document.getElementById('terrainForm').addEventListener('submit', function (event) {
    event.preventDefault();
    var terrain = document.getElementById('terrainType').value;

    // Insert the loading.gif before making the fetch request
    let resultSection = document.getElementById('resultSection');
    resultSection.innerHTML = '';
    let imgElement = document.createElement('img');
    imgElement.src = 'img/checking.gif';
    imgElement.style.width = '500px';
    imgElement.style.height = '500px';
    imgElement.style.display = 'block';
    imgElement.style.marginLeft = 'auto';
    imgElement.style.marginRight = 'auto';
    resultSection.appendChild(imgElement);

    fetch('https://gammaworld.gmgauthier.com/roll/encounter', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({
            terrain: terrain,
        }),
    })
        .then((response) => {
            if (!response.ok) {
                throw response;
            }
            return response.json(); // we only get here if there is no error
        })
        .then((json) => {
            // Handle null encounter
            let encounterText = json.encounter ? json.encounter : 'No Encounter';

            // Change the src attribute of the image after fetch resolves
            setTimeout(() => {
                imgElement.src = './img/' + encounterText + ".jpg";
            }, 1000);

            imgElement.onerror = function () {
                this.onerror = null;
                this.src = './img/404.jpg';
            };
        })
        .catch((err) => {
            err.text().then((errorMessage) => {
                imgElement.src = './img/404.jpg';
            });
        });
});