<?php

namespace App\Livewire\Wireguard;

use App\Models\AuditEvent;
use App\Services\WgBridge;
use App\Services\WgStatus;
use App\Services\WgTraffic;
use App\Support\Confirm\ConfirmToken;
use App\Support\Confirm\InvalidConfirmToken;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\RateLimiter;
use Livewire\Attributes\Layout;
use Livewire\Attributes\On;
use Livewire\Attributes\Url;
use Livewire\Component;
use Symfony\Component\HttpFoundation\StreamedResponse;

/**
 * WireGuard dashboard — live status (P1) + traffic (P2) + peer management (P3). Reads the
 * host-collected status; mutations go through the host write-bridge (WgBridge), never a shell.
 */
#[Layout('layouts.app')]
class Index extends Component
{
    public const WINDOWS = [3600, 86400, 604800];

    /** Peer-name charset, shared by every app-side validation site (the host re-validates too). */
    private const PEER_NAME_RE = '/^[A-Za-z0-9._-]{1,64}$/';

    public int $window = self::WINDOWS[0];

    /** Active tab when configured: 'peers' (list + traffic) or 'server' (settings). Deep-linkable. */
    #[Url]
    public string $tab = 'peers';

    public string $newPeer = '';

    public string $newEndpoint = '';

    public string $newPort = '';

    public string $newSubnet = '';

    public string $newDns = '';

    // first-time setup form
    public string $setupSubnet = '10.99.0.0/24';

    public string $setupPort = '51820';

    public string $setupEndpoint = '';

    public string $setupPeer = 'client-1';

    /** id of an in-flight write-request we are polling for. */
    public ?string $pendingId = null;

    public ?string $pendingAction = null;

    /** Unix time the current request started polling — used to time out a non-responding host. */
    public ?int $pendingSince = null;

    /** Show-once add-peer result (config text + QR svg). Never persisted. */
    public ?string $resultConfig = null;

    public ?string $resultQr = null;

    /** Peer name of the in-flight request, carried to the result so the download gets a meaningful filename. */
    public ?string $pendingName = null;

    public ?string $resultName = null;

    public function setWindow(int $seconds): void
    {
        $this->window = $this->clampWindow($seconds);
    }

    public function setTab(string $tab): void
    {
        $this->tab = in_array($tab, ['peers', 'server'], true) ? $tab : 'peers';
    }

    public function addPeer(WgBridge $bridge): void
    {
        $this->validate(['newPeer' => ['required', 'regex:'.self::PEER_NAME_RE]], [
            'newPeer.regex' => __('wireguard.peer_name_invalid'),
            'newPeer.required' => __('wireguard.peer_name_invalid'),
        ]);
        if (! $this->throttle()) {
            return;
        }
        $name = $this->newPeer;
        $this->pendingId = $bridge->request('add-peer', ['name' => $name]);
        $this->pendingAction = 'add-peer';
        $this->pendingName = $name;
        $this->newPeer = '';
        $this->audit('wg.add-peer', $name);
    }

    public function setupWg(WgBridge $bridge): void
    {
        $this->validate([
            'setupSubnet' => ['required', 'regex:#^\d{1,3}(\.\d{1,3}){3}/\d{1,2}$#'],
            'setupPort' => ['required', 'regex:/^\d{1,5}$/'],
            'setupEndpoint' => ['nullable', 'regex:/^[A-Za-z0-9.:_-]{1,128}$/'],
            'setupPeer' => ['required', 'regex:'.self::PEER_NAME_RE],
        ], [
            'setupSubnet.regex' => __('wireguard.subnet_invalid'),
            'setupPort.regex' => __('wireguard.port_invalid'),
            'setupEndpoint.regex' => __('wireguard.endpoint_invalid'),
            'setupPeer.regex' => __('wireguard.peer_name_invalid'),
        ]);
        if (! $this->portInRange($this->setupPort)) {
            $this->addError('setupPort', __('wireguard.port_invalid'));

            return;
        }
        if (! $this->throttle()) {
            return;
        }
        $this->pendingId = $bridge->request('setup', [
            'subnet' => $this->setupSubnet, 'port' => $this->setupPort,
            'endpoint' => $this->setupEndpoint, 'name' => $this->setupPeer,
        ]);
        $this->pendingAction = 'setup';
        $this->pendingName = $this->setupPeer;
        $this->audit('wg.setup', $this->setupSubnet);
    }

