/**
   * `rawlist` type prompt
   */
  
  var _ = require("lodash");
  var util = require("util");
  var chalk = require("chalk");
  var Base = require("./base");
  var Separator = require("../objects/separator");
  var observe = require("../utils/events");
  var Paginator = require("../utils/paginator");
  
  
  /**
   * Module exports
   */
  
  module.exports = Prompt;
  
  
  /**
   * Constructor
   */
  
  function Prompt() {
    Base.apply( this, arguments );
  
    if (!this.opt.choices) {
      this.throwParamError("choices");
    }
  
    this.opt.validChoices = this.opt.choices.filter(Separator.exclude);
  
    this.selected = 0;
    this.rawDefault = 0;
  
    _.extend(this.opt, {
      validate: function( index ) {
        return this.opt.choices.getChoice( index ) != null;
      }.bind(this)
    });
  
    var def = this.opt.default;
    if ( _.isNumber(def) && def >= 0 && def < this.opt.choices.realLength ) {
      this.selected = this.rawDefault = def;
    }
  
    // Make sure no default is set (so it won't be printed)
    this.opt.default = null;
  
    this.paginator = new Paginator();
  }
  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 the prompt
    this.render();
  
    return this;
  };
  
  
  /**
   * Render the prompt to screen
   * @return {Prompt} self
   */
  
  Prompt.prototype.render = function (error) {
    // Render question
    var message = this.getQuestion();
    var bottomContent = '';
  
    if ( this.status === "answered" ) {
      message += chalk.cyan(this.opt.choices.getChoice(this.selected).name);
    } else {
      var choicesStr = renderChoices(this.opt.choices, this.selected);
      message += this.paginator.paginate(choicesStr, this.selected, this.opt.pageSize);
      message += "
    Answer: ";
    }
  
    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 == null || input === "" ) {
      return this.rawDefault;
    } else {
      return input - 1;
    }
  };
  
  Prompt.prototype.onEnd = function( state ) {
    this.status = "answered";
    this.selected = state.value;
  
    var selectedChoice = this.opt.choices.getChoice( this.selected );
  
    // Re-render prompt
    this.render();
  
    this.screen.done();
    this.done( selectedChoice.value );
  };
  
  Prompt.prototype.onError = function() {
    this.render("Please enter a valid index");
  };
  
  /**
   * When user press a key
   */
  
  Prompt.prototype.onKeypress = function() {
    var index = this.rl.line.length ? Number(this.rl.line) - 1 : 0;
  
    if ( this.opt.choices.getChoice(index) ) {
      this.selected = index;
    } else {
      this.selected = undefined;
    }
  
    this.render();
  };
  
  
  /**
   * Function for rendering list choices
   * @param  {Number} pointer Position of the pointer
   * @return {String}         Rendered content
   */
  
  function renderChoices(choices, pointer) {
    var output = '';
    var separatorOffset = 0;
  
    choices.forEach(function (choice, i) {
      output += '
    ';
  
      if (choice.type === 'separator') {
        separatorOffset++;
        output += ' ' + choice;
        return;
      }
  
      var index = i - separatorOffset;
      var display = (index + 1) + ') ' + choice.name;
      if (index === pointer) {
        display = chalk.cyan( display );
      }
      output += display;
    });
  
    return output;
  }