from __future__ import annotations
import asyncio
import uuid
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.ansible import executor, sources as ansible_src
from steward.auth.middleware import require_role
from steward.core.audit import log_audit
from steward.models.ansible import AnsibleRun, AnsibleRunStatus
from steward.models.hosts import Host
from steward.models.monitors import Monitor, MonitorResult
from steward.models.users import UserRole
from steward.core.status import _last_n_results, _uptime_by_monitor, _heartbeat_title

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


def _ansible_source_names() -> list[str]:
    try:
        return [s["name"] for s in ansible_src.get_sources(current_app.config.get("ANSIBLE", {}))]
    except Exception:
        return []


async def _compute_uptime(db) -> dict[str, dict]:
    """Per-host uptime % for 24h/7d/30d, aggregated over the host's monitors.

    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(
            Monitor.host_id,
            func.count(MonitorResult.id).label("total_30d"),
            func.sum(case((MonitorResult.is_up.is_(True), 1), else_=0)).label("up_30d"),
            func.sum(case((MonitorResult.checked_at >= cutoff_7d, 1), else_=0)).label("total_7d"),
            func.sum(case(
                (and_(MonitorResult.checked_at >= cutoff_7d, MonitorResult.is_up.is_(True)), 1),
                else_=0,
            )).label("up_7d"),
            func.sum(case((MonitorResult.checked_at >= cutoff_24h, 1), else_=0)).label("total_24h"),
            func.sum(case(
                (and_(MonitorResult.checked_at >= cutoff_24h, MonitorResult.is_up.is_(True)), 1),
                else_=0,
            )).label("up_24h"),
        )
        .join(Monitor, Monitor.id == MonitorResult.monitor_id)
        .where(Monitor.host_id.isnot(None), MonitorResult.checked_at >= cutoff_30d)
        .group_by(Monitor.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


async def _host_status(db, host_ids: list[str]) -> dict[str, dict]:
    """Per-host status rollup from the latest result of each linked monitor.

    {host_id: {"state": "up"|"down"|"pending", "latency_ms": float|None,
               "count": int}}. State is down if ANY linked monitor's latest
    result is down (worst-case), up if at least one is up, else pending.
    """
    if not host_ids:
        return {}
    rn = func.row_number().over(
        partition_by=MonitorResult.monitor_id, order_by=MonitorResult.checked_at.desc()
    ).label("rn")
    subq = (
        select(MonitorResult.id, rn)
        .join(Monitor, Monitor.id == MonitorResult.monitor_id)
        .where(Monitor.host_id.in_(host_ids), Monitor.enabled.is_(True))
        .subquery()
    )
    rows = (await db.execute(
        select(MonitorResult, Monitor.host_id)
        .join(subq, MonitorResult.id == subq.c.id)
        .join(Monitor, Monitor.id == MonitorResult.monitor_id)
        .where(subq.c.rn == 1)
    )).all()
    out: dict[str, dict] = {}
    for res, host_id in rows:
        d = out.setdefault(host_id, {"state": "pending", "latency_ms": None, "count": 0})
        d["count"] += 1
        if not res.is_up:
            d["state"] = "down"
        elif d["state"] != "down":
            d["state"] = "up"
        if res.is_up and res.response_ms is not None:
            d["latency_ms"] = (res.response_ms if d["latency_ms"] is None
                               else min(d["latency_ms"], res.response_ms))
    return out


async def _host_monitors(db, host_id: str) -> list[dict]:
    """Display rows for the monitors linked to one host (host hub section)."""
    monitors = (await db.execute(
        select(Monitor).where(Monitor.host_id == host_id).order_by(Monitor.name)
    )).scalars().all()
    ids = [m.id for m in monitors]
    recent = await _last_n_results(db, ids)
    uptime = await _uptime_by_monitor(db, ids)
    data = []
    for m in monitors:
        mrows = recent.get(m.id, [])
        latest = mrows[-1] if mrows else None
        data.append({
            "monitor": m, "latest": latest,
            "heartbeat": [{"state": "up" if r.is_up else "down",
                           "title": _heartbeat_title(m.type, r)} for r in mrows],
            "uptime_pct": uptime.get(m.id, {}).get("24h"),
        })
    return data


async def _agent_metrics_by_host(db, host_names: list[str]) -> dict[str, dict]:
    """Latest agent cpu/mem per host name from the generic PluginMetric table.

