'use strict';

/* exported $$AnimationProvider */

var $$AnimationProvider = ['$animateProvider', /** @this */ function($animateProvider) {
  var NG_ANIMATE_REF_ATTR = 'ng-animate-ref';

  var drivers = this.drivers = [];

  var RUNNER_STORAGE_KEY = '$$animationRunner';
  var PREPARE_CLASSES_KEY = '$$animatePrepareClasses';

  function setRunner(element, runner) {
    element.data(RUNNER_STORAGE_KEY, runner);
  }

  function removeRunner(element) {
    element.removeData(RUNNER_STORAGE_KEY);
  }

  function getRunner(element) {
    return element.data(RUNNER_STORAGE_KEY);
  }

  this.$get = ['$$jqLite', '$rootScope', '$injector', '$$AnimateRunner', '$$Map', '$$rAFScheduler', '$$animateCache',
       function($$jqLite,   $rootScope,   $injector,   $$AnimateRunner,   $$Map,   $$rAFScheduler, $$animateCache) {

    var animationQueue = [];
    var applyAnimationClasses = applyAnimationClassesFactory($$jqLite);

    function sortAnimations(animations) {
      var tree = { children: [] };
      var i, lookup = new $$Map();

      // this is done first beforehand so that the map
      // is filled with a list of the elements that will be animated
      for (i = 0; i < animations.length; i++) {
        var animation = animations[i];
        lookup.set(animation.domNode, animations[i] = {
          domNode: animation.domNode,
          element: animation.element,
          fn: animation.fn,
          children: []
        });
      }

      for (i = 0; i < animations.length; i++) {
        processNode(animations[i]);
      }

      return flatten(tree);

      function processNode(entry) {
        if (entry.processed) return entry;
        entry.processed = true;

        var elementNode = entry.domNode;
        var parentNode = elementNode.parentNode;
        lookup.set(elementNode, entry);

        var parentEntry;
        while (parentNode) {
          parentEntry = lookup.get(parentNode);
          if (parentEntry) {
            if (!parentEntry.processed) {
              parentEntry = processNode(parentEntry);
            }
            break;
          }
          parentNode = parentNode.parentNode;
        }

        (parentEntry || tree).children.push(entry);
        return entry;
      }

      function flatten(tree) {
        var result = [];
        var queue = [];
        var i;

        for (i = 0; i < tree.children.length; i++) {
          queue.push(tree.children[i]);
        }

        var remainingLevelEntries = queue.length;
        var nextLevelEntries = 0;
        var row = [];

        for (i = 0; i < queue.length; i++) {
          var entry = queue[i];
          if (remainingLevelEntries <= 0) {
            remainingLevelEntries = nextLevelEntries;
            nextLevelEntries = 0;
            result.push(row);
            row = [];
          }
          row.push(entry);
          entry.children.forEach(function(childEntry) {
            nextLevelEntries++;
            queue.push(childEntry);
          });
          remainingLevelEntries--;
        }

        if (row.length) {
          result.push(row);
        }

        return result;
      }
    }

    // TODO(matsko): document the signature in a better way
    return function(element, event, options) {
      options = prepareAnimationOptions(options);
      var isStructural = ['enter', 'move', 'leave'].indexOf(event) >= 0;

      // there is no animation at the current moment, however
      // these runner methods will get later updated with the
      // methods leading into the driver's end/cancel methods
      // for now they just stop the animation from starting
      var runner = new $$AnimateRunner({
        end: function() { close(); },
        cancel: function() { close(true); }
      });

      if (!drivers.length) {
        close();
        return runner;
      }

      var classes = mergeClasses(element.attr('class'), mergeClasses(options.addClass, options.removeClass));
      var tempClasses = options.tempClasses;
      if (tempClasses) {
        classes += ' ' + tempClasses;
        options.tempClasses = null;
      }

      if (isStructural) {
        element.data(PREPARE_CLASSES_KEY, 'ng-' + event + PREPARE_CLASS_SUFFIX);
      }

      setRunner(element, runner);

      animationQueue.push({
        // this data is used by the postDigest code and passed into
        // the driver step function
        element: element,
        classes: classes,
        event: event,
        structural: isStructural,
        options: options,
        beforeStart: beforeStart,
        close: close
      });

      element.on('$destroy', handleDestroyedElement);

