feat: referral_code

database/migrations/2026_06_06_000000_add_referral_code_and_referred_by_to_users_table.php

@@ -0,0 +1,49 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Support\Str;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::table('users', function (Blueprint $table) {
+            if (!Schema::hasColumn('users', 'referral_code')) {
+                $table->string('referral_code', 12)->nullable()->unique()->after('uuid');
+            }
+            if (!Schema::hasColumn('users', 'referred_by')) {
+                $table->foreignId('referred_by')->nullable()->after('referral_code')
+                    ->constrained('users')->nullOnDelete();
+            }
+        });
+
+        // Backfill a unique referral code for existing users
+        $existing = DB::table('users')->whereNull('referral_code')->pluck('id');
+        $used = DB::table('users')->whereNotNull('referral_code')->pluck('referral_code')->all();
+        $used = array_flip($used);
+
+        foreach ($existing as $id) {
+            do {
+                $code = strtoupper(Str::random(8));
+            } while (isset($used[$code]));
+            $used[$code] = true;
+            DB::table('users')->where('id', $id)->update(['referral_code' => $code]);
+        }
+    }
+
+    public function down(): void
+    {
+        Schema::table('users', function (Blueprint $table) {
+            if (Schema::hasColumn('users', 'referred_by')) {
+                $table->dropForeign(['referred_by']);
+                $table->dropColumn('referred_by');
+            }
+            if (Schema::hasColumn('users', 'referral_code')) {
+                $table->dropColumn('referral_code');
+            }
+        });
+    }
+};