    Read directly (PluginMetric is a core model) so the Hosts list can show an
    at-a-glance agent column without importing the host_agent plugin.
    """
    from steward.models.metrics import PluginMetric
    if not host_names:
        return {}
    wanted = ("cpu_pct", "mem_used_pct")
    subq = (
        select(
            PluginMetric.resource_name, PluginMetric.metric_name,
            func.max(PluginMetric.recorded_at).label("m"),
        )
        .where(
            PluginMetric.source_module == "host_agent",
            PluginMetric.metric_name.in_(wanted),
            PluginMetric.resource_name.in_(host_names),
        )
        .group_by(PluginMetric.resource_name, PluginMetric.metric_name)
    ).subquery()
    rows = (await db.execute(
        select(PluginMetric).join(
            subq,
            (PluginMetric.resource_name == subq.c.resource_name)
            & (PluginMetric.metric_name == subq.c.metric_name)
            & (PluginMetric.recorded_at == subq.c.m),
        )
    )).scalars().all()
    out: dict[str, dict] = {}
    for r in rows:
        out.setdefault(r.resource_name, {})[r.metric_name] = r.value
    return out


async def _agent_overview_by_host(db, host_names: list[str]) -> dict[str, dict]:
    """Per-host agent glance (cpu/mem/root-disk + freshness) from PluginMetric.

    Core-safe (no host_agent import). Freshness compares the latest host-level
    sample against the plugin's stale window (config), defaulting to 180s.
    """
    from steward.models.metrics import PluginMetric
    if not host_names:
        return {}
    now = datetime.now(timezone.utc)
    stale_after = int(
        (current_app.config.get("PLUGINS", {}).get("host_agent", {}) or {})
        .get("stale_after_seconds", 180))
    resources = list(host_names) + [h + ":/" for h in host_names]
    subq = (
        select(
            PluginMetric.resource_name, PluginMetric.metric_name,
            func.max(PluginMetric.recorded_at).label("m"),
        )
        .where(
            PluginMetric.source_module == "host_agent",
            PluginMetric.resource_name.in_(resources),
            PluginMetric.metric_name.in_(("cpu_pct", "mem_used_pct", "disk_used_pct")),
        )
        .group_by(PluginMetric.resource_name, PluginMetric.metric_name)
    ).subquery()
    rows = (await db.execute(
        select(PluginMetric).join(
            subq,
            (PluginMetric.resource_name == subq.c.resource_name)
            & (PluginMetric.metric_name == subq.c.metric_name)
            & (PluginMetric.recorded_at == subq.c.m),
        ).where(PluginMetric.source_module == "host_agent")
    )).scalars().all()
    out: dict[str, dict] = {}
    for r in rows:
        if r.resource_name.endswith(":/") and r.metric_name == "disk_used_pct":
            out.setdefault(r.resource_name[:-2], {})["disk_root"] = r.value
        elif r.resource_name in host_names:
            d = out.setdefault(r.resource_name, {})
            d[r.metric_name] = r.value
            if d.get("_ts") is None or r.recorded_at > d["_ts"]:
                d["_ts"] = r.recorded_at
    for d in out.values():
        ts = d.pop("_ts", None)
        d["fresh"] = bool(ts and (now - ts).total_seconds() <= stale_after)
    return out


async def _agent_cpu_sparks_by_host(db, host_names: list[str], hours: int = 1) -> dict[str, str]:
    """{host_name: inline-SVG cpu sparkline} over the last `hours` (core-safe).

