#!/usr/bin/env ruby

# This is free and unencumbered software released into the public domain.
# See the `UNLICENSE` file or <http://unlicense.org/> for more details.

require 'open-uri'
require 'socket'
require 'timeout'
require 'webrick'

IP_DISCO_SERVICE = 'http://automation.whatismyip.com/n09230945.asp'
LAN_IP = '169.254.0.1'
PRIVATE_LIST_FILE = '.private'
MAX_PORT = 2**16
MAX_DISCOVER_WAIT = 4 # seconds

def check_args(dir, port)
	if !File.directory?(File.expand_path(dir))
		puts "WARNING: '#{dir}' is not a directory"
	end

	if port > MAX_PORT
		puts "ERROR: port numer too high, #{port} is > #{MAX_PORT}"
		exit
	end
end

def print_addresses(dir, port)
	puts "Discovering addresses and hostnames..."

	begin
		ip = Timeout::timeout(MAX_DISCOVER_WAIT) do
			open(IP_DISCO_SERVICE).read
		end
	rescue
		puts "WARNING: Cannot reach IP discovery service"
		ip = "NOT_AVAILABLE"
	end

	begin
		lan_ip = UDPSocket.open { |s| s.connect(LAN_IP, 1); s.addr[2] }
	rescue
		puts "WARNING: Cannot find LAN-local hostname"
		lan_ip = "NOT_AVAILABLE"
	end

	local_uri = "http://localhost:#{port}/"
	lan_uri = "http://#{lan_ip}:#{port}/"
	remote_uri = "http://#{ip}:#{port}/"

	puts "Server starting... (CTRL-C to terminate)"
	puts
	puts "  local address: <#{local_uri}>"
	puts "  LAN address: <#{lan_uri}>"
	puts "  public address: <#{remote_uri}>"
	puts
end

def start_server(dir, port)
	config = {
		:DocumentRoot => dir,
		:Port => port,
		:DocumentRootOptions => { :FancyIndexing => true },
	}

	private_list_file = File.join(dir, PRIVATE_LIST_FILE)
	if File.exist?(private_list_file)
		patterns = File.readlines(private_list_file).map(&:strip)
		ignored_files = patterns.reject(&:empty?).reject { |f| f.start_with?('#') }
		ignored_files << PRIVATE_LIST_FILE
		config[:DocumentRootOptions][:NondisclosureName] = ignored_files
	end

	server = WEBrick::HTTPServer.new(config)

	['INT', 'TERM'].each { |signal|
		trap(signal) {server.shutdown}
	}

	server.start
end

if ARGV.count < 2
	puts "servedir [DIRECTORY] [PORT]"
	exit
end

dir = ARGV[0] || Dir.pwd
port = ARGV[1].to_i || 8080

check_args(dir, port)
print_addresses(dir, port)
start_server(dir, port)