google.charts.load('current', {'packages':['corechart']});

google.charts.setOnLoadCallback(draw_chart);

var p_int = 0;

var data = [

    ['X', 'Evolutia XYZ'],
    [2, 2],
    [3, 5],
    [7, 15],
    [10, 20],

];

function draw_chart() {

    var data_obj = new google.visualization.arrayToDataTable(data);

    var options = {

        title: 'Grafic de test',
        hAxis: {title: 'Axa X'},
        vAxis: {title: 'Axa Y'},
        legend: {position: 'top'}

    };

    /*
    TODO:
    - de adaugat optiuni care sa stilizeze axele graficului
    - de adaugat optiiuni care sa stilizeze legenda
    */

    var chart_el = document.getElementById('chart');

    var chart_obj = new google.visualization.AreaChart(chart_el);

    chart_obj.draw(data_obj, options);

}

document.getElementById('adaugare').onclick = function(event) {

    event.preventDefault();

    adaugare_punct();
    adaugare_istoric();

}

// document.getElementById('stergere').onclick = function(event) {

//  event.preventDefault();

//  stergere_element_istoric();

// }

function adaugare_punct() {

    var x_val = Number(document.getElementById('x').value);
    var y_val = Number(document.getElementById('y').value);

    /*
    TODO:
    - de verificat ca ambele campuri au valori non-empty
    - de verificat ca valorile sunt de tip number
    - daca sunt probleme, trebuie afisat un mesaj de eroare si oprita re-desenarea graficului
    */

    var new_array = [x_val, y_val];

    // START - determinam index-ul la care trebuie adaugat in array noua pereche de valori

    var add_index = data.length;

    for (i in data) {

        var c_array = data[i];
        var c_x = c_array[0];

        if (c_x > x_val) {

            add_index = i;
            break;

        }

    }

    // END - determinam index-ul la care trebuie adaugat in array noua pereche de valori

    data.splice(add_index, 0, new_array);

    draw_chart();


}

function adaugare_istoric() {
    /*
    TODO:
    - de creat un nou div, in care sa pastrez istoricul punctelor care au fost adaugate
    - de adaugat in dreptul fiecarei perechi de puncte nou adaugate un eventual link de delete
    */

    var x_val = Number(document.getElementById('x').value);
    var y_val = Number(document.getElementById('y').value);

    var para = document.createElement("P");
    para.setAttribute("id",p_int);                      // Create a <p> node
    var t = document.createTextNode("x: " + x_val + " y: " + y_val);      // Create a text node
    para.appendChild(t);                                          // Append the text to <p>
    var ah = document.createElement("A");
    ah.setAttribute("href","#");
    ah.setAttribute("id","stergere");
    ah.setAttribute("onclick","javascript:stergere_element_istoric(this)");
    var linkText = document.createTextNode("Stergere");
    ah.appendChild(linkText);
    para.appendChild(ah);
    document.getElementById("istoric").appendChild(para);           // Append <p> to <div> with id="myDIV"

    p_int++;
}

function stergere_element_istoric(e) {

    e.parentNode.parentNode.removeChild(e.parentNode);


}