var DEFAULT_SUBJECT_TEXT = "predmet";
var DEFAULT_EMAIL_TEXT = "e-mail";
var DEFAULT_CONTACT_TEXT = "kontakt";
var DEFAULT_MESSAGE_TEXT = "správa";

var subjectTxt;
var emailTxt;
var contactTxt;
var messageTxt;

function initContactForm() {
	subjectTxt = document.getElementById("subject");
	subjectTxt.value = DEFAULT_SUBJECT_TEXT;
	
	emailTxt = document.getElementById("email");
	emailTxt.value = DEFAULT_EMAIL_TEXT;
	
	contactTxt = document.getElementById("contact");
	contactTxt.value = DEFAULT_CONTACT_TEXT;
	
	messageTxt = document.getElementById("message");
	
	messageTxt.value = DEFAULT_MESSAGE_TEXT;
}

function validateContactForm() {
	var out = true;
	 
	if(!isFieldValid(subjectTxt, subjectTxt.value, DEFAULT_SUBJECT_TEXT)) out = false;
	if(!isFieldValid(emailTxt, emailTxt.value, DEFAULT_EMAIL_TEXT)) out = false;
	if(!isFieldValid(contactTxt, contactTxt.value, DEFAULT_CONTACT_TEXT)) out = false;
	if(!isFieldValid(messageTxt, messageTxt.value, DEFAULT_MESSAGE_TEXT)) out = false;
	
	if(out) {
		document.getElementById("contact-form").submit();
	}
}
               
function isFieldValid(target, value, defaultValue) {
	if(value == "" || value == defaultValue) {
		highlightField(target);
		return false;
	}
	return true;
}

function highlightField(target) {
	target.setAttribute("class", "textinput highlight");
	target.setAttribute("className", "textinput highlight");
}

function focusHandler(target) {
	target.setAttribute("class", "textinput active");
	target.setAttribute("className", "textinput active");
	
	var defaultValue;
	switch(target) {
		case subjectTxt:
			defaultValue = DEFAULT_SUBJECT_TEXT;
			break;
		case emailTxt:
			defaultValue = DEFAULT_EMAIL_TEXT;
			break;
		case contactTxt:
			defaultValue = DEFAULT_CONTACT_TEXT;
			break;
		case messageTxt:
			defaultValue = DEFAULT_MESSAGE_TEXT;
			break;
	}
	
	if(target.value == defaultValue) target.value = "";
}

function blurHandler(target) {
	target.setAttribute("class", "textinput normal");
	target.setAttribute("className", "textinput normal");
	
	var defaultValue;
	switch(target) {
		case subjectTxt:
			defaultValue = DEFAULT_SUBJECT_TEXT;
			break;
		case emailTxt:
			defaultValue = DEFAULT_EMAIL_TEXT;
			break;
		case contactTxt:
			defaultValue = DEFAULT_CONTACT_TEXT;
			break;
		case messageTxt:
			defaultValue = DEFAULT_MESSAGE_TEXT;
			break;
	}
	
	if(target.value == "") target.value = defaultValue;
}