text: 'use strict';
  
  var _ = require('lodash');
  var chalk = require('chalk');
  
  /**
   * The paginator keeps track of a pointer index in a list and returns
   * a subset of the choices if the list is too long.
   */
  
  class Paginator {
    constructor(screen) {
      this.pointer = 0;
      this.lastIndex = 0;
      this.screen = screen;
    }
  
    paginate(output, active, pageSize) {
      pageSize = pageSize || 7;
      var middleOfList = Math.floor(pageSize / 2);
      var lines = output.split('\n');
  
      if (this.screen) {
        lines = this.screen.breakLines(lines);
        active = _.sum(lines.map(lineParts => lineParts.length).splice(0, active));
        lines = _.flatten(lines);
      }
  
      // Make sure there's enough lines to paginate
      if (lines.length <= pageSize) {
        return output;
      }
  
      // Move the pointer only when the user go down and limit it to the middle of the list
      if (
        this.pointer < middleOfList &&
        this.lastIndex < active &&
        active - this.lastIndex < pageSize
      ) {
        this.pointer = Math.min(middleOfList, this.pointer + active - this.lastIndex);
      }
  
      this.lastIndex = active;
  
      // Duplicate the lines so it give an infinite list look
      var infinite = _.flatten([lines, lines, lines]);
      var topIndex = Math.max(0, active + lines.length - this.pointer);
  
      var section = infinite.splice(topIndex, pageSize).join('\n');
      return section + '\n' + chalk.dim('(Move up and down to reveal more choices)');
    }
  }
  
  module.exports = Paginator;
  