document.addEventListener("DOMContentLoaded", function() {
    const accCi = document.getElementById('accCi');
    const pCi = document.getElementById('pCi');

    const accidentsMin = 1, accidentsMax = 999; 
    const periodMin = 1, periodMax = 20; 

    accCi.addEventListener('input', () => validateInputCi(accCi, accidentsMin, accidentsMax));
    pCi.addEventListener('input', () => validateInputCi(pCi, periodMin, periodMax));

    document.getElementById("accCi").addEventListener("input", calculateConfidenceInterval);
    document.getElementById("pCi").addEventListener("input", calculateConfidenceInterval);
    document.getElementById("kCi").addEventListener("change", calculateConfidenceInterval);
});

function validateInputCi(inputElement, min, max) {
    const value = parseFloat(inputElement.value);
    if (value < min || value > max) {
        alert(`The value must be a number between ${min} y ${max}.`);
        inputElement.value = ''; 
    }
}

function calculateConfidenceInterval() {
    const accCi = parseInt(document.getElementById("accCi").value);
    const pCi = parseInt(document.getElementById("pCi").value);
    const kCi = parseFloat(document.getElementById("kCi").value) / 100;

    if (isNaN(accCi) || isNaN(pCi) || pCi <= 0 || accCi < 0) {
        document.getElementById("pCi").textContent = "0.0";
        return;
    }

    const m = accCi / pCi;
    document.getElementById("pCi").textContent = m.toFixed(1);

    let z;
    switch (kCi) {
        case 0.80: z = 1.282; break;
        case 0.85: z = 1.440; break;
        case 0.90: z = 1.645; break;
        case 0.95: z = 1.960; break;
        case 0.99: z = 2.576; break;
        default: z = 1.960; 
    }

    const stdError = m / Math.sqrt(accCi);

    const marginOfError = z * stdError;
    const lowerLimit = m - marginOfError;
    const upperLimit = m + marginOfError;

    document.getElementById("accFCi").textContent = m.toFixed(1);
    document.getElementById("lowerCi").textContent = lowerLimit.toFixed(1);
    document.getElementById("upperCi").textContent = upperLimit.toFixed(1);
}