    /** Opens the wire-elements/modal confirm dialog for peer removal. */
    public function confirmRemovePeer(string $name): void
    {
        if (preg_match(self::PEER_NAME_RE, $name) !== 1) {
            return;
        }

        $this->openConfirm('wgPeerRemoved', ['name' => $name],
            __('wireguard.remove_confirm_title'), __('wireguard.remove_confirm_body'),
            __('wireguard.remove'), danger: true, icon: 'trash');
    }

    /** Apply handler — called after the ConfirmAction modal confirms the removal. */
    #[On('wgPeerRemoved')]
    public function applyRemovePeer(string $confirmToken, WgBridge $bridge): void
    {
        try {
            $payload = ConfirmToken::consume($confirmToken, 'wgPeerRemoved');
        } catch (InvalidConfirmToken) {
            return;
        }

        $name = $payload['params']['name'] ?? '';
        if ($name === '' || preg_match(self::PEER_NAME_RE, $name) !== 1) {
            return;
        }

        $this->removePeer($bridge, $name);
    }

    public function removePeer(WgBridge $bridge, string $name): void
    {
        if (preg_match(self::PEER_NAME_RE, $name) !== 1 || ! $this->throttle()) {
            return;
        }
        $this->pendingId = $bridge->request('remove-peer', ['name' => $name]);
        $this->pendingAction = 'remove-peer';
        $this->audit('wg.remove-peer', $name);
    }

    public function setEndpoint(WgBridge $bridge): void
    {
        $this->validate(['newEndpoint' => ['required', 'regex:/^[A-Za-z0-9.:_-]{1,128}$/']], [
            'newEndpoint.regex' => __('wireguard.endpoint_invalid'),
            'newEndpoint.required' => __('wireguard.endpoint_invalid'),
        ]);
        if (! $this->throttle()) {
            return;
        }
        $this->pendingId = $bridge->request('set-endpoint', ['endpoint' => $this->newEndpoint]);
        $this->pendingAction = 'set-endpoint';
        $this->audit('wg.set-endpoint', $this->newEndpoint);
        $this->newEndpoint = '';
    }

    /** Set the DNS server(s) baked into future peer configs. Non-destructive (no confirm needed). */
    public function setDns(WgBridge $bridge): void
    {
        $this->validate(['newDns' => ['required', 'regex:/^\d{1,3}(\.\d{1,3}){3}([,\s]+\d{1,3}(\.\d{1,3}){3})*$/']], [
            'newDns.regex' => __('wireguard.dns_invalid'),
            'newDns.required' => __('wireguard.dns_invalid'),
        ]);
        if (! $this->throttle()) {
            return;
        }
        $this->pendingId = $bridge->request('set-dns', ['dns' => $this->newDns]);
        $this->pendingAction = 'set-dns';
        $this->audit('wg.set-dns', $this->newDns);
        $this->newDns = '';
    }

    public function confirmGate(bool $on): void
    {
        $this->openConfirm('wgGateToggle', ['on' => $on ? '1' : '0'],
            $on ? __('wireguard.gate_on_title') : __('wireguard.gate_off_title'),
            $on ? __('wireguard.gate_on_body') : __('wireguard.gate_off_body'),
            $on ? __('wireguard.gate_turn_on') : __('wireguard.gate_turn_off'),
            danger: ! $on, icon: 'shield');
    }

    #[On('wgGateToggle')]
    public function applyGateToggle(string $confirmToken, WgBridge $bridge): void
    {
        try {
            $payload = ConfirmToken::consume($confirmToken, 'wgGateToggle');
        } catch (InvalidConfirmToken) {
            return;
        }

        $this->runGate($this->onFlag($payload), $bridge);
    }

    public function runGate(bool $on, ?WgBridge $bridge = null): void
    {
        if (! $this->throttle()) {
            return;
        }
        $bridge ??= app(WgBridge::class);
        $this->pendingId = $bridge->request($on ? 'gate-up' : 'gate-down', []);
        $this->pendingAction = $on ? 'gate-up' : 'gate-down';
        $this->audit($on ? 'wg.gate-up' : 'wg.gate-down', $on ? 'on' : 'off');
    }

