<?php

namespace BeyondCode\LaravelWebSockets\API;

use BeyondCode\LaravelWebSockets\Channels\Channel;
use Illuminate\Http\Request;
use Illuminate\Support\Str;
use stdClass;
use Symfony\Component\HttpKernel\Exception\HttpException;

class FetchChannels extends Controller
{
    /**
     * Handle the incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Http\Response
     */
    public function __invoke(Request $request)
    {
        $attributes = [];

        if ($request->has('info')) {
            $attributes = explode(',', trim($request->info));

            if (in_array('user_count', $attributes) && ! Str::startsWith($request->filter_by_prefix, 'presence-')) {
                throw new HttpException(400, 'Request must be limited to presence channels in order to fetch user_count');
            }
        }

        return $this->channelManager->getGlobalChannels($request->appId)->then(function ($channels) use ($request, $attributes) {
            $channels = collect($channels)->keyBy(function ($channel) {
                return $channel instanceof Channel
                    ? $channel->getName()
                    : $channel;
            });

            if ($request->has('filter_by_prefix')) {
                $channels = $channels->filter(function ($channel, $channelName) use ($request) {
                    return Str::startsWith($channelName, $request->filter_by_prefix);
                });
            }

            $channelNames = $channels->map(function ($channel) {
                return $channel instanceof Channel
                    ? $channel->getName()
                    : $channel;
            })->toArray();

            return $this->channelManager
                ->getChannelsMembersCount($request->appId, $channelNames)
                ->then(function ($counts) use ($channels, $attributes) {
                    $channels = $channels->map(function ($channel) use ($counts, $attributes) {
                        $info = new stdClass;

                        $channelName = $channel instanceof Channel
                            ? $channel->getName()
                            : $channel;

                        if (in_array('user_count', $attributes)) {
                            $info->user_count = $counts[$channelName];
                        }

                        return $info;
                    })->sortBy(function ($content, $name) {
                        return $name;
                    })->all();

                    return [
                        'channels' => $channels ?: new stdClass,
                    ];
                });
        });
    }
}