opentok-editor.js

/*
 *    /\
 *   /  \ ot 0.0.15
 *  /    \ http://operational-transformation.github.com
 *  \    /
 *   \  / (c) 2012-2016 Tim Baumann <tim@timbaumann.info> (http://timbaumann.info)
 *    \/ ot may be freely distributed under the MIT license.
 */

if (typeof ot === 'undefined') {
  // Export for browsers
  var ot = {};
}

ot.TextOperation = (function () {
  'use strict';

  // Constructor for new operations.
  function TextOperation () {
    if (!this || this.constructor !== TextOperation) {
      // => function was called without 'new'
      return new TextOperation();
    }

    // When an operation is applied to an input string, you can think of this as
    // if an imaginary cursor runs over the entire string and skips over some
    // parts, deletes some parts and inserts characters at some positions. These
    // actions (skip/delete/insert) are stored as an array in the "ops" property.
    this.ops = [];
    // An operation's baseLength is the length of every string the operation
    // can be applied to.
    this.baseLength = 0;
    // The targetLength is the length of every string that results from applying
    // the operation on a valid input string.
    this.targetLength = 0;
  }

  TextOperation.prototype.equals = function (other) {
    if (this.baseLength !== other.baseLength) { return false; }
    if (this.targetLength !== other.targetLength) { return false; }
    if (this.ops.length !== other.ops.length) { return false; }
    for (var i = 0; i < this.ops.length; i++) {
      if (this.ops[i] !== other.ops[i]) { return false; }
    }
    return true;
  };

  // Operation are essentially lists of ops. There are three types of ops:
  //
  // * Retain ops: Advance the cursor position by a given number of characters.
  //   Represented by positive ints.
  // * Insert ops: Insert a given string at the current cursor position.
  //   Represented by strings.
  // * Delete ops: Delete the next n characters. Represented by negative ints.

  var isRetain = TextOperation.isRetain = function (op) {
    return typeof op === 'number' && op > 0;
  };

  var isInsert = TextOperation.isInsert = function (op) {
    return typeof op === 'string';
  };

  var isDelete = TextOperation.isDelete = function (op) {
    return typeof op === 'number' && op < 0;
  };


  // After an operation is constructed, the user of the library can specify the
  // actions of an operation (skip/insert/delete) with these three builder
  // methods. They all return the operation for convenient chaining.

  // Skip over a given number of characters.
  TextOperation.prototype.retain = function (n) {
    if (typeof n !== 'number') {
      throw new Error("retain expects an integer");
    }
    if (n === 0) { return this; }
    this.baseLength += n;
    this.targetLength += n;
    if (isRetain(this.ops[this.ops.length-1])) {
      // The last op is a retain op => we can merge them into one op.
      this.ops[this.ops.length-1] += n;
    } else {
      // Create a new op.
      this.ops.push(n);
    }
    return this;
  };

  // Insert a string at the current position.
  TextOperation.prototype.insert = function (str) {
    if (typeof str !== 'string') {
      throw new Error("insert expects a string");
    }
    if (str === '') { return this; }
    this.targetLength += str.length;
    var ops = this.ops;
    if (isInsert(ops[ops.length-1])) {
      // Merge insert op.
      ops[ops.length-1] += str;
    } else if (isDelete(ops[ops.length-1])) {
      // It doesn't matter when an operation is applied whether the operation
      // is delete(3), insert("something") or insert("something"), delete(3).
      // Here we enforce that in this case, the insert op always comes first.
      // This makes all operations that have the same effect when applied to
      // a document of the right length equal in respect to the `equals` method.
      if (isInsert(ops[ops.length-2])) {
        ops[ops.length-2] += str;
      } else {
        ops[ops.length] = ops[ops.length-1];
        ops[ops.length-2] = str;
      }
    } else {
      ops.push(str);
    }
    return this;
  };

  // Delete a string at the current position.
  TextOperation.prototype['delete'] = function (n) {
    if (typeof n === 'string') { n = n.length; }
    if (typeof n !== 'number') {
      throw new Error("delete expects an integer or a string");
    }
    if (n === 0) { return this; }
    if (n > 0) { n = -n; }
    this.baseLength -= n;
    if (isDelete(this.ops[this.ops.length-1])) {
      this.ops[this.ops.length-1] += n;
    } else {
      this.ops.push(n);
    }
    return this;
  };

  // Tests whether this operation has no effect.
  TextOperation.prototype.isNoop = function () {
    return this.ops.length === 0 || (this.ops.length === 1 && isRetain(this.ops[0]));
  };

  // Pretty printing.
  TextOperation.prototype.toString = function () {
    // map: build a new array by applying a function to every element in an old
    // array.
    var map = Array.prototype.map || function (fn) {
      var arr = this;
      var newArr = [];
      for (var i = 0, l = arr.length; i < l; i++) {
        newArr[i] = fn(arr[i]);
      }
      return newArr;
    };
    return map.call(this.ops, function (op) {
      if (isRetain(op)) {
        return "retain " + op;
      } else if (isInsert(op)) {
        return "insert '" + op + "'";
      } else {
        return "delete " + (-op);
      }
    }).join(', ');
  };

  // Converts operation into a JSON value.
  TextOperation.prototype.toJSON = function () {
    return this.ops;
  };

  // Converts a plain JS object into an operation and validates it.
  TextOperation.fromJSON = function (ops) {
    var o = new TextOperation();
    for (var i = 0, l = ops.length; i < l; i++) {
      var op = ops[i];
      if (isRetain(op)) {
        o.retain(op);
      } else if (isInsert(op)) {
        o.insert(op);
      } else if (isDelete(op)) {
        o['delete'](op);
      } else {
        throw new Error("unknown operation: " + JSON.stringify(op));
      }
    }
    return o;
  };

  // Apply an operation to a string, returning a new string. Throws an error if
  // there's a mismatch between the input string and the operation.
  TextOperation.prototype.apply = function (str) {
    var operation = this;
    if (str.length !== operation.baseLength) {
      throw new Error("The operation's base length must be equal to the string's length.");
    }
    var newStr = [], j = 0;
    var strIndex = 0;
    var ops = this.ops;
    for (var i = 0, l = ops.length; i < l; i++) {
      var op = ops[i];
      if (isRetain(op)) {
        if (strIndex + op > str.length) {
          throw new Error("Operation can't retain more characters than are left in the string.");
        }
        // Copy skipped part of the old string.
        newStr[j++] = str.slice(strIndex, strIndex + op);
        strIndex += op;
      } else if (isInsert(op)) {
        // Insert string.
        newStr[j++] = op;
      } else { // delete op
        strIndex -= op;
      }
    }
    if (strIndex !== str.length) {
      throw new Error("The operation didn't operate on the whole string.");
    }
    return newStr.join('');
  };

  // Computes the inverse of an operation. The inverse of an operation is the
  // operation that reverts the effects of the operation, e.g. when you have an
  // operation 'insert("hello "); skip(6);' then the inverse is 'delete("hello ");
  // skip(6);'. The inverse should be used for implementing undo.
  TextOperation.prototype.invert = function (str) {
    var strIndex = 0;
    var inverse = new TextOperation();
    var ops = this.ops;
    for (var i = 0, l = ops.length; i < l; i++) {
      var op = ops[i];
      if (isRetain(op)) {
        inverse.retain(op);
        strIndex += op;
      } else if (isInsert(op)) {
        inverse['delete'](op.length);
      } else { // delete op
        inverse.insert(str.slice(strIndex, strIndex - op));
        strIndex -= op;
      }
    }
    return inverse;
  };

