# -*- coding: utf-8 -*-
'''
The default file server backend

This fileserver backend serves files from the Master's local filesystem. If
:conf_master:`fileserver_backend` is not defined in the Master config file,
then this backend is enabled by default. If it *is* defined then ``roots`` must
be in the :conf_master:`fileserver_backend` list to enable this backend.

.. code-block:: yaml

    fileserver_backend:
      - roots

Fileserver environments are defined using the :conf_master:`file_roots`
configuration option.
'''
from __future__ import absolute_import, print_function, unicode_literals

# Import python libs
import os
import errno
import logging

# Import salt libs
import salt.fileserver
import salt.utils.event
import salt.utils.files
import salt.utils.gzip_util
import salt.utils.hashutils
import salt.utils.path
import salt.utils.platform
import salt.utils.stringutils
import salt.utils.versions
from salt.ext import six

log = logging.getLogger(__name__)


def find_file(path, saltenv='base', **kwargs):
    '''
    Search the environment for the relative path.
    '''
    if 'env' in kwargs:
        # "env" is not supported; Use "saltenv".
        kwargs.pop('env')

    path = os.path.normpath(path)
    fnd = {'path': '',
           'rel': ''}
    if os.path.isabs(path):
        return fnd
    if saltenv not in __opts__['file_roots']:
        return fnd

    def _add_file_stat(fnd):
        '''
        Stat the file and, assuming no errors were found, convert the stat
        result to a list of values and add to the return dict.

        Converting the stat result to a list, the elements of the list
        correspond to the following stat_result params:

        0 => st_mode=33188
        1 => st_ino=10227377
        2 => st_dev=65026
        3 => st_nlink=1
        4 => st_uid=1000
        5 => st_gid=1000
        6 => st_size=1056233
        7 => st_atime=1468284229
        8 => st_mtime=1456338235
        9 => st_ctime=1456338235
        '''
        try:
            fnd['stat'] = list(os.stat(fnd['path']))
        except Exception:
            pass
        return fnd

    if 'index' in kwargs:
        try:
            root = __opts__['file_roots'][saltenv][int(kwargs['index'])]
        except IndexError:
            # An invalid index was passed
            return fnd
        except ValueError:
            # An invalid index option was passed
            return fnd
        full = os.path.join(root, path)
        if os.path.isfile(full) and not salt.fileserver.is_file_ignored(__opts__, full):
            fnd['path'] = full
            fnd['rel'] = path
            return _add_file_stat(fnd)
        return fnd
    for root in __opts__['file_roots'][saltenv]:
        full = os.path.join(root, path)
        if os.path.isfile(full) and not salt.fileserver.is_file_ignored(__opts__, full):
            fnd['path'] = full
            fnd['rel'] = path
            return _add_file_stat(fnd)
    return fnd


def envs():
    '''
    Return the file server environments
    '''
    return sorted(__opts__['file_roots'])


def serve_file(load, fnd):
    '''
    Return a chunk from a file based on the data received
    '''
    if 'env' in load:
        # "env" is not supported; Use "saltenv".
        load.pop('env')

    ret = {'data': '',
           'dest': ''}
    if 'path' not in load or 'loc' not in load or 'saltenv' not in load:
        return ret
    if not fnd['path']:
        return ret
    ret['dest'] = fnd['rel']
    gzip = load.get('gzip', None)
    fpath = os.path.normpath(fnd['path'])
    with salt.utils.files.fopen(fpath, 'rb') as fp_:
        fp_.seek(load['loc'])
        data = fp_.read(__opts__['file_buffer_size'])
        if gzip and data:
            data = salt.utils.gzip_util.compress(data, gzip)
            ret['gzip'] = gzip
        ret['data'] = data
    return ret


def update():
    '''
    When we are asked to update (regular interval) lets reap the cache
    '''
    try:
        salt.fileserver.reap_fileserver_cache_dir(
            os.path.join(__opts__['cachedir'], 'roots', 'hash'),
            find_file
        )
    except (IOError, OSError):
        # Hash file won't exist if no files have yet been served up
        pass

    mtime_map_path = os.path.join(__opts__['cachedir'], 'roots', 'mtime_map')
    # data to send on event
    data = {'changed': False,
            'files': {'changed': []},
            'backend': 'roots'}

    # generate the new map
    new_mtime_map = salt.fileserver.generate_mtime_map(__opts__, __opts__['file_roots'])

    old_mtime_map = {}
    # if you have an old map, load that
    if os.path.exists(mtime_map_path):
        with salt.utils.files.fopen(mtime_map_path, 'r') as fp_:
            for line in fp_:
                line = salt.utils.stringutils.to_unicode(line)
                try:
                    file_path, mtime = line.replace('\n', '').split(':', 1)
                    old_mtime_map[file_path] = mtime
                    if mtime != new_mtime_map.get(file_path, mtime):
                        data['files']['changed'].append(file_path)
                except ValueError:
                    # Document the invalid entry in the log
                    log.warning(
                        'Skipped invalid cache mtime entry in %s: %s',
                        mtime_map_path, line
                    )

