<?php

declare(strict_types=1);

namespace App\Modules\Clients;

use App\Models\User;
use App\Modules\Audit\Action;
use App\Modules\Audit\ActivityLogger;
use App\Modules\Clients\Notifications\AdminClientRegisteredNotification;
use App\Modules\Groups\Models\Group;
use App\Modules\Identity\AuthSource;
use App\Modules\Identity\Models\Role;
use App\Modules\Identity\Permissions\SystemRole;
use App\Modules\Identity\Permissions\Permission;
use App\Modules\Identity\Permissions\PermissionChecker;
use App\Modules\Identity\UserType;
use App\Modules\Notifications\Notifier;
use App\Modules\Platform\Seats\SeatAllowance;
use App\Modules\Platform\Settings\Setting;
use App\Modules\Platform\Settings\Settings;
use Illuminate\Support\Facades\Notification;

/**
 * A client account coming into existence without a staff member creating
 * it by hand.
 *
 * Two entry points now reach this — the public registration form and a
 * first successful LDAP sign-in — and they must agree on the parts that
 * are policy rather than presentation: whether the account is active or
 * waits for approval, which group it joins, and who gets told. Keeping one
 * definition is the same reasoning FileSharing and StoreUploadedFile
 * already follow.
 *
 * What stays with each caller is what genuinely differs: the registration
 * form's custom fields and group requests, and LDAP's directory stamp.
 */
class ClientProvisioning
{
    public function __construct(
        private readonly Settings $settings,
        private readonly ActivityLogger $activity,
        private readonly SeatAllowance $seats,
        private readonly Notifier $notifier,
        private readonly PermissionChecker $permissions,
    ) {}

    /**
     * Whether a newly provisioned client can sign in straight away.
     */
    public function autoApproves(): bool
    {
        return $this->settings->get(Setting::ClientsAutoApprove) === true;
    }

    /**
     * Whether an address is free for a new account.
     *
     * The unique index on `email` spans soft-deleted rows — AvailableEmailRule
     * is built on exactly that, so a deleted account keeps its address until
     * erasure takes the row away. The registration form learns this from
     * validation. The machine paths have no form to validate: a directory or
     * an identity provider hands over an address and provision() inserts it,
     * so without asking first the insert raises a QueryException in the
     * middle of somebody's sign-in.
     */
    public function addressIsFree(string $email): bool
    {
        return ! User::withTrashed()->where('email', $email)->exists();
    }

    /**
     * @param  bool|null  $autoApprove  Null asks Setting::ClientsAutoApprove,
     *                                  which is the right question for the
     *                                  public registration form. A caller
     *                                  that has already established who
     *                                  somebody is — LDAP, an identity
     *                                  provider — passes its own answer
     *                                  instead.
     * @param  array<string, mixed>  $context  Placeholders for the action's
     *                                         log template, e.g. which
     *                                         provider an account came from.
     * @param  int  $storageQuotaMb  0 means no per-account quota and
     *                               inherits the site default at
     *                               enforcement time — see
     *                               ClientStorageUsage::quotaMb(). Same
     *                               meaning as ClientAccounts::create()'s
     *                               parameter of the same name; a caller
     *                               with no quota to offer (the public
     *                               registration form, LDAP) leaves it at 0.
     */
    public function provision(
        string $name,
        string $email,
        string $password,
        Action $action,
        AuthSource $source = AuthSource::Local,
        ?string $ldapDn = null,
        ?bool $autoApprove = null,
        array $context = [],
        int $storageQuotaMb = 0,
    ): User {
        $autoApprove ??= $this->autoApproves();

        // Only when the account arrives already approved. A request that
        // still needs a decision is not yet a client this installation has
        // taken on, and counting one would let a stranger exhaust a paid
        // limit from the registration form — see SeatAllowance. The guard
        // for those sits on approval instead.
        if ($autoApprove) {
            $this->seats->guardClient();
        }

        $client = User::create([
            'type' => UserType::Client,
            'active' => $autoApprove,
            'account_requested' => ! $autoApprove,
            'role_id' => Role::query()->where('name', SystemRole::Client->value)->value('id'),
            'name' => $name,
            'email' => $email,
            'password' => $password,
            'storage_quota_mb' => $storageQuotaMb,
        ]);

        // Not mass-assignable: where an account's credentials live is a
        // security decision, not an attribute a form may set.
        if ($source !== AuthSource::Local || $ldapDn !== null) {
            $client->forceFill([
                'auth_source' => $source,
                'ldap_dn' => $ldapDn,
                'ldap_synced_at' => $ldapDn === null ? null : now(),
            ])->save();
        }

        $this->activity->log($action, $client, $client, $context);

        $this->joinAutoGroup($client);
        $this->notifyAdministrators($client, pending: ! $autoApprove);
        $this->notifyStaffInApp($client);

        return $client;
    }

    /**
     * The group every self-provisioned client joins, if one is configured.
     * Direct membership, no approval — an administrator chose this in
     * settings.
     */
    private function joinAutoGroup(User $client): void
    {
        $autoGroupId = (int) $this->settings->get(Setting::ClientsAutoGroup);

        if ($autoGroupId <= 0) {
            return;
        }

        $group = Group::query()->find($autoGroupId);

        $group?->members()->syncWithoutDetaching([$client->id]);
    }

    /**
     * The bell, for staff who administer clients.
     *
     * Separate from notifyAdministrators() above, and not a replacement for
     * it: that one emails a list of raw addresses an operator typed into a
     * setting, which need not correspond to any account in this
     * installation. This one reaches the people actually signed in, which
     * is the only place an account arriving unannounced was ever going to
     * be noticed.
     *
     * Recipients are resolved here rather than inside Notifier, which
     * authorizes nothing by design — see its security contract. Two rules,
     * and the second is the one worth stating: a client-scoped staff member
     * is not told. Their whole view is the clients assigned to them, and a
     * brand-new account is assigned to nobody, so the notification would
     * link them to a screen they are refused.
     */
    private function notifyStaffInApp(User $client): void
    {
        $recipients = User::query()
            ->where('type', UserType::Staff)
            ->get()
            ->filter(fn (User $staff): bool => ! $staff->isClientScoped()
                && $this->permissions->allows($staff, Permission::ManageClients));

        $this->notifier->send('client_registered', $recipients, subject: $client, data: [
            'clientName' => $client->name,
            'clientEmail' => $client->email,
        ]);
    }

    private function notifyAdministrators(User $client, bool $pending): void
    {
        if ($this->settings->get(Setting::EmailNotificationsEnabled) !== true) {
            return;
        }

        $addresses = $this->settings->get(Setting::AdminNotificationEmails);

        foreach (is_array($addresses) ? $addresses : [] as $address) {
            Notification::route('mail', $address)->notify(
                new AdminClientRegisteredNotification($client->name, $client->email, $pending)
            );
        }
    }
}