人資系統關鍵功能，2025/114年勞健保扣多少？人資與開發都該關心的事

<?php

class InsuranceCalculator
{
    protected $year;
    protected $salary;
    protected $dependents; // 員工眷屬人數（上限3）
    
    // 可動變數統一在此設定或從config引入
    protected $insuranceParams = [
        '2024' => [
            'labor_insurance_rate' => 0.12,   // 12%
            'labor_employer_ratio' => 0.70,
            'labor_employee_ratio' => 0.20,
            'health_insurance_rate' => 0.0517, // 5.17%
            'health_employer_ratio' => 0.60,
            'health_employee_ratio' => 0.30,
            'health_gov_ratio' => 0.10,
            'avg_dependent_factor' => 1.57,    // 雇主計算時使用
            'min_wage_level' => 27470,         // 2024年最低投保薪資
            // ...其他級距、上限設定...
        ],
        '2025' => [
            'labor_insurance_rate' => 0.125,  // 12.5%
            'labor_employer_ratio' => 0.70,
            'labor_employee_ratio' => 0.20,
            'health_insurance_rate' => 0.0517, // 5.17%不變
            'health_employer_ratio' => 0.60,
            'health_employee_ratio' => 0.30,
            'health_gov_ratio' => 0.10,
            'avg_dependent_factor' => 1.57,    // 假設不變
            'min_wage_level' => 28590,         // 2025年最低投保薪資
            // ...其他級距、上限設定...
        ],
    ];

    public function __construct($year, $salary, $dependents = 0)
    {
        $this->year = (string)$year;
        $this->salary = $salary;
        $this->dependents = min($dependents, 3); // 眷屬上限3
    }

    public function calculateAll()
    {
        // 根據年度取得設定值
        $params = $this->insuranceParams[$this->year];

        // 投保薪資級距邏輯（示意：若實際上需根據薪資對照表調整salary）
        $adjustedSalary = $this->getAdjustedSalary($this->salary, $params);

        // 計算勞保員工、雇主負擔
        $laborEmployee = $adjustedSalary * $params['labor_insurance_rate'] * $params['labor_employee_ratio'];
        $laborEmployer = $adjustedSalary * $params['labor_insurance_rate'] * $params['labor_employer_ratio'];

        // 計算健保員工、雇主負擔
        // 員工健保負擔: 投保薪資 × 健保費率 × 30% × (本人+眷屬人數)
        $healthEmployee = $adjustedSalary * $params['health_insurance_rate'] * $params['health_employee_ratio'] * (1 + $this->dependents);

        // 雇主健保負擔: 投保薪資 × 健保費率 × 60% × 平均眷口數因子(1.57)
        $healthEmployer = $adjustedSalary * $params['health_insurance_rate'] * $params['health_employer_ratio'] * $params['avg_dependent_factor'];

        // 職災保險費率可另外加入，如職災僅雇主負擔
        // 假設職災費率為 dynamic_rate 例如0.005，則:
        $occupationalInjuryRate = 0.005; // 範例費率
        $occupationalInsurance = $adjustedSalary * $occupationalInjuryRate; // 全由雇主負擔

        // 勞退 6% 全由雇主負擔
        $pension = $adjustedSalary * 0.06; 

        return [
            'employee' => [
                'labor' => round($laborEmployee),
                'health' => round($healthEmployee),
            ],
            'employer' => [
                'labor' => round($laborEmployer),
                'health' => round($healthEmployer),
                'occupational' => round($occupationalInsurance),
                'pension' => round($pension),
            ],
        ];
    }

    protected function getAdjustedSalary($salary, $params)
    {
        // 此處可根據勞保投保級距表，將實際月薪對應到最近的級距
        // 簡化示範：若月薪小於最低投保薪資則以最低投保薪資計算
        if ($salary < $params['min_wage_level']) {
            return $params['min_wage_level'];
        }

        // 若超過最高級距(45800)則以45800為上限
        if ($salary > 45800) {
            return 45800;
        }

        // 實務上應用「投保薪資級距表」尋找對應級距，
        // 這裡簡化僅示意直接回傳salary
        return $salary;
    }
}

// 範例呼叫:
$calculator2025 = new InsuranceCalculator(2025, 30300, 2);
$result = $calculator2025->calculateAll();
print_r($result);