#!/usr/bin/env python

import os
import stat
import json
from subprocess import check_output
from collections import OrderedDict, defaultdict
from collections.abc import Mapping
import glob
from contextlib import contextmanager
from getpass import getpass
from pathlib import Path

import requests
from requests.auth import HTTPBasicAuth
from requests_oauthlib import OAuth2


def main(version, push=None):
    """
    WARNING: If push is given as --push then this will push the release to
    github.
    """
    push = push == '--push'
    _GitHub_release(version, push)


def error(msg):
    raise ValueError(msg)


def blue(text):
    return "\033[34m%s\033[0m" % text

def red(text):
    return "\033[31m%s\033[0m" % text

def green(text):
    return "\033[32m%s\033[0m" % text


def _GitHub_release(version, push, username=None, user='sympy', token=None,
    token_file_path="~/.sympy/release-token", repo='sympy', draft=False):
    """
    Upload the release files to GitHub.

    The tag must be pushed up first. You can test on another repo by changing
    user and repo.
    """
    if not requests:
        error("requests and requests-oauthlib must be installed to upload to GitHub")

    release_text = GitHub_release_text(version)
    short_version = get_sympy_short_version(version)
    tag = 'sympy-' + version
    prerelease = short_version != version

    urls = URLs(user=user, repo=repo)
    if not username:
        username = input("GitHub username: ")
    token = load_token_file(token_file_path)
    if not token:
        username, password, token = GitHub_authenticate(urls, username, token)

    # If the tag in question is not pushed up yet, then GitHub will just
    # create it off of master automatically, which is not what we want.  We
    # could make it create it off the release branch, but even then, we would
    # not be sure that the correct commit is tagged.  So we require that the
    # tag exist first.
    if not check_tag_exists(version):
        sys.exit(red("The tag for this version has not been pushed yet. Cannot upload the release."))

    # See https://developer.github.com/v3/repos/releases/#create-a-release
    # First, create the release
    post = {}
    post['tag_name'] = tag
    post['name'] = "SymPy " + version
    post['body'] = release_text
    post['draft'] = draft
    post['prerelease'] = prerelease

    print("Creating release for tag", tag, end=' ')

    if push:
        result = query_GitHub(urls.releases_url, username, password=None,
            token=token, data=json.dumps(post)).json()
        release_id = result['id']
    else:
        print(green("Not pushing!"))

    print(green("Done"))

    # Then, upload all the files to it.
    for key in descriptions:
        tarball = get_tarball_name(key, version)

        params = {}
        params['name'] = tarball

        if tarball.endswith('gz'):
            headers = {'Content-Type':'application/gzip'}
        elif tarball.endswith('pdf'):
            headers = {'Content-Type':'application/pdf'}
        elif tarball.endswith('zip'):
            headers = {'Content-Type':'application/zip'}
        else:
            headers = {'Content-Type':'application/octet-stream'}

        print("Uploading", tarball, end=' ')
        sys.stdout.flush()
        with open(os.path.join('release/release-' + version, tarball), 'rb') as f:
            if push:
                result = query_GitHub(urls.release_uploads_url % release_id, username,
                    password=None, token=token, data=f, params=params,
                    headers=headers).json()
            else:
                print(green("Not uploading!"))

        print(green("Done"))

    # TODO: download the files and check that they have the right sha256 sum


def GitHub_release_text(version):
    """
    Generate text to put in the GitHub release Markdown box
    """
    shortversion = get_sympy_short_version(version)
    htmltable = table(version)
    out = """\
See https://github.com/sympy/sympy/wiki/release-notes-for-{shortversion} for the release notes.

