<?php

namespace App\Services;

use Illuminate\Support\Facades\Redis;
use Cache;
use DB;
use App\{
    Follower,
    Profile,
    User
};
use App\Jobs\FollowPipeline\FollowServiceWarmCache;

class FollowerService
{
    const CACHE_KEY = 'pf:services:followers:';
    const FOLLOWERS_SYNC_KEY = 'pf:services:followers:sync-followers:';
    const FOLLOWING_SYNC_KEY = 'pf:services:followers:sync-following:';
    const FOLLOWING_KEY = 'pf:services:follow:following:id:';
    const FOLLOWERS_KEY = 'pf:services:follow:followers:id:';
    const FOLLOWERS_LOCAL_KEY = 'pf:services:follow:local-follower-ids:';
    const FOLLOWERS_INTER_KEY = 'pf:services:follow:followers:inter:id:';

    public static function add($actor, $target, $refresh = true)
    {
        $ts = (int) microtime(true);
        if($refresh) {
          RelationshipService::refresh($actor, $target);
        } else {
          RelationshipService::forget($actor, $target);
        }
        Redis::zadd(self::FOLLOWING_KEY . $actor, $ts, $target);
        Redis::zadd(self::FOLLOWERS_KEY . $target, $ts, $actor);
        Cache::forget('profile:following:' . $actor);
    }

    public static function remove($actor, $target, $silent = false)
    {
        Redis::zrem(self::FOLLOWING_KEY . $actor, $target);
        Redis::zrem(self::FOLLOWERS_KEY . $target, $actor);
        if($silent !== true) {
            AccountService::del($actor);
            AccountService::del($target);
            RelationshipService::refresh($actor, $target);
            Cache::forget('profile:following:' . $actor);
        } else {
            RelationshipService::forget($actor, $target);
        }
    }

    public static function followers($id, $start = 0, $stop = 10)
    {
        self::cacheSyncCheck($id, 'followers');
        return Redis::zrevrange(self::FOLLOWERS_KEY . $id, $start, $stop);
    }

    public static function following($id, $start = 0, $stop = 10)
    {
        self::cacheSyncCheck($id, 'following');
        return Redis::zrevrange(self::FOLLOWING_KEY . $id, $start, $stop);
    }

    public static function followersPaginate($id, $page = 1, $limit = 10)
    {
        $start = $page == 1 ? 0 : $page * $limit - $limit;
        $end = $start + ($limit - 1);
        return self::followers($id, $start, $end);
    }

    public static function followingPaginate($id, $page = 1, $limit = 10)
    {
        $start = $page == 1 ? 0 : $page * $limit - $limit;
        $end = $start + ($limit - 1);
        return self::following($id, $start, $end);
    }

    public static function followerCount($id, $warmCache = true)
    {
        if($warmCache) {
            self::cacheSyncCheck($id, 'followers');
        }
        return Redis::zCard(self::FOLLOWERS_KEY . $id);
    }

    public static function followingCount($id, $warmCache = true)
    {
        if($warmCache) {
            self::cacheSyncCheck($id, 'following');
        }
        return Redis::zCard(self::FOLLOWING_KEY . $id);
    }

    public static function follows(string $actor, string $target, $quickCheck = false)
    {
        if($actor == $target) {
            return false;
        }

        if($quickCheck) {
            return (bool) Redis::zScore(self::FOLLOWERS_KEY . $target, $actor);
        }

        if(self::followerCount($target, false) && self::followingCount($actor, false)) {
            self::cacheSyncCheck($target, 'followers');
            return (bool) Redis::zScore(self::FOLLOWERS_KEY . $target, $actor);
        } else {
            self::cacheSyncCheck($target, 'followers');
            self::cacheSyncCheck($actor, 'following');
            return Follower::whereProfileId($actor)->whereFollowingId($target)->exists();
        }
    }

