327 lines
11 KiB
PHP
327 lines
11 KiB
PHP
<?php
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namespace App\Services;
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use App\Models\User;
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use App\Services\Activity\UserActivityService;
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use App\Events\Achievements\AchievementCheckRequested;
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use App\Services\FollowAnalyticsService;
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use App\Support\AvatarUrl;
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use Illuminate\Support\Collection;
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use Illuminate\Support\Facades\DB;
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/**
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* FollowService
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*
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* Manages follow / unfollow operations on the user_followers table.
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* Convention:
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* follower_id = the user doing the following
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* user_id = the user being followed
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*
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* Counters in user_statistics are kept in sync atomically inside a transaction.
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*/
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final class FollowService
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{
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public function __construct(
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private readonly XPService $xp,
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private readonly NotificationService $notifications,
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private readonly FollowAnalyticsService $analytics,
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) {
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}
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/**
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* Follow $targetId on behalf of $actorId.
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*
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* @return bool true if a new follow was created, false if already following
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*
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* @throws \InvalidArgumentException if self-follow attempted
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*/
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public function follow(int $actorId, int $targetId): bool
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{
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if ($actorId === $targetId) {
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throw new \InvalidArgumentException('Cannot follow yourself.');
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}
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$inserted = false;
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DB::transaction(function () use ($actorId, $targetId, &$inserted) {
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$rows = DB::table('user_followers')->insertOrIgnore([
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'user_id' => $targetId,
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'follower_id' => $actorId,
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'created_at' => now(),
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]);
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if ($rows === 0) {
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// Already following – nothing to do
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return;
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}
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$inserted = true;
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// Increment following_count for actor, followers_count for target
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$this->incrementCounter($actorId, 'following_count');
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$this->incrementCounter($targetId, 'followers_count');
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});
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// Record activity event outside the transaction to avoid deadlocks
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if ($inserted) {
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try {
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\App\Models\ActivityEvent::record(
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actorId: $actorId,
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type: \App\Models\ActivityEvent::TYPE_FOLLOW,
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targetType: \App\Models\ActivityEvent::TARGET_USER,
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targetId: $targetId,
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);
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} catch (\Throwable) {}
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try {
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app(UserActivityService::class)->logFollow($actorId, $targetId);
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} catch (\Throwable) {}
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$targetUser = User::query()->find($targetId);
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$actorUser = User::query()->find($actorId);
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if ($targetUser && $actorUser) {
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$this->notifications->notifyUserFollowed($targetUser->loadMissing('profile'), $actorUser->loadMissing('profile'));
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}
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$this->analytics->recordFollow($actorId, $targetId);
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$this->xp->awardFollowerReceived($targetId, $actorId);
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event(new AchievementCheckRequested($targetId));
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}
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return $inserted;
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}
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/**
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* Unfollow $targetId on behalf of $actorId.
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*
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* @return bool true if a follow row was removed, false if wasn't following
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*/
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public function unfollow(int $actorId, int $targetId): bool
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{
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if ($actorId === $targetId) {
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return false;
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}
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$deleted = false;
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DB::transaction(function () use ($actorId, $targetId, &$deleted) {
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$rows = DB::table('user_followers')
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->where('user_id', $targetId)
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->where('follower_id', $actorId)
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->delete();
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if ($rows === 0) {
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return;
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}
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$deleted = true;
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$this->decrementCounter($actorId, 'following_count');
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$this->decrementCounter($targetId, 'followers_count');
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});
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if ($deleted) {
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$this->analytics->recordUnfollow($actorId, $targetId);
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}
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return $deleted;
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}
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/**
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* Toggle follow state. Returns the new following state.
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*/
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public function toggle(int $actorId, int $targetId): bool
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{
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if ($this->isFollowing($actorId, $targetId)) {
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$this->unfollow($actorId, $targetId);
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return false;
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}
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$this->follow($actorId, $targetId);
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return true;
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}
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public function isFollowing(int $actorId, int $targetId): bool
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{
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return DB::table('user_followers')
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->where('user_id', $targetId)
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->where('follower_id', $actorId)
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->exists();
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}
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/**
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* Current followers_count for a user (from cached column, not live count).
