restructure retribution calculations table

app/Models/HeightIndex.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+class HeightIndex extends Model
+{
+    protected $fillable = [
+        'floor_number',
+        'height_index'
+    ];
+
+    protected $casts = [
+        'floor_number' => 'integer',
+        'height_index' => 'decimal:6'
+    ];
+
+    /**
+     * Get height index by floor number
+     */
+    public static function getByFloor(int $floorNumber): ?HeightIndex
+    {
+        return self::where('floor_number', $floorNumber)->first();
+    }
+
+    /**
+     * Get height index value by floor number
+     */
+    public static function getHeightIndexByFloor(int $floorNumber): float
+    {
+        $index = self::getByFloor($floorNumber);
+        return $index ? (float) $index->height_index : 1.0;
+    }
+
+    /**
+     * Get all height indices as array
+     */
+    public static function getAllMapping(): array
+    {
+        return self::orderBy('floor_number')
+            ->pluck('height_index', 'floor_number')
+            ->toArray();
+    }
+
+    /**
+     * Get available floor numbers
+     */
+    public static function getAvailableFloors(): array
+    {
+        return self::orderBy('floor_number')
+            ->pluck('floor_number')
+            ->toArray();
+    }
+}