    public static function cacheSyncCheck($id, $scope = 'followers')
    {
        if($scope === 'followers') {
            if(Cache::get(self::FOLLOWERS_SYNC_KEY . $id) != null) {
                return;
            }
            FollowServiceWarmCache::dispatch($id)->onQueue('low');
        }
        if($scope === 'following') {
            if(Cache::get(self::FOLLOWING_SYNC_KEY . $id) != null) {
                return;
            }
            FollowServiceWarmCache::dispatch($id)->onQueue('low');
        }
        return;
    }

    public static function audience($profile, $scope = null)
    {
        return (new self)->getAudienceInboxes($profile, $scope);
    }

    public static function softwareAudience($profile, $software = 'pixelfed')
    {
        return collect(self::audience($profile))
            ->filter(function($inbox) use($software) {
                $domain = parse_url($inbox, PHP_URL_HOST);
                if(!$domain) {
                    return false;
                }
                return InstanceService::software($domain) === strtolower($software);
            })
            ->unique()
            ->values()
            ->toArray();
    }

    protected function getAudienceInboxes($pid, $scope = null)
    {
        $key = 'pf:services:follower:audience:' . $pid;
        $domains = Cache::remember($key, 432000, function() use($pid) {
            $profile = Profile::whereNull(['status', 'domain'])->find($pid);
            if(!$profile) {
                return [];
            }
            return $profile
                ->followers()
                ->get()
                ->map(function($follow) {
                    return $follow->sharedInbox ?? $follow->inbox_url;
                })
                ->filter()
                ->unique()
                ->values();
        });

        if(!$domains || !$domains->count()) {
            return [];
        }

        $banned = InstanceService::getBannedDomains();

        if(!$banned || count($banned) === 0) {
            return $domains->toArray();
        }

        $res = $domains->filter(function($domain) use($banned) {
            $parsed = parse_url($domain, PHP_URL_HOST);
            return !in_array($parsed, $banned);
        })
        ->values()
        ->toArray();

        return $res;
    }

    public static function mutualCount($pid, $mid)
    {
        return Cache::remember(self::CACHE_KEY . ':mutualcount:' . $pid . ':' . $mid, 3600, function() use($pid, $mid) {
            return DB::table('followers as u')
                ->join('followers as s', 'u.following_id', '=', 's.following_id')
                ->where('s.profile_id', $mid)
                ->where('u.profile_id', $pid)
                ->count();
        });
    }

    public static function mutualIds($pid, $mid, $limit = 3)
    {
        $key = self::CACHE_KEY . ':mutualids:' . $pid . ':' . $mid . ':limit_' . $limit;
        return Cache::remember($key, 3600, function() use($pid, $mid, $limit) {
            return DB::table('followers as u')
                ->join('followers as s', 'u.following_id', '=', 's.following_id')
                ->where('s.profile_id', $mid)
                ->where('u.profile_id', $pid)
                ->limit($limit)
                ->pluck('s.following_id')
                ->toArray();
        });
    }

    public static function mutualAccounts($actorId, $profileId)
    {
        if($actorId == $profileId) {
            return [];
        }
        $actorKey = self::FOLLOWING_KEY . $actorId;
        $profileKey = self::FOLLOWERS_KEY . $profileId;
        $key = self::FOLLOWERS_INTER_KEY . $actorId . ':' . $profileId;
        $res = Redis::zinterstore($key, [$actorKey, $profileKey]);
        if($res) {
            return Redis::zrange($key, 0, -1);
        } else {
            return [];
        }
    }

    public static function delCache($id)
    {
        Redis::del(self::CACHE_KEY . $id);
        Redis::del(self::FOLLOWING_KEY . $id);
        Redis::del(self::FOLLOWERS_KEY . $id);
        Cache::forget(self::FOLLOWERS_SYNC_KEY . $id);
        Cache::forget(self::FOLLOWING_SYNC_KEY . $id);
    }

    public static function localFollowerIds($pid, $limit = 0)
    {
        $key = self::FOLLOWERS_LOCAL_KEY . $pid;
        $res = Cache::remember($key, 7200, function() use($pid) {
            return DB::table('followers')->whereFollowingId($pid)->whereLocalProfile(true)->pluck('profile_id')->sort();
        });
        return $limit ?
            $res->take($limit)->values()->toArray() :
            $res->values()->toArray();
    }
}