  // Compose merges two consecutive operations into one operation, that
  // preserves the changes of both. Or, in other words, for each input string S
  // and a pair of consecutive operations A and B,
  // apply(apply(S, A), B) = apply(S, compose(A, B)) must hold.
  TextOperation.prototype.compose = function (operation2) {
    var operation1 = this;
    if (operation1.targetLength !== operation2.baseLength) {
      throw new Error("The base length of the second operation has to be the target length of the first operation");
    }

    var operation = new TextOperation(); // the combined operation
    var ops1 = operation1.ops, ops2 = operation2.ops; // for fast access
    var i1 = 0, i2 = 0; // current index into ops1 respectively ops2
    var op1 = ops1[i1++], op2 = ops2[i2++]; // current ops
    while (true) {
      // Dispatch on the type of op1 and op2
      if (typeof op1 === 'undefined' && typeof op2 === 'undefined') {
        // end condition: both ops1 and ops2 have been processed
        break;
      }

      if (isDelete(op1)) {
        operation['delete'](op1);
        op1 = ops1[i1++];
        continue;
      }
      if (isInsert(op2)) {
        operation.insert(op2);
        op2 = ops2[i2++];
        continue;
      }

      if (typeof op1 === 'undefined') {
        throw new Error("Cannot compose operations: first operation is too short.");
      }
      if (typeof op2 === 'undefined') {
        throw new Error("Cannot compose operations: first operation is too long.");
      }

      if (isRetain(op1) && isRetain(op2)) {
        if (op1 > op2) {
          operation.retain(op2);
          op1 = op1 - op2;
          op2 = ops2[i2++];
        } else if (op1 === op2) {
          operation.retain(op1);
          op1 = ops1[i1++];
          op2 = ops2[i2++];
        } else {
          operation.retain(op1);
          op2 = op2 - op1;
          op1 = ops1[i1++];
        }
      } else if (isInsert(op1) && isDelete(op2)) {
        if (op1.length > -op2) {
          op1 = op1.slice(-op2);
          op2 = ops2[i2++];
        } else if (op1.length === -op2) {
          op1 = ops1[i1++];
          op2 = ops2[i2++];
        } else {
          op2 = op2 + op1.length;
          op1 = ops1[i1++];
        }
      } else if (isInsert(op1) && isRetain(op2)) {
        if (op1.length > op2) {
          operation.insert(op1.slice(0, op2));
          op1 = op1.slice(op2);
          op2 = ops2[i2++];
        } else if (op1.length === op2) {
          operation.insert(op1);
          op1 = ops1[i1++];
          op2 = ops2[i2++];
        } else {
          operation.insert(op1);
          op2 = op2 - op1.length;
          op1 = ops1[i1++];
        }
      } else if (isRetain(op1) && isDelete(op2)) {
        if (op1 > -op2) {
          operation['delete'](op2);
          op1 = op1 + op2;
          op2 = ops2[i2++];
        } else if (op1 === -op2) {
          operation['delete'](op2);
          op1 = ops1[i1++];
          op2 = ops2[i2++];
        } else {
          operation['delete'](op1);
          op2 = op2 + op1;
          op1 = ops1[i1++];
        }
      } else {
        throw new Error(
          "This shouldn't happen: op1: " +
          JSON.stringify(op1) + ", op2: " +
          JSON.stringify(op2)
        );
      }
    }
    return operation;
  };

  function getSimpleOp (operation, fn) {
    var ops = operation.ops;
    var isRetain = TextOperation.isRetain;
    switch (ops.length) {
    case 1:
      return ops[0];
    case 2:
      return isRetain(ops[0]) ? ops[1] : (isRetain(ops[1]) ? ops[0] : null);
    case 3:
      if (isRetain(ops[0]) && isRetain(ops[2])) { return ops[1]; }
    }
    return null;
  }

  function getStartIndex (operation) {
    if (isRetain(operation.ops[0])) { return operation.ops[0]; }
    return 0;
  }

  // When you use ctrl-z to undo your latest changes, you expect the program not
  // to undo every single keystroke but to undo your last sentence you wrote at
  // a stretch or the deletion you did by holding the backspace key down. This
  // This can be implemented by composing operations on the undo stack. This
  // method can help decide whether two operations should be composed. It
  // returns true if the operations are consecutive insert operations or both
  // operations delete text at the same position. You may want to include other
  // factors like the time since the last change in your decision.
  TextOperation.prototype.shouldBeComposedWith = function (other) {
    if (this.isNoop() || other.isNoop()) { return true; }

    var startA = getStartIndex(this), startB = getStartIndex(other);
    var simpleA = getSimpleOp(this), simpleB = getSimpleOp(other);
    if (!simpleA || !simpleB) { return false; }

    if (isInsert(simpleA) && isInsert(simpleB)) {
      return startA + simpleA.length === startB;
    }

    if (isDelete(simpleA) && isDelete(simpleB)) {
      // there are two possibilities to delete: with backspace and with the
      // delete key.
      return (startB - simpleB === startA) || startA === startB;
    }

    return false;
  };

  // Decides whether two operations should be composed with each other
  // if they were inverted, that is
  // `shouldBeComposedWith(a, b) = shouldBeComposedWithInverted(b^{-1}, a^{-1})`.
  TextOperation.prototype.shouldBeComposedWithInverted = function (other) {
    if (this.isNoop() || other.isNoop()) { return true; }

    var startA = getStartIndex(this), startB = getStartIndex(other);
    var simpleA = getSimpleOp(this), simpleB = getSimpleOp(other);
    if (!simpleA || !simpleB) { return false; }

    if (isInsert(simpleA) && isInsert(simpleB)) {
      return startA + simpleA.length === startB || startA === startB;
    }

    if (isDelete(simpleA) && isDelete(simpleB)) {
      return startB - simpleB === startA;
    }

    return false;
  };

  // Transform takes two operations A and B that happened concurrently and
  // produces two operations A' and B' (in an array) such that
  // `apply(apply(S, A), B') = apply(apply(S, B), A')`. This function is the
  // heart of OT.
  TextOperation.transform = function (operation1, operation2) {
    if (operation1.baseLength !== operation2.baseLength) {
      throw new Error("Both operations have to have the same base length");
    }

    var operation1prime = new TextOperation();
    var operation2prime = new TextOperation();
    var ops1 = operation1.ops, ops2 = operation2.ops;
    var i1 = 0, i2 = 0;
    var op1 = ops1[i1++], op2 = ops2[i2++];
    while (true) {
      // At every iteration of the loop, the imaginary cursor that both
      // operation1 and operation2 have that operates on the input string must
      // have the same position in the input string.

      if (typeof op1 === 'undefined' && typeof op2 === 'undefined') {
        // end condition: both ops1 and ops2 have been processed
        break;
      }

      // next two cases: one or both ops are insert ops
      // => insert the string in the corresponding prime operation, skip it in
      // the other one. If both op1 and op2 are insert ops, prefer op1.
      if (isInsert(op1)) {
        operation1prime.insert(op1);
        operation2prime.retain(op1.length);
        op1 = ops1[i1++];
        continue;
      }
      if (isInsert(op2)) {
        operation1prime.retain(op2.length);
        operation2prime.insert(op2);
        op2 = ops2[i2++];
        continue;
      }

      if (typeof op1 === 'undefined') {
        throw new Error("Cannot compose operations: first operation is too short.");
      }
      if (typeof op2 === 'undefined') {
        throw new Error("Cannot compose operations: first operation is too long.");
      }

      var minl;
      if (isRetain(op1) && isRetain(op2)) {
        // Simple case: retain/retain
        if (op1 > op2) {
          minl = op2;
          op1 = op1 - op2;
          op2 = ops2[i2++];
        } else if (op1 === op2) {
          minl = op2;
          op1 = ops1[i1++];
          op2 = ops2[i2++];
        } else {
          minl = op1;
          op2 = op2 - op1;
          op1 = ops1[i1++];
        }
        operation1prime.retain(minl);
        operation2prime.retain(minl);
      } else if (isDelete(op1) && isDelete(op2)) {
        // Both operations delete the same string at the same position. We don't
        // need to produce any operations, we just skip over the delete ops and
        // handle the case that one operation deletes more than the other.
        if (-op1 > -op2) {
          op1 = op1 - op2;
          op2 = ops2[i2++];
        } else if (op1 === op2) {
          op1 = ops1[i1++];
          op2 = ops2[i2++];
        } else {
          op2 = op2 - op1;
          op1 = ops1[i1++];
        }
      // next two cases: delete/retain and retain/delete
      } else if (isDelete(op1) && isRetain(op2)) {
        if (-op1 > op2) {
          minl = op2;
          op1 = op1 + op2;
          op2 = ops2[i2++];
        } else if (-op1 === op2) {
          minl = op2;
          op1 = ops1[i1++];
          op2 = ops2[i2++];
        } else {
          minl = -op1;
          op2 = op2 + op1;
          op1 = ops1[i1++];
        }
        operation1prime['delete'](minl);
      } else if (isRetain(op1) && isDelete(op2)) {
        if (op1 > -op2) {
          minl = -op2;
          op1 = op1 + op2;
          op2 = ops2[i2++];
        } else if (op1 === -op2) {
          minl = op1;
          op1 = ops1[i1++];
          op2 = ops2[i2++];
        } else {
          minl = op1;
          op2 = op2 + op1;
          op1 = ops1[i1++];
        }
        operation2prime['delete'](minl);
      } else {
        throw new Error("The two operations aren't compatible");
      }
    }

    return [operation1prime, operation2prime];
  };

  return TextOperation;

