#!/usr/bin/env python3

import re
import subprocess
import sys
import urllib.parse

def oneliner(*args):
	return subprocess.check_output(args, universal_newlines=True).strip()

local_branch = oneliner('git', 'name-rev', '--name-only', 'HEAD')
tracking_remote = oneliner('git', 'config', 'branch.%s.remote' % local_branch)
tracking_branch = oneliner('git', 'config', 'branch.%s.merge' % local_branch)
remote_url = oneliner('git', 'config', 'remote.%s.url' % tracking_remote)
relpath = oneliner('git', 'rev-parse', '--show-prefix')[:-1]

if tracking_branch.startswith('refs/heads/'):
	tracking_branch = tracking_branch[len('refs/heads/'):]
else:
	raise Exception("can't handle " + tracking_branch)

remote_url = re.sub(r'^(.+@.+):(.+)$', r'ssh://\1/\2', remote_url)
if remote_url.endswith('.git'):
	remote_url = remote_url[:-len('.git')]
parsed = urllib.parse.urlparse(remote_url)
hostname = parsed.hostname
if hostname == 'github.com-private':
	hostname = 'github.com'

if hostname == 'github.com':
	repo_url = urllib.parse.urlunparse(('https', hostname, parsed.path, '', '', ''))
	dir_url = '%s/tree/%s' % (repo_url, tracking_branch)
	if relpath:
		dir_url = '%s/%s' % (dir_url, relpath)
	if len(sys.argv) == 2:
		print('%s/%s' % (dir_url, sys.argv[1]))
	else:
		print(dir_url)
else:
	raise Exception("can't handle " + parsed.hostname)