/*
 * The client side script that cgit serves with every page. Its main job is
 * to refresh the relative ages that cgit_print_age renders in
 * source/ui-shared.c, so the thresholds, suffixes and class names tabulated
 * below mirror the constants there and the two have to move together. One
 * smaller piece follows, the highlight laid over the source line a URL
 * fragment names. Each piece is wrapped in a function of its own so that
 * nothing is left behind in the global scope.
 */

(function () {

// Written the way SECONDS_PER_* are derived in source/cgit.h, so that the
// bucket a browser picks is the bucket cgit_print_age already picked on the
// server. A month is a twelfth of a year rather than thirty days, which is
// the definition the server uses.
var MINUTE = 60;
var HOUR   = 60 * MINUTE;
var DAY    = 24 * HOUR;
var WEEK   = 7 * DAY;
var YEAR   = 365 * DAY;
var MONTH  = YEAR / 12;

// The five arrays are indexed together by the bucket an age falls into. The
// search in render_age can stop one place past the last class, so the arrays
// it reads there repeat their final entry. Each limit is twice the next unit
// up, matching the thresholds cgit_print_age compares against.
var age_classes  = [ "age-mins", "age-hours", "age-days", "age-weeks", "age-months", "age-years" ];
var age_suffix   = [ "min.",     "hours",     "days",     "weeks",     "months",     "years",     "years" ];
var age_unit     = [ MINUTE,     HOUR,        DAY,        WEEK,        MONTH,        YEAR,        YEAR ];
var age_limit    = [ 2 * HOUR,   2 * DAY,     2 * WEEK,   2 * MONTH,   2 * YEAR,     2 * YEAR ];
var update_delay = [ 10,         5 * MINUTE,  30 * MINUTE, DAY,        DAY,          DAY,         DAY ];

function render_age(element, age) {
  var text, bucket;

  for (bucket = 0; bucket < age_classes.length; bucket++)
    if (age < age_limit[bucket])
      break;

  text = Math.round(age / age_unit[bucket]) + " " + age_suffix[bucket];

  // Every age on the page is measured again on each pass, so most of
  // them are already reading correctly and writing to them would cost a
  // repaint for nothing.
  if (element.textContent != text) {
    element.textContent = text;
    // An age past the last limit is still counted in years, but
    // there is no class beyond age-years to put on it.
    if (bucket == age_classes.length)
      bucket--;
    if (element.className != age_classes[bucket])
      element.className = age_classes[bucket];
  }
}

/*
 * Measures every age on the page against the clock and books the next pass.
 * There is no point coming back before the coarsest unit on the page could
 * change, so a page already counted in hours is left alone for minutes and
 * one counted in years for a day.
 */
function refresh_ages() {
  var bucket, elements, i, age;
  var delay = 24 * 3600;
  var now = Math.round(new Date().getTime() / 1000);

  for (bucket = 0; bucket < age_classes.length; bucket++) {
    elements = document.getElementsByClassName(age_classes[bucket]);

    if (elements.length && update_delay[bucket] < delay)
      delay = update_delay[bucket];

    for (i = 0; i < elements.length; i++) {
      age = now - elements[i].getAttribute("data-ut");

      // A commit dated ahead of the viewer's clock would
      // otherwise show a negative age, and ui-shared.c
      // clamps it the same way.
      if (age < 0)
        age = 0;

      render_age(elements[i], age);
    }
  }

  window.setTimeout(refresh_ages, delay * 1000);
}

document.addEventListener("DOMContentLoaded", function () {
  // Nothing here depends on layout, so the first pass can run as soon
  // as the document is parsed.
  refresh_ages();
}, false);

})();

/*
 * Washes a faded highlight over the source line a URL fragment names, either
 * a single line as in #n231 or a range as in #n5-n12. The line anchors live
 * in the number gutter, so the anchor is measured and a bar of the same
 * height is laid across the full width of the code. Without scripting the
 * CSS target rule still tints the line number itself.
 */

(function () {

var bar = null;

function place_bar() {
  var match, first, last, table;
  var table_box, first_box, last_box, top, bottom;

  if (bar) {
    bar.remove();
    bar = null;
  }
  match = /^#n(\d+)(?:-n?(\d+))?$/.exec(location.hash);
  if (!match)
    return;
  first = document.getElementById("n" + match[1]);
  if (!first)
    return;
  last = (match[2] && document.getElementById("n" + match[2])) || first;
  table = first.closest("table");
  if (!table)
    return;
  table_box = table.getBoundingClientRect();
  first_box = first.getBoundingClientRect();
  last_box = last.getBoundingClientRect();
  top = Math.min(first_box.top, last_box.top) - table_box.top;
  bottom = Math.max(first_box.bottom, last_box.bottom) - table_box.top;
  bar = document.createElement("div");
  bar.className = "line-hl";
  bar.style.top = top + "px";
  bar.style.height = (bottom - top) + "px";
  table.appendChild(bar);

  // A browser only scrolls to a fragment that names a real id, which a
  // range never does, so bring the start of one into view here.
  if (match[2])
    first.scrollIntoView({ block: "center" });
}

document.addEventListener("DOMContentLoaded", place_bar, false);
window.addEventListener("hashchange", place_bar, false);

})();