}());

// Export for CommonJS
if (typeof module === 'object') {
  module.exports = ot.TextOperation;
}
if (typeof ot === 'undefined') {
  // Export for browsers
  var ot = {};
}

ot.Selection = (function (global) {
  'use strict';

  var TextOperation = global.ot ? global.ot.TextOperation : require('./text-operation');

  // Range has `anchor` and `head` properties, which are zero-based indices into
  // the document. The `anchor` is the side of the selection that stays fixed,
  // `head` is the side of the selection where the cursor is. When both are
  // equal, the range represents a cursor.
  function Range (anchor, head) {
    this.anchor = anchor;
    this.head = head;
  }

  Range.fromJSON = function (obj) {
    return new Range(obj.anchor, obj.head);
  };

  Range.prototype.equals = function (other) {
    return this.anchor === other.anchor && this.head === other.head;
  };

  Range.prototype.isEmpty = function () {
    return this.anchor === this.head;
  };

  Range.prototype.transform = function (other) {
    function transformIndex (index) {
      var newIndex = index;
      var ops = other.ops;
      for (var i = 0, l = other.ops.length; i < l; i++) {
        if (TextOperation.isRetain(ops[i])) {
          index -= ops[i];
        } else if (TextOperation.isInsert(ops[i])) {
          newIndex += ops[i].length;
        } else {
          newIndex -= Math.min(index, -ops[i]);
          index += ops[i];
        }
        if (index < 0) { break; }
      }
      return newIndex;
    }

    var newAnchor = transformIndex(this.anchor);
    if (this.anchor === this.head) {
      return new Range(newAnchor, newAnchor);
    }
    return new Range(newAnchor, transformIndex(this.head));
  };

  // A selection is basically an array of ranges. Every range represents a real
  // selection or a cursor in the document (when the start position equals the
  // end position of the range). The array must not be empty.
  function Selection (ranges) {
    this.ranges = ranges || [];
  }

  Selection.Range = Range;

  // Convenience method for creating selections only containing a single cursor
  // and no real selection range.
  Selection.createCursor = function (position) {
    return new Selection([new Range(position, position)]);
  };

  Selection.fromJSON = function (obj) {
    var objRanges = obj.ranges || obj;
    for (var i = 0, ranges = []; i < objRanges.length; i++) {
      ranges[i] = Range.fromJSON(objRanges[i]);
    }
    return new Selection(ranges);
  };

  Selection.prototype.equals = function (other) {
    if (this.position !== other.position) { return false; }
    if (this.ranges.length !== other.ranges.length) { return false; }
    // FIXME: Sort ranges before comparing them?
    for (var i = 0; i < this.ranges.length; i++) {
      if (!this.ranges[i].equals(other.ranges[i])) { return false; }
    }
    return true;
  };

  Selection.prototype.somethingSelected = function () {
    for (var i = 0; i < this.ranges.length; i++) {
      if (!this.ranges[i].isEmpty()) { return true; }
    }
    return false;
  };

  // Return the more current selection information.
  Selection.prototype.compose = function (other) {
    return other;
  };

  // Update the selection with respect to an operation.
  Selection.prototype.transform = function (other) {
    for (var i = 0, newRanges = []; i < this.ranges.length; i++) {
      newRanges[i] = this.ranges[i].transform(other);
    }
    return new Selection(newRanges);
  };

  return Selection;

}(this));

// Export for CommonJS
if (typeof module === 'object') {
  module.exports = ot.Selection;
}

if (typeof ot === 'undefined') {
  // Export for browsers
  var ot = {};
}

ot.WrappedOperation = (function (global) {
  'use strict';

  // A WrappedOperation contains an operation and corresponing metadata.
  function WrappedOperation (operation, meta) {
    this.wrapped = operation;
    this.meta    = meta;
  }

  WrappedOperation.prototype.apply = function () {
    return this.wrapped.apply.apply(this.wrapped, arguments);
  };

  WrappedOperation.prototype.invert = function () {
    var meta = this.meta;
    return new WrappedOperation(
      this.wrapped.invert.apply(this.wrapped, arguments),
      meta && typeof meta === 'object' && typeof meta.invert === 'function' ?
        meta.invert.apply(meta, arguments) : meta
    );
  };

  // Copy all properties from source to target.
  function copy (source, target) {
    for (var key in source) {
      if (source.hasOwnProperty(key)) {
        target[key] = source[key];
      }
    }
  }

  function composeMeta (a, b) {
    if (a && typeof a === 'object') {
      if (typeof a.compose === 'function') { return a.compose(b); }
      var meta = {};
      copy(a, meta);
      copy(b, meta);
      return meta;
    }
    return b;
  }

  WrappedOperation.prototype.compose = function (other) {
    return new WrappedOperation(
      this.wrapped.compose(other.wrapped),
      composeMeta(this.meta, other.meta)
    );
  };

  function transformMeta (meta, operation) {
    if (meta && typeof meta === 'object') {
      if (typeof meta.transform === 'function') {
        return meta.transform(operation);
      }
    }
    return meta;
  }

  WrappedOperation.transform = function (a, b) {
    var transform = a.wrapped.constructor.transform;
    var pair = transform(a.wrapped, b.wrapped);
    return [
      new WrappedOperation(pair[0], transformMeta(a.meta, b.wrapped)),
      new WrappedOperation(pair[1], transformMeta(b.meta, a.wrapped))
    ];
  };

  return WrappedOperation;

}(this));

// Export for CommonJS
if (typeof module === 'object') {
  module.exports = ot.WrappedOperation;
}
if (typeof ot === 'undefined') {
  // Export for browsers
  var ot = {};
}

ot.UndoManager = (function () {
  'use strict';

  var NORMAL_STATE = 'normal';
  var UNDOING_STATE = 'undoing';
  var REDOING_STATE = 'redoing';

  // Create a new UndoManager with an optional maximum history size.
  function UndoManager (maxItems) {
    this.maxItems  = maxItems || 50;
    this.state = NORMAL_STATE;
    this.dontCompose = false;
    this.undoStack = [];
    this.redoStack = [];
  }

  // Add an operation to the undo or redo stack, depending on the current state
  // of the UndoManager. The operation added must be the inverse of the last
  // edit. When `compose` is true, compose the operation with the last operation
  // unless the last operation was alread pushed on the redo stack or was hidden
  // by a newer operation on the undo stack.
  UndoManager.prototype.add = function (operation, compose) {
    if (this.state === UNDOING_STATE) {
      this.redoStack.push(operation);
      this.dontCompose = true;
    } else if (this.state === REDOING_STATE) {
      this.undoStack.push(operation);
      this.dontCompose = true;
    } else {
      var undoStack = this.undoStack;
      if (!this.dontCompose && compose && undoStack.length > 0) {
        undoStack.push(operation.compose(undoStack.pop()));
      } else {
        undoStack.push(operation);
        if (undoStack.length > this.maxItems) { undoStack.shift(); }
      }
      this.dontCompose = false;
      this.redoStack = [];
    }
  };

  function transformStack (stack, operation) {
    var newStack = [];
    var Operation = operation.constructor;
    for (var i = stack.length - 1; i >= 0; i--) {
      var pair = Operation.transform(stack[i], operation);
      if (typeof pair[0].isNoop !== 'function' || !pair[0].isNoop()) {
        newStack.push(pair[0]);
      }
      operation = pair[1];
    }
    return newStack.reverse();
  }

  // Transform the undo and redo stacks against a operation by another client.
  UndoManager.prototype.transform = function (operation) {
    this.undoStack = transformStack(this.undoStack, operation);
    this.redoStack = transformStack(this.redoStack, operation);
  };

  // Perform an undo by calling a function with the latest operation on the undo
  // stack. The function is expected to call the `add` method with the inverse
  // of the operation, which pushes the inverse on the redo stack.
  UndoManager.prototype.performUndo = function (fn) {
    this.state = UNDOING_STATE;
    if (this.undoStack.length === 0) { throw new Error("undo not possible"); }
    fn(this.undoStack.pop());
    this.state = NORMAL_STATE;
  };

  // The inverse of `performUndo`.
  UndoManager.prototype.performRedo = function (fn) {
    this.state = REDOING_STATE;
    if (this.redoStack.length === 0) { throw new Error("redo not possible"); }
    fn(this.redoStack.pop());
    this.state = NORMAL_STATE;
  };

  // Is the undo stack not empty?
  UndoManager.prototype.canUndo = function () {
    return this.undoStack.length !== 0;
  };

