"""Non-interactive, branch-specific Git updates of the configured wiki."""
from __future__ import annotations

import os
import re
import subprocess
from pathlib import Path
from urllib.parse import urlsplit

GIT_TIMEOUT_SECONDS = 120


def expected_branch() -> str:
    branch = os.getenv('EXPECTED_GITEA_BRANCH', 'master').strip()
    if (not branch or branch.startswith(('-', '/')) or branch.endswith(('/', '.'))
            or '..' in branch or '@{' in branch or branch == '@'
            or re.search(r'[\s\x00-\x1f\x7f~^:?*\[\\]', branch)
            or any(not part or part.startswith('.') or part.endswith('.lock') for part in branch.split('/'))):
        raise RuntimeError('EXPECTED_GITEA_BRANCH nie je platný názov Git vetvy')
    return branch


def repository_from_url(url: str) -> str | None:
    if '://' in url:
        parsed = urlsplit(url)
        if parsed.scheme not in {'ssh', 'https', 'http', 'git'}:
            return None
        path = parsed.path
    elif re.match(r'[^/\s]+:[^\s]+', url):
        path = url.split(':', 1)[1]
    else:
        return None
    path = path.strip('/').removesuffix('.git')
    return path if len(path.split('/')) == 2 else None


def update_wiki(repo_path: Path) -> None:
    if not repo_path.exists():
        raise RuntimeError(f'ZPWIKI_ROOT neexistuje: {repo_path}')
    if not (repo_path / '.git').exists():
        raise RuntimeError(f'Nie je to git repozitár: {repo_path}')
    environment = {**os.environ, 'GIT_TERMINAL_PROMPT': '0'}

    def git(*args):
        try:
            result = subprocess.run(['git', *args], cwd=repo_path, env=environment,
                text=True, capture_output=True, timeout=GIT_TIMEOUT_SECONDS, check=False)
        except subprocess.TimeoutExpired as error:
            raise RuntimeError(f'Git aktualizácia prekročila limit {GIT_TIMEOUT_SECONDS} sekúnd') from error
        if result.returncode:
            # Remote URLs and credentials can occur in Git stderr; do not place
            # them in API responses or ordinary application logs.
            raise RuntimeError(f'Git operácia {args[0]} zlyhala s návratovým kódom {result.returncode}')
        return result.stdout.strip()

    expected = os.getenv('EXPECTED_GITEA_REPOSITORY', '').strip()
    origin = repository_from_url(git('remote', 'get-url', 'origin'))
    if not expected or origin is None or origin.casefold() != expected.casefold():
        raise RuntimeError('Git origin nezodpovedá EXPECTED_GITEA_REPOSITORY')
    branch = expected_branch()
    if git('branch', '--show-current') != branch:
        raise RuntimeError('Aktívna Git vetva nezodpovedá EXPECTED_GITEA_BRANCH')
    if git('status', '--porcelain', '--untracked-files=normal'):
        raise RuntimeError('Wiki obsahuje lokálne zmeny; automatická aktualizácia ich neprepíše')
    git('fetch', '--no-tags', '--no-recurse-submodules', 'origin',
        f'refs/heads/{branch}:refs/remotes/origin/{branch}')
    git('merge', '--ff-only', f'refs/remotes/origin/{branch}')