<?php

namespace App\Actions\Admin;

use App\Models\User;
use Illuminate\Auth\Access\AuthorizationException;
use Illuminate\Support\Facades\Auth;

class UserImpersonation
{
    public const SessionKey = 'impersonate_from';

    public function canInitiate(User $user): bool
    {
        return $user->is_super_admin || $user->can('users:manage');
    }

    public function canStart(User $admin, User $target): bool
    {
        return $this->canInitiate($admin)
            && ! $admin->is($target)
            && ! $this->isActive()
            && $this->canBeImpersonated($target);
    }

    public function canBeImpersonated(User $target): bool
    {
        return $target->canAccessCustomer();
    }

    /**
     * @throws AuthorizationException
     */
    public function start(User $admin, User $target): void
    {
        if (! $this->canInitiate($admin)) {
            throw new AuthorizationException(__('Du darfst keine Benutzer-Impersonation starten.'));
        }

        if ($admin->is($target)) {
            return;
        }

        if ($this->isActive()) {
            throw new AuthorizationException(__('Verschachtelte Benutzer-Impersonation ist nicht erlaubt.'));
        }

        if (! $this->canBeImpersonated($target)) {
            throw new AuthorizationException(__('Dieser Benutzer kann nicht im Panel angemeldet werden.'));
        }

        session([self::SessionKey => $admin->getKey()]);

        Auth::login($target);
    }

    public function stop(): ?User
    {
        $adminUserId = session(self::SessionKey);

        session()->forget(self::SessionKey);

        if (! is_numeric($adminUserId)) {
            return null;
        }

        $admin = User::query()->find((int) $adminUserId);

        if (! $admin?->canAccessAdmin()) {
            return null;
        }

        Auth::login($admin);

        return $admin;
    }

    public function isActive(): bool
    {
        return session()->has(self::SessionKey);
    }

    public function impersonator(): ?User
    {
        $adminUserId = session(self::SessionKey);

        if (! is_numeric($adminUserId)) {
            return null;
        }

        return User::query()->find((int) $adminUserId);
    }
}