  // Is the redo stack not empty?
  UndoManager.prototype.canRedo = function () {
    return this.redoStack.length !== 0;
  };

  // Whether the UndoManager is currently performing an undo.
  UndoManager.prototype.isUndoing = function () {
    return this.state === UNDOING_STATE;
  };

  // Whether the UndoManager is currently performing a redo.
  UndoManager.prototype.isRedoing = function () {
    return this.state === REDOING_STATE;
  };

  return UndoManager;

}());

// Export for CommonJS
if (typeof module === 'object') {
  module.exports = ot.UndoManager;
}

// translation of https://github.com/djspiewak/cccp/blob/master/agent/src/main/scala/com/codecommit/cccp/agent/state.scala

if (typeof ot === 'undefined') {
  var ot = {};
}

ot.Client = (function (global) {
  'use strict';

  // Client constructor
  function Client (revision) {
    this.revision = revision; // the next expected revision number
    this.state = synchronized_; // start state
  }

  Client.prototype.setState = function (state) {
    this.state = state;
  };

  // Call this method when the user changes the document.
  Client.prototype.applyClient = function (operation) {
    this.setState(this.state.applyClient(this, operation));
  };

  // Call this method with a new operation from the server
  Client.prototype.applyServer = function (operation) {
    this.revision++;
    this.setState(this.state.applyServer(this, operation));
  };

  Client.prototype.serverAck = function () {
    this.revision++;
    this.setState(this.state.serverAck(this));
  };
  
  Client.prototype.serverReconnect = function () {
    if (typeof this.state.resend === 'function') { this.state.resend(this); }
  };

  // Transforms a selection from the latest known server state to the current
  // client state. For example, if we get from the server the information that
  // another user's cursor is at position 3, but the server hasn't yet received
  // our newest operation, an insertion of 5 characters at the beginning of the
  // document, the correct position of the other user's cursor in our current
  // document is 8.
  Client.prototype.transformSelection = function (selection) {
    return this.state.transformSelection(selection);
  };

  // Override this method.
  Client.prototype.sendOperation = function (revision, operation) {
    throw new Error("sendOperation must be defined in child class");
  };

  // Override this method.
  Client.prototype.applyOperation = function (operation) {
    throw new Error("applyOperation must be defined in child class");
  };


  // In the 'Synchronized' state, there is no pending operation that the client
  // has sent to the server.
  function Synchronized () {}
  Client.Synchronized = Synchronized;

  Synchronized.prototype.applyClient = function (client, operation) {
    // When the user makes an edit, send the operation to the server and
    // switch to the 'AwaitingConfirm' state
    client.sendOperation(client.revision, operation);
    return new AwaitingConfirm(operation);
  };

  Synchronized.prototype.applyServer = function (client, operation) {
    // When we receive a new operation from the server, the operation can be
    // simply applied to the current document
    client.applyOperation(operation);
    return this;
  };

  Synchronized.prototype.serverAck = function (client) {
    throw new Error("There is no pending operation.");
  };

  // Nothing to do because the latest server state and client state are the same.
  Synchronized.prototype.transformSelection = function (x) { return x; };

  // Singleton
  var synchronized_ = new Synchronized();


  // In the 'AwaitingConfirm' state, there's one operation the client has sent
  // to the server and is still waiting for an acknowledgement.
  function AwaitingConfirm (outstanding) {
    // Save the pending operation
    this.outstanding = outstanding;
  }
  Client.AwaitingConfirm = AwaitingConfirm;

  AwaitingConfirm.prototype.applyClient = function (client, operation) {
    // When the user makes an edit, don't send the operation immediately,
    // instead switch to 'AwaitingWithBuffer' state
    return new AwaitingWithBuffer(this.outstanding, operation);
  };

  AwaitingConfirm.prototype.applyServer = function (client, operation) {
    // This is another client's operation. Visualization:
    //
    //                   /\
    // this.outstanding /  \ operation
    //                 /    \
    //                 \    /
    //  pair[1]         \  / pair[0] (new outstanding)
    //  (can be applied  \/
    //  to the client's
    //  current document)
    var pair = operation.constructor.transform(this.outstanding, operation);
    client.applyOperation(pair[1]);
    return new AwaitingConfirm(pair[0]);
  };

  AwaitingConfirm.prototype.serverAck = function (client) {
    // The client's operation has been acknowledged
    // => switch to synchronized state
    return synchronized_;
  };

  AwaitingConfirm.prototype.transformSelection = function (selection) {
    return selection.transform(this.outstanding);
  };

  AwaitingConfirm.prototype.resend = function (client) {
    // The confirm didn't come because the client was disconnected.
    // Now that it has reconnected, we resend the outstanding operation.
    client.sendOperation(client.revision, this.outstanding);
  };


  // In the 'AwaitingWithBuffer' state, the client is waiting for an operation
  // to be acknowledged by the server while buffering the edits the user makes
  function AwaitingWithBuffer (outstanding, buffer) {
    // Save the pending operation and the user's edits since then
    this.outstanding = outstanding;
    this.buffer = buffer;
  }
  Client.AwaitingWithBuffer = AwaitingWithBuffer;

  AwaitingWithBuffer.prototype.applyClient = function (client, operation) {
    // Compose the user's changes onto the buffer
    var newBuffer = this.buffer.compose(operation);
    return new AwaitingWithBuffer(this.outstanding, newBuffer);
  };

  AwaitingWithBuffer.prototype.applyServer = function (client, operation) {
    // Operation comes from another client
    //
    //                       /\
    //     this.outstanding /  \ operation
    //                     /    \
    //                    /\    /
    //       this.buffer /  \* / pair1[0] (new outstanding)
    //                  /    \/
    //                  \    /
    //          pair2[1] \  / pair2[0] (new buffer)
    // the transformed    \/
    // operation -- can
    // be applied to the
    // client's current
    // document
    //
    // * pair1[1]
    var transform = operation.constructor.transform;
    var pair1 = transform(this.outstanding, operation);
    var pair2 = transform(this.buffer, pair1[1]);
    client.applyOperation(pair2[1]);
    return new AwaitingWithBuffer(pair1[0], pair2[0]);
  };

  AwaitingWithBuffer.prototype.serverAck = function (client) {
    // The pending operation has been acknowledged
    // => send buffer
    client.sendOperation(client.revision, this.buffer);
    return new AwaitingConfirm(this.buffer);
  };

  AwaitingWithBuffer.prototype.transformSelection = function (selection) {
    return selection.transform(this.outstanding).transform(this.buffer);
  };

  AwaitingWithBuffer.prototype.resend = function (client) {
    // The confirm didn't come because the client was disconnected.
    // Now that it has reconnected, we resend the outstanding operation.
    client.sendOperation(client.revision, this.outstanding);
  };


  return Client;

}(this));

if (typeof module === 'object') {
  module.exports = ot.Client;
}

/*global ot */

ot.CodeMirrorAdapter = (function (global) {
  'use strict';

  var TextOperation = ot.TextOperation;
  var Selection = ot.Selection;

  function CodeMirrorAdapter (cm) {
    this.cm = cm;
    this.ignoreNextChange = false;
    this.changeInProgress = false;
    this.selectionChanged = false;

    bind(this, 'onChanges');
    bind(this, 'onChange');
    bind(this, 'onCursorActivity');
    bind(this, 'onFocus');
    bind(this, 'onBlur');

    cm.on('changes', this.onChanges);
    cm.on('change', this.onChange);
    cm.on('cursorActivity', this.onCursorActivity);
    cm.on('focus', this.onFocus);
    cm.on('blur', this.onBlur);
  }

  // Removes all event listeners from the CodeMirror instance.
  CodeMirrorAdapter.prototype.detach = function () {
    this.cm.off('changes', this.onChanges);
    this.cm.off('change', this.onChange);
    this.cm.off('cursorActivity', this.onCursorActivity);
    this.cm.off('focus', this.onFocus);
    this.cm.off('blur', this.onBlur);
  };

  function cmpPos (a, b) {
    if (a.line < b.line) { return -1; }
    if (a.line > b.line) { return 1; }
    if (a.ch < b.ch)     { return -1; }
    if (a.ch > b.ch)     { return 1; }
    return 0;
  }
  function posEq (a, b) { return cmpPos(a, b) === 0; }
  function posLe (a, b) { return cmpPos(a, b) <= 0; }

  function minPos (a, b) { return posLe(a, b) ? a : b; }
  function maxPos (a, b) { return posLe(a, b) ? b : a; }

  function codemirrorDocLength (doc) {
    return doc.indexFromPos({ line: doc.lastLine(), ch: 0 }) +
      doc.getLine(doc.lastLine()).length;
  }

