#!/usr/bin/env ruby
# 2018  Luke Shumaker

require 'json'
require 'net/http'
require 'optparse'
require 'set'
devnull = open("/dev/null")

begin
	OptionParser.new do |parser|
	parser.on("-h", "--help", "Display this help") do
		puts parser
		exit
	end
	end.parse!
rescue OptionParser::ParseError => e
	STDERR.puts "#{$0}: #{e}"
	STDERR.puts "Try '#{$0} --help' for more information."
	exit 2
end
unless ARGV.empty?
	STDERR.puts "#{$0}: extra argument '#{ARGV[0]}'"
	STDERR.puts "Try '#{$0} --help' for more information."
	exit 2
end

# Get a listing of hostnames that have HTTP Arch Linux ARM mirrors
data = JSON::parse(Net::HTTP.post(
	URI("https://archlinuxarm.org/data/mirrors/list"), "", {
		'Referer' => 'https://archlinuxarm.org/about/mirrors',
		'X-Requested-With' => 'XMLHttpRequest',
	}).body)

hosts = data["data"].map{|m|m[2]}

# Get a listing of rsync URLs for each host
modulelist_procs = {}
hosts.each do |host|
	modulelist_procs[host] ||= IO.popen(["timeout", "2s", "rsync", "--password-file", "/dev/null", "#{host}::"], :err => devnull)
end
rsync_urls = Set.new()
modulelist_procs.each do |host,modulelist_proc|
	modules = modulelist_proc.read.lines.map{|line| line.chomp.sub(/\s.*/, '') }
	modulelist_proc.close
	rsync_urls.merge(modules.map{|m| "rsync://#{host}/#{m}/"})
end

# Get a listing of the top-level files in each
listing_procs = {}
rsync_urls.each do |url|
	listing_procs[url] ||= IO.popen(["rsync", "--password-file", "/dev/null", "--no-motd", "--list-only", "--", url], :err => devnull)
end
listings = {}
listing_procs.map.each do |url,listing_proc|
	listings[url] = listing_proc.read.lines.map{|line|line.chomp.sub(/.*\s/,'')}
	listing_proc.close
end

# Filter for listings that look like Arch Linux ARM mirrors
requires = ['aarch64', 'arm', 'armv6h', 'armv7h', 'os']
rsync_urls = rsync_urls.select{|url| requires.all?{|file|listings[url].include?(file)} }

# Print the results
rsync_urls.sort.each do |url|
	puts url
end