fix matching if somebody withdraws and dont rematch everybody!

app/Models/Participant.php

@@ -2,15 +2,18 @@
 
 namespace App\Models;
 
+use Illuminate\Database\Eloquent\Casts\Attribute;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\HasOne;
+use Illuminate\Database\Eloquent\SoftDeletes;
 use Illuminate\Support\Facades\Log;
 
 class Participant extends Model
 {
     use HasFactory;
+    use SoftDeletes;
 
     protected $fillable = [
         'user_id',
@@ -20,18 +23,6 @@ class Participant extends Model
         'token',
     ];
 
-    protected $appends = ['desperate'];
-
-    public function receiver() : belongsTo
-    {
-        return $this->belongsTo(Participant::class, 'giving_id');
-    }
-
-    public function giver(): hasOne
-    {
-        return $this->hasOne(Participant::class, 'giving_id', 'id');
-    }
-
     public static function findByToken(string $token): ?self
     {
         return self::where('token', $token)->first();
@@ -69,16 +60,60 @@ class Participant extends Model
             ->whereDoesntHave('receiver');
     }
 
-    public function getDesperateAttribute(): bool
+    public function receiver(): BelongsTo
     {
-        $gives = !is_null($this->giver);
+        return $this->belongsTo(Participant::class, 'giving_id');
-        $gets  = !is_null($this->receiver);
+    }
 
-        return ($gives && !$gets) || (!$gives && $gets);
+    public function giver(): HasOne
+    {
+        return $this->hasOne(Participant::class, 'giving_id', 'id');
+    }
+
+    public function hasReceiver(): bool
+    {
+        return !is_null($this->giving_id); // The simplest and most direct check for an outgoing link
+    }
+
+    public function hasGiver(): bool
+    {
+       return $this->hasOne(Participant::class, 'giving_id', 'id')
+            ->exists();
+    }
+
+    protected function isUnmatched(): Attribute
+    {
+        return Attribute::make(
+            get: fn () => !$this->hasReceiver() && !$this->hasGiver(),
+        );
+    }
+
+    protected function isDesperate(): Attribute
+    {
+        return Attribute::make(
+            get: fn () => $this->hasReceiver() xor $this->hasGiver(),
+        );
     }
 
     public function withdraw(): bool
     {
-        return false;
+        if (!$this->id) {
+            return false;
+        }
+
+        $giver = Participant::where('giving_id', $this->id)->first();
+        if ($giver) {
+            $giver->giving_id = null;
+            $giver->save();
+        }
+
+        $userB_id = $this->giving_id;
+        if ($userB_id) {
+            $this->giving_id = null;
+        }
+
+        $this->delete();
+
+        return true;
     }
 }

app/Services/MatcherService.php

@@ -14,92 +14,57 @@ class MatcherService
             return;
         }
 
-        // desperate denotes a user A that is supposed to give to a user B that dropped out
-        // whilst user A has a user C giving to them, or vice versa
-        $desperate     = $participants->where('desperate', true)->values();
-        $nonDesperate  = $participants->where('desperate', false)->values();
-
-        $desperate     = $desperate->shuffle();
-        $nonDesperate  = $nonDesperate->shuffle();
-
         $assignments = [];
 
-        /*
+        $newParticipantIds = $participants
-        |--------------------------------------------------------------------------
+            ->filter(fn($p) => $p->is_unmatched)
-        | 1. Match DESPERATE participants
+            ->pluck('id')
-        |--------------------------------------------------------------------------
+            ->shuffle()
-        | A desperate user should match:
+            ->all();
-        |   - First to another desperate participant
-        |   - If none left, match to a non-desperate participant
-        |--------------------------------------------------------------------------
-        */
 
-        foreach ($desperate as $p) {
+        $desperateGiverIds = $participants
-            // Exclude self from possible options
+            ->filter(fn($p) => $p->is_desperate && !$p->hasReceiver())
-            $pool = $desperate->filter(fn($d) => $d->id !== $p->id);
+            ->pluck('id')
+            ->shuffle()
+            ->all();
 
-            if ($pool->isEmpty()) {
+        $desperateReceiverIds = $participants
-                $pool = $nonDesperate;
+            ->filter(fn($p) => $p->is_desperate && !$p->hasGiver())
-            }
+            ->pluck('id')
+            ->shuffle()
+            ->all();
 
-            if ($pool->isEmpty()) {
+        while (!empty($desperateGiverIds) && !empty($desperateReceiverIds)) {
+
+            $giverId = array_shift($desperateGiverIds);
+            $receiverId = array_shift($desperateReceiverIds);
+
+            if ($giverId === $receiverId) {
+                array_unshift($desperateReceiverIds, $receiverId);
                 continue;
             }
 