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*/
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public function followersCount(int $userId): int
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{
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return (int) DB::table('user_statistics')
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->where('user_id', $userId)
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->value('followers_count');
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}
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public function followingCount(int $userId): int
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{
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return (int) DB::table('user_statistics')
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->where('user_id', $userId)
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->value('following_count');
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}
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public function getMutualFollowers(int $userA, int $userB, int $limit = 13): array
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{
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$rows = DB::table('user_followers as left_follow')
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->join('user_followers as right_follow', 'right_follow.follower_id', '=', 'left_follow.follower_id')
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->join('users as u', 'u.id', '=', 'left_follow.follower_id')
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->leftJoin('user_profiles as up', 'up.user_id', '=', 'u.id')
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->where('left_follow.user_id', $userA)
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->where('right_follow.user_id', $userB)
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->where('left_follow.follower_id', '!=', $userA)
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->where('left_follow.follower_id', '!=', $userB)
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->whereNull('u.deleted_at')
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->where('u.is_active', true)
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->orderByDesc('left_follow.created_at')
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->limit(max(1, $limit))
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->select(['u.id', 'u.username', 'u.name', 'up.avatar_hash'])
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->get();
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return $this->mapUsers($rows);
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}
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public function relationshipContext(int $viewerId, int $targetId): array
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{
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if ($viewerId === $targetId) {
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return [
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'follower_overlap' => null,
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'shared_following' => null,
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'mutual_followers' => [
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'count' => 0,
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'users' => [],
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],
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];
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}
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$followerOverlap = $this->buildFollowerOverlapSummary($viewerId, $targetId);
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$sharedFollowing = $this->buildSharedFollowingSummary($viewerId, $targetId);
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$mutualFollowers = $this->getMutualFollowers($viewerId, $targetId, 6);
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return [
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'follower_overlap' => $followerOverlap,
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'shared_following' => $sharedFollowing,
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'mutual_followers' => [
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'count' => count($mutualFollowers),
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'users' => $mutualFollowers,
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],
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];
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}
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// ─── Private helpers ─────────────────────────────────────────────────────
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private function incrementCounter(int $userId, string $column): void
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{
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DB::table('user_statistics')->updateOrInsert(
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['user_id' => $userId],
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[
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$column => DB::raw("COALESCE({$column}, 0) + 1"),
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'updated_at' => now(),
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'created_at' => now(), // ignored on update
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]
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);
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}
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private function decrementCounter(int $userId, string $column): void
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{
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DB::table('user_statistics')
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->where('user_id', $userId)
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->where($column, '>', 0)
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->update([
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$column => DB::raw("{$column} - 1"),
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'updated_at' => now(),
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]);
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}
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private function buildFollowerOverlapSummary(int $viewerId, int $targetId): ?array
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{
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$preview = DB::table('user_followers as viewer_following')
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->join('user_followers as target_followers', 'target_followers.follower_id', '=', 'viewer_following.user_id')
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->join('users as u', 'u.id', '=', 'viewer_following.user_id')
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->leftJoin('user_profiles as up', 'up.user_id', '=', 'u.id')
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->where('viewer_following.follower_id', $viewerId)
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->where('target_followers.user_id', $targetId)
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->whereNull('u.deleted_at')
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->where('u.is_active', true)
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->orderByDesc('target_followers.created_at')
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->limit(3)
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->select(['u.id', 'u.username', 'u.name', 'up.avatar_hash'])
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->get();
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if ($preview->isEmpty()) {
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return null;
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}
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$count = DB::table('user_followers as viewer_following')
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->join('user_followers as target_followers', 'target_followers.follower_id', '=', 'viewer_following.user_id')
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->where('viewer_following.follower_id', $viewerId)
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->where('target_followers.user_id', $targetId)
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->count();
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$lead = $preview->first();
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$label = $count > 1
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? sprintf('Followed by %s and %d other%s', $lead->username ?? $lead->name ?? 'someone', $count - 1, $count - 1 === 1 ? '' : 's')
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: sprintf('Followed by %s', $lead->username ?? $lead->name ?? 'someone');
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return [
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'count' => (int) $count,
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'label' => $label,
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'users' => $this->mapUsers($preview),
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];
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}
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private function buildSharedFollowingSummary(int $viewerId, int $targetId): ?array
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{
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$preview = DB::table('user_followers as viewer_following')
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->join('user_followers as target_following', 'target_following.user_id', '=', 'viewer_following.user_id')
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->join('users as u', 'u.id', '=', 'viewer_following.user_id')
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->leftJoin('user_profiles as up', 'up.user_id', '=', 'u.id')
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->where('viewer_following.follower_id', $viewerId)
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->where('target_following.follower_id', $targetId)
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->whereNull('u.deleted_at')
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->where('u.is_active', true)
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->orderByDesc('viewer_following.created_at')
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->limit(3)
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->select(['u.id', 'u.username', 'u.name', 'up.avatar_hash'])
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->get();
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if ($preview->isEmpty()) {
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return null;
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}
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$count = DB::table('user_followers as viewer_following')
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->join('user_followers as target_following', 'target_following.user_id', '=', 'viewer_following.user_id')
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->where('viewer_following.follower_id', $viewerId)
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->where('target_following.follower_id', $targetId)
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->count();
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$lead = $preview->first();
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$label = $count > 1
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? sprintf('You both follow %s and %d other%s', $lead->username ?? $lead->name ?? 'someone', $count - 1, $count - 1 === 1 ? '' : 's')
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: sprintf('You both follow %s', $lead->username ?? $lead->name ?? 'someone');
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return [
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'count' => (int) $count,
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'label' => $label,
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'users' => $this->mapUsers($preview),
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];
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}
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private function mapUsers(Collection $rows): array
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{
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return $rows->map(fn ($row) => [
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'id' => (int) $row->id,
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'username' => (string) ($row->username ?? ''),
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'name' => (string) ($row->name ?? $row->username ?? ''),
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'profile_url' => '/@' . strtolower((string) ($row->username ?? $row->id)),
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'avatar_url' => AvatarUrl::forUser((int) $row->id, $row->avatar_hash ?? null, 48),
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])->values()->all();
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}
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}
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