function pgsh(ev) {
  var self = this

  ev.on('cmd_entered', function(input) {
    // First word is the command, all others are arguments.
    var parts = input.trim().split(' ')
    var command = self.active ? self.active : parts.splice(0, 1).toString()
    var args = parts
    if (command in self.commands) {
      self.commands[command].run(args)
    } else if (command) {
      show(command + ' not found')
    }
  })

  var show = function(text) {
    ev.trigger('disp_add', text)
  }

  this.prompt = '<span style="color:blueviolet">pgs </span>' +
    '<span style="color:green">$ </span>'
  var welc = 'Linux parsleygardens.net 3.4.5-6-7-i286 #8 PGS Vimputer ' +
    '3.4.56-7 i286\n\n' +
    '~ Welcome to Parsley Gardens! ~\n' +
    '"He maketh me to lie down in green pa..."\n\n' +
    'Type `help` for list of commands\n\n'
  this.welcome = welc
  this.commands = {
    'about': {
      'help': 'Author Information\nUsage: about',
      'run': function(args) {
        if (args.length > 0) { show(this.help); return }
        var me = 'Site by Weiyi Lou ' + new Date().getFullYear() + '\n\n'
        show(me)
      }
    },
    'clear': {
      'help': 'Clears the screen\nUsage: clear',
      'run' : function(args) {
        ev.trigger('disp_clear')
      }
    },
    'version': {
      'help': 'Shell Information\nUsage: version',
      'run': function(args) {
        if (args.length > 0) { show(this.help); return }
        var ve = 'Parsley Gardens Shell (pgsh) 1.0.0 Built with ' +
          '<a target="_blank" href="http://riotjs.com/">Riot.js</a>'
        show(ve)
      }
    },
    'git': {
      'help': 'Link to Code Repository\nUsage: git',
      'run': function(args) {
        if (args.length > 0) { show(this.help); return }
        var repo = 'Self-Hosted Code Repository at <a target="_blank" ' +
          'href="https://code.parsleygardens.net/explore/projects">' +
        'code.parsleygardens.net</a>'
        show(repo)
      }
    },
    'hello': {
      'help': 'Say hello to the computer\nUsage: hello [name]',
      'run': function(args) {
        address = args.join(' ').trim()
        if (address.length == 0) {
          show('Hello to you too')
        } else if (address == 'pgsh') {
          show('Hello human')
        } else {
          show('My name is not "' + address + '"')
        }
      }
    },
    'magic': {
      'help': 'Link to Artist\nUsage: magic',
      'run': function(args) {
        if (args.length > 0) { show(this.help); return }
        var art = 'Animation and Illustration at <a target="_blank" ' +
          'href="http://slightlymagic.com.au">slightlymagic.com.au</a>'
        show(art)
      }
    },
    'su': {
      'help': 'Gain Phenomenal Cosmic Power\nUsage: su',
      'run': function(args) {
        if (args.length > 0) { show(this.help); return }
        if (!self.su) {
          self.su = true
          if (!self.su_warned) {
            self.su_warned = true
            var wa = 'We trust you have received the usual lecture from the ' +
              'local System Administrator.\n' +
              'It usually boils down to these three things:\n\n' +
              '    #1) Respect the privacy of others.\n' +
              '    #2) Think before you type.\n' +
              '    #3) With great power comes great\n\n'
            show(wa)
          }
          var p = '<span style="color:tomato">root </span>'
          p += '<span style="color:red">% </span>'
          ev.trigger('prompt_set', p)
        }
      }
    },
    'exit': {
      'help': 'Leave the current context\nUsage: exit',
      'run': function(args) {
        if (args.length > 0) { show(this.help); return }
        if (self.su) {
          self.su = false
          ev.trigger('prompt_set', self.prompt)
          return
        }
        show('Close browser window to exit')
      }
    },
    'search': {
      'help': 'Search the Web (with a Duck)\nUsage: search [query]',
      'run': function(args) {
        if (!args.join(' ').trim()) { show(this.help); return }
        ev.trigger('prompt_hide')
        show('Searching for "' + args.join(' ') + '" in new window...')
        setTimeout(function() {
          window.open('https://duckduckgo.com/?q=' + args.join('+'), '_blank')
          ev.trigger('prompt_show')
        }, 1000)
      }
    },
    'questions': {
      'help': 'Answer some questions!\nUsage: questions',
      'run': function(args) {
        if (!self.active) {
          self.active = 'questions'
          ev.trigger('disp_hide')
          ev.trigger('prompt_hide')
          show('Welcome to the questions. Do you want to continue?')
          return
        }
        if (args == 'exit') {
          self.active = ''
          ev.trigger('disp_restore')
          ev.trigger('prompt_show')
          show('Thanks for answering questions!')
          return
        }
        var output = 'You answered with "' + args + '"!\nNext question!\n' +
          '<span style="color:#555">(Type "exit" to end)</span>\n\n'
        ev.trigger('disp_set', output)
        var rand = Math.floor(Math.random() * this.questions.length);
        show(this.questions[rand])
      },
      'questions': [
        'Isn\'t <a href="https://www.youtube.com/watch?v=dQw4w9WgXcQ"' +
        ' target="_blank">this song</a> the best?',
        'Iggledy Piggledy?',
        '1 + 2 = ?',
        'Am I a sandwich?',
        'Where were you at 3:15am on April 14th?',
        "Don't you mean prism?",
        'Butts twelve by pies?',
        'I say there, Monstrosity. Do you know the times?',
        '...is essay-writing an exercise in masking ignorance?',
        'What is the name of the spaces. Between the teeth. Of a comb?',
        'Why are you dressed up like Ship\'s Captain?'
      ]
    },
    'help': {
      'help': 'List available commands or view information for a given ' +
        'command\nUsage: help [command]',
      'run': function(args) {
        command = args.join(' ').trim()
        if (command in self.commands) {
          show(self.commands[command].help)
        } else if (command) {
          show('No information for: ' + command)
        } else {
          var commands = [];
          for(var name in self.commands) {
            commands.push(name)
          }
          show('Available commands:\n' + commands.sort().join(' ') +
               '\n\n`help [command]` for more information.')
        }
      }
    }
  }
}