<!DOCTYPE html>
<!--
Copyright (c) 2015 The Chromium Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->

<link rel="import" href="/base/event_target.html">
<link rel="import" href="/base/task.html">
<link rel="import" href="/core/selection.html">
<link rel="import" href="/core/brushing_state.html">
<link rel="import" href="/core/trace_model/selection_state.html">
<link rel="import" href="/core/timeline_viewport.html">
<link rel="import" href="/core/ui_state.html">

<script>
'use strict';

tv.exportTo('tv.c', function() {
  var BrushingState = tv.c.BrushingState;
  var Selection = tv.c.Selection;
  var SelectionState = tv.c.trace_model.SelectionState;
  var Viewport = tv.c.TimelineViewport;

  function SelectionController(timelineView) {
    tv.b.EventTarget.call(this);

    this.timelineView_ = timelineView;
    this.currentBrushingState_ = new BrushingState();

    this.onPopState_ = this.onPopState_.bind(this);
    this.historyEnabled_ = false;
    this.selections_ = {};
  }

  SelectionController.prototype = {
    __proto__: tv.b.EventTarget.prototype,

    dispatchChangeEvent_: function() {
      var e = new tv.b.Event('change', false, false);
      this.dispatchEvent(e);
    },

    get model() {
      if (!this.timelineView_)
        return undefined;
      return this.timelineView_.model;
    },

    get trackView() {
      if (!this.timelineView_)
        return undefined;
      return this.timelineView_.trackView;
    },

    get viewport() {
      if (!this.timelineView_)
        return undefined;
      if (!this.timelineView_.trackView)
        return undefined;
      return this.timelineView_.trackView.viewport;
    },

    /* History system */
    get historyEnabled() {
      return this.historyEnabled_;
    },

    set historyEnabled(historyEnabled) {
      this.historyEnabled_ = !!historyEnabled;
      if (historyEnabled)
        window.addEventListener('popstate', this.onPopState_);
      else
        window.removeEventListener('popstate', this.onPopState_);
    },

    modelWillChange: function() {
      if (this.currentBrushingState_.isAppliedToModel)
        this.currentBrushingState_.unapplyFromModelSelectionState();
    },

    modelDidChange: function() {
      this.selections_ = {};
      this.currentBrushingState_.applyToModelSelectionState(this.model);

      var e = new tv.b.Event('model-changed', false, false);
      this.dispatchEvent(e);
    },

    onUserInitiatedSelectionChange_: function() {
      var selection = this.selection;
      if (this.historyEnabled) {
        // Save the selection so that when back button is pressed,
        // it could be retrieved.
        this.selections_[selection.guid] = selection;
        var state = {
          selection_guid: selection.guid
        };

        window.history.pushState(state, document.title);
      }
    },

    onPopState_: function(e) {
      if (e.state === null)
        return;

      var selection = this.selections_[e.state.selection_guid];
      if (selection) {
        var newState = this.currentBrushingState_.clone();
        newState.selection = selection;
        this.currentBrushingState = newState;
      }
      e.stopPropagation();
    },

    get selection() {
      return this.currentBrushingState_.selection;
    },
    get findMatches() {
      return this.currentBrushingState_.findMatches;
    },

    get selectionOfInterest() {
      return this.currentBrushingState_.selectionOfInterest;
    },

    get currentBrushingState() {
      return this.currentBrushingState_;
    },

    set currentBrushingState(newBrushingState) {
      if (newBrushingState.isAppliedToModel)
        throw new Error('Cannot apply this state, it is applied');

      // This function uses value-equality on the states so that state can
      // changed to a clone of itself without causing a change event, while
      // still having the actual state object change to the new clone.
      var hasValueChanged = !this.currentBrushingState_.equals(
          newBrushingState);

      if (newBrushingState !== this.currentBrushingState_ &&
          hasValueChanged == false) {
        this.currentBrushingState_.transferModelOwnershipToClone(
            newBrushingState);
        this.currentBrushingState_ = newBrushingState;
        return;
      }

      if (this.currentBrushingState_.isAppliedToModel)
        this.currentBrushingState_.unapplyFromModelSelectionState();

      this.currentBrushingState_ = newBrushingState;

      if (this.model)
        this.currentBrushingState_.applyToModelSelectionState(this.model);

      this.dispatchChangeEvent_();
    },

    /**
     * @param {Filter} filter The filter to use for finding matches.
     * @param {Selection} selection The selection to add matches to.
     * @return {Task} which performs the filtering.
     */
    addAllEventsMatchingFilterToSelectionAsTask: function(filter, selection) {
      var timelineView = this.timelineView_.trackView;
      if (!timelineView)
        return new tv.b.Task();
      return timelineView.addAllEventsMatchingFilterToSelectionAsTask(
          filter, selection);
    },

    findTextChangedTo: function(allPossibleMatches) {
      var newBrushingState = this.currentBrushingState_.clone();
      newBrushingState.findMatches = allPossibleMatches;
      this.currentBrushingState = newBrushingState;
    },

    findFocusChangedTo: function(currentFocus) {
      var newBrushingState = this.currentBrushingState_.clone();
      newBrushingState.selection = currentFocus;
      this.currentBrushingState = newBrushingState;

      this.onUserInitiatedSelectionChange_();
    },

    findTextCleared: function() {
      if (this.xNavStringMarker_ !== undefined) {
        this.model.removeAnnotation(this.xNavStringMarker_);
        this.xNavStringMarker_ = undefined;
      }

      if (this.guideLineAnnotation_ !== undefined) {
        this.model.removeAnnotation(this.guideLineAnnotation_);
        this.guideLineAnnotation_ = undefined;
      }

      var newBrushingState = this.currentBrushingState_.clone();
      newBrushingState.selection = new Selection();
      newBrushingState.findMatches = new Selection();
      this.currentBrushingState = newBrushingState;

      this.onUserInitiatedSelectionChange_();
    },

    uiStateFromString: function(string) {
      return tv.c.UIState.fromUserFriendlyString(
          this.model, this.viewport, string);
    },

    navToPosition: function(uiState, showNavLine) {
      this.trackView.navToPosition(uiState, showNavLine);
    },

    changeSelectionFromTimeline: function(selection) {
      var newBrushingState = this.currentBrushingState_.clone();
      newBrushingState.selection = selection;
      newBrushingState.findMatches = new Selection();
      this.currentBrushingState = newBrushingState;

      this.onUserInitiatedSelectionChange_();
    },

    showScriptControlSelection: function(selection) {
      var newBrushingState = this.currentBrushingState_.clone();
      newBrushingState.selection = selection;
      newBrushingState.findMatches = new Selection();
      this.currentBrushingState = newBrushingState;
    },

    changeSelectionFromRequestSelectionChangeEvent: function(selection) {
      var newBrushingState = this.currentBrushingState_.clone();
      newBrushingState.selection = selection;
      newBrushingState.findMatches = new Selection();
      this.currentBrushingState = newBrushingState;

      this.onUserInitiatedSelectionChange_();
    },

    changeAnalysisViewRelatedEvents: function(selection) {
      var newBrushingState = this.currentBrushingState_.clone();
      newBrushingState.analysisViewRelatedEvents = selection;
      this.currentBrushingState = newBrushingState;
    }
  };

  return {
    SelectionController: SelectionController
  };
});
</script>