class SysInfo

def execute_platform_specific(dtype)
  criteria = [@vm, @os, @impl]
  while !criteria.empty?
    meth = [dtype, criteria].join('_').to_sym
    return self.send(meth) if SysInfo.private_method_defined?(meth)
    criteria.pop
  end
  raise "#{dtype}_#{@vm}_#{@os}_#{@impl} not implemented"
end

def find_hostname; Socket.gethostname; end

def find_ipaddress_internal
  # turn off reverse DNS resolution temporarily
  orig, Socket.do_not_reverse_lookup = Socket.do_not_reverse_lookup, true
  UDPSocket.open {|s| s.connect('65.74.177.129', 1); s.addr.last } # GitHub IP
ensure
  Socket.do_not_reverse_lookup = orig
end

def find_network_info
  hostname, ipaddr, uptime = :unknown, :unknown, :unknown
  begin
    hostname = find_hostname
    ipaddr = find_ipaddress_internal
    uptime = find_uptime
  rescue => ex # Be silent!
  end
  [hostname, ipaddr, uptime]
end

def find_platform_info
  vm, os, impl, arch = :ruby, :unknown, :unknown, :unknown
  IMPLEMENTATIONS.each do |r, o, i|
    next unless RUBY_PLATFORM =~ r
    os, impl = [o, i]
    break
  end
  ARCHITECTURES.each do |r, a|
    next unless RUBY_PLATFORM =~ r
    arch = a
    break
  end
  os == :java ? guess_java : [vm, os, impl, arch]
end

def find_uptime
  hours = 0
  begin
    seconds = execute_platform_specific("find_uptime") || 0
    hours = seconds / 3600 # seconds to hours
  rescue => ex
    #puts ex.message  # TODO: implement debug?
  end
  hours
end

def find_uptime_java_windows_windows
  kernel32 = com.sun.jna.NativeLibrary.getInstance('kernel32')
  buf = java.nio.ByteBuffer.allocate(256)
  (kernel32.getFunction('GetTickCount').invokeInt([256, buf].to_java).to_f / 1000).to_f
end

def find_uptime_ruby_unix
  # who is sloooooow. Use File.read('/proc/uptime')
  (Time.now.to_i - Time.parse(`who -b 2>/dev/null`).to_f)
end

def find_uptime_ruby_unix_osx
  # This is faster than "who" and could work on BSD also.
  (Time.now.to_f - Time.at(`sysctl -b kern.boottime 2>/dev/null`.unpack('L').first).to_f).to_f
end

def find_uptime_ruby_windows_windows
  # Win32API is required in self.guess
  getTickCount = Win32API.new("kernel32", "GetTickCount", nil, 'L')
  ((getTickCount.call()).to_f / 1000).to_f
end

def getpwattr(pwattr)
  passwd = Etc.getpwuid(Process::Sys.getuid) || {}
  passwd[pwattr]
end

def guess_java
  vm, os, impl, arch = :java, :unknown, :unknown, :unknown
  require 'java'
  include_class java.lang.System unless defined?(System)
  osname = System.getProperty("os.name")
  IMPLEMENTATIONS.each do |r, o, i|
    next unless osname =~ r
    os, impl = [o, i]
    break
  end
  osarch = System.getProperty("os.arch")
  ARCHITECTURES.each do |r, a|
    next unless osarch =~ r
    arch = a
    break
  end
  [vm, os, impl, arch]
end

def home; execute_platform_specific(:home); end

def home_java
  if @impl == :windows
    File.expand_path(ENV['USERPROFILE'])
  else
    File.expand_path(getpwattr(:dir))
  end
end

def home_ruby_unix; File.expand_path(getpwattr(:dir)); end

def home_ruby_windows; File.expand_path(ENV['USERPROFILE']); end

def initialize
  @vm, @os, @impl, @arch = find_platform_info
  @hostname, @ipaddress_internal, @uptime = find_network_info
  @ruby = RUBY_VERSION.split('.').collect { |v| v.to_i }
  @user = getpwattr(:name) || ENV['USER']
  require 'Win32API' if @os == :windows && @vm == :ruby
end

def ip_address_internal_alt
  ipaddr = :unknown
  begin
    saddr = Socket.getaddrinfo(  Socket.gethostname, nil, Socket::AF_UNSPEC, Socket::SOCK_STREAM, nil, Socket::AI_CANONNAME)
    ipaddr = saddr.select{|type| type[0] == 'AF_INET' }[0][3]
  rescue => ex
  end
  ipaddr
end

def paths; execute_platform_specific(:paths); end

def paths_java
  delim = @impl == :windows ? ';' : ':'
  (ENV['PATH'] || '').split(delim)
end

def paths_ruby_unix; (ENV['PATH'] || '').split(':'); end

def paths_ruby_windows; (ENV['PATH'] || '').split(';'); end # Not tested!

def platform
  "#{@vm}-#{@os}-#{@impl}-#{@arch}"
end

def shell; execute_platform_specific(:shell); end

def shell_ruby_unix; (ENV['SHELL'] || getpwattr(:shell) || 'bash').to_sym; end

def shell_ruby_windows; :dos; end

def tmpdir; execute_platform_specific(:tmpdir); end

def tmpdir_java
  default = @impl == :windows ? 'C:\\temp' : '/tmp'
  (Dir.tmpdir || default)
end

def tmpdir_ruby_unix; (Dir.tmpdir || '/tmp'); end

def tmpdir_ruby_windows; (Dir.tmpdir || 'C:\\temp'); end