text: /* ***** BEGIN LICENSE BLOCK *****
   * Distributed under the BSD license:
   *
   * Copyright (c) 2010, Ajax.org B.V.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *     * Redistributions of source code must retain the above copyright
   *       notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above copyright
   *       notice, this list of conditions and the following disclaimer in the
   *       documentation and/or other materials provided with the distribution.
   *     * Neither the name of Ajax.org B.V. nor the
   *       names of its contributors may be used to endorse or promote products
   *       derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL AJAX.ORG B.V. BE LIABLE FOR ANY
   * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * ***** END LICENSE BLOCK ***** */
  
  define(function(require, exports, module) {
  "use strict";
  
  var oop = require("./lib/oop");
  var EventEmitter = require("./lib/event_emitter").EventEmitter;
  
  /**
   *
   * Defines the floating pointer in the document. Whenever text is inserted or deleted before the cursor, the position of the cursor is updated.
   *
   * @class Anchor
   **/
  
  /**
   * Creates a new `Anchor` and associates it with a document.
   *
   * @param {Document} doc The document to associate with the anchor
   * @param {Number} row The starting row position
   * @param {Number} column The starting column position
   *
   * @constructor
   **/
  
  var Anchor = exports.Anchor = function(doc, row, column) {
      this.$onChange = this.onChange.bind(this);
      this.attach(doc);
      
      if (typeof column == "undefined")
          this.setPosition(row.row, row.column);
      else
          this.setPosition(row, column);
  };
  
  (function() {
  
      oop.implement(this, EventEmitter);
  
      /**
       * Returns an object identifying the `row` and `column` position of the current anchor.
       * @returns {Object}
       **/
      this.getPosition = function() {
          return this.$clipPositionToDocument(this.row, this.column);
      };
  
      /**
       *
       * Returns the current document.
       * @returns {Document}
       **/
      this.getDocument = function() {
          return this.document;
      };
  
      /**
       * experimental: allows anchor to stick to the next on the left
       */
      this.$insertRight = false;
      /**
       * Fires whenever the anchor position changes.
       *
       * Both of these objects have a `row` and `column` property corresponding to the position.
       *
       * Events that can trigger this function include [[Anchor.setPosition `setPosition()`]].
       *
       * @event change
       * @param {Object} e  An object containing information about the anchor position. It has two properties:
       *  - `old`: An object describing the old Anchor position
       *  - `value`: An object describing the new Anchor position
       *
       **/
      this.onChange = function(e) {
          var delta = e.data;
          var range = delta.range;
  
          if (range.start.row == range.end.row && range.start.row != this.row)
              return;
  
          if (range.start.row > this.row)
              return;
  
          if (range.start.row == this.row && range.start.column > this.column)
              return;
  
          var row = this.row;
          var column = this.column;
          var start = range.start;
          var end = range.end;
  
          if (delta.action === "insertText") {
              if (start.row === row && start.column <= column) {
                  if (start.column === column && this.$insertRight) {
                      // do nothing
                  } else if (start.row === end.row) {
                      column += end.column - start.column;
                  } else {
                      column -= start.column;
                      row += end.row - start.row;
                  }
              } else if (start.row !== end.row && start.row < row) {
                  row += end.row - start.row;
              }
          } else if (delta.action === "insertLines") {
              if (start.row <= row) {
                  row += end.row - start.row;
              }
          } else if (delta.action === "removeText") {
              if (start.row === row && start.column < column) {
                  if (end.column >= column)
                      column = start.column;
                  else
                      column = Math.max(0, column - (end.column - start.column));
  
              } else if (start.row !== end.row && start.row < row) {
                  if (end.row === row)
                      column = Math.max(0, column - end.column) + start.column;
                  row -= (end.row - start.row);
              } else if (end.row === row) {
                  row -= end.row - start.row;
                  column = Math.max(0, column - end.column) + start.column;
              }
          } else if (delta.action == "removeLines") {
              if (start.row <= row) {
                  if (end.row <= row)
                      row -= end.row - start.row;
                  else {
                      row = start.row;
                      column = 0;
                  }
              }
          }
  
          this.setPosition(row, column, true);
      };
  
      /**
       * Sets the anchor position to the specified row and column. If `noClip` is `true`, the position is not clipped.
       * @param {Number} row The row index to move the anchor to
       * @param {Number} column The column index to move the anchor to
       * @param {Boolean} noClip Identifies if you want the position to be clipped
       *
       **/
      this.setPosition = function(row, column, noClip) {
          var pos;
          if (noClip) {
              pos = {
                  row: row,
                  column: column
              };
          } else {
              pos = this.$clipPositionToDocument(row, column);
          }
  
          if (this.row == pos.row && this.column == pos.column)
              return;
  
          var old = {
              row: this.row,
              column: this.column
          };
  
          this.row = pos.row;
          this.column = pos.column;
          this._emit("change", {
              old: old,
              value: pos
          });
      };
  
      /**
       * When called, the `'change'` event listener is removed.
       *
       **/
      this.detach = function() {
          this.document.removeEventListener("change", this.$onChange);
      };
      this.attach = function(doc) {
          this.document = doc || this.document;
          this.document.on("change", this.$onChange);
      };
  
      /**
       * Clips the anchor position to the specified row and column.
       * @param {Number} row The row index to clip the anchor to
       * @param {Number} column The column index to clip the anchor to
       *
       **/
      this.$clipPositionToDocument = function(row, column) {
          var pos = {};
  
          if (row >= this.document.getLength()) {
              pos.row = Math.max(0, this.document.getLength() - 1);
              pos.column = this.document.getLine(pos.row).length;
          }
          else if (row < 0) {
              pos.row = 0;
              pos.column = 0;
          }
          else {
              pos.row = row;
              pos.column = Math.min(this.document.getLine(pos.row).length, Math.max(0, column));
          }
  
          if (column < 0)
              pos.column = 0;
  
          return pos;
      };
  
  }).call(Anchor.prototype);
  
  });
  