<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\HasMany;

class RetributionFormula extends Model
{
    protected $fillable = [
        'building_function_id',
        'name',
        'formula_expression',
        'description',
        'is_active'
    ];

    protected $casts = [
        'is_active' => 'boolean'
    ];

    /**
     * Building function relationship (1:1)
     */
    public function buildingFunction(): BelongsTo
    {
        return $this->belongsTo(BuildingFunction::class);
    }

    /**
     * Retribution calculations relationship (1:n)
     */
    public function retributionCalculations(): HasMany
    {
        return $this->hasMany(RetributionCalculation::class);
    }

    /**
     * Scope: Active formulas only
     */
    public function scopeActive($query)
    {
        return $query->where('is_active', true);
    }

    /**
     * Execute formula calculation
     */
    public function calculate(float $luasBangunan, array $parameters): float
    {
        // Replace placeholders in formula with actual values
        $formula = $this->formula_expression;
        
        // Replace luas_bangunan
        $formula = str_replace('luas_bangunan', $luasBangunan, $formula);
        
        // Replace parameter values
        foreach ($parameters as $key => $value) {
            $formula = str_replace($key, $value, $formula);
        }
        
        // Evaluate the mathematical expression
        // Note: In production, use a safer math expression evaluator
        try {
            $result = eval("return $formula;");
            return (float) $result;
        } catch (Exception $e) {
            throw new \Exception("Error calculating formula: " . $e->getMessage());
        }
    }

    /**
     * Get formula with parameter placeholders replaced for display
     */
    public function getDisplayFormula(array $parameters = []): string
    {
        $formula = $this->formula_expression;
        
        if (!empty($parameters)) {
            foreach ($parameters as $key => $value) {
                $formula = str_replace($key, "({$key}={$value})", $formula);
            }
        }
        
        return $formula;
    }

    /**
     * Validate formula expression
     */
    public function validateFormula(): bool
    {
        // Basic validation - check if formula contains required elements
        $requiredElements = ['luas_bangunan'];
        
        foreach ($requiredElements as $element) {
            if (strpos($this->formula_expression, $element) === false) {
                return false;
            }
        }
        
        return true;
    }
}