# -*- coding: utf-8 -*-
'''
This is a shim that handles checking and updating salt thin and
then invoking thin.

This is not intended to be instantiated as a module, rather it is a
helper script used by salt.client.ssh.Single.  It is here, in a
separate file, for convenience of development.
'''

from __future__ import absolute_import

import hashlib
import tarfile
import shutil
import sys
import os
import stat
import subprocess

THIN_ARCHIVE = 'salt-thin.tgz'
EXT_ARCHIVE = 'salt-ext_mods.tgz'

# Keep these in sync with salt/exitcodes.py
EX_THIN_DEPLOY = 11
EX_THIN_CHECKSUM = 12
EX_MOD_DEPLOY = 13
EX_SCP_NOT_FOUND = 14


class OBJ(object):
    """An empty class for holding instance attribute values."""
    pass


OPTIONS = None
ARGS = None
# The below line is where OPTIONS can be redefined with internal options
# (rather than cli arguments) when the shim is bundled by
# client.ssh.Single._cmd_str()
# pylint: disable=block-comment-should-start-with-cardinal-space
#%%OPTS


def need_deployment():
    """
    Salt thin needs to be deployed - prep the target directory and emit the
    delimeter and exit code that signals a required deployment.
    """
    if os.path.exists(OPTIONS.saltdir):
        shutil.rmtree(OPTIONS.saltdir)
    old_umask = os.umask(0o077)
    os.makedirs(OPTIONS.saltdir)
    os.umask(old_umask)
    # Verify perms on saltdir
    euid = os.geteuid()
    dstat = os.stat(OPTIONS.saltdir)
    if dstat.st_uid != euid:
        # Attack detected, try again
        need_deployment()
    if dstat.st_mode != 16832:
        # Attack detected
        need_deployment()
    # If SUDOing then also give the super user group write permissions
    sudo_gid = os.environ.get('SUDO_GID')
    if sudo_gid:
        os.chown(OPTIONS.saltdir, -1, int(sudo_gid))
        stt = os.stat(OPTIONS.saltdir)
        os.chmod(OPTIONS.saltdir, stt.st_mode | stat.S_IWGRP | stat.S_IRGRP | stat.S_IXGRP)

    # Delimiter emitted on stdout *only* to indicate shim message to master.
    sys.stdout.write("{0}\ndeploy\n".format(OPTIONS.delimiter))
    sys.exit(EX_THIN_DEPLOY)


# Adapted from salt.utils.get_hash()
def get_hash(path, form='sha1', chunk_size=4096):
    """Generate a hash digest string for a file."""
    try:
        hash_type = getattr(hashlib, form)
    except AttributeError:
        raise ValueError('Invalid hash type: {0}'.format(form))
    with open(path, 'rb') as ifile:
        hash_obj = hash_type()
        # read the file in in chunks, not the entire file
        for chunk in iter(lambda: ifile.read(chunk_size), b''):
            hash_obj.update(chunk)
        return hash_obj.hexdigest()


def unpack_thin(thin_path):
    """Unpack the Salt thin archive."""
    tfile = tarfile.TarFile.gzopen(thin_path)
    tfile.extractall(path=OPTIONS.saltdir)
    tfile.close()
    os.unlink(thin_path)


def need_ext():
    """Signal that external modules need to be deployed."""
    sys.stdout.write("{0}\next_mods\n".format(OPTIONS.delimiter))
    sys.exit(EX_MOD_DEPLOY)


def unpack_ext(ext_path):
    """Unpack the external modules."""
    modcache = os.path.join(
            OPTIONS.saltdir,
            'running_data',
            'var',
            'cache',
            'salt',
            'minion',
            'extmods')
    tfile = tarfile.TarFile.gzopen(ext_path)
    tfile.extractall(path=modcache)
    tfile.close()
    os.unlink(ext_path)
    ver_path = os.path.join(modcache, 'ext_version')
    ver_dst = os.path.join(OPTIONS.saltdir, 'ext_version')
    shutil.move(ver_path, ver_dst)


