function drawCalendarPicker()

in webui/js/source/datepicker.js [569:676]
90 lines of code
12 McCabe index (conditional complexity)

function drawCalendarPicker(obj, date) {


    obj.focus()

    // Default to NOW for calendar.
    let now = new Date()

    // if called with an existing date (YYYY-MM-DD),
    // convert it to a JS date object and use that for
    // rendering the calendar
    if (date) {
        let ar = date.split(/-/)
        now = new Date(ar[0], parseInt(ar[1]) - 1, ar[2])
    }
    let mat = now

    // Go to first day of the month
    mat.setDate(1)

    obj.innerHTML = "<h3>" + MONTHS[mat.getMonth()] + ", " + mat.getFullYear() + ":</h3>"
    let tm = mat.getMonth()

    // -- Nav buttons --

    // back-a-year button
    let a = document.createElement('a')
    fixupPicker(a)
    a.setAttribute("onclick", "drawCalendarPicker(this.parentNode, '" + (mat.getFullYear() - 1) + '-' + (mat.getMonth() + 1) + '-' + mat.getDate() + "');")
    a.setAttribute("href", "javascript:void(0);")
    a.setAttribute("class", "glyphicon glyphicon-fast-backward");
    obj.appendChild(a)

    // back-a-month button
    a = document.createElement('a')
    fixupPicker(a)
    a.setAttribute("onclick", "drawCalendarPicker(this.parentNode, '" + mat.getFullYear() + '-' + (mat.getMonth()) + '-' + mat.getDate() + "');")
    a.setAttribute("href", "javascript:void(0);")
    a.setAttribute("class", "glyphicon glyphicon-step-backward");
    obj.appendChild(a)

    // forward-a-month button
    a = document.createElement('a')
    fixupPicker(a)
    a.setAttribute("onclick", "drawCalendarPicker(this.parentNode, '" + mat.getFullYear() + '-' + (mat.getMonth() + 2) + '-' + mat.getDate() + "');")
    a.setAttribute("href", "javascript:void(0);")
    a.setAttribute("class", "glyphicon glyphicon-step-forward");
    obj.appendChild(a)

    // forward-a-year button
    a = document.createElement('a')
    fixupPicker(a)
    a.setAttribute("onclick", "drawCalendarPicker(this.parentNode, '" + (mat.getFullYear() + 1) + '-' + (mat.getMonth() + 1) + '-' + mat.getDate() + "');")
    a.setAttribute("href", "javascript:void(0);")
    a.setAttribute("class", "glyphicon glyphicon-fast-forward");
    obj.appendChild(a)
    obj.appendChild(document.createElement('br'))


    // Table containing the dates of the selected month
    let table = document.createElement('table')

    table.setAttribute("border", "1")
    table.style.margin = "0 auto"

    // Add header day names
    let tr = document.createElement('tr');
    for (let m = 0; m < 7; m++) {
        let td = document.createElement('th')
        td.innerHTML = DAYS_SHORTENED[m]
        tr.appendChild(td)
    }
    table.appendChild(tr)

    // Until we hit the first day in a month, add blank days
    tr = document.createElement('tr');
    let weekday = mat.getDay()
    if (weekday == 0) {
        weekday = 7
    }
    weekday--;
    for (let i = 0; i < weekday; i++) {
        let td = document.createElement('td')
        tr.appendChild(td)
    }

    // While still in this month, add day then increment date by 1 day.
    while (mat.getMonth() == tm) {
        weekday = mat.getDay()
        if (weekday == 0) {
            weekday = 7
        }
        weekday--;
        if (weekday == 0) {
            table.appendChild(tr)
            tr = document.createElement('tr');
        }
        let td = document.createElement('td')
        // onclick for setting the calendarPicker's parent to this val.
        td.setAttribute("onclick", "setCalendarDate('" + mat.getFullYear() + '-' + (mat.getMonth() + 1) + '-' + mat.getDate() + "');")
        td.innerHTML = mat.getDate()
        mat.setDate(mat.getDate() + 1)
        tr.appendChild(td)
    }

    table.appendChild(tr)
    obj.appendChild(table)
}