// from:  https://www.tornadoweb.org/en/stable/guide/security.html
// with changes: removed datatype and callback from original postJSON
function getCookie(name) {
    var r = document.cookie.match("\\b" + name + "=([^;]*)\\b");
    return r ? r[1] : undefined;
}

jQuery.postJSON = function(url, args) {
    args._xsrf = getCookie("_xsrf");
    $.ajax({url: url, data: $.param(args), type: "POST"});
};

// ---------------------------------------------------------------------------
$(document).ready(function() {
    function button_handlers() {
        // button handlers (runs once)
        $("#allow_all").click(
            function() {
                $(":checkbox").prop("checked", true).trigger('change');
            }
        );
        $("#deny_all").click(
            function() {
                $(":checkbox").prop("checked", false).trigger('change');
            }
        );
        $("#reset_password").click(
            function () {
                $.postJSON("/admin", {
                    "cmd": "reset_password",
                    "value": $("#reset_number").val()
                });
            }
        );
        $("#inserir_novo_aluno").click(
            function () {
                $.postJSON("/admin", {
                    "cmd": "insert_student",
                    "value": JSON.stringify({
                        "number": $("#novo_numero").val(),
                        "name": $("#novo_nome").val()
                    })
                });
            }
        );
        // authorization checkboxes in the students_table:
        $("tbody", "#students_table").on("change", "input", autorizeStudent);
    }

    // ----------------------------------------------------------------------
    // checkbox handler to allow/deny students individually
    function autorizeStudent(e) {
        if (this.checked) {
            // $(this).parent().parent().addClass("table-primary"); // row class
            $.postJSON("/admin", {"cmd": "allow", "value": this.name});
        }
        else {
            // $(this).parent().parent().removeClass("active");
            $.postJSON("/admin", {"cmd": "deny", "value": this.name});
        }
    }

    // ----------------------------------------------------------------------
    function generate_grade_bar(grade) {
        var barcolor;
        if (grade < 10)
            barcolor = 'bg-danger';
        else if (grade < 15)
            barcolor = 'bg-warning';
        else
            barcolor = 'bg-success';

        return '<div class="progress"><div class="progress-bar ' + barcolor
            + '" role="progressbar" aria-valuenow="' + grade
            + '" aria-valuemin="0" aria-valuemax="20" style="min-width: 2em; width: '
            + (5*grade) + '%;">' + grade + '</div></div>';
    }

    // ----------------------------------------------------------------------
    function populateHeader() {
        $.ajax({
            url: "/admin",
            data: {"cmd": "test", "value": ""},
            dataType: "json",
            success: function(data) {
                // fill jumbotron data
                $("#title").html(data['data']['title']);
                $("#ref").html(data['data']['ref']);
                $("#filename").html(data['data']['filename']);
                $("#database").html(data['data']['database']);
                $("#answers_dir").html(data['data']['answers_dir']);
            },
            error: function() {alert("Servidor não responde.");}
        });
    }

    // ----------------------------------------------------------------------
    function populateStudentsTable() {
        var table = $('#students_table').DataTable({
            stateSave: true,
            paging: false,
            responsive: true,
            language: {
                search:         "Pesquisar: ",
                info:           "Visíveis _TOTAL_ alunos",
                infoEmpty:      "Visíveis _TOTAL_ alunos",
                infoFiltered:   "(filtrados de _MAX_ no total)",
                zeroRecords:    "Não encontrado",
                emptyTable:     "Não há alunos inscritos",
            },
            ajax: {
                url: "admin", // students_table
                data: {"cmd": "students_table", "value": ""},
                dataType: "json",
                dataSrc: function ( json ) {
                    var t = [];
                    for ( var i=0; i < json.data.length ; i++ ) {
                        d = json.data[i];
                        var uid = d['uid'];
                        var checked = d['allowed'] ? 'checked' : '';
                        var password_defined = d['password_defined'] ? ' <span class="badge badge-secondary"><i class="fa fa-key" aria-hidden="true"></i></span>' : '';
                        var hora_inicio = d['start_time'] ? ' <span class="badge badge-success">' + d['start_time'].slice(11,19) + '</span>': '';
                        var g = d['grades'];

                        t[i] = [];
                        t[i][0] = i+1;
                        t[i][1] = '<input type="checkbox" name="' + uid + '" value="true"' + checked + '> ';
                        t[i][2] = uid;
                        t[i][3] = d['name'];
                        t[i][4] = password_defined + hora_inicio;

                        var gbar = '';
                        for (var j=0; j < g.length; j++)
                            gbar += '<div data-toggle="tooltip" data-placement="top" title="' + g[j][1].slice(0,19) + '"><a href="review?test_id=' + g[j][2] + '">' + generate_grade_bar(g[j][0]) + '</a></div>';
                        t[i][5] = gbar;
                    }
                    return t;
                }
            },
        });
        setInterval( function () {
            table.ajax.reload();
        }, 3000 );
    }

    populateHeader();              // run once when the page is loaded
    populateStudentsTable();
    button_handlers();             // assign handlers to buttons
});