require 'uri'
require 'net/http'
require 'fusefs'
require 'rexml/document'

class Twitter
  User = Struct.new(:user_id, :screen_name, :status)

  def initialize(username, password)
    @username, @password = username, password

    @status = nil
    @users = {}
    @friends = nil
    @followers = nil
  end
  attr_reader :followers, :friends, :status

  def user(s)
    @users[s]
  end

  def crawl
    @friends = crawl_users('/statuses/friends.xml')
    @followers = crawl_users('/statuses/followers.xml')
  end

  def status=(s)
    @status = s

    req = create_request('/statuses/update.json')
    req.body = 'status=' + URI.encode(@status)
    post(req)
  end

  private
  def crawl_users(path)
    result = []

    req = create_request(path)
    doc = REXML::Document.new(post(req))
    doc.root.elements.each('/users/user') do |u|
      ary = (%w(id screen_name status/text).collect do |i|
               u.elements[i].text
             end)
      result << update_user(*ary)
    end
    result
  end

  def update_user(user_id, screen_name, status)
    u = @users[screen_name]
    if u
      u.status = status
    else
      @users[screen_name] = User.new(user_id, screen_name, status)
    end
  end

  def create_request(path)
    req = Net::HTTP::Post.new(path)
    req.basic_auth(@username, @password)
    req
  end

  def post(req)
    result = nil
    Net::HTTP.start('twitter.com', 80) do |http|
      resp = http.request(req)
      result = resp.body
    end
    result
  end
end

class TwitterFS
  def initialize(username, password)
    @twitter = Twitter.new(username, password)
    @twitter.crawl
  end

  def contents(path)
    case path
    when '/'
      %w(me friends followers)
    when '/friends'
      @twitter.friends.collect do |f| f.screen_name end
    when '/followers'
      @twitter.followers.collect do |f| f.screen_name end
    end
  end

  def file?(path)
    not directory?(path)
  end

  def directory?(path)
    path == '/friends' or path == '/followers'
  end

  def read_file(path)
    if path =~ %r{^/friends/} or path =~ %r{^/followers/}
      @twitter.user(File.basename(path)).status
    elsif path == '/me'
      @twitter.status
    else
      ''
    end + "\n"
  end

  def size(path)
    read_file(path).length
  end

  def can_delete?(path)
    can_write?(path)
  end

  def can_write?(path)
    path == '/me'
  end

  def write_to(path, body)
    if path == '/me'
      @twitter.status = body
    else
      raise
    end
  end
end

exit if ARGV.length != 3
username, password, path = *ARGV

fs = TwitterFS.new(username, password)
FuseFS.set_root(fs)
FuseFS.mount_under(path)
FuseFS.run