<?php

declare(strict_types=1);

namespace App\Modules\Platform\Installation\Console;

use App\Modules\Audit\Action;
use App\Modules\Audit\ActivityLog;
use App\Modules\Identity\UserType;
use App\Modules\Platform\Capabilities\CapabilityRegistry;
use App\Modules\Platform\Seats\SeatAllowance;
use Illuminate\Console\Command;
use Illuminate\Support\Carbon;

/**
 * What this installation is, as a fact rather than a screen.
 *
 * Written for whatever watches a managed installation from outside the
 * container. Everything here is already visible to any signed-in
 * administrator — a version, an edition, which capabilities the edition
 * grants, how many accounts exist against how many are allowed. Nothing
 * is a secret and nothing is a credential.
 *
 * ### Why a command and not a shell one-liner
 *
 * A reconciler that observes tenants has to be able to say it never sends
 * instructions, only reads state. `docker exec … php -r '…'` is an
 * instruction with the caller's argv in it, however harmless the argv;
 * a named command is an observation, the same kind of thing as reading a
 * directory size. The distinction is the whole reason this exists rather
 * than a documented incantation.
 *
 * ### The counts are the enforcing code's own
 *
 * `used` comes from SeatAllowance, which is what refuses the account past
 * the limit. Two counts that merely agree will diverge eventually — over
 * an inactive account, or a soft-deleted one — and the divergence looks
 * like a billing fault rather than a counting one. So there is one
 * definition and this reads it.
 *
 * ### Is anybody there
 *
 * `activity.last_staff_login_at` answers the one question a platform
 * cannot answer from outside: whether a human still uses this
 * installation. It is a timestamp and nothing else — no name, no address,
 * no session. Only interactive sign-ins reach it, because that is all
 * Laravel's Login event fires for: an integration polling the API every
 * hour must not make a dormant installation look busy.
 *
 * Derived from the activity log rather than denormalised onto `users`. A
 * column would need a migration, a listener change and a backfill to save
 * one indexed MAX() over a table that is small on exactly the
 * installations anybody asks this about. The log is never pruned, and
 * erasure anonymises entries rather than deleting them (`actor_type`
 * survives on purpose — see AccountEraser), so the answer does not change
 * when the person who gave it is forgotten.
 */
class StatusCommand extends Command
{
    protected $signature = 'projectsend:status {--json : Emit machine-readable JSON on stdout}';

    protected $description = 'Report this installation\'s version, edition, capabilities and seat usage';

    public function handle(CapabilityRegistry $capabilities, SeatAllowance $seats): int
    {
        $status = [
            'version' => (string) config('projectsend.version'),
            'edition' => $capabilities->edition()->value,
            'capabilities' => $capabilities->enabledKeys(),
            'seats' => [
                'staff' => [
                    'used' => $seats->staffUsed(),
                    // null is unlimited, and is emitted as null rather than
                    // as 0 or as an absent key: a reader that mistook one
                    // for the other would report an installation selling
                    // unlimited accounts as one that may hold none.
                    'limit' => $seats->staffLimit(),
                ],
                'clients' => [
                    'used' => $seats->clientUsed(),
                    'limit' => $seats->clientLimit(),
                ],
            ],
            'activity' => [
                // Null means "no staff account has ever signed in here",
                // and is emitted rather than left out for the same reason
                // an unlimited seat count is: a watcher has to be able to
                // tell that apart from "we got no answer". Collapsing the
                // two is how a broken probe reads as a dormant fleet.
                'last_staff_login_at' => $this->lastStaffLoginAt(),
            ],
        ];

        if ($this->option('json')) {
            $this->line((string) json_encode($status, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));

            return self::SUCCESS;
        }

        $this->line("ProjectSend {$status['version']} ({$status['edition']})");
        $this->line('Capabilities: '.(implode(', ', $status['capabilities']) ?: 'none'));
        $this->line('Staff seats:  '.$this->seatLine($status['seats']['staff']));
        $this->line('Clients:      '.$this->seatLine($status['seats']['clients']));
        $this->line('Last staff login: '.($status['activity']['last_staff_login_at'] ?? 'never'));

        return self::SUCCESS;
    }

    /**
     * The most recent interactive staff sign-in, or null if there has
     * never been one.
     */
    private function lastStaffLoginAt(): ?string
    {
        $latest = ActivityLog::query()
            ->where('action', Action::Login->value)
            ->where('actor_type', UserType::Staff->value)
            ->max('created_at');

        // `action` and `actor_type` carry an index each, so this narrows
        // on one of them rather than reading the log.
        return $latest === null ? null : Carbon::parse($latest)->toIso8601String();
    }

    /**
     * @param  array{used: int, limit: int|null}  $seat
     */
    private function seatLine(array $seat): string
    {
        return $seat['limit'] === null
            ? "{$seat['used']} of unlimited"
            : "{$seat['used']} of {$seat['limit']}";
    }
}