<?php

namespace App\Services;

use App\Jobs\InternalPipeline\NotificationEpochUpdatePipeline;
use App\Models\Notification;
use App\Transformer\Api\NotificationTransformer;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Redis;

class NotificationService
{
    const CACHE_KEY = 'pf:services:notifications:ids:';

    const EPOCH_CACHE_KEY = 'pf:services:notifications:epoch-id:by-months:';

    const ITEM_CACHE_TTL = 86400;

    const MASTODON_TYPES = [
        'follow',
        'follow_request',
        'mention',
        'reblog',
        'favourite',
        'poll',
        'status',
    ];

    public static function get($id, $start = 0, $stop = 400)
    {
        $res = collect([]);
        $key = self::CACHE_KEY.$id;
        $stop = $stop > 400 ? 400 : $stop;
        $ids = Redis::zrangebyscore($key, $start, $stop);
        if (empty($ids)) {
            $ids = self::coldGet($id, $start, $stop);
        }
        foreach ($ids as $id) {
            $n = self::getNotification($id);
            if ($n != null) {
                $res->push($n);
            }
        }

        return $res;
    }

    public static function getEpochId($months = 6)
    {
        $epoch = Cache::get(self::EPOCH_CACHE_KEY.$months);
        if (! $epoch) {
            NotificationEpochUpdatePipeline::dispatch();

            return 1;
        }

        return $epoch;
    }

    public static function coldGet($id, $start = 0, $stop = 400)
    {
        $stop = $stop > 400 ? 400 : $stop;
        $ids = Notification::where('id', '>', self::getEpochId())
            ->where('profile_id', $id)
            ->orderByDesc('id')
            ->skip($start)
            ->take($stop)
            ->pluck('id');
        foreach ($ids as $key) {
            self::set($id, $key);
        }

        return $ids;
    }

    public static function getMax($id = false, $start = 0, $limit = 10)
    {
        $ids = self::getRankedMaxId($id, $start, $limit);

        if (empty($ids)) {
            return [];
        }

        $res = collect([]);
        foreach ($ids as $id) {
            $n = self::getNotification($id);
            if ($n != null) {
                $res->push($n);
            }
        }

        return $res->toArray();
    }

    public static function getMin($id = false, $start = 0, $limit = 10)
    {
        $ids = self::getRankedMinId($id, $start, $limit);

        if (empty($ids)) {
            return [];
        }

        $res = collect([]);
        foreach ($ids as $id) {
            $n = self::getNotification($id);
            if ($n != null) {
                $res->push($n);
            }
        }

        return $res->toArray();
    }

    public static function getMaxMastodon($id = false, $start = 0, $limit = 10)
    {
        $ids = self::getRankedMaxId($id, $start, $limit);

        if (empty($ids)) {
            return [];
        }

        $res = collect([]);
        foreach ($ids as $id) {
            $n = self::rewriteMastodonTypes(self::getNotification($id));
            if ($n != null && in_array($n['type'], self::MASTODON_TYPES)) {
                if (isset($n['account'])) {
                    $n['account'] = AccountService::getMastodon($n['account']['id']);
                }

                if (isset($n['relationship'])) {
                    unset($n['relationship']);
                }

                if ($n['type'] === 'mention' && isset($n['tagged'], $n['tagged']['status_id'])) {
                    $n['status'] = StatusService::getMastodon($n['tagged']['status_id'], false);
                    unset($n['tagged']);
                }

                if (isset($n['status'])) {
                    $n['status'] = StatusService::getMastodon($n['status']['id'], false);
                }

                $res->push($n);
            }
        }

        return $res->toArray();
    }

    public static function getMinMastodon($id = false, $start = 0, $limit = 10)
    {
        $ids = self::getRankedMinId($id, $start, $limit);

        if (empty($ids)) {
            return [];
        }

        $res = collect([]);
        foreach ($ids as $id) {
            $n = self::rewriteMastodonTypes(self::getNotification($id));
            if ($n != null && in_array($n['type'], self::MASTODON_TYPES)) {
                if (isset($n['account'])) {
                    $n['account'] = AccountService::getMastodon($n['account']['id']);
                }

                if (isset($n['relationship'])) {
                    unset($n['relationship']);
                }

                if ($n['type'] === 'mention' && isset($n['tagged'], $n['tagged']['status_id'])) {
                    $n['status'] = StatusService::getMastodon($n['tagged']['status_id'], false);
                    unset($n['tagged']);
                }

                if (isset($n['status'])) {
                    $n['status'] = StatusService::getMastodon($n['status']['id'], false);
                }