    A tiny at-a-glance trend in each row — the host-view sparkline, on the widget.
    """
    from steward.models.metrics import PluginMetric
    from steward.core.status import sparkline_svg
    if not host_names:
        return {}
    cutoff = datetime.now(timezone.utc) - timedelta(hours=hours)
    rows = (await db.execute(
        select(PluginMetric.resource_name, PluginMetric.value, PluginMetric.recorded_at)
        .where(
            PluginMetric.source_module == "host_agent",
            PluginMetric.metric_name == "cpu_pct",
            PluginMetric.resource_name.in_(host_names),
            PluginMetric.recorded_at >= cutoff,
        )
        .order_by(PluginMetric.recorded_at)
    )).all()
    by_host: dict[str, list[float]] = {}
    for r in rows:
        by_host.setdefault(r.resource_name, []).append(r.value)
    # Amber line to read as "CPU"; only draw when there are a couple of points.
    return {
        name: sparkline_svg(vals[-40:], width=64, height=18, stroke="#c8a840")
        for name, vals in by_host.items() if len(vals) >= 2
    }


@hosts_bp.get("/overview/widget")
@require_role(UserRole.viewer)
async def overview_widget():
    """Dashboard widget: unified per-host monitor + agent glance, linking to the hub."""
    async with current_app.db_sessionmaker() as db:
        hosts = (await db.execute(select(Host).order_by(Host.name))).scalars().all()
        host_status = await _host_status(db, [h.id for h in hosts])
        uptime = await _compute_uptime(db)
        host_names = [h.name for h in hosts]
        agent = await _agent_overview_by_host(db, host_names)
        cpu_sparks = await _agent_cpu_sparks_by_host(db, host_names)

    return await render_template(
        "hosts/overview_widget.html",
        hosts=hosts, host_status=host_status,
        uptime=uptime, agent=agent, cpu_sparks=cpu_sparks,
    )


@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()
        host_status = await _host_status(db, [h.id for h in hosts])
        uptime = await _compute_uptime(db)
        agent_metrics = await _agent_metrics_by_host(db, [h.name for h in hosts])

    return await render_template(
        "hosts/list.html",
        hosts=hosts,
        host_status=host_status,
        uptime=uptime,
        agent_metrics=agent_metrics,
    )


@hosts_bp.get("/<host_id>")
@require_role(UserRole.viewer)
async def host_detail(host_id: str):
    """The host hub: monitors + agent (embedded fragment) + Ansible, one view."""
    from steward.models.ansible_inventory import AnsibleTarget
    from sqlalchemy.orm import selectinload

    async with current_app.db_sessionmaker() as db:
        host = (await db.execute(
            select(Host).where(Host.id == host_id))).scalar_one_or_none()
        if host is None:
            return "Not found", 404
        monitors = await _host_monitors(db, host_id)
        uptime = (await _compute_uptime(db)).get(host_id)
        linked_target = (await db.execute(
            select(AnsibleTarget).where(AnsibleTarget.host_id == host_id)
            .options(selectinload(AnsibleTarget.groups)))).scalar_one_or_none()
        linkable_targets = (await db.execute(
            select(AnsibleTarget).where(AnsibleTarget.host_id.is_(None))
            .order_by(AnsibleTarget.name))).scalars().all()

    from steward.models.monitors import MonitorType
    return await render_template(
        "hosts/detail.html",
        host=host, monitors=monitors, uptime=uptime,
        monitor_types=list(MonitorType),
        linked_target=linked_target, linkable_targets=linkable_targets,
        ansible_sources=_ansible_source_names(),
    )


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


@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(),
    )
    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})
    # Land on the new host's hub so monitors/agent/ansible can be set up next.
    return redirect(url_for("hosts.host_detail", host_id=host.id))


@hosts_bp.get("/<host_id>/edit")
@require_role(UserRole.operator)
async def edit_host(host_id: str):
    # Pure host config (name/address/monitors). Agent, Ansible target linking,
    # and playbook runs live on the host detail page (the hub), not here.
    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)


@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()
    return redirect(url_for("hosts.host_detail", host_id=host_id))


