#!/usr/bin/env python3
"""List pip dependencies or system package dependencies for cloud-init."""

# You might be tempted to rewrite this as a shell script, but you
# would be surprised to discover that things like 'egrep' or 'sed' may
# differ between Linux and *BSD.

try:
    from argparse import ArgumentParser
except ImportError:
    raise RuntimeError(
        'Could not import python-argparse. Please install python-argparse '
        'package to continue')

import json
import os
import re
import subprocess
import sys

DEFAULT_REQUIREMENTS = 'requirements.txt'

# Map the appropriate package dir needed for each distro choice
DISTRO_PKG_TYPE_MAP = {
    'centos': 'redhat',
    'redhat': 'redhat',
    'debian': 'debian',
    'ubuntu': 'debian',
    'opensuse': 'suse',
    'suse': 'suse'
}

MAYBE_RELIABLE_YUM_INSTALL = [
    'sh', '-c',
    """
    error() { echo "$@" 1>&2; }
    n=0; max=10;
    bcmd="yum install --downloadonly --assumeyes --setopt=keepcache=1"
    while n=$(($n+1)); do
       error ":: running $bcmd $* [$n/$max]"
       $bcmd "$@"
       r=$?
       [ $r -eq 0 ] && break
       [ $n -ge $max ] && { error "gave up on $bcmd"; exit $r; }
       nap=$(($n*5))
       error ":: failed [$r] ($n/$max). sleeping $nap."
       sleep $nap
    done
    error ":: running yum install --cacheonly --assumeyes $*"
    yum install --cacheonly --assumeyes "$@"
    """,
    'reliable-yum-install']

ZYPPER_INSTALL = [
    'zypper', '--non-interactive', '--gpg-auto-import-keys', 'install',
    '--auto-agree-with-licenses']

DRY_DISTRO_INSTALL_PKG_CMD = {
    'centos': ['yum', 'install', '--assumeyes'],
    'redhat': ['yum', 'install', '--assumeyes'],
}

DISTRO_INSTALL_PKG_CMD = {
    'centos': MAYBE_RELIABLE_YUM_INSTALL,
    'redhat': MAYBE_RELIABLE_YUM_INSTALL,
    'debian': ['apt', 'install', '-y'],
    'ubuntu': ['apt', 'install', '-y'],
    'opensuse': ZYPPER_INSTALL,
    'suse': ZYPPER_INSTALL,
}


# List of base system packages required to enable ci automation
CI_SYSTEM_BASE_PKGS = {
    'common': ['make', 'sudo', 'tar'],
    'redhat': ['python-tox'],
    'centos': ['python-tox'],
    'ubuntu': ['devscripts', 'python3-dev', 'libssl-dev', 'tox', 'sbuild'],
    'debian': ['devscripts', 'python3-dev', 'libssl-dev', 'tox', 'sbuild']}


# JSON definition of distro-specific package dependencies
DISTRO_PKG_DEPS_PATH = "packages/pkg-deps.json"


def get_parser():
    """Return an argument parser for this command."""
    parser = ArgumentParser(description=__doc__)
    parser.add_argument(
        '-r', '--requirements-file', type=str, dest='req_files',
        action='append', default=None,
        help='pip-style requirements file [default=%s]' % DEFAULT_REQUIREMENTS)
    parser.add_argument(
        '-d', '--distro', type=str, choices=DISTRO_PKG_TYPE_MAP.keys(),
        help='The name of the distro to generate package deps for.')
    parser.add_argument(
        '--dry-run', action='store_true', default=False, dest='dry_run',
        help='Dry run the install, making no package changes.')
    parser.add_argument(
        '-s', '--system-pkg-names', action='store_true', default=False,
        dest='system_pkg_names',
        help='The name of the distro to generate package deps for.')
    parser.add_argument(
        '-i', '--install', action='store_true', default=False,
        dest='install',
        help='When specified, install the required system packages.')
    parser.add_argument(
        '-t', '--test-distro', action='store_true', default=False,
        dest='test_distro',
        help='Additionally install continuous integration system packages '
             'required for build and test automation.')
    parser.add_argument(
        '-v', '--python-version', type=str, dest='python_version',
        default=None, choices=["2", "3"],
        help='Override the version of python we want to generate system '
             'package dependencies for. Defaults to the version of python '
             'this script is called with')
    return parser


def get_package_deps_from_json(topdir, distro):
    """Get a dict of build and runtime package requirements for a distro.

