# -*- coding: utf-8 -*-
'''
Salt module to manage RAID arrays with mdadm
'''
from __future__ import absolute_import

# Import python libs
import os
import logging
import re

# Import salt libs
import salt.utils
from salt.exceptions import CommandExecutionError, SaltInvocationError

# Set up logger
log = logging.getLogger(__name__)


# Define a function alias in order not to shadow built-in's
__func_alias__ = {
    'list_': 'list'
}

# Define the module's virtual name
__virtualname__ = 'raid'


def __virtual__():
    '''
    mdadm provides raid functions for Linux
    '''
    if __grains__['kernel'] != 'Linux':
        return (False, 'The mdadm execution module cannot be loaded: only available on Linux.')
    if not salt.utils.which('mdadm'):
        return (False, 'The mdadm execution module cannot be loaded: the mdadm binary is not in the path.')
    return __virtualname__


def list_():
    '''
    List the RAID devices.

    CLI Example:

    .. code-block:: bash

        salt '*' raid.list
    '''
    ret = {}
    for line in (__salt__['cmd.run_stdout']
                    (['mdadm', '--detail', '--scan'],
                     python_shell=False).splitlines()):
        if ' ' not in line:
            continue
        comps = line.split()
        device = comps[1]
        ret[device] = {"device": device}
        for comp in comps[2:]:
            key = comp.split('=')[0].lower()
            value = comp.split('=')[1]
            ret[device][key] = value
    return ret


def detail(device='/dev/md0'):
    '''
    Show detail for a specified RAID device

    CLI Example:

    .. code-block:: bash

        salt '*' raid.detail '/dev/md0'
    '''
    ret = {}
    ret['members'] = {}

    # Lets make sure the device exists before running mdadm
    if not os.path.exists(device):
        msg = "Device {0} doesn't exist!"
        raise CommandExecutionError(msg.format(device))

    cmd = ['mdadm', '--detail', device]
    for line in __salt__['cmd.run_stdout'](cmd, python_shell=False).splitlines():
        if line.startswith(device):
            continue
        if ' ' not in line:
            continue
        if ':' not in line:
            if '/dev/' in line:
                comps = line.split()
                state = comps[4:-1]
                ret['members'][comps[0]] = {
                    'device': comps[-1],
                    'major': comps[1],
                    'minor': comps[2],
                    'number': comps[0],
                    'raiddevice': comps[3],
                    'state': ' '.join(state),
                }
            continue
        comps = line.split(' : ')
        comps[0] = comps[0].lower()
        comps[0] = comps[0].strip()
        comps[0] = comps[0].replace(' ', '_')
        ret[comps[0]] = comps[1].strip()
    return ret


def destroy(device):
    '''
    Destroy a RAID device.

    WARNING This will zero the superblock of all members of the RAID array..

    CLI Example:

    .. code-block:: bash

        salt '*' raid.destroy /dev/md0
    '''
    try:
        details = detail(device)
    except CommandExecutionError:
        return False

    stop_cmd = ['mdadm', '--stop', device]
    zero_cmd = ['mdadm', '--zero-superblock']

    if __salt__['cmd.retcode'](stop_cmd, python_shell=False):
        for number in details['members']:
            zero_cmd.append(details['members'][number]['device'])
        __salt__['cmd.retcode'](zero_cmd, python_shell=False)

    # Remove entry from config file:
    if __grains__.get('os_family') == 'Debian':
        cfg_file = '/etc/mdadm/mdadm.conf'
    else:
        cfg_file = '/etc/mdadm.conf'

    try:
        __salt__['file.replace'](cfg_file, 'ARRAY {0} .*'.format(device), '')
    except SaltInvocationError:
        pass

    if __salt__['raid.list']().get(device) is None:
        return True
    else:
        return False


def stop():
    '''
    Shut down all arrays that can be shut down (i.e. are not currently in use).

    CLI Example:

    .. code-block:: bash

        salt '*' raid.stop
    '''
    cmd = 'mdadm --stop --scan'

    if __salt__['cmd.retcode'](cmd):
        return True

    return False


def create(name,
           level,
           devices,
           metadata='default',
           test_mode=False,
           **kwargs):
    '''
    Create a RAID device.

    .. versionchanged:: 2014.7.0

    .. warning::
        Use with CAUTION, as this function can be very destructive if not used
        properly!