{htmltable}

**Note**: Do not download the **Source code (zip)** or the **Source code (tar.gz)**
files below.
"""
    out = out.format(shortversion=shortversion, htmltable=htmltable)
    print(blue("Here are the release notes to copy into the GitHub release "
        "Markdown form:"))
    print()
    print(out)
    return out


def get_sympy_short_version(version):
    """
    Get the short version of SymPy being released, not including any rc tags
    (like 0.7.3)
    """
    parts = version.split('.')
    # Remove rc tags e.g. 1.10rc1 -> [1, 10]
    lastpart = ''
    for dig in parts[-1]:
        if dig.isdigit():
            lastpart += dig
        else:
            break
    parts[-1] = lastpart
    return '.'.join(parts)


class URLs(object):
    """
    This class contains URLs and templates which used in requests to GitHub API
    """

    def __init__(self, user="sympy", repo="sympy",
        api_url="https://api.github.com",
        authorize_url="https://api.github.com/authorizations",
        uploads_url='https://uploads.github.com',
        main_url='https://github.com'):
        """Generates all URLs and templates"""

        self.user = user
        self.repo = repo
        self.api_url = api_url
        self.authorize_url = authorize_url
        self.uploads_url = uploads_url
        self.main_url = main_url

        self.pull_list_url = api_url + "/repos" + "/" + user + "/" + repo + "/pulls"
        self.issue_list_url = api_url + "/repos/" + user + "/" + repo + "/issues"
        self.releases_url = api_url + "/repos/" + user + "/" + repo + "/releases"
        self.single_issue_template = self.issue_list_url + "/%d"
        self.single_pull_template = self.pull_list_url + "/%d"
        self.user_info_template = api_url + "/users/%s"
        self.user_repos_template = api_url + "/users/%s/repos"
        self.issue_comment_template = (api_url + "/repos" + "/" + user + "/" + repo + "/issues/%d" +
            "/comments")
        self.release_uploads_url = (uploads_url + "/repos/" + user + "/" +
            repo + "/releases/%d" + "/assets")
        self.release_download_url = (main_url + "/" + user + "/" + repo +
            "/releases/download/%s/%s")


def load_token_file(path="~/.sympy/release-token"):
    print("> Using token file %s" % path)

    path = os.path.expanduser(path)
    path = os.path.abspath(path)

    if os.path.isfile(path):
        try:
            with open(path) as f:
                token = f.readline()
        except IOError:
            print("> Unable to read token file")
            return
    else:
        print("> Token file does not exist")
        return

    return token.strip()


def GitHub_authenticate(urls, username, token=None):
    _login_message = """\
Enter your GitHub username & password or press ^C to quit. The password
will be kept as a Python variable as long as this script is running and
https to authenticate with GitHub, otherwise not saved anywhere else:\
"""
    if username:
        print("> Authenticating as %s" % username)
    else:
        print(_login_message)
        username = input("Username: ")

    authenticated = False

    if token:
        print("> Authenticating using token")
        try:
            GitHub_check_authentication(urls, username, None, token)
        except AuthenticationFailed:
            print(">     Authentication failed")
        else:
            print(">     OK")
            password = None
            authenticated = True

    while not authenticated:
        password = getpass("Password: ")
        try:
            print("> Checking username and password ...")
            GitHub_check_authentication(urls, username, password, None)
        except AuthenticationFailed:
            print(">     Authentication failed")
        else:
            print(">     OK.")
            authenticated = True

    if password:
        generate = input("> Generate API token? [Y/n] ")
        if generate.lower() in ["y", "ye", "yes", ""]:
            name = input("> Name of token on GitHub? [SymPy Release] ")
            if name == "":
                name = "SymPy Release"
            token = generate_token(urls, username, password, name=name)
            print("Your token is", token)
            print("Use this token from now on as GitHub_release:token=" + token +
                ",username=" + username)
            print(red("DO NOT share this token with anyone"))
            save = input("Do you want to save this token to a file [yes]? ")
            if save.lower().strip() in ['y', 'yes', 'ye', '']:
                save_token_file(token)

    return username, password, token


def run(*cmdline, cwd=None):
    """
    Run command in subprocess and get lines of output
    """
    return check_output(cmdline, encoding='utf-8', cwd=cwd).splitlines()


