require "net/https"
require "optparse"
require "json"
require "uri"

options = {:ttl => "3600", :records => {}}
req_headers = {"Content-Type" => "application/json"}

OptionParser.new do |opts|
	opts.banner = "Usage: ddns.rb -a -p -f file/path -t 3600 -r example.com"

	opts.on("-f", "--token TOKEN_PATH", "Absolute path of file containing a Cloudflare API token.") do |path|
		if File.file?(path) then
			if File.readable?(path) then
				cf_token = File.read(path)
				cf_token = cf_token.gsub("\s", "")

				req_headers["Authorization"] = "Bearer " + cf_token
			else
				warn "Token file not readable."
				exit 11
			end
		else
			warn "Failed to find token file."
			exit 10
		end
	end

	opts.on("-t", "--ttl TTL", "TTL") do |ttl|
		options[:ttl] = ttl
	end

	opts.on("-a", "--aaaa", "Update AAAA records as well as A records.") do |aaaa|
		options[:update_aaaa] = aaaa
	end

	opts.on("-p", "--proxy", "Enable proxy on updated DNS records.") do |proxy|
		options[:enable_proxy] = proxy
	end

	opts.on("-r", "--record RECORD", "Add record name to update.") do |record|
		options[:records][record] = true
	end
end.parse!

print "Fetching external IP... "

ip_res, external_ip = Net::HTTP.get_response("checkip.amazonaws.com", "/")
if ip_res.code == "200" then
	external_ip = ip_res.body.tr("\n", "")
	puts "#{external_ip}."
else
	puts "Failed."
	puts "#{ip_res.code}: #{ip_res.body}"
	exit 20
end

puts "Updating DDNS records."

zone_uri = URI.parse("https://api.cloudflare.com/client/v4/zones")
https = Net::HTTP.new(zone_uri.host, zone_uri.port)
https.use_ssl = true

zone_req = Net::HTTP::Get.new(zone_uri, req_headers)
zone_res = JSON.parse(https.request(zone_req).body)

if zone_res["success"] == true then
	puts "Found #{zone_res["result"].count()} zone(s) to update."

	zone_res["result"].each do |zone|
		puts "Fetching records from zone '#{zone["name"]}'."

		zone_id = zone["id"]

		record_uri = URI.parse("https://api.cloudflare.com/client/v4/zones/#{zone_id}/dns_records")
		https = Net::HTTP.new(record_uri.host, record_uri.port)
		https.use_ssl = true

		record_req = Net::HTTP::Get.new(record_uri, req_headers)
		record_res = JSON.parse(https.request(record_req).body)

		if record_res["success"] == true then
			record_res["result"].each do |record|
				record_name = record["name"]
				record_type = record["type"]

				if options[:records][record_name] && (record_type == "A" or (options[:update_aaaa] && record_type == "AAAA")) then
					print "Updating record '#{record_name}'... "

					if record["content"] == external_ip then
						puts "Content doesn't need updating, skipping record."
					else
						update = {
							"type" => record_type,
							"name" => record_name,
							"content" => external_ip,
							"ttl" => options[:ttl],
							"proxied" => options[:enable_proxy]
						}

						update_uri = URI.parse("https://api.cloudflare.com/client/v4/zones/#{zone_id}/dns_records/#{record["id"]}")
						https = Net::HTTP.new(update_uri.host, update_uri.port)
						https.use_ssl = true

						update_req = Net::HTTP::Put.new(update_uri, req_headers)
						update_req.body = update.to_json

						update_res = JSON.parse(https.request(update_req).body)

						if update_res["success"] == true then
							puts "Updated successfully!"
						else
							puts "Update failed!"
							pp update_res
						end
					end
				end
			end
		else
			puts record_res
			exit 22
		end
	end
else
	puts zone_res
	exit 21
end

puts "Updated DDNS records successfully."