/**
   * `input` type prompt
   */
  
  var util = require("util");
  var chalk = require("chalk");
  var Base = require("./base");
  var observe = require("../utils/events");
  
  
  /**
   * Module exports
   */
  
  module.exports = Prompt;
  
  
  /**
   * Constructor
   */
  
  function Prompt() {
    return Base.apply( this, arguments );
  }
  util.inherits( Prompt, Base );
  
  
  /**
   * Start the Inquiry session
   * @param  {Function} cb      Callback when prompt is done
   * @return {this}
   */
  
  Prompt.prototype._run = function( cb ) {
    this.done = cb;
  
    // Once user confirm (enter key)
    var events = observe(this.rl);
    var submit = events.line.map( this.filterInput.bind(this) );
  
    var validation = this.handleSubmitEvents( submit );
    validation.success.forEach( this.onEnd.bind(this) );
    validation.error.forEach( this.onError.bind(this) );
  
    events.keypress.takeUntil( validation.success ).forEach( this.onKeypress.bind(this) );
  
    // Init
    this.render();
  
    return this;
  };
  
  
  /**
   * Render the prompt to screen
   * @return {Prompt} self
   */
  
  Prompt.prototype.render = function (error) {
    var bottomContent = '';
    var message = this.getQuestion();
  
    if (this.status === 'answered') {
      message += chalk.cyan(this.answer);
    } else {
      message += this.rl.line;
    }
  
    if (error) {
      bottomContent = chalk.red('>> ') + error;
    }
  
    this.screen.render(message, bottomContent);
  };
  
  
  /**
   * When user press `enter` key
   */
  
  Prompt.prototype.filterInput = function( input ) {
    if ( !input ) {
      return this.opt.default != null ? this.opt.default : "";
    }
    return input;
  };
  
  Prompt.prototype.onEnd = function( state ) {
    this.filter( state.value, function( filteredValue ) {
      this.answer = filteredValue;
      this.status = "answered";
  
      // Re-render prompt
      this.render();
  
      this.screen.done();
      this.done( state.value );
    }.bind(this));
  };
  
  Prompt.prototype.onError = function( state ) {
    this.render(state.isValid);
  };
  
  /**
   * When user press a key
   */
  
  Prompt.prototype.onKeypress = function() {
    this.render();
  };