from __future__ import annotations
import asyncio
import uuid
from datetime import datetime, timezone
from quart import Blueprint, make_response, render_template, request, redirect, url_for, current_app, session
from sqlalchemy import select
from steward.ansible import executor, sources as ansible_src
from steward.alerts import service as alert_svc
from steward.auth.middleware import require_role
from steward.core import renames
from steward.core.audit import audit_request, log_audit
from steward.models.ansible import AnsibleRun, AnsibleRunStatus
from steward.models.hosts import Host
from steward.models.users import UserRole
from steward.hosts import service as host_svc

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 []


@hosts_bp.get("/overview/widget")
@require_role(UserRole.viewer)
async def overview_widget():
    """Dashboard widget: each host's resources, worst first (#5251). Uptime and
    latency belong to the Monitors widget, so this one doesn't read them."""
    async with current_app.db_sessionmaker() as db:
        hosts = (await db.execute(select(Host).order_by(Host.name))).scalars().all()
        host_status = await host_svc.host_status(db, [h.id for h in hosts])
        agent = await host_svc.agent_overview_by_host(
            db, [h.name for h in hosts], host_svc.agent_stale_after_seconds(current_app.config))
    rows = host_svc.host_glance(hosts, host_status, agent, current_app.config.get("THRESHOLDS", {}))
    return await render_template("hosts/overview_widget.html", rows=rows)


@hosts_bp.get("/")
@require_role(UserRole.viewer)
async def list_hosts():
    # ?add=1 opens the Add host dialog on load (#5291).
    return await _list_page(add={} if request.args.get("add") else None)


async def _list_page(add: dict | None = None):
    """The Hosts list. `add` opens the Add host dialog: {} for an empty form,
    or {"values": form, "error": msg} when a submit comes back.

    Search, group and Status filters and a column sort come from the query
    string (#5294). An HTMX request from the filter bar gets the table alone."""
    args = request.args
    sort = args.get("sort") if args.get("sort") in host_svc.HOST_SORTS else "status"
    default_desc = host_svc.HOST_SORTS[sort]
    desc = {"desc": True, "asc": False}.get(args.get("dir"), default_desc)
    f = {"q": args.get("q", "").strip(), "group": args.get("group", ""),
         "state": args.get("state") if args.get("state") in host_svc.HOST_STATES else "",
         "sort": sort, "dir": "desc" if desc else "asc"}

    async with current_app.db_sessionmaker() as db:
        result = await db.execute(select(Host).order_by(Host.name))
        hosts = result.scalars().all()
        ids = [h.id for h in hosts]
        host_status = await host_svc.host_status(db, ids)
        uptime = await host_svc.compute_uptime(db)
        agent = await host_svc.agent_overview_by_host(
            db, [h.name for h in hosts], host_svc.agent_stale_after_seconds(current_app.config))
        groups = await host_svc.host_groups(db, ids)
        group_names = await host_svc.group_names(db)

    shown = host_svc.filter_hosts(hosts, q=f["q"], group=f["group"], state=f["state"],
                                  status=host_status, agent=agent, groups=groups)
    shown = host_svc.sort_hosts(shown, sort, desc, status=host_status, agent=agent, uptime=uptime)

    def filter_url(**change) -> str:
        """This list's URL with some filters changed; defaults are left out."""
        want = {**f, **change}
        if want["dir"] == ("desc" if host_svc.HOST_SORTS[want["sort"]] else "asc"):
            want["dir"] = ""
        if want["sort"] == "status":
            want["sort"] = ""
        return url_for("hosts.list_hosts", **{k: v for k, v in want.items() if v})

    def sort_url(key: str) -> str:
        """A column header's link: its own default direction, or the other
        way when it is already the sort."""
        if key == sort:
            return filter_url(sort=key, dir="asc" if desc else "desc")
        return filter_url(sort=key, dir="desc" if host_svc.HOST_SORTS[key] else "asc")

    ctx = dict(hosts=shown, total=len(hosts), host_status=host_status, uptime=uptime, agent=agent,
               groups=groups, group_names=group_names, f=f, filter_url=filter_url, sort_url=sort_url,
               states=host_svc.HOST_STATES, no_group=host_svc.NO_GROUP, add=add)
    # The filter bar's swap gets the table alone. A history restore (Back to a
    # pushed URL) is an HTMX request too but wants the page, so key on the
    # target; Vary keeps the browser from caching one as the other.
    partial = request.headers.get("HX-Target") == "hosts-table" \
        and not request.headers.get("HX-History-Restore-Request")
    resp = await make_response(await render_template(
        "hosts/_table.html" if partial else "hosts/list.html", **ctx))
    resp.vary.add("HX-Request")
    return resp


@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_svc.host_monitors(db, host_id)
        uptime = (await host_svc.compute_uptime(db)).get(host_id)
        monitor_keys = {(getattr(d["monitor"].type, "value", d["monitor"].type), d["monitor"].name)
                        for d in monitors}
        alerts = [r for r in await alert_svc.active_rows(db, datetime.now(timezone.utc))
                  if alert_svc.watches_host(r["rule"], host.name, monitor_keys)]
        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, monitors=monitors, uptime=uptime, alerts=alerts,
        linked_target=linked_target, linkable_targets=linkable_targets,
        ansible_sources=_ansible_source_names(),
    )


@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():
            try:
                await host_svc.check_name_free(db, host.name)
            except ValueError as exc:
                return await _list_page(add={"values": form, "error": str(exc)}), 400
            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
            old_name, name = host.name, form["name"].strip()
            if name != old_name:
                try:
                    await host_svc.check_name_free(db, name, exclude_id=host.id)
                except ValueError as exc:
                    return await render_template("hosts/form.html", host=host, values=form,
                                                 error=str(exc)), 400
            host.name = name
            host.address = form["address"].strip()
            # Agent and container metrics, and the rules and windows on them,
            # go by the host's name: move them with it.
            moved = await renames.carry_rename(db, renames.HOST_SOURCES, old_name, name)
    if moved:
        await audit_request("host.renamed", "host", name,
                            {"host_id": host_id, "renamed_from": old_name, "carried": moved})
    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, _run_vars, check_run_form
    params_or_none, secret_vars, err = _parse_run_params(form)
    if err:
        return err, 400
    err = check_run_form(form, source, playbook, params_or_none, secret_vars)
    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, "run_id": run_id,
                            "check": bool((params_or_none or {}).get("check")),
                            "vars": sorted(_run_vars(params_or_none, secret_vars))})
    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"))