"""Aggregate status handler.

Exposes pending changes across all subsystems, a single apply-all
endpoint that invokes each subsystem's apply in the correct order, and a
cancel-all endpoint that reverts pending edits to the last applied config.
"""

from __future__ import annotations

import logging
from pathlib import Path
from typing import Any

from daemon.handlers import dnsmasq as _dnsmasq_h
from daemon.handlers import firewall as _firewall_h
from daemon.handlers import nginx as _nginx_h
from daemon.handlers.dnsmasq import apply_config as dnsmasq_apply_config
from daemon.handlers.firewall import config_apply as firewall_config_apply
from daemon.handlers.network import apply_all as network_apply_all
from daemon.handlers.nginx import apply as nginx_apply
from daemon.handlers.wireguard import apply as wireguard_apply
from daemon.iface import (
    GET_STATUS_PENDING,
    POST_STATUS_APPLY_ALL,
    POST_STATUS_CANCEL_ALL,
)
from daemon.server import refresh_state, registry
from lib import network as _net
from lib import wireguard as _wg
from lib.common import revert_to_applied
from lib.firewall import fw_change_summary
from lib.state import state as state_store

logger = logging.getLogger(__name__)

SYS_ORDER = ["networkd", "firewall", "wireguard", "dnsmasq", "nginx"]
SYS_LABELS = {
    "networkd": "Network",
    "firewall": "Firewall",
    "wireguard": "WireGuard",
    "dnsmasq": "DHCP/DNS",
    "nginx": "Nginx",
}
SYS_APPLY = {
    "networkd": network_apply_all,
    "firewall": firewall_config_apply,
    "wireguard": wireguard_apply,
    "dnsmasq": dnsmasq_apply_config,
    "nginx": nginx_apply,
}
# (module, attribute) pairs for each subsystem's on-disk config path.
# Resolved at call time so tests can monkeypatch the module constants.
SYS_CONFIG_PATHS: dict[str, tuple[Any, str]] = {
    "firewall": (_firewall_h, "CONFIG_FILE"),
    "dnsmasq": (_dnsmasq_h, "CONFIG_PATH"),
    "nginx": (_nginx_h, "CONFIG_FILE"),
    "wireguard": (_wg, "CONFIG_PATH"),
    "networkd": (_net, "CONFIG_FILE"),
}


@registry.register(GET_STATUS_PENDING)
def status_pending(_request: Any, _body: Any) -> dict[str, Any]:
    """Aggregate pending changes across all subsystems.

    Returns:
        Dict with per-subsystem pending status and total change count.
    """
    fw = state_store.get("firewall") or {}
    pending_fw = fw.get("pending", {})
    fw_needs_apply = pending_fw.get("needs_apply", False)
    fw_pending_list = pending_fw.get("pending", [])

    fw_changes = []
    for c in fw_pending_list:
        zone = c.get("zone", "unknown")
        ctype = c.get("type", "unknown")
        summary = fw_change_summary(zone, ctype, c)
        fw_changes.append({"summary": summary, "detail": ""})

    fw_result = {
        "needs_apply": fw_needs_apply,
        "change_count": len(fw_changes),
        "changes": fw_changes,
    }

    hash_subsystems = {
        "dnsmasq": _hash_subsystem("dnsmasq", state_store.get("dnsmasq")),
        "nginx": _hash_subsystem("nginx", state_store.get("nginx")),
        "wireguard": _hash_subsystem("wireguard", state_store.get("wireguard")),
        "networkd": _hash_subsystem("networkd", state_store.get("networkd")),
    }

    total = len(fw_changes)
    for _name, result in hash_subsystems.items():
        total += len(result["changes"])

    return {
        "firewall": fw_result,
        "dnsmasq": hash_subsystems["dnsmasq"],
        "nginx": hash_subsystems["nginx"],
        "wireguard": hash_subsystems["wireguard"],
        "networkd": hash_subsystems["networkd"],
        "total_changes": total,
    }


@registry.register(POST_STATUS_APPLY_ALL)
def status_apply_all(_request: Any, _body: Any) -> dict[str, Any]:
    """Apply pending changes for all subsystems in dependency order.