    CLI Examples:

    .. code-block:: bash

        salt '*' raid.create /dev/md0 level=1 chunk=256 devices="['/dev/xvdd', '/dev/xvde']" test_mode=True

    .. note::

        Adding ``test_mode=True`` as an argument will print out the mdadm
        command that would have been run.

    name
        The name of the array to create.

    level
        The RAID level to use when creating the raid.

    devices
        A list of devices used to build the array.

    metadata
        Version of metadata to use when creating the array.

    kwargs
        Optional arguments to be passed to mdadm.

    returns
        test_mode=True:
            Prints out the full command.
        test_mode=False (Default):
            Executes command on remote the host(s) and
            Prints out the mdadm output.

    .. note::

        It takes time to create a RAID array. You can check the progress in
        "resync_status:" field of the results from the following command:

        .. code-block:: bash

            salt '*' raid.detail /dev/md0

    For more info, read the ``mdadm(8)`` manpage
    '''
    opts = []
    raid_devices = len(devices)

    for key in kwargs:
        if not key.startswith('__'):
            opts.append('--{0}'.format(key))
            if kwargs[key] is not True:
                opts.append(str(kwargs[key]))
        if key == 'spare-devices':
            raid_devices -= int(kwargs[key])

    cmd = ['mdadm',
           '-C', name,
           '-R',
           '-v'] + opts + [
           '-l', str(level),
           '-e', metadata,
           '-n', str(raid_devices)] + devices

    cmd_str = ' '.join(cmd)

    if test_mode is True:
        return cmd_str
    elif test_mode is False:
        return __salt__['cmd.run'](cmd, python_shell=False)


def save_config():
    '''
    Save RAID configuration to config file.

    Same as:
    mdadm --detail --scan >> /etc/mdadm/mdadm.conf

    Fixes this issue with Ubuntu
    REF: http://askubuntu.com/questions/209702/why-is-my-raid-dev-md1-showing-up-as-dev-md126-is-mdadm-conf-being-ignored

    CLI Example:

    .. code-block:: bash

        salt '*' raid.save_config

    '''
    scan = __salt__['cmd.run']('mdadm --detail --scan', python_shell=False).splitlines()
    # Issue with mdadm and ubuntu
    # REF: http://askubuntu.com/questions/209702/why-is-my-raid-dev-md1-showing-up-as-dev-md126-is-mdadm-conf-being-ignored
    if __grains__['os'] == 'Ubuntu':
        buggy_ubuntu_tags = ['name', 'metadata']
        for i, elem in enumerate(scan):
            for bad_tag in buggy_ubuntu_tags:
                pattern = r'\s{0}=\S+'.format(re.escape(bad_tag))
                pattern = re.compile(pattern, flags=re.I)
                scan[i] = re.sub(pattern, '', scan[i])

    if __grains__.get('os_family') == 'Debian':
        cfg_file = '/etc/mdadm/mdadm.conf'
    else:
        cfg_file = '/etc/mdadm.conf'

    try:
        vol_d = dict([(line.split()[1], line) for line in scan])
        for vol in vol_d:
            pattern = r'^ARRAY\s+{0}'.format(re.escape(vol))
            __salt__['file.replace'](cfg_file, pattern, vol_d[vol], append_if_not_found=True)
    except SaltInvocationError:  # File is missing
        __salt__['file.write'](cfg_file, args=scan)

    return __salt__['cmd.run']('update-initramfs -u')


def assemble(name,
             devices,
             test_mode=False,
             **kwargs):
    '''
    Assemble a RAID device.

    CLI Examples:

    .. code-block:: bash

        salt '*' raid.assemble /dev/md0 ['/dev/xvdd', '/dev/xvde']

    .. note::

        Adding ``test_mode=True`` as an argument will print out the mdadm
        command that would have been run.

    name
        The name of the array to assemble.

    devices
        The list of devices comprising the array to assemble.

    kwargs
        Optional arguments to be passed to mdadm.

    returns
        test_mode=True:
            Prints out the full command.
        test_mode=False (Default):
            Executes command on the host(s) and prints out the mdadm output.

    For more info, read the ``mdadm`` manpage.
    '''
    opts = []
    for key in kwargs:
        if not key.startswith('__'):
            opts.append('--{0}'.format(key))
            if kwargs[key] is not True:
                opts.append(kwargs[key])

    # Devices may have been written with a blob:
    if isinstance(devices, str):
        devices = devices.split(',')

    cmd = ['mdadm', '-A', name, '-v'] + opts + devices

    if test_mode is True:
        return cmd
    elif test_mode is False:
        return __salt__['cmd.run'](cmd, python_shell=False)