      // we only want there to be one function called within the post digest
      // block. This way we can group animations for all the animations that
      // were apart of the same postDigest flush call.
      if (animationQueue.length > 1) return runner;

      $rootScope.$$postDigest(function() {
        var animations = [];
        forEach(animationQueue, function(entry) {
          // the element was destroyed early on which removed the runner
          // form its storage. This means we can't animate this element
          // at all and it already has been closed due to destruction.
          if (getRunner(entry.element)) {
            animations.push(entry);
          } else {
            entry.close();
          }
        });

        // now any future animations will be in another postDigest
        animationQueue.length = 0;

        var groupedAnimations = groupAnimations(animations);
        var toBeSortedAnimations = [];

        forEach(groupedAnimations, function(animationEntry) {
          var element = animationEntry.from ? animationEntry.from.element : animationEntry.element;
          var extraClasses = options.addClass;

          extraClasses = (extraClasses ? (extraClasses + ' ') : '') + NG_ANIMATE_CLASSNAME;
          var cacheKey = $$animateCache.cacheKey(element[0], animationEntry.event, extraClasses, options.removeClass);

          toBeSortedAnimations.push({
            element: element,
            domNode: getDomNode(element),
            fn: function triggerAnimationStart() {
              var startAnimationFn, closeFn = animationEntry.close;

              // in the event that we've cached the animation status for this element
              // and it's in fact an invalid animation (something that has duration = 0)
              // then we should skip all the heavy work from here on
              if ($$animateCache.containsCachedAnimationWithoutDuration(cacheKey)) {
                closeFn();
                return;
              }

              // it's important that we apply the `ng-animate` CSS class and the
              // temporary classes before we do any driver invoking since these
              // CSS classes may be required for proper CSS detection.
              animationEntry.beforeStart();

              // in the event that the element was removed before the digest runs or
              // during the RAF sequencing then we should not trigger the animation.
              var targetElement = animationEntry.anchors
                  ? (animationEntry.from.element || animationEntry.to.element)
                  : animationEntry.element;

              if (getRunner(targetElement)) {
                var operation = invokeFirstDriver(animationEntry);
                if (operation) {
                  startAnimationFn = operation.start;
                }
              }

              if (!startAnimationFn) {
                closeFn();
              } else {
                var animationRunner = startAnimationFn();
                animationRunner.done(function(status) {
                  closeFn(!status);
                });
                updateAnimationRunners(animationEntry, animationRunner);
              }
            }
          });
        });

        // we need to sort each of the animations in order of parent to child
        // relationships. This ensures that the child classes are applied at the
        // right time.
        var finalAnimations = sortAnimations(toBeSortedAnimations);
        for (var i = 0; i < finalAnimations.length; i++) {
          var innerArray = finalAnimations[i];
          for (var j = 0; j < innerArray.length; j++) {
            var entry = innerArray[j];
            var element = entry.element;

            // the RAFScheduler code only uses functions
            finalAnimations[i][j] = entry.fn;

            // the first row of elements shouldn't have a prepare-class added to them
            // since the elements are at the top of the animation hierarchy and they
            // will be applied without a RAF having to pass...
            if (i === 0) {
              element.removeData(PREPARE_CLASSES_KEY);
              continue;
            }

            var prepareClassName = element.data(PREPARE_CLASSES_KEY);
            if (prepareClassName) {
              $$jqLite.addClass(element, prepareClassName);
            }
          }
        }

        $$rAFScheduler(finalAnimations);
      });

      return runner;

      // TODO(matsko): change to reference nodes
      function getAnchorNodes(node) {
        var SELECTOR = '[' + NG_ANIMATE_REF_ATTR + ']';
        var items = node.hasAttribute(NG_ANIMATE_REF_ATTR)
              ? [node]
              : node.querySelectorAll(SELECTOR);
        var anchors = [];
        forEach(items, function(node) {
          var attr = node.getAttribute(NG_ANIMATE_REF_ATTR);
          if (attr && attr.length) {
            anchors.push(node);
          }
        });
        return anchors;
      }

      function groupAnimations(animations) {
        var preparedAnimations = [];
        var refLookup = {};
        forEach(animations, function(animation, index) {
          var element = animation.element;
          var node = getDomNode(element);
          var event = animation.event;
          var enterOrMove = ['enter', 'move'].indexOf(event) >= 0;
          var anchorNodes = animation.structural ? getAnchorNodes(node) : [];