def main(argv):  # pylint: disable=W0613
    """Main program body"""
    thin_path = os.path.join(OPTIONS.saltdir, THIN_ARCHIVE)
    if os.path.isfile(thin_path):
        if OPTIONS.checksum != get_hash(thin_path, OPTIONS.hashfunc):
            sys.stderr.write('{0}\n'.format(OPTIONS.checksum))
            sys.stderr.write('{0}\n'.format(get_hash(thin_path, OPTIONS.hashfunc)))
            os.unlink(thin_path)
            sys.stderr.write('WARNING: checksum mismatch for "{0}"\n'.format(thin_path))
            sys.exit(EX_THIN_CHECKSUM)
        unpack_thin(thin_path)
        # Salt thin now is available to use
    else:
        scpstat = subprocess.Popen(['/bin/bash', '-c', 'command -v scp']).wait()
        if not scpstat == 0:
            sys.exit(EX_SCP_NOT_FOUND)

        if not os.path.exists(OPTIONS.saltdir):
            need_deployment()

        if not os.path.isdir(OPTIONS.saltdir):
            sys.stderr.write(
                'ERROR: salt path "{0}" exists but is'
                ' not a directory\n'.format(OPTIONS.saltdir)
            )
            sys.exit(os.EX_CANTCREAT)

        version_path = os.path.join(OPTIONS.saltdir, 'version')
        if not os.path.exists(version_path) or not os.path.isfile(version_path):
            sys.stderr.write(
                'WARNING: Unable to locate current thin '
                ' version: {0}.\n'.format(version_path)
            )
            need_deployment()
        with open(version_path, 'r') as vpo:
            cur_version = vpo.readline().strip()
        if cur_version != OPTIONS.version:
            sys.stderr.write(
                'WARNING: current thin version {0}'
                ' is not up-to-date with {1}.\n'.format(
                    cur_version, OPTIONS.version
                )
            )
            need_deployment()
        # Salt thin exists and is up-to-date - fall through and use it

    salt_call_path = os.path.join(OPTIONS.saltdir, 'salt-call')
    if not os.path.isfile(salt_call_path):
        sys.stderr.write('ERROR: thin is missing "{0}"\n'.format(salt_call_path))
        need_deployment()

    with open(os.path.join(OPTIONS.saltdir, 'minion'), 'w') as config:
        config.write(OPTIONS.config + '\n')
    if OPTIONS.ext_mods:
        ext_path = os.path.join(OPTIONS.saltdir, EXT_ARCHIVE)
        if os.path.exists(ext_path):
            unpack_ext(ext_path)
        else:
            version_path = os.path.join(OPTIONS.saltdir, 'ext_version')
            if not os.path.exists(version_path) or not os.path.isfile(version_path):
                need_ext()
            with open(version_path, 'r') as vpo:
                cur_version = vpo.readline().strip()
            if cur_version != OPTIONS.ext_mods:
                need_ext()
    # Fix parameter passing issue
    if len(ARGS) == 1:
        argv_prepared = ARGS[0].split()
    else:
        argv_prepared = ARGS

    salt_argv = [
        sys.executable,
        salt_call_path,
        '--local',
        '--metadata',
        '--out', 'json',
        '-l', 'quiet',
        '-c', OPTIONS.saltdir,
        '--',
    ] + argv_prepared

    sys.stderr.write('SALT_ARGV: {0}\n'.format(salt_argv))

    # Only emit the delimiter on *both* stdout and stderr when completely successful.
    # Yes, the flush() is necessary.
    sys.stdout.write(OPTIONS.delimiter + '\n')
    sys.stdout.flush()
    sys.stderr.write(OPTIONS.delimiter + '\n')
    sys.stderr.flush()
    if OPTIONS.tty:
        stdout, _ = subprocess.Popen(salt_argv, stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()
        sys.stdout.write(stdout)
        sys.stdout.flush()
        if OPTIONS.wipe:
            shutil.rmtree(OPTIONS.saltdir)
    elif OPTIONS.wipe:
        subprocess.call(salt_argv)
        shutil.rmtree(OPTIONS.saltdir)
    else:
        os.execv(sys.executable, salt_argv)

if __name__ == '__main__':
    sys.exit(main(sys.argv))
