<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class MasterFormula extends Model
{
    use HasFactory;

    protected $fillable = [
        'formula_code',
        'formula_name',
        'formula_expression',
        'formula_category',
        'description',
        'usage_notes',
    ];

    /**
     * Relationship to FormulaParameter (Many-to-Many dengan MasterParameter)
     */
    public function formulaParameters()
    {
        return $this->hasMany(FormulaParameter::class, 'formula_id');
    }

    /**
     * Relationship to MasterParameter through FormulaParameter
     */
    public function parameters()
    {
        return $this->belongsToMany(MasterParameter::class, 'formula_parameters', 'formula_id', 'parameter_id');
    }

    /**
     * Relationship to BuildingFunctionFormulaConfig
     */
    public function buildingConfigs()
    {
        return $this->hasMany(BuildingFunctionFormulaConfig::class, 'formula_id');
    }

    /**
     * Scope untuk mencari berdasarkan kategori
     */
    public function scopeByCategory($query, $category)
    {
        return $query->where('formula_category', $category);
    }

    /**
     * Method untuk mendapatkan parameter yang diperlukan formula ini
     */
    public function getRequiredParameters()
    {
        return $this->parameters()->get();
    }

    /**
     * Method untuk evaluate formula dengan parameter values
     */
    public function evaluateFormula($parameterValues = [])
    {
        $expression = $this->formula_expression;
        
        // Replace parameter codes dengan nilai actual
        foreach ($parameterValues as $parameterCode => $value) {
            $expression = str_replace('{' . $parameterCode . '}', $value, $expression);
        }
        
        // Evaluasi mathematical expression (hati-hati dengan security!)
        // Untuk production, gunakan library yang aman seperti SymfonyExpressionLanguage
        try {
            return eval("return $expression;");
        } catch (Exception $e) {
            throw new \Exception("Error evaluating formula: " . $e->getMessage());
        }
    }
}