  // Converts a CodeMirror change array (as obtained from the 'changes' event
  // in CodeMirror v4) or single change or linked list of changes (as returned
  // by the 'change' event in CodeMirror prior to version 4) into a
  // TextOperation and its inverse and returns them as a two-element array.
  CodeMirrorAdapter.operationFromCodeMirrorChanges = function (changes, doc) {
    // Approach: Replay the changes, beginning with the most recent one, and
    // construct the operation and its inverse. We have to convert the position
    // in the pre-change coordinate system to an index. We have a method to
    // convert a position in the coordinate system after all changes to an index,
    // namely CodeMirror's `indexFromPos` method. We can use the information of
    // a single change object to convert a post-change coordinate system to a
    // pre-change coordinate system. We can now proceed inductively to get a
    // pre-change coordinate system for all changes in the linked list.
    // A disadvantage of this approach is its complexity `O(n^2)` in the length
    // of the linked list of changes.

    var docEndLength = codemirrorDocLength(doc);
    var operation    = new TextOperation().retain(docEndLength);
    var inverse      = new TextOperation().retain(docEndLength);

    var indexFromPos = function (pos) {
      return doc.indexFromPos(pos);
    };

    function last (arr) { return arr[arr.length - 1]; }

    function sumLengths (strArr) {
      if (strArr.length === 0) { return 0; }
      var sum = 0;
      for (var i = 0; i < strArr.length; i++) { sum += strArr[i].length; }
      return sum + strArr.length - 1;
    }

    function updateIndexFromPos (indexFromPos, change) {
      return function (pos) {
        if (posLe(pos, change.from)) { return indexFromPos(pos); }
        if (posLe(change.to, pos)) {
          return indexFromPos({
            line: pos.line + change.text.length - 1 - (change.to.line - change.from.line),
            ch: (change.to.line < pos.line) ?
              pos.ch :
              (change.text.length <= 1) ?
                pos.ch - (change.to.ch - change.from.ch) + sumLengths(change.text) :
                pos.ch - change.to.ch + last(change.text).length
          }) + sumLengths(change.removed) - sumLengths(change.text);
        }
        if (change.from.line === pos.line) {
          return indexFromPos(change.from) + pos.ch - change.from.ch;
        }
        return indexFromPos(change.from) +
          sumLengths(change.removed.slice(0, pos.line - change.from.line)) +
          1 + pos.ch;
      };
    }

    for (var i = changes.length - 1; i >= 0; i--) {
      var change = changes[i];
      indexFromPos = updateIndexFromPos(indexFromPos, change);

      var fromIndex = indexFromPos(change.from);
      var restLength = docEndLength - fromIndex - sumLengths(change.text);

      operation = new TextOperation()
        .retain(fromIndex)
        ['delete'](sumLengths(change.removed))
        .insert(change.text.join('\n'))
        .retain(restLength)
        .compose(operation);

      inverse = inverse.compose(new TextOperation()
        .retain(fromIndex)
        ['delete'](sumLengths(change.text))
        .insert(change.removed.join('\n'))
        .retain(restLength)
      );

      docEndLength += sumLengths(change.removed) - sumLengths(change.text);
    }

    return [operation, inverse];
  };

  // Singular form for backwards compatibility.
  CodeMirrorAdapter.operationFromCodeMirrorChange =
    CodeMirrorAdapter.operationFromCodeMirrorChanges;

  // Apply an operation to a CodeMirror instance.
  CodeMirrorAdapter.applyOperationToCodeMirror = function (operation, cm) {
    cm.operation(function () {
      var ops = operation.ops;
      var index = 0; // holds the current index into CodeMirror's content
      for (var i = 0, l = ops.length; i < l; i++) {
        var op = ops[i];
        if (TextOperation.isRetain(op)) {
          index += op;
        } else if (TextOperation.isInsert(op)) {
          cm.replaceRange(op, cm.posFromIndex(index));
          index += op.length;
        } else if (TextOperation.isDelete(op)) {
          var from = cm.posFromIndex(index);
          var to   = cm.posFromIndex(index - op);
          cm.replaceRange('', from, to);
        }
      }
    });
  };

  CodeMirrorAdapter.prototype.registerCallbacks = function (cb) {
    this.callbacks = cb;
  };

  CodeMirrorAdapter.prototype.onChange = function () {
    // By default, CodeMirror's event order is the following:
    // 1. 'change', 2. 'cursorActivity', 3. 'changes'.
    // We want to fire the 'selectionChange' event after the 'change' event,
    // but need the information from the 'changes' event. Therefore, we detect
    // when a change is in progress by listening to the change event, setting
    // a flag that makes this adapter defer all 'cursorActivity' events.
    this.changeInProgress = true;
  };

  CodeMirrorAdapter.prototype.onChanges = function (_, changes) {
    if (!this.ignoreNextChange) {
      var pair = CodeMirrorAdapter.operationFromCodeMirrorChanges(changes, this.cm);
      this.trigger('change', pair[0], pair[1]);
    }
    if (this.selectionChanged) { this.trigger('selectionChange'); }
    this.changeInProgress = false;
    this.ignoreNextChange = false;
  };

  CodeMirrorAdapter.prototype.onCursorActivity =
  CodeMirrorAdapter.prototype.onFocus = function () {
    if (this.changeInProgress) {
      this.selectionChanged = true;
    } else {
      this.trigger('selectionChange');
    }
  };

  CodeMirrorAdapter.prototype.onBlur = function () {
    if (!this.cm.somethingSelected()) { this.trigger('blur'); }
  };

  CodeMirrorAdapter.prototype.getValue = function () {
    return this.cm.getValue();
  };

  CodeMirrorAdapter.prototype.getSelection = function () {
    var cm = this.cm;

    var selectionList = cm.listSelections();
    var ranges = [];
    for (var i = 0; i < selectionList.length; i++) {
      ranges[i] = new Selection.Range(
        cm.indexFromPos(selectionList[i].anchor),
        cm.indexFromPos(selectionList[i].head)
      );
    }

    return new Selection(ranges);
  };

  CodeMirrorAdapter.prototype.setSelection = function (selection) {
    var ranges = [];
    for (var i = 0; i < selection.ranges.length; i++) {
      var range = selection.ranges[i];
      ranges[i] = {
        anchor: this.cm.posFromIndex(range.anchor),
        head:   this.cm.posFromIndex(range.head)
      };
    }
    this.cm.setSelections(ranges);
  };

  var addStyleRule = (function () {
    var added = {};
    var styleElement = document.createElement('style');
    document.documentElement.getElementsByTagName('head')[0].appendChild(styleElement);
    var styleSheet = styleElement.sheet;

    return function (css) {
      if (added[css]) { return; }
      added[css] = true;
      styleSheet.insertRule(css, (styleSheet.cssRules || styleSheet.rules).length);
    };
  }());

  CodeMirrorAdapter.prototype.setOtherCursor = function (position, color, clientId) {
    var cursorPos = this.cm.posFromIndex(position);
    var cursorCoords = this.cm.cursorCoords(cursorPos);
    var cursorEl = document.createElement('span');
    cursorEl.className = 'other-client';
    cursorEl.style.display = 'inline-block';
    cursorEl.style.padding = '0';
    cursorEl.style.marginLeft = cursorEl.style.marginRight = '-1px';
    cursorEl.style.borderLeftWidth = '2px';
    cursorEl.style.borderLeftStyle = 'solid';
    cursorEl.style.borderLeftColor = color;
    cursorEl.style.height = (cursorCoords.bottom - cursorCoords.top) * 0.9 + 'px';
    cursorEl.style.zIndex = 0;
    cursorEl.setAttribute('data-clientid', clientId);
    return this.cm.setBookmark(cursorPos, { widget: cursorEl, insertLeft: true });
  };

  CodeMirrorAdapter.prototype.setOtherSelectionRange = function (range, color, clientId) {
    var match = /^#([0-9a-fA-F]{6})$/.exec(color);
    if (!match) { throw new Error("only six-digit hex colors are allowed."); }
    var selectionClassName = 'selection-' + match[1];
    var rule = '.' + selectionClassName + ' { background: ' + color + '; }';
    addStyleRule(rule);

    var anchorPos = this.cm.posFromIndex(range.anchor);
    var headPos   = this.cm.posFromIndex(range.head);

    return this.cm.markText(
      minPos(anchorPos, headPos),
      maxPos(anchorPos, headPos),
      { className: selectionClassName }
    );
  };

