#!/usr/bin/python3
# -*- coding: utf-8 -*-

# Give me a random hostname!

import sys, os
import random


def read_file(filename) :
	ret = []
	with open(filename, 'r') as f_in :
		for line in f_in.readlines():
			line = line.strip()
			# ignore empty lines or comment
			if len(line) == 0 or line[0] in "#:!$%" : continue
			ret.append(line)
	return ret

def file_exists(filename) :
	return os.path.exists(filename)

def scan_files(path, suffix = ".txt") :
	ret = []
	with os.scandir(path) as dirs:
		for entry in dirs :
			filename = entry.name
			if filename.endswith(".txt") :
				ret.append(filename)
	return ret

def usage() :
	print("print hostname suggestions")
	print("Usage: %s [OPTIONS] [FILES...]" % (sys.argv[0]))
	print("OPTIONS")
	print("  -h, --help                        Print this help message")
	print("  -l, --ls                          Print source files")

if __name__ == "__main__" :
	# By default, print 10 lines, 4 entries each line
	n = 10
	c = 4

	hostnames = []
	filenames = []
	
	args = sys.argv[1:]
	for arg in args :
		if arg == "" : continue
		if arg[0] == '-' :
			if arg == "-h" or arg == "--help" :
				usage()
				sys.exit(0)
			elif arg == "-l" or arg == "--ls" :
				for filename in scan_files(".") :
					print(filename)
				sys.exit(0)
		else :
			filenames.append(arg)
	
	# If no files are given, take all files
	if len(filenames) == 0 :
		filenames = scan_files(".")
	
	# Load hostnames from files
	for filename in filenames :
		# Add txt if not yet present
		if not file_exists(filename) and not filename.endswith(".txt") :
			if file_exists(filename + ".txt") : filename += ".txt"
		if not file_exists(filename) :
			sys.stderr.write("file not found: %s\n" % (filename))
			sys.exit(1)
		hostnames += read_file(filename)
	
	if len(hostnames) == 0 :
		sys.stderr.write("no hostnames found\n")
		sys.exit(1)
	
	for i in range(n) :
		if len(hostnames) == 0 : break
		for j in range(c) :
			if len(hostnames) == 0 : break
			hostname = hostnames[random.randint(0, len(hostnames)-1)]
			hostnames.remove(hostname)
			sys.stdout.write("%-20s" % (hostname))
		sys.stdout.write("\n")