done restructure calculation retribution

app/Models/RetributionCalculation.php

@@ -4,6 +4,7 @@ namespace App\Models;
 
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 use Carbon\Carbon;
 
 class RetributionCalculation extends Model
@@ -15,23 +16,39 @@ class RetributionCalculation extends Model
         'building_area',
         'retribution_amount',
         'calculation_detail',
-        'calculated_at'
+        'calculated_at',
     ];
 
     protected $casts = [
-        'floor_number' => 'integer',
         'building_area' => 'decimal:2',
         'retribution_amount' => 'decimal:2',
         'calculation_detail' => 'array',
-        'calculated_at' => 'datetime'
+        'calculated_at' => 'timestamp',
+        'floor_number' => 'integer',
     ];
 
     /**
-     * Building type relationship
+     * Get the building type
      */
     public function buildingType(): BelongsTo
     {
-        return $this->belongsTo(BuildingType::class, 'building_type_id');
+        return $this->belongsTo(BuildingType::class);
+    }
+
+    /**
+     * Get all calculable assignments
+     */
+    public function calculableRetributions(): HasMany
+    {
+        return $this->hasMany(CalculableRetribution::class);
+    }
+
+    /**
+     * Get active assignments only
+     */
+    public function activeAssignments(): HasMany
+    {
+        return $this->hasMany(CalculableRetribution::class)->where('is_active', true);
     }
 
     /**
@@ -39,7 +56,48 @@ class RetributionCalculation extends Model
      */
     public static function generateCalculationId(): string
     {
-        return 'RTB' . Carbon::now()->format('ymdHis') . rand(10, 99);
+        return 'CALC-' . date('Ymd') . '-' . str_pad(mt_rand(1, 9999), 4, '0', STR_PAD_LEFT);
+    }
+
+    /**
+     * Boot method to auto-generate calculation_id
+     */
+    protected static function boot()
+    {
+        parent::boot();
+
+        static::creating(function ($model) {
+            if (empty($model->calculation_id)) {
+                $model->calculation_id = self::generateCalculationId();
+            }
+            if (empty($model->calculated_at)) {
+                $model->calculated_at = now();
+            }
+        });
+    }
+
+    /**
+     * Check if calculation is being used
+     */
+    public function isInUse(): bool
+    {
+        return $this->activeAssignments()->exists();
+    }
+
+    /**
+     * Get calculation summary
+     */
+    public function getSummary(): array
+    {
+        return [
+            'calculation_id' => $this->calculation_id,
+            'building_type' => $this->buildingType->name ?? 'Unknown',
+            'floor_number' => $this->floor_number,
+            'building_area' => $this->building_area,
+            'retribution_amount' => $this->retribution_amount,
+            'calculated_at' => $this->calculated_at->format('Y-m-d H:i:s'),
+            'in_use' => $this->isInUse(),
+        ];
     }
 
     /**