    @param topdir: The root directory in which to search for the
        DISTRO_PKG_DEPS_PATH json blob of package requirements information.
    @param distro: The specific distribution shortname to pull dependencies
        for.
    @return: Dict containing "requires", "build-requires" and "rename" lists
        for a given distribution.
    """
    with open(os.path.join(topdir, DISTRO_PKG_DEPS_PATH), 'r') as stream:
        deps = json.loads(stream.read())
    if distro is None:
        return {}
    return deps[DISTRO_PKG_TYPE_MAP[distro]]


def parse_pip_requirements(requirements_path):
    """Return the pip requirement names from pip-style requirements_path."""
    dep_names = []
    with open(requirements_path, "r") as fp:
        for line in fp:
            line = line.strip()
            if not line or line.startswith("#"):
                continue

            # remove pip-style markers
            dep = line.split(';')[0]

            # remove version requirements
            if re.search('[>=.<]+', dep):
                dep_names.append(re.split(r'[>=.<]+', dep)[0].strip())
            else:
                dep_names.append(dep)
    return dep_names


def translate_pip_to_system_pkg(pip_requires, renames, python_ver):
    """Translate pip package names to distro-specific package names.

    @param pip_requires: List of versionless pip package names to translate.
    @param renames: Dict containg special case renames from pip name to system
        package name for the distro.
    @param python_ver: Optional python version string "2" or "3". When None,
     use the python version that is calling this script via sys.version_info.
    """
    if python_ver is None:
        python_ver = str(sys.version_info[0])
    if python_ver == "2":
        prefix = "python-"
    else:
        prefix = "python3-"
    standard_pkg_name = "{0}{1}"
    translated_names = []
    for pip_name in pip_requires:
        pip_name = pip_name.lower()
        # Find a rename if present for the distro package and python version
        rename = renames.get(pip_name, {}).get(python_ver, None)
        if rename:
            translated_names.append(rename)
        else:
            translated_names.append(
                standard_pkg_name.format(prefix, pip_name))
    return translated_names


def main(distro):
    parser = get_parser()
    args = parser.parse_args()
    if 'CLOUD_INIT_TOP_D' in os.environ:
        topd = os.path.realpath(os.environ.get('CLOUD_INIT_TOP_D'))
    else:
        topd = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))

    if args.test_distro:
        # Give us all the system deps we need for continuous integration
        if args.req_files:
            sys.stderr.write(
                "Parameter --test-distro overrides --requirements-file. Use "
                "one or the other.\n")
            sys.exit(1)
        args.req_files = [os.path.join(topd, DEFAULT_REQUIREMENTS),
                          os.path.join(topd, 'test-' + DEFAULT_REQUIREMENTS)]
        args.install = True
    if args.req_files is None:
        args.req_files = [os.path.join(topd, DEFAULT_REQUIREMENTS)]
        if not os.path.isfile(args.req_files[0]):
            sys.stderr.write("Unable to locate '%s' file that should "
                             "exist in cloud-init root directory." %
                             args.req_files[0])
            sys.exit(1)

    bad_files = [r for r in args.req_files if not os.path.isfile(r)]
    if bad_files:
        sys.stderr.write(
            "Unable to find requirements files: %s\n" % ','.join(bad_files))
        sys.exit(1)

    pip_pkg_names = set()
    for req_path in args.req_files:
        pip_pkg_names.update(set(parse_pip_requirements(req_path)))
    deps_from_json = get_package_deps_from_json(topd, args.distro)
    renames = deps_from_json.get('renames', {})
    translated_pip_names = translate_pip_to_system_pkg(
        pip_pkg_names, renames, args.python_version)
    all_deps = []
    if args.distro:
        all_deps.extend(
            translated_pip_names + deps_from_json['requires'] +
            deps_from_json['build-requires'])
    else:
        if args.system_pkg_names:
            all_deps = translated_pip_names
        else:
            all_deps = pip_pkg_names
    if args.install:
        pkg_install(all_deps, args.distro, args.test_distro, args.dry_run)
    else:
        print('\n'.join(all_deps))


def pkg_install(pkg_list, distro, test_distro=False, dry_run=False):
    """Install a list of packages using the DISTRO_INSTALL_PKG_CMD."""
    if test_distro:
        pkg_list = list(pkg_list) + CI_SYSTEM_BASE_PKGS['common']
        distro_base_pkgs = CI_SYSTEM_BASE_PKGS.get(distro, [])
        pkg_list += distro_base_pkgs
    print('Installing deps: {0}{1}'.format(
          '(dryrun)' if dry_run else '', ' '.join(pkg_list)))
    install_cmd = []
    if dry_run:
        install_cmd.append('echo')
    if os.geteuid() != 0:
        install_cmd.append('sudo')

    cmd = DISTRO_INSTALL_PKG_CMD[distro]
    if dry_run and distro in DRY_DISTRO_INSTALL_PKG_CMD:
        cmd = DRY_DISTRO_INSTALL_PKG_CMD[distro]
    install_cmd.extend(cmd)

    if distro in ['centos', 'redhat']:
        # CentOS and Redhat need epel-release to access oauthlib and jsonschema
        subprocess.check_call(install_cmd + ['epel-release'])
    if distro in ['suse', 'opensuse', 'redhat', 'centos']:
        pkg_list.append('rpm-build')
    subprocess.check_call(install_cmd + pkg_list)


if __name__ == "__main__":
    parser = get_parser()
    args = parser.parse_args()
    sys.exit(main(args.distro))

# vi: ts=4 expandtab