    /**
     * The SSH lock (port 22). Turning it ON is the most dangerous action on this page: a user with no
     * surviving WG access locks themselves out of SSH entirely (only the server console / `clusev wg
     * down` recovers it). The confirm body spells that out and recommends a backup peer first.
     */
    public function confirmSshGate(bool $on): void
    {
        $this->openConfirm('wgSshGate', ['on' => $on ? '1' : '0'],
            $on ? __('wireguard.ssh_lock_on_title') : __('wireguard.ssh_lock_off_title'),
            $on ? __('wireguard.ssh_lock_on_body') : __('wireguard.ssh_lock_off_body'),
            $on ? __('wireguard.ssh_lock_turn_on') : __('wireguard.ssh_lock_turn_off'),
            danger: $on, icon: 'alert');
    }

    #[On('wgSshGate')]
    public function applySshGate(string $confirmToken, WgBridge $bridge): void
    {
        try {
            $payload = ConfirmToken::consume($confirmToken, 'wgSshGate');
        } catch (InvalidConfirmToken) {
            return;
        }

        $this->runSshGate($this->onFlag($payload), $bridge);
    }

    public function runSshGate(bool $on, ?WgBridge $bridge = null): void
    {
        if (! $this->throttle()) {
            return;
        }
        $bridge ??= app(WgBridge::class);
        $this->pendingId = $bridge->request($on ? 'gate-ssh-on' : 'gate-ssh-off', []);
        $this->pendingAction = $on ? 'gate-ssh-on' : 'gate-ssh-off';
        $this->audit($on ? 'wg.ssh-lock' : 'wg.ssh-unlock', $on ? 'on' : 'off');
    }

    public function confirmSetPort(): void
    {
        $this->validate(
            ['newPort' => ['required', 'regex:/^\d{1,5}$/']],
            ['newPort.regex' => __('wireguard.port_invalid'), 'newPort.required' => __('wireguard.port_invalid')],
        );
        if (! $this->portInRange($this->newPort)) {
            $this->addError('newPort', __('wireguard.port_invalid'));

            return;
        }

        $this->openConfirm('wgSetPort', ['port' => $this->newPort],
            __('wireguard.port_confirm_title'), __('wireguard.port_confirm_body'),
            __('wireguard.apply'), danger: true, icon: 'alert');
    }

    #[On('wgSetPort')]
    public function applySetPort(string $confirmToken, WgBridge $bridge): void
    {
        try {
            $payload = ConfirmToken::consume($confirmToken, 'wgSetPort');
        } catch (InvalidConfirmToken) {
            return;
        }

        if (! $this->throttle()) {
            return;
        }
        $port = (string) ($payload['params']['port'] ?? '');
        $this->pendingId = $bridge->request('set-port', ['port' => $port]);
        $this->pendingAction = 'set-port';
        $this->audit('wg.set-port', $port);
        $this->newPort = '';
    }

    public function confirmSetSubnet(): void
    {
        $this->validate(
            ['newSubnet' => ['required', 'regex:#^\d{1,3}(\.\d{1,3}){3}/\d{1,2}$#']],
            ['newSubnet.regex' => __('wireguard.subnet_invalid'), 'newSubnet.required' => __('wireguard.subnet_invalid')],
        );

        $this->openConfirm('wgSetSubnet', ['subnet' => $this->newSubnet],
            __('wireguard.subnet_confirm_title'), __('wireguard.subnet_confirm_body'),
            __('wireguard.apply'), danger: true, icon: 'alert');
    }

    #[On('wgSetSubnet')]
    public function applySetSubnet(string $confirmToken, WgBridge $bridge): void
    {
        try {
            $payload = ConfirmToken::consume($confirmToken, 'wgSetSubnet');
        } catch (InvalidConfirmToken) {
            return;
        }

        if (! $this->throttle()) {
            return;
        }
        $subnet = (string) ($payload['params']['subnet'] ?? '');
        $this->pendingId = $bridge->request('set-subnet', ['subnet' => $subnet]);
        $this->pendingAction = 'set-subnet';
        $this->audit('wg.set-subnet', $subnet);
        $this->newSubnet = '';
    }

    public function pollResult(WgBridge $bridge): void
    {
        if ($this->pendingId === null) {
            return;
        }
        $this->pendingSince ??= time();   // first poll after a request — start the clock
        $res = $bridge->result($this->pendingId);
        if ($res === null) {
            // No host response after a while → the host watcher (systemd) likely isn't running yet.
            // Stop spinning forever and tell the operator instead of leaving "Wird angewendet …".
            if (time() - $this->pendingSince > 30) {
                $this->pendingId = null;
                $this->pendingAction = null;
                $this->pendingSince = null;
                $this->dispatch('notify', message: __('wireguard.no_host_response'), level: 'error');
            }

