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, ProbeType
from steward.models.monitors import PingResult, DnsResult, PingStatus
from steward.models.users import UserRole

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]:
    """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("/<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
        ping = (await db.execute(
            select(PingResult).where(PingResult.host_id == host_id)
            .order_by(PingResult.probed_at.desc()).limit(1))).scalar_one_or_none()
        dns = (await db.execute(
            select(DnsResult).where(DnsResult.host_id == host_id)
            .order_by(DnsResult.resolved_at.desc()).limit(1))).scalar_one_or_none()
        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()

    return await render_template(
        "hosts/detail.html",
        host=host, ping=ping, dns=dns, uptime=uptime,
        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, 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):
    from steward.models.ansible_inventory import AnsibleTarget
    from sqlalchemy.orm import selectinload

    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

        linked_result = await db.execute(
            select(AnsibleTarget)
            .where(AnsibleTarget.host_id == host_id)
            .options(selectinload(AnsibleTarget.groups))
        )
        linked_target = linked_result.scalar_one_or_none()

        # Only show targets not yet linked to any host (plus the currently linked one)
        linkable_result = await db.execute(
            select(AnsibleTarget)
            .where(AnsibleTarget.host_id.is_(None))
            .order_by(AnsibleTarget.name)
        )
        linkable_targets = linkable_result.scalars().all()

    return await render_template(
        "hosts/form.html",
        host=host,
        probe_types=list(ProbeType),
        ansible_sources=_ansible_source_names(),
        linked_target=linked_target,
        linkable_targets=linkable_targets,
    )


@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>/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

    # Optional params (no --limit — there's exactly one host).
    extra_vars: list[str] = []
    for line in (form.get("extra_vars", "") or "").splitlines():
        line = line.strip()
        if not line:
            continue
        if "=" not in line:
            return f"Invalid extra var (expected key=value): {line!r}", 400
        extra_vars.append(line)
    params: dict = {}
    if extra_vars:
        params["extra_vars"] = extra_vars
    tags = (form.get("tags", "") or "").strip()
    if tags:
        params["tags"] = tags
    if "check" in form:
        params["check"] = True
    params_or_none = params or None

    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,
        )
    )
    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).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,
    )