feat: following recommendation

app/Http/Controllers/FollowSuggestionsController.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Http\Resources\TinyUserResource;
+use App\Services\FollowSuggestions;
+
+class FollowSuggestionsController extends Controller
+{
+    public function __construct()
+    {
+        $this->middleware('auth:sanctum');
+    }
+
+    public function index(FollowSuggestions $followSuggestionsService)
+    {
+        $suggestions = $followSuggestionsService->suggest();
+
+        return $this->ok(
+            TinyUserResource::collection($suggestions)
+        );
+    }
+}

app/Services/FollowSuggestions.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace App\Services;
+
+use App\Models\User;
+use Illuminate\Support\Facades\DB;
+
+class FollowSuggestions
+{
+    public function __construct(
+        private $user = null
+    ) {
+    }
+
+    public function suggest($count = 5)
+    {
+        $user = $this->user ?: request()->user();
+
+        $followingIds = DB::table('followers')
+            ->select('following_id')
+            ->where('follower_id', $user->id)
+            ->pluck('following_id');
+
+        return User::query()
+            ->select('id', 'nick_name', 'avatar_url', 'bio')
+            ->whereNotIn('id', $followingIds)
+            ->whereNot('id', $user->id)
+            ->where('country_id', '=', $user->country_id)
+            ->where('addiction_type', '=', $user->addiction_type)
+            ->inRandomOrder()
+            ->limit($count)
+            ->get();
+    }
+}

database/migrations/2014_10_12_000000_create_users_table.php

@@ -19,7 +19,7 @@ public function up(): void
             $table->string('bio')->nullable();
             $table->string('avatar_url')->nullable();
             $table->foreignId('country_id')->constrained();
-            $table->unsignedTinyInteger('addiction_type');
+            $table->unsignedTinyInteger('addiction_type')->index('addiction_type_index');
             $table->boolean('is_recovered')->default(false);
             $table->unsignedInteger('score')->default(0);
             $table->date('birth_date')->nullable();

routes/api.php

@@ -8,6 +8,7 @@
 use App\Http\Controllers\ContinueChallengeController;
 use App\Http\Controllers\CountriesController;
 use App\Http\Controllers\DeactivationRequestsController;
+use App\Http\Controllers\FollowSuggestionsController;
 use App\Http\Controllers\NotificationsController;
 use App\Http\Controllers\ProfileController;
 use App\Http\Controllers\ReportsController;
@@ -51,6 +52,8 @@
 Route::delete('users/{user}/followers', [UserFollowersController::class, 'destroy']);
 Route::get('users/{user}/achievements', [UserAchievementsController::class, 'index']);
 
+Route::get('follow-suggestions', [FollowSuggestionsController::class, 'index']);
+
 Route::post('reports', [ReportsController::class, 'store']);
 
 Route::get('countries', [CountriesController::class, 'index']);

tests/Feature/FollowSuggestionsControllerTest.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\Country;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class FollowSuggestionsControllerTest extends TestCase
+{
+    use RefreshDatabase;
+
+    private $user;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        Country::create([
+            'code' => 'GB',
+            'name' => 'United Kingdom',
+        ]);
+
+        $this->user = $this->signIn();
+    }
+
+    public function test_user_can_get_suggestion_list()
+    {
+        $followers = User::factory()->count(5)->create();
+
+        $this->user->following()->attach($followers->pluck('id'));
+
+        User::factory()->create();
+
+        User::factory()->count(5)->create([
+            'country_id' => $this->user->country_id,
+            'addiction_type' => $this->user->addiction_type,
+        ]);
+
+        $this
+            ->getJson('api/follow-suggestions')
+            ->assertOk()
+            ->assertJsonCount(5, 'data');
+    }
+
+    public function test_user_can_not_get_suggestion_for_him_self()
+    {
+        $this
+            ->getJson('api/follow-suggestions')
+            ->assertOk()
+            ->assertJsonCount(0, 'data');
+    }
+
+    public function test_user_can_not_get_suggestion_for_his_followings()
+    {
+        $followers = User::factory()->count(5)->create();
+
+        $this->user->following()->attach($followers->pluck('id'));
+
+        $this
+            ->getJson('api/follow-suggestions')
+            ->assertOk()
+            ->assertJsonCount(0, 'data');
+    }
+}