-            $candidate = $this->pickValidTarget($p, $pool, $assignments);
+            $assignments[$giverId] = $receiverId;
-            if ($candidate) {
+        }
-                $assignments[$p->id] = $candidate->id;
+
+        $newCount = count($newParticipantIds);
+        if ($newCount >= 2) {
+
+            for ($i = 0; $i < $newCount; $i++) {
+
+                $currentId = $newParticipantIds[$i];
+
+                $nextId = $newParticipantIds[($i + 1) % $newCount];
+
+                $assignments[$currentId] = $nextId;
             }
         }
 
-        /*
-        |--------------------------------------------------------------------------
-        | 2. Match NON-DESPERATE participants
-        |--------------------------------------------------------------------------
-        | A non-desperate participant always matches to the non-desperate pool.
-        |--------------------------------------------------------------------------
-        */
 
-        foreach ($nonDesperate as $p) {
+        foreach ($assignments as $giverId => $receiverId) {
-            // Exclude self
+            Participant::where('id', $giverId)->update([
-            $pool = $nonDesperate->filter(fn($d) => $d->id !== $p->id);
+                'giving_id' => $receiverId,
-
-            if ($pool->isEmpty()) {
-                continue;
-            }
-
-            $candidate = $this->pickValidTarget($p, $pool, $assignments);
-            if ($candidate) {
-                $assignments[$p->id] = $candidate->id;
-            }
-        }
-
-        /*
-        |--------------------------------------------------------------------------
-        | 3. Write all results back to DB
-        |--------------------------------------------------------------------------
-        */
-
-        foreach ($assignments as $id => $givingId) {
-            Participant::where('id', $id)->update([
-                'giving_id' => $givingId,
             ]);
         }
     }
-
-    private function pickValidTarget(Participant $giver, Collection $pool, array $assignments): ?Participant
-    {
-        $shuffled = $pool->shuffle();
-
-        // Avoid duplicates
-        foreach ($shuffled as $candidate) {
-            if (($assignments[$candidate->id] ?? null) === $giver->id) {
-                continue;
-            }
-
-            return $candidate;
-        }
-
-        return null;
-    }
 }

database/migrations/2025_12_04_105253_add_participants_table.php

@@ -24,6 +24,7 @@ return new class extends Migration
 
             $table->string('token');
             $table->timestamps();
+            $table->softDeletes();
         });
     }
 

resources/views/livewire/pages/profile.blade.php

@@ -27,7 +27,7 @@ rules([
     ],
 ]);
 
-mount(function ($token): null
+mount(function ($token)
 {
     $this->token = $token;
     if ($this->token) {
@@ -51,7 +51,7 @@ mount(function ($token): null
     }
 });
 
-$saveEditingPrompt = function (): null
+$saveEditingPrompt = function ()
 {
     if ($this->participant) {
         $this->validate();
@@ -62,13 +62,13 @@ $saveEditingPrompt = function (): null
     }
 };
 
-$cancelEditingPrompt = function (): null
+$cancelEditingPrompt = function ()
 {
     $this->prompt = $this->participant->prompt ?? '';
     $this->isEditingPrompt = false;
 };
 
-$saveEditingSubmission = function (): null
+$saveEditingSubmission = function ()
 {
     if ($this->participant) {
         $this->validate();
@@ -79,7 +79,7 @@ $saveEditingSubmission = function (): null
     }
 };
 
-$cancelEditingSubmission = function (): null
+$cancelEditingSubmission = function ()
 {
     $this->submissionUrl = $this->participant->submission_url ?? '';
     $this->isEditingSubmission = false;

resources/views/livewire/pages/table.blade.php

@@ -88,8 +88,8 @@ $runMatch = function () {
 
                             <td class="px-6 py-4 whitespace-nowrap text-sm">
                             <span class="px-2 inline-flex text-xs leading-5 font-semibold rounded-full
-                                {{ $participant->desperate ? 'bg-red-100 text-red-800' : 'bg-green-100 text-green-800' }}">
+                                {{ $participant->is_desperate ? 'bg-red-100 text-red-800' : 'bg-green-100 text-green-800' }}">
-                                {{ $participant->desperate ? 'YES' : 'No' }}
+                                {{ $participant->is_desperate ? 'YES' : 'No' }}
                             </span>
                             </td>
 

resources/views/livewire/pages/withdraw.blade.php

@@ -12,7 +12,7 @@ state([
     'participant' => null,
 ]);
 
-mount(function ($token): null
+mount(function ($token)
 {
     $this->token = $token;
     if ($this->token) {
@@ -20,7 +20,7 @@ mount(function ($token): null
     }
 });
 
-$confirmWithdrawal = function (): null
+$confirmWithdrawal = function ()
 {
     $this->js(<<<'JS'
         if (confirm('Are you sure you want to withdraw from the event? This action cannot be undone.')) {
@@ -29,7 +29,7 @@ $confirmWithdrawal = function (): null
     JS);
 };
 
-$withdraw = function (): mixed
+$withdraw = function ()
 {
     if($this->participant->withdraw()) {
         $this->js('alert("Withdrawal complete")');