  CodeMirrorAdapter.prototype.setOtherSelection = function (selection, color, clientId) {
    var selectionObjects = [];
    for (var i = 0; i < selection.ranges.length; i++) {
      var range = selection.ranges[i];
      if (range.isEmpty()) {
        selectionObjects[i] = this.setOtherCursor(range.head, color, clientId);
      } else {
        selectionObjects[i] = this.setOtherSelectionRange(range, color, clientId);
      }
    }
    return {
      clear: function () {
        for (var i = 0; i < selectionObjects.length; i++) {
          selectionObjects[i].clear();
        }
      }
    };
  };

  CodeMirrorAdapter.prototype.trigger = function (event) {
    var args = Array.prototype.slice.call(arguments, 1);
    var action = this.callbacks && this.callbacks[event];
    if (action) { action.apply(this, args); }
  };

  CodeMirrorAdapter.prototype.applyOperation = function (operation) {
    if (!operation.isNoop()) {
      this.ignoreNextChange = true;
    }
    CodeMirrorAdapter.applyOperationToCodeMirror(operation, this.cm);
  };

  CodeMirrorAdapter.prototype.registerUndo = function (undoFn) {
    this.cm.undo = undoFn;
  };

  CodeMirrorAdapter.prototype.registerRedo = function (redoFn) {
    this.cm.redo = redoFn;
  };

  // Throws an error if the first argument is falsy. Useful for debugging.
  function assert (b, msg) {
    if (!b) {
      throw new Error(msg || "assertion error");
    }
  }

  // Bind a method to an object, so it doesn't matter whether you call
  // object.method() directly or pass object.method as a reference to another
  // function.
  function bind (obj, method) {
    var fn = obj[method];
    obj[method] = function () {
      fn.apply(obj, arguments);
    };
  }

  return CodeMirrorAdapter;

}(this));

/*global ot */

ot.SocketIOAdapter = (function () {
  'use strict';

  function SocketIOAdapter (socket) {
    this.socket = socket;

    var self = this;
    socket
      .on('client_left', function (clientId) {
        self.trigger('client_left', clientId);
      })
      .on('set_name', function (clientId, name) {
        self.trigger('set_name', clientId, name);
      })
      .on('ack', function () { self.trigger('ack'); })
      .on('operation', function (clientId, operation, selection) {
        self.trigger('operation', operation);
        self.trigger('selection', clientId, selection);
      })
      .on('selection', function (clientId, selection) {
        self.trigger('selection', clientId, selection);
      })
      .on('reconnect', function () {
        self.trigger('reconnect');
      });
  }

  SocketIOAdapter.prototype.sendOperation = function (revision, operation, selection) {
    this.socket.emit('operation', revision, operation, selection);
  };

  SocketIOAdapter.prototype.sendSelection = function (selection) {
    this.socket.emit('selection', selection);
  };

  SocketIOAdapter.prototype.registerCallbacks = function (cb) {
    this.callbacks = cb;
  };

  SocketIOAdapter.prototype.trigger = function (event) {
    var args = Array.prototype.slice.call(arguments, 1);
    var action = this.callbacks && this.callbacks[event];
    if (action) { action.apply(this, args); }
  };

  return SocketIOAdapter;

}());
/*global ot, $ */

ot.AjaxAdapter = (function () {
  'use strict';

  function AjaxAdapter (path, ownUserName, revision) {
    if (path[path.length - 1] !== '/') { path += '/'; }
    this.path = path;
    this.ownUserName = ownUserName;
    this.majorRevision = revision.major || 0;
    this.minorRevision = revision.minor || 0;
    this.poll();
  }

  AjaxAdapter.prototype.renderRevisionPath = function () {
    return 'revision/' + this.majorRevision + '-' + this.minorRevision;
  };

  AjaxAdapter.prototype.handleResponse = function (data) {
    var i;
    var operations = data.operations;
    for (i = 0; i < operations.length; i++) {
      if (operations[i].user === this.ownUserName) {
        this.trigger('ack');
      } else {
        this.trigger('operation', operations[i].operation);
      }
    }
    if (operations.length > 0) {
      this.majorRevision += operations.length;
      this.minorRevision = 0;
    }

    var events = data.events;
    if (events) {
      for (i = 0; i < events.length; i++) {
        var user = events[i].user;
        if (user === this.ownUserName) { continue; }
        switch (events[i].event) {
          case 'joined':    this.trigger('set_name', user, user); break;
          case 'left':      this.trigger('client_left', user); break;
          case 'selection': this.trigger('selection', user, events[i].selection); break;
        }
      }
      this.minorRevision += events.length;
    }

    var users = data.users;
    if (users) {
      delete users[this.ownUserName];
      this.trigger('clients', users);
    }

    if (data.revision) {
      this.majorRevision = data.revision.major;
      this.minorRevision = data.revision.minor;
    }
  };

  AjaxAdapter.prototype.poll = function () {
    var self = this;
    $.ajax({
      url: this.path + this.renderRevisionPath(),
      type: 'GET',
      dataType: 'json',
      timeout: 5000,
      success: function (data) {
        self.handleResponse(data);
        self.poll();
      },
      error: function () {
        setTimeout(function () { self.poll(); }, 500);
      }
    });
  };

  AjaxAdapter.prototype.sendOperation = function (revision, operation, selection) {
    if (revision !== this.majorRevision) { throw new Error("Revision numbers out of sync"); }
    var self = this;
    $.ajax({
      url: this.path + this.renderRevisionPath(),
      type: 'POST',
      data: JSON.stringify({ operation: operation, selection: selection }),
      contentType: 'application/json',
      processData: false,
      success: function (data) {},
      error: function () {
        setTimeout(function () { self.sendOperation(revision, operation, selection); }, 500);
      }
    });
  };

  AjaxAdapter.prototype.sendSelection = function (obj) {
    $.ajax({
      url: this.path + this.renderRevisionPath() + '/selection',
      type: 'POST',
      data: JSON.stringify(obj),
      contentType: 'application/json',
      processData: false,
      timeout: 1000
    });
  };

  AjaxAdapter.prototype.registerCallbacks = function (cb) {
    this.callbacks = cb;
  };

  AjaxAdapter.prototype.trigger = function (event) {
    var args = Array.prototype.slice.call(arguments, 1);
    var action = this.callbacks && this.callbacks[event];
    if (action) { action.apply(this, args); }
  };

  return AjaxAdapter;

})();
/*global ot */

ot.EditorClient = (function () {
  'use strict';

  var Client = ot.Client;
  var Selection = ot.Selection;
  var UndoManager = ot.UndoManager;
  var TextOperation = ot.TextOperation;
  var WrappedOperation = ot.WrappedOperation;


  function SelfMeta (selectionBefore, selectionAfter) {
    this.selectionBefore = selectionBefore;
    this.selectionAfter  = selectionAfter;
  }

  SelfMeta.prototype.invert = function () {
    return new SelfMeta(this.selectionAfter, this.selectionBefore);
  };

  SelfMeta.prototype.compose = function (other) {
    return new SelfMeta(this.selectionBefore, other.selectionAfter);
  };

  SelfMeta.prototype.transform = function (operation) {
    return new SelfMeta(
      this.selectionBefore.transform(operation),
      this.selectionAfter.transform(operation)
    );
  };


  function OtherMeta (clientId, selection) {
    this.clientId  = clientId;
    this.selection = selection;
  }

  OtherMeta.fromJSON = function (obj) {
    return new OtherMeta(
      obj.clientId,
      obj.selection && Selection.fromJSON(obj.selection)
    );
  };

  OtherMeta.prototype.transform = function (operation) {
    return new OtherMeta(
      this.clientId,
      this.selection && this.selection.transform(operation)
    );
  };


  function OtherClient (id, listEl, editorAdapter, name, selection) {
    this.id = id;
    this.listEl = listEl;
    this.editorAdapter = editorAdapter;
    this.name = name;

    this.li = document.createElement('li');
    if (name) {
      this.li.textContent = name;
      this.listEl.appendChild(this.li);
    }

    this.setColor(name ? hueFromName(name) : Math.random());
    if (selection) { this.updateSelection(selection); }
  }

  OtherClient.prototype.setColor = function (hue) {
    this.hue = hue;
    this.color = hsl2hex(hue, 0.75, 0.5);
    this.lightColor = hsl2hex(hue, 0.5, 0.9);
    if (this.li) { this.li.style.color = this.color; }
  };

