module.exports = function(input){

	var html_stack = [];
	var previous_line_num_tabs = -1;
	var lines;
	var html = '';

	var insertTabs = function(num_tabs) {
		var result = '';
		for(var i  = 0; i < num_tabs; i++){
			result += '\t';
		}
		return result;
	}

	var popHTMLStack = function(current_line_num_tabs, previous_line_num_tabs){
		var result = ''; 
		for(var i = previous_line_num_tabs; i > current_line_num_tabs; i--){
			result += html_stack.pop();
			result += html_stack.pop();
		}
		if(html_stack.length > 0){
			result += html_stack.pop();
		}
		return result;
	}

	var processList = function(i){
		var tabs_array = lines[i].split('\t');
		var current_line_num_tabs = tabs_array.length - 1;
		if(current_line_num_tabs > previous_line_num_tabs){
			html += insertTabs(current_line_num_tabs * 2) + '<ul>\n';
			html_stack.push(insertTabs(current_line_num_tabs * 2) + '</ul>\n');
		} else { 
			html += popHTMLStack(current_line_num_tabs, previous_line_num_tabs);
		}
		html += insertTabs((current_line_num_tabs * 2) + 1) + '<li>\n';
		html += insertTabs((current_line_num_tabs * 2) + 2) + tabs_array[tabs_array.length - 1] + '\n';
		html_stack.push(insertTabs((current_line_num_tabs * 2) + 1) + '</li>\n');
		previous_line_num_tabs = current_line_num_tabs;
	}

	var processSingleLine = function(i){
		html += popHTMLStack(-1, previous_line_num_tabs); 
		previous_line_num_tabs = -1;
		if(lines[i].indexOf('.') > 0){
			html += '<p>' + lines[i] + '</p>\n';
		} else if( i > 0 ) {
			html += '<h2>' + lines[i] + '</h2>\n';
		} else {
			html += '<h1>' + lines[i] + '</h1>\n';
		}
	}

	var parseFile = function(data){
		lines = data.split('\n');
		for(var i = 0; i < lines.length; i++){
			if(lines[i] !== ''){
				if(lines[ i + 1 ] === '' && (i === 0 || lines[ i - 1 ] === '')){
					processSingleLine(i);
				} else {
					processList(i);
				}
			}
		}
		html += popHTMLStack(-1, previous_line_num_tabs); 
		html = html.replace(/(https?:\/\/[^\s<]*)/g, '<a href="$1">$1</a>');
		previous_line_num_tabs = -1;
		return html
	}
	
	return parseFile(input).trim();
};