    # compare the maps, set changed to the return value
    data['changed'] = salt.fileserver.diff_mtime_map(old_mtime_map, new_mtime_map)

    # compute files that were removed and added
    old_files = set(old_mtime_map.keys())
    new_files = set(new_mtime_map.keys())
    data['files']['removed'] = list(old_files - new_files)
    data['files']['added'] = list(new_files - old_files)

    # write out the new map
    mtime_map_path_dir = os.path.dirname(mtime_map_path)
    if not os.path.exists(mtime_map_path_dir):
        os.makedirs(mtime_map_path_dir)
    with salt.utils.files.fopen(mtime_map_path, 'w') as fp_:
        for file_path, mtime in six.iteritems(new_mtime_map):
            fp_.write(
                salt.utils.stringutils.to_str(
                    '{0}:{1}\n'.format(file_path, mtime)
                )
            )

    if __opts__.get('fileserver_events', False):
        # if there is a change, fire an event
        event = salt.utils.event.get_event(
                'master',
                __opts__['sock_dir'],
                __opts__['transport'],
                opts=__opts__,
                listen=False)
        event.fire_event(data,
                         salt.utils.event.tagify(['roots', 'update'], prefix='fileserver'))


def file_hash(load, fnd):
    '''
    Return a file hash, the hash type is set in the master config file
    '''
    if 'env' in load:
        # "env" is not supported; Use "saltenv".
        load.pop('env')

    if 'path' not in load or 'saltenv' not in load:
        return ''
    path = fnd['path']
    ret = {}

    # if the file doesn't exist, we can't get a hash
    if not path or not os.path.isfile(path):
        return ret

    # set the hash_type as it is determined by config-- so mechanism won't change that
    ret['hash_type'] = __opts__['hash_type']

    # check if the hash is cached
    # cache file's contents should be "hash:mtime"
    cache_path = os.path.join(__opts__['cachedir'],
                              'roots',
                              'hash',
                              load['saltenv'],
                              '{0}.hash.{1}'.format(fnd['rel'],
                              __opts__['hash_type']))
    # if we have a cache, serve that if the mtime hasn't changed
    if os.path.exists(cache_path):
        try:
            with salt.utils.files.fopen(cache_path, 'r') as fp_:
                try:
                    hsum, mtime = salt.utils.stringutils.to_unicode(fp_.read()).split(':')
                except ValueError:
                    log.debug('Fileserver attempted to read incomplete cache file. Retrying.')
                    # Delete the file since its incomplete (either corrupted or incomplete)
                    try:
                        os.unlink(cache_path)
                    except OSError:
                        pass
                    return file_hash(load, fnd)
                if str(os.path.getmtime(path)) == mtime:
                    # check if mtime changed
                    ret['hsum'] = hsum
                    return ret
        except (os.error, IOError):  # Can't use Python select() because we need Windows support
            log.debug("Fileserver encountered lock when reading cache file. Retrying.")
            # Delete the file since its incomplete (either corrupted or incomplete)
            try:
                os.unlink(cache_path)
            except OSError:
                pass
            return file_hash(load, fnd)

    # if we don't have a cache entry-- lets make one
    ret['hsum'] = salt.utils.hashutils.get_hash(path, __opts__['hash_type'])
    cache_dir = os.path.dirname(cache_path)
    # make cache directory if it doesn't exist
    if not os.path.exists(cache_dir):
        try:
            os.makedirs(cache_dir)
        except OSError as err:
            if err.errno == errno.EEXIST:
                # rarely, the directory can be already concurrently created between
                # the os.path.exists and the os.makedirs lines above
                pass
            else:
                raise
    # save the cache object "hash:mtime"
    cache_object = '{0}:{1}'.format(ret['hsum'], os.path.getmtime(path))
    with salt.utils.files.flopen(cache_path, 'w') as fp_:
        fp_.write(cache_object)
    return ret


def _file_lists(load, form):
    '''
    Return a dict containing the file lists for files, dirs, emtydirs and symlinks
    '''
    if 'env' in load:
        # "env" is not supported; Use "saltenv".
        load.pop('env')

    if load['saltenv'] not in __opts__['file_roots']:
        return []

