Stirling-PDF/src/main/resources/static/js/fileInput.js

document.addEventListener('DOMContentLoaded', function() {

    let overlay;
    let dragCounter = 0;

    const dragenterListener = function() {
        dragCounter++;
        if (!overlay) {
            // Create and show the overlay
            overlay = document.createElement('div');
            overlay.style.position = 'fixed';
            overlay.style.top = 0;
            overlay.style.left = 0;
            overlay.style.width = '100%';
            overlay.style.height = '100%';
            overlay.style.background = 'rgba(0, 0, 0, 0.5)';
            overlay.style.color = '#fff';
            overlay.style.zIndex = '1000';
            overlay.style.display = 'flex';
            overlay.style.alignItems = 'center';
            overlay.style.justifyContent = 'center';
            overlay.style.pointerEvents = 'none';
            overlay.innerHTML = '<p>Drop files anywhere to upload</p>';
            document.getElementById('content-wrap').appendChild(overlay);
        }
    };

    const dragleaveListener = function() {
        dragCounter--;
        if (dragCounter === 0) {
            // Hide and remove the overlay
            if (overlay) {
                overlay.remove();
                overlay = null;
            }
        }
    };

    const dropListener = function(e) {
        const dt = e.dataTransfer;
        const files = dt.files;

        // Access the file input element and assign dropped files
        const fileInput = document.getElementById(elementID);
        fileInput.files = files;

        // Hide and remove the overlay
        if (overlay) {
            overlay.remove();
            overlay = null;
        }

        // Reset drag counter
        dragCounter = 0;

        handleFileInputChange(fileInput);
    };

    // Prevent default behavior for drag events
    ['dragenter', 'dragover', 'dragleave', 'drop'].forEach(eventName => {
        document.body.addEventListener(eventName, preventDefaults, false);
    });

    function preventDefaults(e) {
        e.preventDefault();
        e.stopPropagation();
    }

    document.body.addEventListener('dragenter', dragenterListener);
    document.body.addEventListener('dragleave', dragleaveListener);
    // Add drop event listener
    document.body.addEventListener('drop', dropListener);

});

$("#"+elementID).on("change", function() {
    handleFileInputChange(this);
});


function handleFileInputChange(inputElement) {
	const files = $(inputElement).get(0).files;
	const fileNames = Array.from(files).map(f => f.name);
	const selectedFilesContainer = $(inputElement).siblings(".selected-files");
	selectedFilesContainer.empty();
	fileNames.forEach(fileName => {
		selectedFilesContainer.append("<div>" + fileName + "</div>");
	});
	if (fileNames.length === 1) {
		$(inputElement).siblings(".custom-file-label").addClass("selected").html(fileNames[0]);
	} else if (fileNames.length > 1) {
		$(inputElement).siblings(".custom-file-label").addClass("selected").html(fileNames.length + " " + filesSelected);
	} else {
		$(inputElement).siblings(".custom-file-label").addClass("selected").html(pdfPrompt);
	}
}