// water invoice builder functions 

function isInteger(input) {

    if (/^[\d]+$/.test(input)){
        return true;
    }
    return false;
}

function isAlphaChar(input) {

    if (/^[a-zA-Z]+$/.test(input)){
        return true;
    }
    return false;
}

function validateIt(e, lb) {
    if (e.value != "") {
        if ( ( !isInteger(e.value) ) || ( parseInt(e.value, 10) == 0 ) ) {
            alert("Η τιμή του πεδίου '" + lb + "' πρέπει να είναι ένας ακέραιος αριθμός μεγαλύτερος του μηδενός.\n");
            e.focus();
            e.value="";
        }
    }
}

function calculateWaterConsumption() {

    var con1 = document.getElementById("prev_reading").value;
    var con2 = document.getElementById("curr_reading").value;
    var water_used;

   if ( ( !isNaN(con1) ) && ( !isNaN(con2) ) ) {
        water_used = parseInt(con2, 10) - parseInt(con1, 10);
        if (water_used >= 0) {
            document.getElementById("water_consumption").value = water_used;
        }else{
            document.getElementById("water_consumption").value = "";
        } 
    }
   
}

function buildSlideShow(imgTotal,startIndex,endIndex) {

    var imgArray = create_unique_random_array(imgTotal,startIndex,endIndex);

    document.getElementById('slide1').src = "images/slideshow/img" + imgArray[0] + ".jpg";
    document.getElementById('slide1').alt = "Εικόνα: " + imgArray[0] + ".jpg";
    document.getElementById('slide1').title = "Εικόνα: " + imgArray[0] + ".jpg";

    document.getElementById('slide2').src = "images/slideshow/img" + imgArray[1] + ".jpg";
    document.getElementById('slide2').alt = "Εικόνα: " + imgArray[1] + ".jpg";
    document.getElementById('slide2').title = "Εικόνα: " + imgArray[1] + ".jpg";

    document.getElementById('slide3').src = "images/slideshow/img" + imgArray[2] + ".jpg";
    document.getElementById('slide3').alt = "Εικόνα: " + imgArray[2] + ".jpg";
    document.getElementById('slide3').title = "Εικόνα: " + imgArray[2] + ".jpg";

    //alert(document.getElementById('slide1').src);
    //alert(document.getElementById('slide2').src);
    //alert(document.getElementById('slide3').src);

}


function create_unique_random_array(num_elements,min,max) {

    var temp, nums = new Array;

    for (var element=0; element<num_elements; element++) {

        //IMPORTANT: DON'T FORGET THE SEMI-COLON AT THE END
        while((temp=number_found(random_number(min,max),nums))==-1);
        nums[element] = temp;
    }

    return (nums);
}

function random_number(lbound,ubound) {
    var rand_n = Math.floor((ubound-(lbound-1))*Math.random()) + lbound;
    return rand_n;
} 

function number_found (random_number,number_array) {

    for (var element=0; element<number_array.length; element++) {

        if (random_number==number_array[element]) {
            return (-1);
	}
   }

    return (random_number);
}