    Order: network -> firewall -> wireguard -> dnsmasq -> nginx.

    Returns:
        Dict with applied subsystems and any errors encountered.
    """
    applied = []
    errors = {}

    pending_data = status_pending(None, None)
    fw_pending = pending_data["firewall"]["needs_apply"]
    hash_pending = {
        "dnsmasq": pending_data["dnsmasq"]["pending_changes"],
        "nginx": pending_data["nginx"]["pending_changes"],
        "wireguard": pending_data["wireguard"]["pending_changes"],
        "networkd": pending_data["networkd"]["pending_changes"],
    }

    for name in SYS_ORDER:
        if name == "firewall":
            if not fw_pending:
                continue
        else:
            if not hash_pending.get(name, False):
                continue

        handler = SYS_APPLY[name]
        try:
            handler(None, None)
            applied.append(name)
        except Exception as exc:
            label = SYS_LABELS.get(name, name)
            errors[label] = str(exc)
            logger.error("Apply-all failed for %s: %s", name, exc)

    refresh_state(SYS_ORDER)
    return {"applied": applied, "errors": errors}


def _config_path(name: str) -> Path:
    """Return the on-disk config path for subsystem *name*.

    Resolved via the owning module at call time so tests can monkeypatch
    the module constants (e.g. ``lib.wireguard.CONFIG_PATH``).
    """
    module, attr = SYS_CONFIG_PATHS[name]
    return getattr(module, attr)


@registry.register(POST_STATUS_CANCEL_ALL)
def status_cancel_all(_request: Any, _body: Any) -> dict[str, Any]:
    """Revert pending changes for all subsystems to the last applied config.

    Restores each pending subsystem's config file from its recorded
    ``_last_applied_config`` snapshot, discarding unapplied edits.
    Subsystems without a recorded baseline (never applied) are skipped
    with a reason instead of being reset. No live-system commands run —
    cancel only touches the declarative config files.

    Returns:
        Dict with ``cancelled`` (list of reverted subsystems),
        ``skipped`` (label -> reason), and ``errors`` (label -> message).
    """
    pending_data = status_pending(None, None)
    fw_pending = pending_data["firewall"]["needs_apply"]
    hash_pending = {
        "dnsmasq": pending_data["dnsmasq"]["pending_changes"],
        "nginx": pending_data["nginx"]["pending_changes"],
        "wireguard": pending_data["wireguard"]["pending_changes"],
        "networkd": pending_data["networkd"]["pending_changes"],
    }

    cancelled: list[str] = []
    skipped: dict[str, str] = {}
    errors: dict[str, str] = {}

    for name in SYS_ORDER:
        pending = fw_pending if name == "firewall" else hash_pending.get(name, False)
        if not pending:
            continue
        label = SYS_LABELS.get(name, name)
        try:
            ok, reason = revert_to_applied(_config_path(name))
            if ok:
                cancelled.append(name)
                logger.info("Cancelled pending changes for %s", name)
            else:
                skipped[label] = reason
                logger.warning("Cancel-all skipped %s: %s", label, reason)
        except Exception as exc:
            errors[label] = str(exc)
            logger.error("Cancel-all failed for %s: %s", name, exc)

    if cancelled:
        refresh_state(SYS_ORDER)
    return {"cancelled": cancelled, "skipped": skipped, "errors": errors}


def _hash_subsystem(name: str, state: dict[str, Any] | None) -> dict[str, Any]:
    """Build pending result for a hash-based subsystem."""
    if state is None:
        return {"pending_changes": False, "summary": "Up to date", "changes": []}

    status = state.get("status", {})
    pending = status.get("pending_changes", False)
    label = SYS_LABELS.get(name, name)

    if pending:
        summary = f"{label} configuration has unapplied changes"
        return {
            "pending_changes": True,
            "summary": summary,
            "changes": [{"summary": summary, "detail": ""}],
        }

    return {"pending_changes": False, "summary": "Up to date", "changes": []}