#!/usr/bin/env python3

"""Manage site and releases.

Usage:
  manage.py release [<branch>]
  manage.py site

For the release command $FMT_TOKEN should contain a GitHub personal access token
obtained from https://github.com/settings/tokens.
"""

from __future__ import print_function
import datetime, docopt, errno, fileinput, json, os
import re, requests, shutil, sys
from contextlib import contextmanager
from distutils.version import LooseVersion
from subprocess import check_call


class Git:
    def __init__(self, dir):
        self.dir = dir

    def call(self, method, args, **kwargs):
        return check_call(['git', method] + list(args), **kwargs)

    def add(self, *args):
        return self.call('add', args, cwd=self.dir)

    def checkout(self, *args):
        return self.call('checkout', args, cwd=self.dir)

    def clean(self, *args):
        return self.call('clean', args, cwd=self.dir)

    def clone(self, *args):
        return self.call('clone', list(args) + [self.dir])

    def commit(self, *args):
        return self.call('commit', args, cwd=self.dir)

    def pull(self, *args):
        return self.call('pull', args, cwd=self.dir)

    def push(self, *args):
        return self.call('push', args, cwd=self.dir)

    def reset(self, *args):
        return self.call('reset', args, cwd=self.dir)

    def update(self, *args):
        clone = not os.path.exists(self.dir)
        if clone:
            self.clone(*args)
        return clone


def clean_checkout(repo, branch):
    repo.clean('-f', '-d')
    repo.reset('--hard')
    repo.checkout(branch)


class Runner:
    def __init__(self, cwd):
        self.cwd = cwd

    def __call__(self, *args, **kwargs):
        kwargs['cwd'] = kwargs.get('cwd', self.cwd)
        check_call(args, **kwargs)


def create_build_env():
    """Create a build environment."""
    class Env:
        pass
    env = Env()
    env.fmt_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
    env.build_dir = 'build'
    env.fmt_repo = Git(os.path.join(env.build_dir, 'fmt'))
    return env


@contextmanager
def rewrite(filename):
    class Buffer:
        pass
    buffer = Buffer()
    if not os.path.exists(filename):
        buffer.data = ''
        yield buffer
        return
    with open(filename) as f:
        buffer.data = f.read()
    yield buffer
    with open(filename, 'w') as f:
        f.write(buffer.data)


fmt_repo_url = 'git@github.com:fmtlib/fmt'


def update_site(env):
    env.fmt_repo.update(fmt_repo_url)

    doc_repo = Git(os.path.join(env.build_dir, 'fmt.dev'))
    doc_repo.update('git@github.com:fmtlib/fmt.dev')

    version = '11.0.0'
    clean_checkout(env.fmt_repo, version)
    target_doc_dir = os.path.join(env.fmt_repo.dir, 'doc')

    # Build the docs.
    html_dir = os.path.join(env.build_dir, 'html')
    if os.path.exists(html_dir):
        shutil.rmtree(html_dir)
    include_dir = env.fmt_repo.dir
    if LooseVersion(version) >= LooseVersion('5.0.0'):
        include_dir = os.path.join(include_dir, 'include', 'fmt')
    elif LooseVersion(version) >= LooseVersion('3.0.0'):
        include_dir = os.path.join(include_dir, 'fmt')
    import build
    build.build_docs(version, doc_dir=target_doc_dir,
                        include_dir=include_dir, work_dir=env.build_dir)
    shutil.rmtree(os.path.join(html_dir, '.doctrees'))
    # Copy docs to the website.
    version_doc_dir = os.path.join(doc_repo.dir, version)
    try:
        shutil.rmtree(version_doc_dir)
    except OSError as e:
        if e.errno != errno.ENOENT:
            raise
    shutil.move(html_dir, version_doc_dir)


def release(args):
    env = create_build_env()
    fmt_repo = env.fmt_repo

    branch = args.get('<branch>')
    if branch is None:
        branch = 'master'
    if not fmt_repo.update('-b', branch, fmt_repo_url):
        clean_checkout(fmt_repo, branch)

    # Update the date in the changelog and extract the version and the first
    # section content.
    changelog = 'ChangeLog.md'
    changelog_path = os.path.join(fmt_repo.dir, changelog)
    is_first_section = True
    first_section = []
    for i, line in enumerate(fileinput.input(changelog_path, inplace=True)):
        if i == 0:
            version = re.match(r'# (.*) - TBD', line).group(1)
            line = '# {} - {}\n'.format(
                version, datetime.date.today().isoformat())
        elif not is_first_section:
            pass
        elif line.startswith('#'):
            is_first_section = False
        else:
            first_section.append(line)
        sys.stdout.write(line)
    if first_section[0] == '\n':
        first_section.pop(0)

    # Workaround GitHub-flavored markdown treating newlines as <br>.
    changes = ''
    code_block = False
    stripped = False
    for line in first_section:
        if re.match(r'^\s*```', line):
            code_block = not code_block
            changes += line
            stripped = False
            continue
        if code_block:
            changes += line
            continue
        if line == '\n' or re.match(r'^\s*\|.*', line):
            if stripped:
                changes += '\n'
                stripped = False
            changes += line
            continue
        if stripped:
            line = ' ' + line.lstrip()
        changes += line.rstrip()
        stripped = True

    fmt_repo.checkout('-B', 'release')
    fmt_repo.add(changelog)
    fmt_repo.commit('-m', 'Update version')

    # Build the docs and package.
    run = Runner(fmt_repo.dir)
    run('cmake', '.')
    run('make', 'doc', 'package_source')

    # Create a release on GitHub.
    fmt_repo.push('origin', 'release')
    auth_headers = {'Authorization': 'token ' + os.getenv('FMT_TOKEN')}
    r = requests.post('https://api.github.com/repos/fmtlib/fmt/releases',
                      headers=auth_headers,
                      data=json.dumps({'tag_name': version,
                                       'target_commitish': 'release',
                                       'body': changes, 'draft': True}))
    if r.status_code != 201:
        raise Exception('Failed to create a release ' + str(r))
    id = r.json()['id']
    uploads_url = 'https://uploads.github.com/repos/fmtlib/fmt/releases'
    package = 'fmt-{}.zip'.format(version)
    r = requests.post(
        '{}/{}/assets?name={}'.format(uploads_url, id, package),
        headers={'Content-Type': 'application/zip'} | auth_headers,
        data=open('build/fmt/' + package, 'rb'))
    if r.status_code != 201:
        raise Exception('Failed to upload an asset ' + str(r))

    update_site(env)

if __name__ == '__main__':
    args = docopt.docopt(__doc__)
    if args.get('release'):
        release(args)
    elif args.get('site'):
        update_site(create_build_env())