/**
 * Detect Element Resize.
 * https://github.com/sdecima/javascript-detect-element-resize
 * Sebastian Decima
 *
 * Forked from version 0.5.3; includes the following modifications:
 * 1) Guard against unsafe 'window' and 'document' references (to support SSR).
 * 2) Defer initialization code via a top-level function wrapper (to support SSR).
 * 3) Avoid unnecessary reflows by not measuring size for scroll events bubbling from children.
 * 4) Add nonce for style element.
 **/

export default function createDetectElementResize(nonce) {
  // Check `document` and `window` in case of server-side rendering
  var _window;
  if (typeof window !== "undefined") {
    _window = window;
  } else if (typeof self !== "undefined") {
    _window = self;
  } else {
    _window = this;
  }

  var attachEvent = typeof document !== "undefined" && document.attachEvent;

  if (!attachEvent) {
    var requestFrame = function () {
      var raf = _window.requestAnimationFrame || _window.mozRequestAnimationFrame || _window.webkitRequestAnimationFrame || function (fn) {
        return _window.setTimeout(fn, 20);
      };
      return function (fn) {
        return raf(fn);
      };
    }();

    var cancelFrame = function () {
      var cancel = _window.cancelAnimationFrame || _window.mozCancelAnimationFrame || _window.webkitCancelAnimationFrame || _window.clearTimeout;
      return function (id) {
        return cancel(id);
      };
    }();

    var resetTriggers = function resetTriggers(element) {
      var triggers = element.__resizeTriggers__,
          expand = triggers.firstElementChild,
          contract = triggers.lastElementChild,
          expandChild = expand.firstElementChild;
      contract.scrollLeft = contract.scrollWidth;
      contract.scrollTop = contract.scrollHeight;
      expandChild.style.width = expand.offsetWidth + 1 + "px";
      expandChild.style.height = expand.offsetHeight + 1 + "px";
      expand.scrollLeft = expand.scrollWidth;
      expand.scrollTop = expand.scrollHeight;
    };

    var checkTriggers = function checkTriggers(element) {
      return element.offsetWidth != element.__resizeLast__.width || element.offsetHeight != element.__resizeLast__.height;
    };

    var scrollListener = function scrollListener(e) {
      // Don't measure (which forces) reflow for scrolls that happen inside of children!
      if (e.target.className.indexOf("contract-trigger") < 0 && e.target.className.indexOf("expand-trigger") < 0) {
        return;
      }

      var element = this;
      resetTriggers(this);
      if (this.__resizeRAF__) cancelFrame(this.__resizeRAF__);
      this.__resizeRAF__ = requestFrame(function () {
        if (checkTriggers(element)) {
          element.__resizeLast__.width = element.offsetWidth;
          element.__resizeLast__.height = element.offsetHeight;
          element.__resizeListeners__.forEach(function (fn) {
            fn.call(element, e);
          });
        }
      });
    };

    /* Detect CSS Animations support to detect element display/re-attach */
    var animation = false,
        keyframeprefix = "",
        animationstartevent = "animationstart",
        domPrefixes = "Webkit Moz O ms".split(" "),
        startEvents = "webkitAnimationStart animationstart oAnimationStart MSAnimationStart".split(" "),
        pfx = "";
    {
      var elm = document.createElement("fakeelement");
      if (elm.style.animationName !== undefined) {
        animation = true;
      }

      if (animation === false) {
        for (var i = 0; i < domPrefixes.length; i++) {
          if (elm.style[domPrefixes[i] + "AnimationName"] !== undefined) {
            pfx = domPrefixes[i];
            keyframeprefix = "-" + pfx.toLowerCase() + "-";
            animationstartevent = startEvents[i];
            animation = true;
            break;
          }
        }
      }
    }

    var animationName = "resizeanim";
    var animationKeyframes = "@" + keyframeprefix + "keyframes " + animationName + " { from { opacity: 0; } to { opacity: 0; } } ";
    var animationStyle = keyframeprefix + "animation: 1ms " + animationName + "; ";
  }

  var createStyles = function createStyles() {
    if (!document.getElementById("detectElementResize")) {
      //opacity:0 works around a chrome bug https://code.google.com/p/chromium/issues/detail?id=286360
      var css = (animationKeyframes ? animationKeyframes : "") + ".resize-triggers { " + (animationStyle ? animationStyle : "") + "visibility: hidden; opacity: 0; } " + '.resize-triggers, .resize-triggers > div, .contract-trigger:before { content: " "; display: block; position: absolute; top: 0; left: 0; height: 100%; width: 100%; overflow: hidden; z-index: -1; } .resize-triggers > div { background: #eee; overflow: auto; } .contract-trigger:before { width: 200%; height: 200%; }',
          head = document.head || document.getElementsByTagName("head")[0],
          style = document.createElement("style");

      style.id = "detectElementResize";
      style.type = "text/css";

      if (nonce != null) {
        style.setAttribute("nonce", nonce);
      }

      if (style.styleSheet) {
        style.styleSheet.cssText = css;
      } else {
        style.appendChild(document.createTextNode(css));
      }

      head.appendChild(style);
    }
  };

  var addResizeListener = function addResizeListener(element, fn) {
    if (attachEvent) element.attachEvent("onresize", fn);else {
      if (!element.__resizeTriggers__) {
        var elementStyle = _window.getComputedStyle(element);
        if (elementStyle && elementStyle.position == "static") {
          element.style.position = "relative";
        }
        createStyles();
        element.__resizeLast__ = {};
        element.__resizeListeners__ = [];
        (element.__resizeTriggers__ = document.createElement("div")).className = "resize-triggers";
        element.__resizeTriggers__.innerHTML = '<div class="expand-trigger"><div></div></div>' + '<div class="contract-trigger"></div>';
        element.appendChild(element.__resizeTriggers__);
        resetTriggers(element);
        element.addEventListener("scroll", scrollListener, true);

        /* Listen for a css animation to detect element display/re-attach */
        if (animationstartevent) {
          element.__resizeTriggers__.__animationListener__ = function animationListener(e) {
            if (e.animationName == animationName) resetTriggers(element);
          };
          element.__resizeTriggers__.addEventListener(animationstartevent, element.__resizeTriggers__.__animationListener__);
        }
      }
      element.__resizeListeners__.push(fn);
    }
  };

  var removeResizeListener = function removeResizeListener(element, fn) {
    if (attachEvent) element.detachEvent("onresize", fn);else {
      element.__resizeListeners__.splice(element.__resizeListeners__.indexOf(fn), 1);
      if (!element.__resizeListeners__.length) {
        element.removeEventListener("scroll", scrollListener, true);
        if (element.__resizeTriggers__.__animationListener__) {
          element.__resizeTriggers__.removeEventListener(animationstartevent, element.__resizeTriggers__.__animationListener__);
          element.__resizeTriggers__.__animationListener__ = null;
        }
        try {
          element.__resizeTriggers__ = !element.removeChild(element.__resizeTriggers__);
        } catch (e) {
          // Preact compat; see developit/preact-compat/issues/228
        }
      }
    }
  };

  return {
    addResizeListener: addResizeListener,
    removeResizeListener: removeResizeListener
  };
}