require 'socket'
require 'open-uri'
require 'date'
require 'timeout'

module Stella
  
  # A motley collection of methods that Stella loves to call!
  module Utils
    extend self
    include Socket::Constants
    
    # Return the external IP address (the one seen by the internet)
    def external_ip_address
      ip = nil
      begin
        %w{solutious.heroku.com/ip}.each do |sponge|
          ipstr = Net::HTTP.get(URI.parse("http://#{sponge}")) || ''
          ip = /([0-9]{1,3}\.){3}[0-9]{1,3}/.match(ipstr).to_s
          break if ip && !ip.empty?
        end
      rescue SocketError, Errno::ETIMEDOUT => ex
        Stella.le "Connection Error. Check your internets!"
      end
      ip
    end
    
    # Return the local IP address which receives external traffic
    # from: http://coderrr.wordpress.com/2008/05/28/get-your-local-ip-address/
    # NOTE: This <em>does not</em> open a connection to the IP address. 
    def internal_ip_address
      # turn off reverse DNS resolution temporarily 
      orig, Socket.do_not_reverse_lookup = Socket.do_not_reverse_lookup, true   
      ip = UDPSocket.open {|s| s.connect('75.101.137.7', 1); s.addr.last } # Solutious IP
      ip
    ensure  
      Socket.do_not_reverse_lookup = orig
    end
    
    
    # <tt>require</tt> a glob of files. 
    # * +path+ is a list of path elements which is sent to File.join 
    # and then to Dir.glob. The list of files found are sent to require. 
    # Nothing is returned but LoadError exceptions are caught. The message
    # is printed to STDERR and the program exits with 7. 
    def require_glob(*path)
      begin
        Dir.glob(File.join(*path.flatten)).each do |path|
          require path
        end
      rescue LoadError => ex
        puts "Error: #{ex.message}"
        exit 7
      end
    end
    
    
    # <tt>require</tt> a library from the vendor directory.
    # The vendor directory should be organized such
    # that +name+ and +version+ can be used to create
    # the path to the library. 
    #
    # e.g.
    # 
    #     vendor/httpclient-2.1.5.2/httpclient
    #
    def require_vendor(name, version)
       $:.unshift File.join(LIB_HOME, '..', 'vendor', "#{name}-#{version}")
       require name
    end
    
    
    # Checks whether something is listening to a socket. 
    # * +host+ A hostname
    # * +port+ The port to check
    # * +wait+ The number of seconds to wait for before timing out. 
    #
    # Returns true if +host+ allows a socket connection on +port+. 
    # Returns false if one of the following exceptions is raised:
    # Errno::EAFNOSUPPORT, Errno::ECONNREFUSED, SocketError, Timeout::Error
    #
    def service_available?(host, port, wait=3)
      if Stella.sysinfo.vm == :java
        begin
          iadd = Java::InetSocketAddress.new host, port      
          socket = Java::Socket.new
          socket.connect iadd, wait * 1000  # milliseconds
          success = !socket.isClosed && socket.isConnected
        rescue NativeException => ex
          puts ex.message, ex.backtrace if Stella.debug?
          false
        end
      else 
        begin
          status = Timeout::timeout(wait) do
            socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
            sockaddr = Socket.pack_sockaddr_in( port, host )
            socket.connect( sockaddr )
          end
          true
        rescue Errno::EAFNOSUPPORT, Errno::ECONNREFUSED, SocketError, Timeout::Error => ex
          puts ex.class, ex.message, ex.backtrace if Stella.debug?
          false
        end
      end
    end
    
    # A basic file writer
    def write_to_file(filename, content, mode, chmod=600)
      mode = (mode == :append) ? 'a' : 'w'
      f = File.open(filename,mode)
      f.puts content
      f.close
      return unless Stella.sysinfo.os == :unix
      raise "Provided chmod is not a Fixnum (#{chmod})" unless chmod.is_a?(Fixnum)
      File.chmod(chmod, filename)
    end

    # 
    # Generates a string of random alphanumeric characters.
    # * +len+ is the length, an Integer. Default: 8
    # * +safe+ in safe-mode, ambiguous characters are removed (default: true):
    #       i l o 1 0
    def strand( len=8, safe=true )
       chars = ("a".."z").to_a + ("0".."9").to_a
       chars.delete_if { |v| %w(i l o 1 0).member?(v) } if safe
       str = ""
       1.upto(len) { |i| str << chars[rand(chars.size-1)] }
       str
    end
    
    # Returns +str+ with the leading indentation removed. 
    # Stolen from http://github.com/mynyml/unindent/ because it was better.
    def noindent(str)
      indent = str.split($/).each {|line| !line.strip.empty? }.map {|line| line.index(/[^\s]/) }.compact.min
      str.gsub(/^[[:blank:]]{#{indent}}/, '')
    end
    
  end
end