  OtherClient.prototype.setName = function (name) {
    if (this.name === name) { return; }
    this.name = name;

    this.li.textContent = name;
    if (!this.li.parentNode) {
      this.listEl.appendChild(this.li);
    }

    this.setColor(hueFromName(name));
  };

  OtherClient.prototype.updateSelection = function (selection) {
    this.removeSelection();
    this.selection = selection;
    this.mark = this.editorAdapter.setOtherSelection(
      selection,
      selection.position === selection.selectionEnd ? this.color : this.lightColor,
      this.id
    );
  };

  OtherClient.prototype.remove = function () {
    if (this.li) { removeElement(this.li); }
    this.removeSelection();
  };

  OtherClient.prototype.removeSelection = function () {
    if (this.mark) {
      this.mark.clear();
      this.mark = null;
    }
  };


  function EditorClient (revision, clients, serverAdapter, editorAdapter) {
    Client.call(this, revision);
    this.serverAdapter = serverAdapter;
    this.editorAdapter = editorAdapter;
    this.undoManager = new UndoManager();

    this.initializeClientList();
    this.initializeClients(clients);

    var self = this;

    this.editorAdapter.registerCallbacks({
      change: function (operation, inverse) { self.onChange(operation, inverse); },
      selectionChange: function () { self.onSelectionChange(); },
      blur: function () { self.onBlur(); }
    });
    this.editorAdapter.registerUndo(function () { self.undo(); });
    this.editorAdapter.registerRedo(function () { self.redo(); });

    this.serverAdapter.registerCallbacks({
      client_left: function (clientId) { self.onClientLeft(clientId); },
      set_name: function (clientId, name) { self.getClientObject(clientId).setName(name); },
      ack: function () { self.serverAck(); },
      operation: function (operation) {
        self.applyServer(TextOperation.fromJSON(operation));
      },
      selection: function (clientId, selection) {
        if (selection) {
          self.getClientObject(clientId).updateSelection(
            self.transformSelection(Selection.fromJSON(selection))
          );
        } else {
          self.getClientObject(clientId).removeSelection();
        }
      },
      clients: function (clients) {
        var clientId;
        for (clientId in self.clients) {
          if (self.clients.hasOwnProperty(clientId) && !clients.hasOwnProperty(clientId)) {
            self.onClientLeft(clientId);
          }
        }

        for (clientId in clients) {
          if (clients.hasOwnProperty(clientId)) {
            var clientObject = self.getClientObject(clientId);

            if (clients[clientId].name) {
              clientObject.setName(clients[clientId].name);
            }

            var selection = clients[clientId].selection;
            if (selection) {
              self.clients[clientId].updateSelection(
                self.transformSelection(Selection.fromJSON(selection))
              );
            } else {
              self.clients[clientId].removeSelection();
            }
          }
        }
      },
      reconnect: function () { self.serverReconnect(); }
    });
  }

  inherit(EditorClient, Client);

  EditorClient.prototype.addClient = function (clientId, clientObj) {
    this.clients[clientId] = new OtherClient(
      clientId,
      this.clientListEl,
      this.editorAdapter,
      clientObj.name || clientId,
      clientObj.selection ? Selection.fromJSON(clientObj.selection) : null
    );
  };

  EditorClient.prototype.initializeClients = function (clients) {
    this.clients = {};
    for (var clientId in clients) {
      if (clients.hasOwnProperty(clientId)) {
        this.addClient(clientId, clients[clientId]);
      }
    }
  };

  EditorClient.prototype.getClientObject = function (clientId) {
    var client = this.clients[clientId];
    if (client) { return client; }
    return this.clients[clientId] = new OtherClient(
      clientId,
      this.clientListEl,
      this.editorAdapter
    );
  };

  EditorClient.prototype.onClientLeft = function (clientId) {
    console.log("User disconnected: " + clientId);
    var client = this.clients[clientId];
    if (!client) { return; }
    client.remove();
    delete this.clients[clientId];
  };

  EditorClient.prototype.initializeClientList = function () {
    this.clientListEl = document.createElement('ul');
  };

  EditorClient.prototype.applyUnredo = function (operation) {
    this.undoManager.add(operation.invert(this.editorAdapter.getValue()));
    this.editorAdapter.applyOperation(operation.wrapped);
    this.selection = operation.meta.selectionAfter;
    this.editorAdapter.setSelection(this.selection);
    this.applyClient(operation.wrapped);
  };

  EditorClient.prototype.undo = function () {
    var self = this;
    if (!this.undoManager.canUndo()) { return; }
    this.undoManager.performUndo(function (o) { self.applyUnredo(o); });
  };

  EditorClient.prototype.redo = function () {
    var self = this;
    if (!this.undoManager.canRedo()) { return; }
    this.undoManager.performRedo(function (o) { self.applyUnredo(o); });
  };

  EditorClient.prototype.onChange = function (textOperation, inverse) {
    var selectionBefore = this.selection;
    this.updateSelection();
    var meta = new SelfMeta(selectionBefore, this.selection);
    var operation = new WrappedOperation(textOperation, meta);

    var compose = this.undoManager.undoStack.length > 0 &&
      inverse.shouldBeComposedWithInverted(last(this.undoManager.undoStack).wrapped);
    var inverseMeta = new SelfMeta(this.selection, selectionBefore);
    this.undoManager.add(new WrappedOperation(inverse, inverseMeta), compose);
    this.applyClient(textOperation);
  };

  EditorClient.prototype.updateSelection = function () {
    this.selection = this.editorAdapter.getSelection();
  };

  EditorClient.prototype.onSelectionChange = function () {
    var oldSelection = this.selection;
    this.updateSelection();
    if (oldSelection && this.selection.equals(oldSelection)) { return; }
    this.sendSelection(this.selection);
  };

  EditorClient.prototype.onBlur = function () {
    this.selection = null;
    this.sendSelection(null);
  };

  EditorClient.prototype.sendSelection = function (selection) {
    if (this.state instanceof Client.AwaitingWithBuffer) { return; }
    this.serverAdapter.sendSelection(selection);
  };

  EditorClient.prototype.sendOperation = function (revision, operation) {
    this.serverAdapter.sendOperation(revision, operation.toJSON(), this.selection);
  };

  EditorClient.prototype.applyOperation = function (operation) {
    this.editorAdapter.applyOperation(operation);
    this.updateSelection();
    this.undoManager.transform(new WrappedOperation(operation, null));
  };

  function rgb2hex (r, g, b) {
    function digits (n) {
      var m = Math.round(255*n).toString(16);
      return m.length === 1 ? '0'+m : m;
    }
    return '#' + digits(r) + digits(g) + digits(b);
  }

  function hsl2hex (h, s, l) {
    if (s === 0) { return rgb2hex(l, l, l); }
    var var2 = l < 0.5 ? l * (1+s) : (l+s) - (s*l);
    var var1 = 2 * l - var2;
    var hue2rgb = function (hue) {
      if (hue < 0) { hue += 1; }
      if (hue > 1) { hue -= 1; }
      if (6*hue < 1) { return var1 + (var2-var1)*6*hue; }
      if (2*hue < 1) { return var2; }
      if (3*hue < 2) { return var1 + (var2-var1)*6*(2/3 - hue); }
      return var1;
    };
    return rgb2hex(hue2rgb(h+1/3), hue2rgb(h), hue2rgb(h-1/3));
  }

  function hueFromName (name) {
    var a = 1;
    for (var i = 0; i < name.length; i++) {
      a = 17 * (a+name.charCodeAt(i)) % 360;
    }
    return a/360;
  }

  // Set Const.prototype.__proto__ to Super.prototype
  function inherit (Const, Super) {
    function F () {}
    F.prototype = Super.prototype;
    Const.prototype = new F();
    Const.prototype.constructor = Const;
  }

  function last (arr) { return arr[arr.length - 1]; }

  // Remove an element from the DOM.
  function removeElement (el) {
    if (el.parentNode) {
      el.parentNode.removeChild(el);
    }
  }

  return EditorClient;
}());

if (typeof ot === 'undefined') {
  var ot = {};
}

ot.Server = (function (global) {
  'use strict';

  // Constructor. Takes the current document as a string and optionally the array
  // of all operations.
  function Server (document, operations) {
    this.document = document;
    this.operations = operations || [];
  }

  // Call this method whenever you receive an operation from a client.
  Server.prototype.receiveOperation = function (revision, operation) {
    if (revision < 0 || this.operations.length < revision) {
      throw new Error("operation revision not in history");
    }
    // Find all operations that the client didn't know of when it sent the
    // operation ...
    var concurrentOperations = this.operations.slice(revision);