                $res->push($n);
            }
        }

        return $res->toArray();
    }

    public static function getRankedMaxId($id = false, $start = null, $limit = 10)
    {
        if (! $start || ! $id) {
            return [];
        }

        return array_keys(Redis::zrevrangebyscore(self::CACHE_KEY.$id, $start, '-inf', [
            'withscores' => true,
            'limit' => [1, $limit],
        ]));
    }

    public static function getRankedMinId($id = false, $end = null, $limit = 10)
    {
        if (! $end || ! $id) {
            return [];
        }

        return array_keys(Redis::zrevrangebyscore(self::CACHE_KEY.$id, '+inf', $end, [
            'withscores' => true,
            'limit' => [0, $limit],
        ]));
    }

    public static function rewriteMastodonTypes($notification)
    {
        if (! $notification || ! isset($notification['type'])) {
            return $notification;
        }

        if ($notification['type'] === 'comment') {
            $notification['type'] = 'mention';
        }

        if ($notification['type'] === 'share') {
            $notification['type'] = 'reblog';
        }

        if ($notification['type'] === 'tagged') {
            $notification['type'] = 'mention';
        }

        return $notification;
    }

    public static function set($id, $val)
    {
        if (self::count($id) > 400) {
            Redis::zpopmin(self::CACHE_KEY.$id);
        }

        return Redis::zadd(self::CACHE_KEY.$id, $val, $val);
    }

    public static function del($id, $val)
    {
        Cache::forget('service:notification:'.$val);

        return Redis::zrem(self::CACHE_KEY.$id, $val);
    }

    public static function add($id, $val)
    {
        return self::set($id, $val);
    }

    public static function rem($id, $val)
    {
        return self::del($id, $val);
    }

    public static function count($id)
    {
        return Redis::zcount(self::CACHE_KEY.$id, '-inf', '+inf');
    }

    public static function getNotification($id)
    {
        $notification = Cache::remember('service:notification:'.$id, self::ITEM_CACHE_TTL, function () use ($id) {
            $n = Notification::with('item')->find($id);

            if (! $n) {
                return null;
            }

            $account = AccountService::get($n->actor_id, true);

            if (! $account) {
                return null;
            }

            return FractalService::item($n, new NotificationTransformer);
        });

        if (! $notification) {
            return;
        }

        if (isset($notification['account'])) {
            $notification['account'] = AccountService::get($notification['account']['id'], true);
        }

        return $notification;
    }

    public static function setNotification(Notification $notification)
    {
        return Cache::remember('service:notification:'.$notification->id, self::ITEM_CACHE_TTL, function () use ($notification) {
            return FractalService::item($notification, new NotificationTransformer);
        });
    }

    /**
     * Create a notification, register it in the cache, and add it to the recipient's feed.
     *
     * @param  int  $profileId  The recipient profile ID
     * @param  int  $actorId  The actor profile ID who triggered the notification
     * @param  string|null  $action  The notification action (e.g. 'comment', 'like', 'follow')
     * @param  int  $itemId  The related item ID
     * @param  string  $itemType  The related item class (e.g. Status::class)
     */
    public static function createNotification(int $profileId, int $actorId, ?string $action, int $itemId, string $itemType): Notification
    {
        $notification = new Notification;
        $notification->profile_id = $profileId;
        $notification->actor_id = $actorId;
        $notification->action = $action;
        $notification->item_id = $itemId;
        $notification->item_type = $itemType;
        $notification->save();

        self::setNotification($notification);
        self::set($notification->profile_id, $notification->id);

        return $notification;
    }

    /**
     * Create a notification only if one doesn't already exist for this actor+action+item combination.
     *
     * Use this for actions that can be triggered multiple times but should only notify once,
     * such as shares/boosts (a user can only boost a post once) and mentions.
     *
     * @param  int  $profileId  The recipient profile ID
     * @param  int  $actorId  The actor profile ID who triggered the notification
     * @param  string  $action  The notification action (e.g. 'share', 'mention')
     * @param  int  $itemId  The related item ID
     * @param  string  $itemType  The related item class (e.g. Status::class)
     */
    public static function firstOrCreateNotification(int $profileId, int $actorId, string $action, int $itemId, string $itemType): Notification
    {
        $notification = Notification::firstOrCreate([
            'profile_id' => $profileId,
            'actor_id' => $actorId,
            'action' => $action,
            'item_id' => $itemId,
            'item_type' => $itemType,
        ]);

        if ($notification->wasRecentlyCreated) {
            self::setNotification($notification);
            self::set($notification->profile_id, $notification->id);
        }

        return $notification;
    }

    public static function warmCache($id, $stop = 400, $force = false)
    {
        if (self::count($id) == 0 || $force == true) {
            $ids = Notification::where('profile_id', $id)
                ->where('id', '>', self::getEpochId())
                ->orderByDesc('id')
                ->limit($stop)
                ->pluck('id');
            foreach ($ids as $key) {
                self::set($id, $key);
            }

            return 1;
        }

        return 0;
    }
}