          if (anchorNodes.length) {
            var direction = enterOrMove ? 'to' : 'from';

            forEach(anchorNodes, function(anchor) {
              var key = anchor.getAttribute(NG_ANIMATE_REF_ATTR);
              refLookup[key] = refLookup[key] || {};
              refLookup[key][direction] = {
                animationID: index,
                element: jqLite(anchor)
              };
            });
          } else {
            preparedAnimations.push(animation);
          }
        });

        var usedIndicesLookup = {};
        var anchorGroups = {};
        forEach(refLookup, function(operations, key) {
          var from = operations.from;
          var to = operations.to;

          if (!from || !to) {
            // only one of these is set therefore we can't have an
            // anchor animation since all three pieces are required
            var index = from ? from.animationID : to.animationID;
            var indexKey = index.toString();
            if (!usedIndicesLookup[indexKey]) {
              usedIndicesLookup[indexKey] = true;
              preparedAnimations.push(animations[index]);
            }
            return;
          }

          var fromAnimation = animations[from.animationID];
          var toAnimation = animations[to.animationID];
          var lookupKey = from.animationID.toString();
          if (!anchorGroups[lookupKey]) {
            var group = anchorGroups[lookupKey] = {
              structural: true,
              beforeStart: function() {
                fromAnimation.beforeStart();
                toAnimation.beforeStart();
              },
              close: function() {
                fromAnimation.close();
                toAnimation.close();
              },
              classes: cssClassesIntersection(fromAnimation.classes, toAnimation.classes),
              from: fromAnimation,
              to: toAnimation,
              anchors: [] // TODO(matsko): change to reference nodes
            };

            // the anchor animations require that the from and to elements both have at least
            // one shared CSS class which effectively marries the two elements together to use
            // the same animation driver and to properly sequence the anchor animation.
            if (group.classes.length) {
              preparedAnimations.push(group);
            } else {
              preparedAnimations.push(fromAnimation);
              preparedAnimations.push(toAnimation);
            }
          }

          anchorGroups[lookupKey].anchors.push({
            'out': from.element, 'in': to.element
          });
        });

        return preparedAnimations;
      }

      function cssClassesIntersection(a,b) {
        a = a.split(' ');
        b = b.split(' ');
        var matches = [];

        for (var i = 0; i < a.length; i++) {
          var aa = a[i];
          if (aa.substring(0,3) === 'ng-') continue;

          for (var j = 0; j < b.length; j++) {
            if (aa === b[j]) {
              matches.push(aa);
              break;
            }
          }
        }

        return matches.join(' ');
      }

      function invokeFirstDriver(animationDetails) {
        // we loop in reverse order since the more general drivers (like CSS and JS)
        // may attempt more elements, but custom drivers are more particular
        for (var i = drivers.length - 1; i >= 0; i--) {
          var driverName = drivers[i];
          var factory = $injector.get(driverName);
          var driver = factory(animationDetails);
          if (driver) {
            return driver;
          }
        }
      }

      function beforeStart() {
        tempClasses = (tempClasses ? (tempClasses + ' ') : '') + NG_ANIMATE_CLASSNAME;
        $$jqLite.addClass(element, tempClasses);

        var prepareClassName = element.data(PREPARE_CLASSES_KEY);
        if (prepareClassName) {
          $$jqLite.removeClass(element, prepareClassName);
          prepareClassName = null;
        }
      }

      function updateAnimationRunners(animation, newRunner) {
        if (animation.from && animation.to) {
          update(animation.from.element);
          update(animation.to.element);
        } else {
          update(animation.element);
        }

        function update(element) {
          var runner = getRunner(element);
          if (runner) runner.setHost(newRunner);
        }
      }

      function handleDestroyedElement() {
        var runner = getRunner(element);
        if (runner && (event !== 'leave' || !options.$$domOperationFired)) {
          runner.end();
        }
      }

      function close(rejected) {
        element.off('$destroy', handleDestroyedElement);
        removeRunner(element);

        applyAnimationClasses(element, options);
        applyAnimationStyles(element, options);
        options.domOperation();

        if (tempClasses) {
          $$jqLite.removeClass(element, tempClasses);
        }

        runner.complete(!rejected);
      }
    };
  }];
}];
