.scalars()}

        # Latest DNS result per host
        latest_dns_subq = (
            select(DnsResult.host_id, func.max(DnsResult.resolved_at).label("max_at"))
            .group_by(DnsResult.host_id)
            .subquery()
        )
        dr = await db.execute(
            select(DnsResult).join(
                latest_dns_subq,
                (DnsResult.host_id == latest_dns_subq.c.host_id)
                & (DnsResult.resolved_at == latest_dns_subq.c.max_at),
            )
        )
        latest_dns = {r.host_id: r for r in dr.scalars()}
        uptime = await _compute_uptime(db)

    return await render_template(
        "hosts/list.html",
        hosts=hosts,
        latest_pings=latest_pings,
        latest_dns=latest_dns,
        uptime=uptime,
    )


@hosts_bp.get("/new")
@require_role(UserRole.operator)
async def new_host():
    return await render_template("hosts/form.html", host=None, probe_types=list(ProbeType))


@hosts_bp.post("/")
@require_role(UserRole.operator)
async def create_host():
    form = await request.form
    host = Host(
        name=form["name"].strip(),
        address=form["address"].strip(),
        probe_type=ProbeType(form.get("probe_type", "tcp")),
        probe_port=int(form.get("probe_port") or 80),
        ping_enabled="ping_enabled" in form,
        dns_enabled="dns_enabled" in form,
        dns_expected_ip=form.get("dns_expected_ip", "").strip() or None,
        # poll_interval_seconds not exposed in UI yet; per-host scheduling not implemented
    )
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            db.add(host)
    await log_audit(current_app, session.get("user_id"), session.get("username", ""),
                    "host.created", entity_type="host", entity_id=host.name,
                    detail={"address": host.address})
    return redirect(url_for("hosts.list_hosts"))


@hosts_bp.get("/<host_id>/edit")
@require_role(UserRole.operator)
async def edit_host(host_id: str):
    async with current_app.db_sessionmaker() as db:
        result = await db.execute(select(Host).where(Host.id == host_id))
        host = result.scalar_one_or_none()
    if host is None:
        return "Not found", 404
    return await render_template("hosts/form.html", host=host, probe_types=list(ProbeType))


@hosts_bp.post("/<host_id>")
@require_role(UserRole.operator)
async def update_host(host_id: str):
    form = await request.form
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            result = await db.execute(select(Host).where(Host.id == host_id))
            host = result.scalar_one_or_none()
            if host is None:
                return "Not found", 404
            host.name = form["name"].strip()
            host.address = form["address"].strip()
            host.probe_type = ProbeType(form.get("probe_type", "tcp"))
            host.probe_port = int(form.get("probe_port") or 80)
            host.ping_enabled = "ping_enabled" in form
            host.dns_enabled = "dns_enabled" in form
            host.dns_expected_ip = form.get("dns_expected_ip", "").strip() or None
            # poll_interval_seconds not exposed in UI yet
    return redirect(url_for("hosts.list_hosts"))


@hosts_bp.post("/<host_id>/delete")
@require_role(UserRole.admin)
async def delete_host(host_id: str):
    host_name = None
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            result = await db.execute(select(Host).where(Host.id == host_id))
            host = result.scalar_one_or_none()
            if host:
                host_name = host.name
                await db.delete(host)
    if host_name:
        await log_audit(current_app, session.get("user_id"), session.get("username", ""),
                        "host.deleted", entity_type="host", entity_id=host_name)
    return redirect(url_for("hosts.list_hosts"))


@hosts_bp.get("/uptime")
@require_role(UserRole.viewer)
async def uptime_page():
    async with current_app.db_sessionmaker() as db:
        result = await db.execute(select(Host).order_by(Host.name))
        hosts = result.scalars().all()
        uptime = await _compute_uptime(db)
    return await render_template("hosts/uptime.html", hosts=hosts, uptime=uptime)


@hosts_bp.get("/uptime/widget")
@require_role(UserRole.viewer)
async def uptime_widget():
    share_token = request.args.get("s")
    async with current_app.db_sessionmaker() as db:
        result = await db.execute(
            select(Host).where(Host.ping_enabled.is_(True)).order_by(Host.name)
        )
        hosts = result.scalars().all()
        uptime = await _compute_uptime(db)
    return await render_template(
        "hosts/uptime_widget.html",
        hosts=hosts,
        uptime=uptime,
        share_token=share_token,
    )