document.addEventListener('DOMContentLoaded', function () {
    const shortenForm = document.getElementById('shortenForm');
    const urlInput = document.getElementById('urlInput');
    const resultDiv = document.getElementById('result');
    const shortUrlSpan = document.getElementById('short-url');
    const copyBtn = document.getElementById('copyBtn');

    shortenForm.addEventListener('submit', function (e) {
        e.preventDefault();
        const longUrl = urlInput.value.trim();

        // Simple URL validation
        if (!isValidHttpUrl(longUrl)) {
            alert('Please enter a valid URL (e.g., https://example.com)');
            urlInput.focus();
            return;
        }

        // --- Dummy Shortener Logic ---
        // In a real app, this would be an API call.
        const randomString = Math.random().toString(36).substring(2, 8);
        const shortUrl = `yourdomain.com/${randomString}`;
        // --- End Dummy Logic ---

        shortUrlSpan.textContent = shortUrl;
        resultDiv.style.display = 'block';
    });

    copyBtn.addEventListener('click', function() {
        navigator.clipboard.writeText(shortUrlSpan.textContent).then(() => {
            copyBtn.textContent = 'Copied!';
            setTimeout(() => {
                copyBtn.textContent = 'Copy';
            }, 2000);
        }).catch(err => {
            console.error('Failed to copy: ', err);
        });
    });

    function isValidHttpUrl(string) {
        let url;
        try {
            url = new URL(string);
        } catch (_) {
            return false;
        }
        return url.protocol === "http:" || url.protocol === "https:";
    }
});