            return;
        }
        $this->pendingId = null;
        $this->pendingSince = null;
        if ($res['ok'] && in_array($this->pendingAction, ['add-peer', 'setup'], true) && $res['config'] !== null) {
            $this->resultConfig = $res['config'];
            $this->resultQr = $res['qr'];
            $this->resultName = $this->pendingName;
        } elseif (! $res['ok']) {
            $msg = ($res['message'] ?? '') !== '' ? $res['message'] : __('wireguard.action_failed');
            // Persist the failure so it's readable later in the audit log, not just a transient toast.
            $this->audit('wg.action-failed', trim(($this->pendingAction ?? '').': '.$msg));
            $this->dispatch('notify', message: $msg, level: 'error');
        } else {
            $this->dispatch('notify', message: __('wireguard.action_done'));
        }
        $this->pendingAction = null;
        $this->pendingName = null;
    }

    public function dismissResult(): void
    {
        $this->resultConfig = null;
        $this->resultQr = null;
        $this->resultName = null;
    }

    /**
     * Download the show-once client config as a .conf file. The filename becomes the tunnel name when
     * imported (WireGuard apps name a tunnel after the file), so build it from the endpoint host + peer
     * name — e.g. "203.0.113.10-laptop.conf". (A QR scan can't carry a name; the app prompts for one.)
     */
    public function downloadConfig(): ?StreamedResponse
    {
        if ($this->resultConfig === null) {
            return null;
        }
        $cfg = $this->resultConfig;

        $host = preg_match('/^Endpoint\s*=\s*([^:\s]+)/m', $cfg, $m) === 1 ? $m[1] : 'clusev';
        $parts = array_filter([$host, (string) $this->resultName]);
        $base = preg_replace('/[^A-Za-z0-9._-]+/', '-', implode('-', $parts));
        $base = trim((string) $base, '-.') ?: 'clusev-wireguard';

        return response()->streamDownload(function () use ($cfg) {
            echo $cfg;
        }, $base.'.conf', ['Content-Type' => 'text/plain; charset=UTF-8']);
    }

    /** Clamp a traffic window to one of the allowed values, falling back to the shortest. */
    private function clampWindow(int $seconds): int
    {
        return in_array($seconds, self::WINDOWS, true) ? $seconds : self::WINDOWS[0];
    }

    /** True when a numeric-string port is within the valid UDP range. */
    private function portInRange(string $port): bool
    {
        return (int) $port >= 1 && (int) $port <= 65535;
    }

    /** Decode the sealed on/off flag a gate-toggle confirm token carries. */
    private function onFlag(array $payload): bool
    {
        return ($payload['params']['on'] ?? '0') === '1';
    }

    /**
     * Open the shared ConfirmAction modal (R5) for one WG action. The issued token carries NO audit
     * descriptor on purpose — each apply handler audits exactly once itself, so auditing here too
     * would double-count. Heading/body/label/danger/icon/params are the only per-action differences.
     *
     * @param  array<string, string>  $params
     */
    private function openConfirm(string $event, array $params, string $heading, string $body, string $confirmLabel, bool $danger, string $icon): void
    {
        $this->dispatch('openModal',
            component: 'modals.confirm-action',
            arguments: [
                'heading' => $heading,
                'body' => $body,
                'confirmLabel' => $confirmLabel,
                'danger' => $danger,
                'icon' => $icon,
                'notify' => '',
                'token' => ConfirmToken::issue($event, $params),
            ],
        );
    }

    private function throttle(): bool
    {
        $key = 'wg-request:'.Auth::id();
        if (RateLimiter::tooManyAttempts($key, 10)) {
            $this->dispatch('notify', message: __('wireguard.throttled'), level: 'error');

            return false;
        }
        RateLimiter::hit($key, 60);

        return true;
    }

    private function audit(string $action, string $target): void
    {
        AuditEvent::create([
            'user_id' => Auth::id(),
            'actor' => Auth::user()?->name ?? 'system',
            'action' => $action,
            'target' => $target,
            'ip' => request()->ip(),
        ]);
    }

    public function render(WgStatus $wg, WgTraffic $traffic)
    {
        $window = $this->clampWindow($this->window);

        return view('livewire.wireguard.index', [
            'status' => $wg->read(),
            'traffic' => $traffic->series($window),
            'windows' => self::WINDOWS,
        ])->title(__('wireguard.title'));
    }
}