    list_cachedir = os.path.join(__opts__['cachedir'], 'file_lists', 'roots')
    if not os.path.isdir(list_cachedir):
        try:
            os.makedirs(list_cachedir)
        except os.error:
            log.critical('Unable to make cachedir %s', list_cachedir)
            return []
    list_cache = os.path.join(list_cachedir, '{0}.p'.format(load['saltenv']))
    w_lock = os.path.join(list_cachedir, '.{0}.w'.format(load['saltenv']))
    cache_match, refresh_cache, save_cache = \
        salt.fileserver.check_file_list_cache(
            __opts__, form, list_cache, w_lock
        )
    if cache_match is not None:
        return cache_match
    if refresh_cache:
        ret = {
            'files': set(),
            'dirs': set(),
            'empty_dirs': set(),
            'links': {}
        }

        def _add_to(tgt, fs_root, parent_dir, items):
            '''
            Add the files to the target set
            '''
            def _translate_sep(path):
                '''
                Translate path separators for Windows masterless minions
                '''
                return path.replace('\\', '/') if os.path.sep == '\\' else path

            for item in items:
                abs_path = os.path.join(parent_dir, item)
                log.trace('roots: Processing %s', abs_path)
                is_link = salt.utils.path.islink(abs_path)
                log.trace(
                    'roots: %s is %sa link',
                    abs_path, 'not ' if not is_link else ''
                )
                if is_link and __opts__['fileserver_ignoresymlinks']:
                    continue
                rel_path = _translate_sep(os.path.relpath(abs_path, fs_root))
                log.trace('roots: %s relative path is %s', abs_path, rel_path)
                if salt.fileserver.is_file_ignored(__opts__, rel_path):
                    continue
                tgt.add(rel_path)
                try:
                    if not os.listdir(abs_path):
                        ret['empty_dirs'].add(rel_path)
                except Exception:
                    # Generic exception because running os.listdir() on a
                    # non-directory path raises an OSError on *NIX and a
                    # WindowsError on Windows.
                    pass
                if is_link:
                    link_dest = salt.utils.path.readlink(abs_path)
                    log.trace(
                        'roots: %s symlink destination is %s',
                        abs_path, link_dest
                    )
                    if salt.utils.platform.is_windows() \
                            and link_dest.startswith('\\\\'):
                        # Symlink points to a network path. Since you can't
                        # join UNC and non-UNC paths, just assume the original
                        # path.
                        log.trace(
                            'roots: %s is a UNC path, using %s instead',
                            link_dest, abs_path
                        )
                        link_dest = abs_path
                    if link_dest.startswith('..'):
                        joined = os.path.join(abs_path, link_dest)
                    else:
                        joined = os.path.join(
                            os.path.dirname(abs_path), link_dest
                        )
                    rel_dest = _translate_sep(
                        os.path.relpath(
                            os.path.realpath(os.path.normpath(joined)),
                            fs_root
                        )
                    )
                    log.trace(
                        'roots: %s relative path is %s',
                        abs_path, rel_dest
                    )
                    if not rel_dest.startswith('..'):
                        # Only count the link if it does not point
                        # outside of the root dir of the fileserver
                        # (i.e. the "path" variable)
                        ret['links'][rel_path] = link_dest

        for path in __opts__['file_roots'][load['saltenv']]:
            for root, dirs, files in salt.utils.path.os_walk(
                    path,
                    followlinks=__opts__['fileserver_followsymlinks']):
                _add_to(ret['dirs'], path, root, dirs)
                _add_to(ret['files'], path, root, files)

        ret['files'] = sorted(ret['files'])
        ret['dirs'] = sorted(ret['dirs'])
        ret['empty_dirs'] = sorted(ret['empty_dirs'])

        if save_cache:
            try:
                salt.fileserver.write_file_list_cache(
                    __opts__, ret, list_cache, w_lock
                )
            except NameError:
                # Catch msgpack error in salt-ssh
                pass
        return ret.get(form, [])
    # Shouldn't get here, but if we do, this prevents a TypeError
    return []


def file_list(load):
    '''
    Return a list of all files on the file server in a specified
    environment
    '''
    return _file_lists(load, 'files')


def file_list_emptydirs(load):
    '''
    Return a list of all empty directories on the master
    '''
    return _file_lists(load, 'empty_dirs')


def dir_list(load):
    '''
    Return a list of all directories on the master
    '''
    return _file_lists(load, 'dirs')


def symlink_list(load):
    '''
    Return a dict of all symlinks based on a given path on the Master
    '''
    if 'env' in load:
        # "env" is not supported; Use "saltenv".
        load.pop('env')

    ret = {}
    if load['saltenv'] not in __opts__['file_roots']:
        return ret

    if 'prefix' in load:
        prefix = load['prefix'].strip('/')
    else:
        prefix = ''

    symlinks = _file_lists(load, 'links')
    return dict([(key, val)
                 for key, val in six.iteritems(symlinks)
                 if key.startswith(prefix)])