    // ... and transform the operation against all these operations ...
    var transform = operation.constructor.transform;
    for (var i = 0; i < concurrentOperations.length; i++) {
      operation = transform(operation, concurrentOperations[i])[0];
    }

    // ... and apply that on the document.
    this.document = operation.apply(this.document);
    // Store operation in history.
    this.operations.push(operation);

    // It's the caller's responsibility to send the operation to all connected
    // clients and an acknowledgement to the creator.
    return operation;
  };

  return Server;

}(this));

if (typeof module === 'object') {
  module.exports = ot.Server;
}
var opTrans;
if (typeof ot === 'undefined' && typeof require !== 'undefined') {
  opTrans = require('ot');
} else {
  opTrans = ot;
}

var OpenTokAdapter = (function () {
  'use strict';

  function OpenTokAdapter (session, revision, doc, operations) {
    OT.$.eventing(this);
    this.registerCallbacks = this.on;
    this.session = session;

    if (operations && revision > operations.length) {
      // the operations have been truncated fill in the beginning with empty space
      var filler = [];
      filler[revision - operations.length - 1] = null;
      this.operations = filler.concat(operations);
    } else {
      this.operations = operations ? operations : [];
    }
    // We pretend to be a server
    var server = new opTrans.Server(doc, this.operations);

    this.session.on({
      connectionDestroyed: function (event) {
        this.trigger('client_left', event.connection.connectionId);
      },
      connectionCreated: function (event) {
        if (event.connection.data && event.connection.data.name) {
          this.trigger('set_name', event.connection.connectionId, event.connection.data.name);
        }
      },
      'signal:opentok-editor-operation': function (event) {
        var data = JSON.parse(event.data),
          wrapped;
          wrapped = new opTrans.WrappedOperation(
            opTrans.TextOperation.fromJSON(data.operation),
            data.selection && opTrans.Selection.fromJSON(data.selection)
          );
          // Might need to try catch here and if it fails wait a little while and
          // try again. This way if we receive operations out of order we might
          // be able to recover
          var wrappedPrime = server.receiveOperation(data.revision, wrapped);
          console.log("new operation: " + wrapped);
          if (event.from.connectionId === session.connection.connectionId) {
            this.trigger('ack');
          } else {
            this.trigger('operation', wrappedPrime.wrapped.toJSON());
            this.trigger('selection', event.from.connectionId, wrappedPrime.meta);
          }
      },
      'signal:opentok-editor-selection': function (event) {
        var selection = JSON.parse(event.data);
        this.trigger('selection', event.from.connectionId, selection);
      }
    }, this);
  }

  OpenTokAdapter.prototype.sendOperation = function (revision, operation, selection) {
    this.session.signal({
      type: 'opentok-editor-operation',
      data: JSON.stringify({
        revision: revision,
        operation: operation,
        selection: selection
      })
    }, function (err) {
      if (err) console.error('Error sending operation', err);
    });
  };

  OpenTokAdapter.prototype.sendSelection = function (selection) {
    this.session.signal({
      type: 'opentok-editor-selection',
      data: JSON.stringify(selection)
    });
  };

  return OpenTokAdapter;

}());

if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') {
  module.exports = OpenTokAdapter;
}

var ng, opTrans;
if (typeof angular === 'undefined' && typeof require !== 'undefined') {
  ng = require('angular');
} else {
  ng = angular;
}
if (typeof ot === 'undefined' && typeof require !== 'undefined') {
  // fixme: We have to make this a global because CodeMirrorAdapter and EditorClient
  // attach themselves to the global ot
  window.ot = require('ot');
  ot.UndoManager = require('ot/lib/undo-manager.js');
  ot.WrappedOperation = require('ot/lib/wrapped-operation.js');
  require('ot/lib/codemirror-adapter.js');
  require('ot/lib/editor-client.js');

  window.OpenTokAdapter = require('./opentok-adapter.js');
}

if (typeof window.CodeMirror === 'undefined') {
  window.CodeMirror = require('codemirror');
}

(function () {
  // Turns the Array of operation Objects into an Array of JSON stringifyable objects
  var serialiseOps = function (operations) {
    return operations.map(function (op) {
      return {
        operation: op.wrapped.toJSON()
      };
    });
  };

  // Turns the JSON form of the Array of operations into ot.TextOperations
  var deserialiseOps = function (operations) {
    return operations.map(function (op) {
      return new ot.WrappedOperation(
              ot.TextOperation.fromJSON(op.operation),
              op.cursor && ot.Selection.fromJSON(op.cursor)
            );
    });
  };

  ng.module('opentok-editor', ['opentok'])
  .directive('otEditor', ['OTSession', '$window', function (OTSession, $window) {
    return {
      restrict: 'E',
      scope: {
          modes: '='
      },
      template: '<div class="opentok-editor-mode-select" ng-show="!connecting">' +
        '<select ng-model="selectedMode" name="modes" ng-options="mode.name for mode in modes"></select>' +
        '</div>' +
        '<div ng-if="connecting" class="opentok-editor-connecting">Connecting...</div>' +
        '<div ng-show="!connecting" class="opentok-editor-connected"><div class="opentok-editor"></div></div>',
      link: function (scope, element, attrs) {
        var opentokEditor = element.context.querySelector('div.opentok-editor'),
            modeSelect = element.context.querySelector('select'),
            myCodeMirror,
            cmClient,
            doc,
            initialised = false,
            session = OTSession.session,
            otAdapter;
        if (typeof require !== 'undefined') {
          // Require all of the modes
          scope.modes.forEach(function(mode) {
            require('codemirror/mode/' + mode.value + '/' + mode.value + '.js');
          });
        }
        scope.connecting = true;
        var selectedMode = scope.modes.filter(function (value) {return value.value === attrs.mode;});
        scope.selectedMode = selectedMode.length > 0 ? selectedMode[0] : scope.modes[0];

        var createEditorClient = function(revision, clients, doc, operations) {
            if (!cmClient) {
              otAdapter =  new OpenTokAdapter(session, revision, doc, operations);
              otAdapter.registerCallbacks('operation', function () {
                scope.$emit('otEditorUpdate');
              });
              cmClient = new ot.EditorClient(
                revision,
                clients,
                otAdapter,
                new ot.CodeMirrorAdapter(myCodeMirror)
              );
              scope.$apply(function () {
                scope.connecting = false;
                setTimeout(function () {
                  myCodeMirror.refresh();
                }, 1000);
              });
            }
        };

        var initialiseDoc = function () {
          if (myCodeMirror && !initialised) {
            initialised = true;
            if (myCodeMirror.getValue() !== doc.str) {
              myCodeMirror.setValue(doc.str);
              scope.$emit('otEditorUpdate');
            }
            createEditorClient(doc.revision, doc.clients, doc.str, deserialiseOps(doc.operations));
          }
        };

        var signalDocState = function (to) {
          var operations = otAdapter && otAdapter.operations ? serialiseOps(otAdapter.operations): [];
          // We only want the most recent 50 because we can't send too much data
          if (operations.length > 50) {
            operations = operations.slice(operations.length - 50);
          }
          var signal = {
            type: 'opentok-editor-doc',
            data: JSON.stringify({
              revision: cmClient.revision,
              clients: [],
              str: myCodeMirror.getValue(),
              operations: operations
            })
          };
          if (to) {
            signal.to = to;
          }
          session.signal(signal);
        };

        var sessionConnected = function () {
          myCodeMirror = CodeMirror(opentokEditor, attrs);
          session.signal({
            type: 'opentok-editor-request-doc'
          });

          setTimeout(function () {
              // We wait 2 seconds for other clients to send us the doc before
              // initialising it to empty
              if (!initialised) {
                initialised = true;
                createEditorClient(0, [], myCodeMirror.getValue());
                // Tell anyone that joined after us that we are initialising it
                signalDocState();
              }
          }, 10000);
        };

        session.on({
          sessionConnected: function (event) {
            sessionConnected();
          },
          'signal:opentok-editor-request-doc': function (event) {
            if (cmClient && event.from.connectionId !== session.connection.connectionId) {
              signalDocState(event.from);
            }
          },
          'signal:opentok-editor-doc': function (event) {
            doc = JSON.parse(event.data);
            initialiseDoc();
          }
        });

        if (session.isConnected()) {
          sessionConnected();
        }

        scope.$watch('selectedMode', function () {
          if (myCodeMirror) {
            myCodeMirror.setOption("mode", scope.selectedMode.value);
          }
        });

        scope.$on('otEditorRefresh', function () {
          myCodeMirror.refresh();
        });
      }
    };
  }]);

})();