def check_tag_exists(version):
    """
    Check if the tag for this release has been uploaded yet.
    """
    tag = 'sympy-' + version
    all_tag_lines = run('git', 'ls-remote', '--tags', 'origin')
    return any(tag in tag_line for tag_line in all_tag_lines)


def generate_token(urls, username, password, OTP=None, name="SymPy Release"):
    enc_data = json.dumps(
        {
            "scopes": ["public_repo"],
            "note": name
        }
    )

    url = urls.authorize_url
    rep = query_GitHub(url, username=username, password=password,
        data=enc_data).json()
    return rep["token"]


def GitHub_check_authentication(urls, username, password, token):
    """
    Checks that username & password is valid.
    """
    query_GitHub(urls.api_url, username, password, token)


class AuthenticationFailed(Exception):
    pass


def query_GitHub(url, username=None, password=None, token=None, data=None,
    OTP=None, headers=None, params=None, files=None):
    """
    Query GitHub API.

    In case of a multipage result, DOES NOT query the next page.

    """
    headers = headers or {}

    if OTP:
        headers['X-GitHub-OTP'] = OTP

    if token:
        auth = OAuth2(client_id=username, token={"access_token": token,
            "token_type": 'bearer'})
    else:
        auth = HTTPBasicAuth(username, password)
    if data:
        r = requests.post(url, auth=auth, data=data, headers=headers,
            params=params, files=files)
    else:
        r = requests.get(url, auth=auth, headers=headers, params=params, stream=True)

    if r.status_code == 401:
        two_factor = r.headers.get('X-GitHub-OTP')
        if two_factor:
            print("A two-factor authentication code is required:", two_factor.split(';')[1].strip())
            OTP = input("Authentication code: ")
            return query_GitHub(url, username=username, password=password,
                token=token, data=data, OTP=OTP)

        raise AuthenticationFailed("invalid username or password")

    r.raise_for_status()
    return r


def save_token_file(token):
    token_file = input("> Enter token file location [~/.sympy/release-token] ")
    token_file = token_file or "~/.sympy/release-token"

    token_file_expand = os.path.expanduser(token_file)
    token_file_expand = os.path.abspath(token_file_expand)
    token_folder, _ = os.path.split(token_file_expand)

    try:
        if not os.path.isdir(token_folder):
            os.mkdir(token_folder, 0o700)
        Path(token_file_expand).write_text(token + '\n')
        os.chmod(token_file_expand, stat.S_IREAD | stat.S_IWRITE)
    except OSError as e:
        print("> Unable to create folder for token file: ", e)
        return
    except IOError as e:
        print("> Unable to save token file: ", e)
        return

    return token_file


def table(version):
    """
    Make an html table of the downloads.

    This is for pasting into the GitHub releases page. See GitHub_release().
    """
    tarball_formatter_dict = dict(_tarball_format(version))
    shortversion = get_sympy_short_version(version)

    tarball_formatter_dict['version'] = shortversion

    sha256s = [i.split('\t') for i in _sha256(version, print_=False, local=True).split('\n')]
    sha256s_dict = {name: sha256 for sha256, name in sha256s}

    sizes = [i.split('\t') for i in _size(version, print_=False).split('\n')]
    sizes_dict = {name: size for size, name in sizes}

    table = []

