var words = Array(sentences.length);
var indexes = Array(sentences.length);
var results = Array(sentences.length);
var selected_words = Array(sentences.length);

function generate_sentences() {
	for(j = 0; j < sentences.length; j++) {
		words[j] = sentences[j].split(' ');
		indexes[j] = Array(words[j].length);
		selected_words[j] = Array(words[j].length);
		results[j] = 0;
		for(i = 0; i < words[j].length;i ++) {
			var notFound = true;
			var random = -1;
			while(notFound) {
				random = Math.floor(words[j].length * Math.random());
				notFound = false;
				for(z = 0 ; z < i ; z ++) {
					if(indexes[j][z] == random) {
						notFound = true;
						break;
					}
				}
			}
			indexes[j][i] = random;
			selected_words[j][i] = false;
		}
		document.write('<div id="words_' + j +'">');
		document.write('<font color="#0000ff" size="2" face="Verdana, Geneva, Arial, Helvetica, sans-serif;">');
		document.write(build_select_words(j));
		document.write('</font></div><br/>')
		document.write('<input type="text" name="sentence_' + j + '" value="" size="70" /> <img name="image_ok_' + j + '" src="images/none.gif"><br/><br/>');
	}
}
function build_select_words(sentence_num) {
		var select_html = '<font color="#0000ff" size="2" face="Verdana, Geneva, Arial, Helvetica, sans-serif;">' + (sentence_num + 1) + '</font>&nbsp;&nbsp;';
		for(i = 0; i < words[sentence_num].length;i ++) {
			if(selected_words[sentence_num][i] == false) {
				select_html += '<a href="javascript:insert_word(' + sentence_num + ', ' + i + ')"><font color="#0000ff" size="2" face="Verdana, Geneva, Arial, Helvetica, sans-serif;">';
				select_html += words[sentence_num][indexes[sentence_num][i]];
				select_html += '</font></a> ';
			} else {
// used words
			select_html += '<font color="#ff0000" size="2" face="Verdana, Geneva, Arial, Helvetica, sans-serif;">' + words[sentence_num][indexes[sentence_num][i]] + ' </font>';
			}
		}
		select_html += '</font>';
		return select_html;
}
function insert_word(sentence_num, word_num) {
	if(results[sentence_num] == words[sentence_num].length) {
		alert('Well Done!');
		return;
	}
	if(words[sentence_num][indexes[sentence_num][word_num]] 
		!= words[sentence_num][results[sentence_num]]) {
		alert('Try again!');
		return;
	}	
	selected_words[sentence_num][word_num] = true;
	var sentence = '';
	for(i = 0; i <= results[sentence_num]; i++) {
		sentence = sentence + words[sentence_num][i] + ' '
	}
	var field_name = 'sentence_' + sentence_num;
	document.all[field_name].value = sentence;
	results[sentence_num] = results[sentence_num] + 1;
	if(results[sentence_num] == words[sentence_num].length) {
		document.all['image_ok_' + sentence_num].src = "images/ok.gif";
	}
	var words_html = build_select_words(sentence_num);
	document.all['words_' + sentence_num].innerHTML = words_html;
}
function clear_fields() {
	for(j = 0; j < sentences.length; j++) {
		document.all['sentence_' + j].value = '';
	}
}