var Delta, Quill, UndoManager, _;

Quill = require('../quill');

_ = Quill.require('lodash');

Delta = Quill.require('delta');

UndoManager = (function() {
  UndoManager.DEFAULTS = {
    delay: 1000,
    maxStack: 100
  };

  UndoManager.hotkeys = {
    UNDO: {
      key: 'Z',
      metaKey: true
    },
    REDO: {
      key: 'Z',
      metaKey: true,
      shiftKey: true
    }
  };

  function UndoManager(quill, options) {
    this.quill = quill;
    this.options = options != null ? options : {};
    this.lastRecorded = 0;
    this.emittedDelta = null;
    this.clear();
    this.initListeners();
  }

  UndoManager.prototype.initListeners = function() {
    this.quill.onModuleLoad('keyboard', (function(_this) {
      return function(keyboard) {
        keyboard.addHotkey(UndoManager.hotkeys.UNDO, function() {
          _this.undo();
          return false;
        });
        return keyboard.addHotkey(UndoManager.hotkeys.REDO, function() {
          _this.redo();
          return false;
        });
      };
    })(this));
    return this.quill.on(this.quill.constructor.events.TEXT_CHANGE, (function(_this) {
      return function(delta, origin) {
        if (_.isEqual(delta, _this.emittedDelta)) {
          return;
        }
        _this.record(delta, _this.oldDelta);
        return _this.oldDelta = _this.quill.getContents();
      };
    })(this));
  };

  UndoManager.prototype.clear = function() {
    this.stack = {
      undo: [],
      redo: []
    };
    return this.oldDelta = this.quill.getContents();
  };

  UndoManager.prototype.record = function(changeDelta, oldDelta) {
    var change, ignored, timestamp, undoDelta;
    if (!(changeDelta.ops.length > 0)) {
      return;
    }
    this.stack.redo = [];
    try {
      undoDelta = this.quill.getContents().diff(this.oldDelta);
      timestamp = new Date().getTime();
      if (this.lastRecorded + this.options.delay > timestamp && this.stack.undo.length > 0) {
        change = this.stack.undo.pop();
        undoDelta = undoDelta.compose(change.undo);
        changeDelta = change.redo.compose(changeDelta);
      } else {
        this.lastRecorded = timestamp;
      }
      this.stack.undo.push({
        redo: changeDelta,
        undo: undoDelta
      });
      if (this.stack.undo.length > this.options.maxStack) {
        return this.stack.undo.unshift();
      }
    } catch (_error) {
      ignored = _error;
      return this.clear();
    }
  };

  UndoManager.prototype.redo = function() {
    return this._change('redo', 'undo');
  };

  UndoManager.prototype.undo = function() {
    return this._change('undo', 'redo');
  };

  UndoManager.prototype._getLastChangeIndex = function(delta) {
    var index, lastIndex;
    lastIndex = 0;
    index = 0;
    delta.ops.forEach(function(op) {
      if (op.insert != null) {
        return lastIndex = Math.max(index + (op.insert.length || 1), lastIndex);
      } else if (op["delete"] != null) {
        return lastIndex = Math.max(index, lastIndex);
      } else if (op.retain != null) {
        if (op.attributes != null) {
          lastIndex = Math.max(index + op.retain, lastIndex);
        }
        return index += op.retain;
      }
    });
    return lastIndex;
  };

  UndoManager.prototype._change = function(source, dest) {
    var change, index;
    if (this.stack[source].length > 0) {
      change = this.stack[source].pop();
      this.lastRecorded = 0;
      this.emittedDelta = change[source];
      this.quill.updateContents(change[source], 'user');
      this.emittedDelta = null;
      index = this._getLastChangeIndex(change[source]);
      this.quill.setSelection(index, index);
      this.oldDelta = this.quill.getContents();
      return this.stack[dest].push(change);
    }
  };

  return UndoManager;

})();

Quill.registerModule('undo-manager', UndoManager);

module.exports = UndoManager;