    # https://docs.python.org/2/library/contextlib.html#contextlib.contextmanager. Not
    # recommended as a real way to generate html, but it works better than
    # anything else I've tried.
    @contextmanager
    def tag(name):
        table.append("<%s>" % name)
        yield
        table.append("</%s>" % name)
    @contextmanager
    def a_href(link):
        table.append("<a href=\"%s\">" % link)
        yield
        table.append("</a>")

    with tag('table'):
        with tag('tr'):
            for headname in ["Filename", "Description", "size", "sha256"]:
                with tag("th"):
                    table.append(headname)

        for key in descriptions:
            name = get_tarball_name(key, version)
            with tag('tr'):
                with tag('td'):
                    with a_href('https://github.com/sympy/sympy/releases/download/sympy-%s/%s' % (version, name)):
                        with tag('b'):
                            table.append(name)
                with tag('td'):
                    table.append(descriptions[key].format(**tarball_formatter_dict))
                with tag('td'):
                    table.append(sizes_dict[name])
                with tag('td'):
                    table.append(sha256s_dict[name])

    out = ' '.join(table)
    return out

descriptions = OrderedDict([
    ('source', "The SymPy source installer.",),
    ('wheel', "A wheel of the package.",),
    ('html', '''Html documentation. This is the same as
the <a href="https://docs.sympy.org/latest/index.html">online documentation</a>.''',),
    ('pdf', '''Pdf version of the <a href="https://docs.sympy.org/latest/index.html"> html documentation</a>.''',),
    ])


def _size(version, print_=True):
    """
    Print the sizes of the release files. Run locally.
    """
    out = run(*(['du', '-h'] + release_files(version)))
    out = [i.split() for i in out]
    out = '\n'.join(["%s\t%s" % (i, os.path.split(j)[1]) for i, j in out])
    if print_:
        print(out)
    return out


def _sha256(version, print_=True, local=False):
    if local:
        out = run(*(['shasum', '-a', '256'] + release_files(version)))
    else:
        raise ValueError('Should not get here...')
        # out = run(*(['shasum', '-a', '256', '/root/release/*']))
    # Remove the release/ part for printing. Useful for copy-pasting into the
    # release notes.
    out = [i.split() for i in out]
    out = '\n'.join(["%s\t%s" % (i, os.path.split(j)[1]) for i, j in out])
    if print_:
        print(out)
    return out


def get_tarball_name(file, version):
    """
    Get the name of a tarball

    file should be one of

    source-orig:       The original name of the source tarball
    source-orig-notar: The name of the untarred directory
    source:            The source tarball (after renaming)
    wheel:             The wheel
    html:              The name of the html zip
    html-nozip:        The name of the html, without ".zip"
    pdf-orig:          The original name of the pdf file
    pdf:               The name of the pdf file (after renaming)
    """
    doctypename = defaultdict(str, {'html': 'zip', 'pdf': 'pdf'})

    if file in {'source-orig', 'source'}:
        name = 'sympy-{version}.tar.gz'
    elif file == 'source-orig-notar':
        name = "sympy-{version}"
    elif file in {'html', 'pdf', 'html-nozip'}:
        name = "sympy-docs-{type}-{version}"
        if file == 'html-nozip':
            # zip files keep the name of the original zipped directory. See
            # https://github.com/sympy/sympy/issues/7087.
            file = 'html'
        else:
            name += ".{extension}"
    elif file == 'pdf-orig':
        name = "sympy-{version}.pdf"
    elif file == 'wheel':
        name = 'sympy-{version}-py3-none-any.whl'
    else:
        raise ValueError(file + " is not a recognized argument")

    ret = name.format(version=version, type=file,
        extension=doctypename[file])
    return ret


def release_files(version):
    """
    Returns the list of local release files
    """
    paths = glob.glob('release/release-' + version + '/*')
    if not paths:
        raise ValueError("No release files found")
    return paths


tarball_name_types = {
    'source-orig',
    'source-orig-notar',
    'source',
    'wheel',
    'html',
    'html-nozip',
    'pdf-orig',
    'pdf',
    }


# Have to make this lazy so that version can be defined.
class _tarball_format(Mapping):

    def __init__(self, version):
        self.version = version

    def __getitem__(self, name):
        return get_tarball_name(name, self.version)

    def __iter__(self):
        return iter(tarball_name_types)

    def __len__(self):
        return len(tarball_name_types)


if __name__ == "__main__":
    import sys
    main(*sys.argv[1:])