@hosts_bp.post("/<host_id>/ansible-link")
@require_role(UserRole.operator)
async def ansible_link(host_id: str):
    """Link, unlink, or create an AnsibleTarget from this host."""
    from steward.models.ansible_inventory import AnsibleTarget

    form = await request.form
    action = form.get("action", "")

    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            if action == "unlink":
                linked_result = await db.execute(
                    select(AnsibleTarget).where(AnsibleTarget.host_id == host_id)
                )
                linked = linked_result.scalar_one_or_none()
                if linked:
                    linked.host_id = None

            elif action == "link":
                target_id = form.get("target_id", "").strip()
                if target_id:
                    result = await db.execute(
                        select(AnsibleTarget).where(AnsibleTarget.id == target_id)
                    )
                    target = result.scalar_one_or_none()
                    if target:
                        # Clear any previous link for this host first
                        old_result = await db.execute(
                            select(AnsibleTarget).where(AnsibleTarget.host_id == host_id)
                        )
                        old = old_result.scalar_one_or_none()
                        if old and old.id != target_id:
                            old.host_id = None
                        target.host_id = host_id

            elif action == "create":
                host_result = await db.execute(select(Host).where(Host.id == host_id))
                host = host_result.scalar_one_or_none()
                if host:
                    new_target = AnsibleTarget(
                        id=str(uuid.uuid4()),
                        name=host.name,
                        address=host.address,
                        host_id=host_id,
                    )
                    db.add(new_target)

    return redirect(f"/hosts/{host_id}")


@hosts_bp.post("/<host_id>/run-playbook")
@require_role(UserRole.operator)
async def run_playbook(host_id: str):
    """Run an Ansible playbook against just this host (ephemeral one-host inventory)."""
    form = await request.form
    async with current_app.db_sessionmaker() as db:
        host = (await db.execute(select(Host).where(Host.id == host_id))).scalar_one_or_none()
    if host is None:
        return "Not found", 404

    source_name = (form.get("source_name", "") or "").strip()
    playbook = (form.get("playbook_path", "") or "").strip()
    if not source_name or not playbook:
        return "source and playbook are required", 400
    try:
        srcs = ansible_src.get_sources(current_app.config.get("ANSIBLE", {}))
    except Exception:
        return "Ansible sources are misconfigured", 400
    source = next((s for s in srcs if s["name"] == source_name), None)
    if source is None:
        return "Source not found", 404
    if playbook not in ansible_src.discover_playbooks(source["path"]):
        return f"Playbook '{playbook}' not found in source '{source_name}'", 404

    # Shared parser: discovered var__ fields → extra_vars_map, secret__ → secret_vars
    # (unpersisted), plus tags/check. No --limit — there's exactly one host.
    from steward.ansible.routes import _parse_run_params
    params_or_none, secret_vars, err = _parse_run_params(form)
    if err:
        return err, 400

    run_id = str(uuid.uuid4())
    inv_content = ansible_src.host_inventory_content(host)
    run = AnsibleRun(
        id=run_id,
        playbook_path=playbook,
        inventory_path=f"host: {host.name}",
        source_name=source_name,
        triggered_by=session.get("user_id"),
        status=AnsibleRunStatus.running,
        params=params_or_none,
    )
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            db.add(run)

    task = asyncio.create_task(
        executor.start_run(
            current_app._get_current_object(),  # type: ignore[attr-defined]
            run_id, playbook, f"host: {host.name}", source["path"],
            params_or_none, inv_content, secret_vars=secret_vars,
        )
    )
    task.add_done_callback(
        lambda t: t.exception() and current_app.logger.error(
            "Host playbook run %s raised: %s", run_id, t.exception()))

    await log_audit(current_app, session.get("user_id"), session.get("username", ""),
                    "ansible.host_run", entity_type="host", entity_id=host.name,
                    detail={"playbook": playbook, "source": source_name})
    return redirect(url_for("ansible.run_detail", run_id=run_id))


@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).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,
    )