bin/git-url

#!/usr/bin/env python3

from __future__ import annotations

import re
import subprocess
import sys
import typing
import urllib.parse

if typing.TYPE_CHECKING:
	from _typeshed import StrOrBytesPath

def oneliner(*args) -> str:
	return subprocess.run(args, check=True, capture_output=True, text=True).stdout.strip()

commit = oneliner('git', 'rev-parse', 'HEAD')
local_branch = oneliner('git', 'branch', '--show-current')

tag = None
if local_branch.startswith('tags/'):
	tag = local_branch[5:]
	if tag.endswith('^0'):
		tag = tag[:-2]
	remote_url = oneliner('git', 'config', 'remote.origin.url')
else:
	tracking_branch = oneliner('git', 'config', 'branch.%s.merge' % local_branch)
	if tracking_branch.startswith('refs/heads/'):
		tracking_branch = tracking_branch[len('refs/heads/'):]
	else:
		raise Exception("can't handle " + tracking_branch)

	tracking_remote = oneliner('git', 'config', 'branch.%s.remote' % local_branch)
	remote_url = oneliner('git', 'config', 'remote.%s.url' % tracking_remote)

relpath = oneliner('git', 'rev-parse', '--show-prefix')[:-1]

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.startswith('github.com-'):
	hostname = 'github.com'

obj_type = 'tree'
if len(sys.argv) == 2:
	obj_type = 'blob'

repo_url = urllib.parse.urlunparse(('https', hostname, parsed.path, '', '', ''))

def url_for(treeish: str) -> str:
	dir_url = '%s/%s/%s' % (repo_url, obj_type, treeish)
	if relpath:
		dir_url = '%s/%s' % (dir_url, relpath)
	if len(sys.argv) == 2:
		return '%s/%s' % (dir_url, sys.argv[1])
	else:
		return dir_url

if tag is not None:
	print(url_for(tag))
else:
	print(url_for(tracking_branch))
print(url_for(commit))