function isEmptyArray(array) {
	return Array.isArray(array) && array.length === 0;
}		
		
function handleFiles(files) {
	const formData = new FormData();
    const validFiles = [];
    for (const file of files) {
		if (file.size > 0) {
			formData.append('files[]', file);
            validFiles.push(file);
        } else {
			console.warn(`The file "${file.name}" is empty and will be skipped.`);
        }
	}

	if (validFiles.length === 0) {
		alert('No valid files to upload. All selected files are empty.');
        return;
	}
            
	fetch('upload.php', {
		method: 'POST',
        body: formData
	}).then(response => {
		if (!response.ok) {
			throw new Error('Network response was not ok: ' + response.status);
		}
		return response.json();
	}).then(results => {
			let successes = [];
			let errors = [];
			results.forEach(result => {
				if (result.status == "success") {
					successes.push(result.message);
				} else {
					errors.push(result.message);
				}	
			});             
			if (!isEmptyArray(successes)) {
				const success = successes.map(text => text).join(", ");
				alert("Successfully uploaded: " + success);
			}
			if (!isEmptyArray(errors)) {
				const error = errors.map(text => text).join(", ");
				alert("Failed on: " + error);
			}
	}).catch(error => {
		if (error.message.startsWith('Network response')) {
			alert('Internal Server Error (500): There was a problem with the server.');
		} else {
			alert('Error:' + error);
		}
	}).finally(() => {
		for (const key in formData) {
		  if (formData.hasOwnProperty(key)) {
			delete formData[key];
		  }
		}
		while (validFiles.length > 0) {
		  validFiles.pop();
		}
	});
}

document.addEventListener('DOMContentLoaded', function() {
	const uploadContainer = document.getElementById('uploadContainer');
	const fileInput = document.getElementById('fileInput');

	uploadContainer.addEventListener('click', () => fileInput.click());

	uploadContainer.addEventListener('dragover', (e) => {
		e.preventDefault();
		uploadContainer.classList.add('dragover');
	});

	uploadContainer.addEventListener('dragleave', () => {
		uploadContainer.classList.remove('dragover');
	});

	uploadContainer.addEventListener('drop', (e) => {
		e.preventDefault();
		uploadContainer.classList.remove('dragover');
		let total = 0;	
		try {
			total = e.dataTransfer.files.length;
		} catch (error) {
			console.error("Opps" + error.message);
		}
		if (total > 0) {
			handleFiles(e.dataTransfer.files);
		} else {
			alert("No files dropped. Please try again.");
		}
	});

	fileInput.addEventListener('change', (e) => handleFiles(e.target.files));
});