/**
 * Generates the actual browserfingerprint.
 */
function GenerateBrowserFingerprint() {
	
	let length = 255;
    let result = '';
	let characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    const charactersLength = characters.length;
    for ( let i = 0; i < length; i++ ) {
        result += characters.charAt(Math.floor(Math.random() * charactersLength));
    }
	
    $('#mfa_browser_fingerprint').val(result);
	
}

/**
 * Updates the trusted browser status.
 * It checks for expired fingerprints and creates a new fingerprint when necessary.
 * Mind that this function does not store/save the fingerprint to the browser's localStorage.
 */
function UpdateTrustedBrowserStatus() {

	var sUserName = $('#user').val();
	var sSettings = localStorage.getItem('mfa_' + sUserName);

	// Check if the client can detect an outdated fingerprint to avoid the user needs to log in again first.
	if(sSettings !== null) {
	
		var oSettings = JSON.parse(sSettings);

		let oSetDate = oSettings.date;
		let oExpirationDate = new Date(new Date(oSetDate).getTime() + (14 * 24 * 60 * 60 * 1000));
		let oCurrentDate = new Date();

		if(oExpirationDate <= oCurrentDate) {
		
			// Destroy and generate, do not save yet
			localStorage.removeItem('mfa_' + sUserName);
			GenerateBrowserFingerprint();
		
		}
		else {
		
			// Use existing print
			$('#mfa_browser_fingerprint').val(oSettings.fingerprint);

		}

	}
	
	// No fingerprint exists.
	else {

		GenerateBrowserFingerprint();

	}


}

/**
 * Toggles the visibility of the "trusted browser" checkbox and OTP fields based on user name.
 */
function UpdateTrustedBrowserVisibility() {
	
	var sUserName = $('#user').val();
	
	if(localStorage.getItem('mfa_' + sUserName) !== null) {
		
		// Fingerprint configured. If it fails, it will be have been unset upon reload (earlier).
		$('#jb-mfa').hide();
		
	}
	else {
		
		$('#jb-mfa').show();
		
	}
	
}

// Various events (e.g. autofilled usernames).
// What about pre-authenticated users? 
$('#user').on('keyup change blur input', function(e) {
	
	UpdateTrustedBrowserVisibility();
	
});

// Initially (could be prefilled e.g. with the auth_user parameter)
UpdateTrustedBrowserVisibility();
	

$(document).ready(function() {

	// Store (new) fingerprint on submission
	$('#login_form').on('submit', function(e) {

		// Only continue if fingerprint has not been set yet
		if($('#mfa_browser_fingerprint').val() != '') {
			return;
		}

		// Prevent original submission (without mfa_browser_fingerprint)
		e.preventDefault();
		
		UpdateTrustedBrowserStatus();
		
		var sUserName = $('#user').val();
		var sFingerprint = $('#mfa_browser_fingerprint').val();

		// Store fingerprint if new and if wanted
		if(localStorage.getItem('mfa_' + sUserName) === null && $('#mfa_browser_trust').prop('checked') == true) {
		
			localStorage.setItem('mfa_' + sUserName, JSON.stringify({
				fingerprint: sFingerprint,
				date: new Date()
			}));
		
		}
		
		// console.log(sFingerprint);
		
		$('#mfa_browser_fingerprint').attr('data-set', '1');
		
		$(this).submit();

	});
	
});