From 4fd12b063b1011a292bc63b62836b802d62b097f Mon Sep 17 00:00:00 2001
From: Daniel Supernault <danielsupernault@gmail.com>
Date: Tue, 27 Dec 2022 04:13:34 -0700
Subject: [PATCH] Add TrendingHashtagService

---
 app/Services/TrendingHashtagService.php | 96 +++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 app/Services/TrendingHashtagService.php

diff --git a/app/Services/TrendingHashtagService.php b/app/Services/TrendingHashtagService.php
new file mode 100644
index 000000000..c27b2f3c3
--- /dev/null
+++ b/app/Services/TrendingHashtagService.php
@@ -0,0 +1,96 @@
+<?php
+
+namespace App\Services;
+
+use Illuminate\Support\Facades\Cache;
+use Illuminate\Support\Facades\Redis;
+use App\Hashtag;
+use App\StatusHashtag;
+
+class TrendingHashtagService
+{
+    const CACHE_KEY = 'api:discover:v1.1:trending:hashtags';
+
+    public static function key($k = null)
+    {
+        return self::CACHE_KEY . $k;
+    }
+
+    public static function getBlockedHashtags()
+    {
+        return Cache::remember(self::key(':is_banned'), 1209600, function() {
+            return Hashtag::whereIsBanned(true)->pluck('id')->toArray();
+        });
+    }
+
+    public static function getNonTrendingHashtags()
+    {
+        return Cache::remember(self::key(':can_trend'), 1209600, function() {
+            return Hashtag::whereCanTrend(false)->pluck('id')->toArray();
+        });
+    }
+
+    public static function getNsfwHashtags()
+    {
+        return Cache::remember(self::key(':is_nsfw'), 1209600, function() {
+            return Hashtag::whereIsNsfw(true)->pluck('id')->toArray();
+        });
+    }
+
+    public static function getMinRecentId()
+    {
+        return Cache::remember(self::key('-min-id'), 86400, function() {
+            $minId = StatusHashtag::where('created_at', '>', now()->subMinutes(config('trending.hashtags.recency_mins')))->first();
+            if(!$minId) {
+                return 0;
+            }
+            return $minId->id;
+        });
+    }
+
+    public static function getTrending()
+    {
+        $minId = self::getMinRecentId();
+
+        $skipIds = array_merge(self::getBlockedHashtags(), self::getNonTrendingHashtags(), self::getNsfwHashtags());
+
+        return Cache::remember(self::CACHE_KEY, config('trending.hashtags.ttl'), function() use($minId, $skipIds) {
+            return StatusHashtag::select('hashtag_id', \DB::raw('count(*) as total'))
+                ->whereNotIn('hashtag_id', $skipIds)
+                ->where('id', '>', $minId)
+                ->groupBy('hashtag_id')
+                ->orderBy('total', 'desc')
+                ->take(config('trending.hashtags.limit'))
+                ->get()
+                ->map(function($h) {
+                    $hashtag = Hashtag::find($h->hashtag_id);
+                    if(!$hashtag) {
+                        return;
+                    }
+                    return [
+                        'id' => $h->hashtag_id,
+                        'total' => $h->total,
+                        'name' => '#'.$hashtag->name,
+                        'hashtag' => $hashtag->name,
+                        'url' => $hashtag->url()
+                    ];
+                })
+                ->filter()
+                ->values();
+        });
+    }
+
+    public static function del($k)
+    {
+        return Cache::forget(self::key($k));
+    }
+
+    public static function refresh()
+    {
+        Cache::forget(self::key(':is_banned'));
+        Cache::forget(self::key(':is_nsfw'));
+        Cache::forget(self::key(':can_trend'));
+        Cache::forget(self::key('-min-id'));
+        Cache::forget(self::key());
+    }
+}