<!DOCTYPE html>
<!--
Copyright (c) 2012 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/task.html">
<link rel="import" href="/core/filter.html">
<link rel="import" href="/core/selection.html">

<script>
'use strict';

/**
 * @fileoverview FindController.
 */
tr.exportTo('tr.c', function() {
  var Task = tr.b.Task;

  function FindController(selectionController) {
    this.selectionController_ = selectionController;
    this.filterHits_ = new tr.c.Selection();
    this.currentHitIndex_ = -1;
    this.activePromise_ = Promise.resolve();
    this.activeTask_ = undefined;
  };

  FindController.prototype = {
    __proto__: Object.prototype,

    get model() {
      return this.selectionController_.model;
    },

    get selectionController() {
      return this.selectionController_;
    },

    enqueueOperation_: function(operation) {
      var task;
      if (operation instanceof tr.b.Task)
        task = operation;
      else
        task = new tr.b.Task(operation, this);
      if (this.activeTask_) {
        this.activeTask_ = this.activeTask_.enqueue(task);
      } else {
        // We're enqueuing the first task, schedule it.
        this.activeTask_ = task;
        this.activePromise_ = Task.RunWhenIdle(this.activeTask_);
        this.activePromise_.then(function() {
          this.activePromise_ = undefined;
          this.activeTask_ = undefined;
        }.bind(this));
      }
    },

    /**
     * Updates the filter hits based on the provided |filterText|. Returns a
     * promise which resolves when |filterHits| has been refreshed.
     */
    startFiltering: function(filterText) {
      var sc = this.selectionController_;
      if (!sc)
        return;

      // TODO(beaudoin): Cancel anything left in the task queue, without
      // invalidating the promise.
      this.enqueueOperation_(function() {
        this.filterHits_ = new tr.c.Selection();
        this.currentHitIndex_ = -1;
      }.bind(this));

      // Try constructing a UIState from the filterText.
      // UIState.fromUserFriendlyString will throw an error only if the string
      // is syntactically correct to a UI state string but with invalid values.
      // It will return undefined if there is no syntactic match.
      var stateFromString;
      try {
        stateFromString = sc.uiStateFromString(filterText);
      } catch (e) {
        this.enqueueOperation_(function() {
          var overlay = new tr.b.ui.Overlay();
          overlay.textContent = e.message;
          overlay.title = 'UI State Navigation Error';
          overlay.visible = true;
        });
        return this.activePromise_;
      }

      if (stateFromString !== undefined) {
        this.enqueueOperation_(
            sc.navToPosition.bind(this, stateFromString, true));
      } else {
        // filterText is not a navString here -- proceed with find and filter.
        if (filterText.length === 0) {
          this.enqueueOperation_(sc.findTextCleared.bind(sc));
        } else {
          var filter = new tr.c.TitleOrCategoryFilter(filterText);
          var filterHits = new tr.c.Selection();
          this.enqueueOperation_(sc.addAllEventsMatchingFilterToSelectionAsTask(
              filter, filterHits));
          this.enqueueOperation_(function() {
            this.filterHits_ = filterHits;
            sc.findTextChangedTo(filterHits);
          }.bind(this));
        }
      }
      return this.activePromise_;
    },

    /**
     * Returns the most recent filter hits as a tr.c.Selection. Call
     * |startFiltering| to ensure this is up to date after the filter settings
     * have been changed.
     */
    get filterHits() {
      return this.filterHits_;
    },

    get currentHitIndex() {
      return this.currentHitIndex_;
    },

    find_: function(dir) {
      var firstHit = this.currentHitIndex_ === -1;
      if (firstHit && dir < 0)
        this.currentHitIndex_ = 0;

      var N = this.filterHits.length;
      this.currentHitIndex_ = (this.currentHitIndex_ + dir + N) % N;

      if (!this.selectionController_)
        return;

      this.selectionController_.findFocusChangedTo(
          this.filterHits.subSelection(this.currentHitIndex_, 1));
    },

    findNext: function() {
      this.find_(1);
    },

    findPrevious: function() {
      this.find_(-1);
    }
  };

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