document.addEventListener('DOMContentLoaded', function () {
    calculateLC();
    calculateR();
    calculateS();
});

function calculateLC() {
    const R = document.getElementById('input11').value;
    const S = document.getElementById('input12').value;

    const lC = R * (1 - Math.cos((28.65 * (S / R)) * Math.PI / 180));

    document.getElementById('resultLC').innerText = lC.toFixed(2);
}

function calculateR() {
    const lC = parseFloat(document.getElementById('input21').value);
    const S = parseFloat(document.getElementById('input22').value);
  
    if (isNaN(lC) || lC <= 0 || isNaN(S) || S <= 0) {
        document.getElementById('resultR').innerText = "NaN";
        return;
    }

    const equation = (R) => lC - R * (1 - Math.cos((28.65 * (S / R)) * Math.PI / 180));
    const derivative = (R) => (Math.cos((28.65 * (S / R)) * Math.PI / 180) * (28.65 * S) / (R * R));

    const initialGuesses = [300, 200, 100, 400, 500]; 
    const tolerance = 1e-10; 
    const maxIterations = 100000; 
    let foundSolution = false;

    for (let guess of initialGuesses) {
        let R = guess;
        for (let i = 0; i < maxIterations; i++) {
            const f_R = equation(R);
            const f_prime_R = derivative(R);

            if (Math.abs(f_prime_R) < tolerance) {
                continue; 
            }

            const new_R = R - f_R / f_prime_R;

            if (Math.abs(new_R - R) < tolerance) {
                document.getElementById('resultR').innerText = Math.max(new_R.toFixed(2), 20);
                foundSolution = true;
                return; 
            }

            R = new_R; 
        }
    }

    document.getElementById('resultR').innerText = "---";
}

  
function calculateS() {
    const R = document.getElementById('input31').value;
    const lC = document.getElementById('input32').value;


    const angleRad = Math.acos(1 - (lC / R));
    const S = (R * angleRad * 180) / (28.65 * Math.PI);

    document.getElementById('resultS').innerText = S.toFixed(0);
}

function showTab(tabId) {
    document.querySelectorAll('.tab-content').forEach(tab => {
        tab.classList.remove('active');
    });
  
    const activeTab = document.getElementById(tabId);
    activeTab.classList.add('active');

    document.querySelectorAll('.tab').forEach(tab => {
        tab.classList.remove('active'); 
    });
    const activeTabElement = document.querySelector(`.tab[onclick*="${tabId}"]`);
    if (activeTabElement) {
        activeTabElement.classList.add('active'); 
    }

    
}