#!/usr/bin/env python3
"""
Copyright (C) 2020 Kunal Mehta <legoktm@member.fsf.org>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
"""
import json
import requests
import os
import subprocess
from pathlib import Path
import shutil

session = requests.Session()


def get_provider(path: Path) -> str:
    if (path / 'gitinfo.json').exists():
        # TODO: gitinfo should point back to the extdist host
        return 'extdist'
    elif (path / '.git').exists():
        return 'git'
    else:
        # TODO: add more types?
        raise RuntimeError(f"Unsure how {path} was downloaded")


def get_current(path: Path) -> str:
    provider = get_provider(path)
    if provider == 'extdist':
        with open(path / 'gitinfo.json') as f:
            data = json.load(f)
        return data['headSHA1'].strip()[:7]
    else:
        return subprocess.check_output(['git', 'rev-list', 'HEAD', '-n1'], cwd=str(path)).decode().strip()


def get_latest(path: Path, mwb: str) -> str:
    provider = get_provider(path)
    name = str(path.name)
    print(f'Getting the latest version of {name}')
    if provider == 'extdist':
        req = session.get('https://www.mediawiki.org/w/api.php', params={
            'action': 'query',
            'list': 'extdistbranches',
            'edbexts': name,
            'format': 'json',
            'formatversion': 2,
        })
        req.raise_for_status()
        data = req.json()
        # TODO: error handling
        # TODO: API should provide raw SHA1
        return data['query']['extdistbranches']['extensions'][name][mwb].split('-')[-1].split('.')[0]
    else:
        # TODO: non-origin remote?
        subprocess.check_call(['git', 'fetch', 'origin'], cwd=str(path))
        return subprocess.check_output(['git', 'show-ref', f'origin/{mwb}'], cwd=str(path)).decode().split(' ')[0]


def download_extdist(path: Path, mwb):
    # TODO make this atomic and safe
    name = str(path.name)
    apireq = session.get('https://www.mediawiki.org/w/api.php', params={
        'action': 'query',
        'list': 'extdistbranches',
        'edbexts': name,
        'format': 'json',
        'formatversion': 2,
    })
    apireq.raise_for_status()
    data = apireq.json()
    url = data['query']['extdistbranches']['extensions'][name][mwb]
    # TODO: automatically restore bak if things go bad
    path.rename(str(path) + '.bak')
    tarball = path.parent / 'tarball.tar.gz'
    print(f'[extdist] Downloading {url}')
    with session.get(url, stream=True) as req:
        req.raise_for_status()
        with open(tarball, 'wb') as f:
            for chunk in req.iter_content(chunk_size=8192):
                f.write(chunk)
    subprocess.check_call(['tar', '-xzf', tarball, '-C', str(tarball.parent)])
    shutil.rmtree(str(path) + '.bak')
    tarball.unlink()
    # TODO: some integrity verification on success


def handle_composer(path: Path) -> bool:
    cmp = path / 'composer.json'
    if not cmp.exists():
        return False
    with open(cmp) as f:
        info = json.load(f)
    if 'require' not in info:
        return False
    ignore = ['php', 'composer/installers']
    if not any(pkg for pkg in info['require'] if (pkg not in ignore and not pkg.startswith('ext-'))):
        # no real composer deps
        # TODO: consider removing if there are no deps??
        return False
    # TODO: in theory we could delete the extdist-provided vendor/
    local = path.parent.parent / 'composer.local.json'
    if local.exists():
       with open(local) as f:
           content = json.load(f)
    else:
        content = {'extra': {'merge-plugin': {'include': []}}}
    save = False
    if cmp not in content['extra']['merge-plugin']['include']:
        # TODO: realpath() equivalency
        save = True
        content['extra']['merge-plugin']['include'].append(str(cmp))
    if save:
        with open(local, 'w') as f:
            json.dump(content, f)

    return True


def update(path: Path, mwb, check_only=False):
    current = get_current(path)
    latest = get_latest(path, mwb)
    print(repr(latest), repr(current))
    if current == latest:
        print(f'{path} is already up to date!')
        return False
    if check_only:
        print(f'{path} needs an update')
        return True
    provider = get_provider(path)
    print(f'[{provider}]: Updating {path}...')
    if provider == 'extdist':
        download_extdist(path, mwb)
    else:
        # TODO: non-origin remote?
        subprocess.check_call(['git', 'fetch', 'origin'], cwd=str(path))
        subprocess.check_call(['git', 'checkout', f'origin/{mwb}'], cwd=str(path))

    print(f'[{provider}] Successfully updated {path}')
    return False


def run_composer(path: Path):
    subprocess.check_call(['composer', 'update', '--no-dev'], cwd=path)


def main():
    # Get this list from listing extensions/ or from user input
    composer = False
    for ext in ['TemplateStyles', 'AbuseFilter']:
        path = Path(f'/home/user/projects/mwext-prototype/test/extensions/{ext}')
        # TODO: Get MediaWiki branch from DefaultSettings.php (or elsewhere)
        mwb = 'REL1_34'
        if not update(path, mwb, check_only=True):
            continue
        update(path, mwb)
        composer = handle_composer(path) or composer

    if composer:
        print('Triggering composer update...')
        run_composer(path.parent.parent)


if __name__ == '__main__':
    main()