# -*- coding: utf-8 -*-
#
# 2011 Steven Armstrong (steven-cdist at armstrong.cc)
# 2011-2015 Nico Schottelius (nico-cdist at schottelius.org)
# 2016-2017 Darko Poljak (darko.poljak at gmail.com)
#
# This file is part of cdist.
#
# cdist is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# cdist is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with cdist. If not, see <http://www.gnu.org/licenses/>.
#
#

import os
import sys
import re
import subprocess
import shutil
import logging
import tempfile
import time
import datetime

import cdist
import cdist.message
from cdist import core
import cdist.exec.util as exec_util

CONF_SUBDIRS_LINKED = ["explorer", "files", "manifest", "type", ]


class Local(object):
    """Execute commands locally.

    All interaction with the local side should be done through this class.
    Directly accessing the local side from python code is a bug.

    """
    def __init__(self,
                 target_host,
                 target_host_tags,
                 base_root_path,
                 host_dir_name,
                 exec_path=sys.argv[0],
                 initial_manifest=None,
                 add_conf_dirs=None,
                 cache_path_pattern=None,
                 quiet_mode=False):

        self.target_host = target_host
        if target_host_tags is None:
            self.target_host_tags = ""
        else:
            self.target_host_tags = ",".join(target_host_tags)
        self.hostdir = host_dir_name
        self.base_path = os.path.join(base_root_path, "data")

        self.exec_path = exec_path
        self.custom_initial_manifest = initial_manifest
        self._add_conf_dirs = add_conf_dirs
        self.cache_path_pattern = cache_path_pattern
        self.quiet_mode = quiet_mode

        self._init_log()
        self._init_permissions()
        self.mkdir(self.base_path)
        # FIXME: create dir that does not require moving later
        self._init_cache_dir(None)
        self._init_paths()
        self._init_object_marker()
        self._init_conf_dirs()

    @property
    def dist_conf_dir(self):
        return os.path.abspath(os.path.join(os.path.dirname(cdist.__file__),
                                            "conf"))

    @property
    def home_dir(self):
        return cdist.home_dir()

    def _init_log(self):
        self.log = logging.getLogger(self.target_host[0])

    # logger is not pickable, so remove it when we pickle
    def __getstate__(self):
        state = self.__dict__.copy()
        if 'log' in state:
            del state['log']
        return state

    # recreate logger when we unpickle
    def __setstate__(self, state):
        self.__dict__.update(state)
        self._init_log()

    def _init_permissions(self):
        # Setup file permissions using umask
        os.umask(0o077)

    def _init_paths(self):
        # Depending on out_path
        self.bin_path = os.path.join(self.base_path, "bin")
        self.conf_path = os.path.join(self.base_path, "conf")
        self.global_explorer_out_path = os.path.join(self.base_path,
                                                     "explorer")
        self.object_path = os.path.join(self.base_path, "object")
        self.messages_path = os.path.join(self.base_path, "messages")
        self.files_path = os.path.join(self.conf_path, "files")

        # Depending on conf_path
        self.global_explorer_path = os.path.join(self.conf_path, "explorer")
        self.manifest_path = os.path.join(self.conf_path, "manifest")
        self.initial_manifest = (self.custom_initial_manifest or
                                 os.path.join(self.manifest_path, "init"))

        self.type_path = os.path.join(self.conf_path, "type")

    def _init_object_marker(self):
        self.object_marker_file = os.path.join(self.base_path, "object_marker")

        # Does not need to be secure - just randomly different from .cdist
        self.object_marker_name = tempfile.mktemp(prefix='.cdist-', dir='')

    def _init_conf_dirs(self):
        self.conf_dirs = []

        self.conf_dirs.append(self.dist_conf_dir)

        # Is the default place for user created explorer, type and manifest
        if self.home_dir:
            self.conf_dirs.append(self.home_dir)

        # Add directories defined in the CDIST_PATH environment variable
        if 'CDIST_PATH' in os.environ:
            cdist_path_dirs = re.split(r'(?<!\\):', os.environ['CDIST_PATH'])
            cdist_path_dirs.reverse()
            self.conf_dirs.extend(cdist_path_dirs)

        # Add command line supplied directories
        if self._add_conf_dirs:
            self.conf_dirs.extend(self._add_conf_dirs)

    def _init_directories(self):
        self.mkdir(self.conf_path)
        self.mkdir(self.global_explorer_out_path)
        self.mkdir(self.object_path)
        self.mkdir(self.bin_path)
        self.mkdir(self.cache_path)

    def create_files_dirs(self):
        self._init_directories()
        self._create_conf_path_and_link_conf_dirs()
        self._create_messages()
        self._link_types_for_emulator()
        self._setup_object_marker_file()

    def _setup_object_marker_file(self):
        with open(self.object_marker_file, 'w') as fd:
            fd.write("%s\n" % self.object_marker_name)

        self.log.trace("Object marker %s saved in %s" % (
            self.object_marker_name, self.object_marker_file))

    def _init_cache_dir(self, cache_dir):
        if cache_dir:
            self.cache_path = cache_dir
        else:
            if self.home_dir:
                self.cache_path = os.path.join(self.home_dir, "cache")
            else:
                raise cdist.Error(
                        "No homedir setup and no cache dir location given")

    def rmdir(self, path):
        """Remove directory on the local side."""
        self.log.trace("Local rmdir: %s", path)
        shutil.rmtree(path)

    def mkdir(self, path):
        """Create directory on the local side."""
        self.log.trace("Local mkdir: %s", path)
        os.makedirs(path, exist_ok=True)

    def run(self, command, env=None, return_output=False, message_prefix=None,
            save_output=True):
        """Run the given command with the given environment.
        Return the output as a string.

        """
        assert isinstance(command, (list, tuple)), (
                "list or tuple argument expected, got: %s" % command)

        if env is None:
            env = os.environ.copy()
        # Export __target_host, __target_hostname, __target_fqdn
        # for use in __remote_{copy,exec} scripts
        env['__target_host'] = self.target_host[0]
        env['__target_hostname'] = self.target_host[1]
        env['__target_fqdn'] = self.target_host[2]

        # Export for emulator
        env['__cdist_object_marker'] = self.object_marker_name

        if message_prefix:
            message = cdist.message.Message(message_prefix, self.messages_path)
            env.update(message.env)

        self.log.trace("Local run: %s", command)
        try:
            if self.quiet_mode:
                stderr = subprocess.DEVNULL
            else:
                stderr = None
            if save_output:
                output, errout = exec_util.call_get_output(
                    command, env=env, stderr=stderr)
                self.log.trace("Local stdout: {}".format(output))
                # Currently, stderr is not captured.
                # self.log.trace("Local stderr: {}".format(errout))
                if return_output:
                    return output.decode()
            else:
                # In some cases no output is saved.
                # This is used for shell command, stdout and stderr
                # must not be catched.
                if self.quiet_mode:
                    stdout = subprocess.DEVNULL
                else:
                    stdout = None
                subprocess.check_call(command, env=env, stderr=stderr,
                                      stdout=stdout)
        except subprocess.CalledProcessError as e:
            exec_util.handle_called_process_error(e, command)
        except OSError as error:
            raise cdist.Error(" ".join(command) + ": " + error.args[1])
        finally:
            if message_prefix:
                message.merge_messages()

    def run_script(self, script, env=None, return_output=False,
                   message_prefix=None, save_output=True):
        """Run the given script with the given environment.
        Return the output as a string.

        """
        if os.access(script, os.X_OK):
            self.log.debug('%s is executable, running it', script)
            command = [script]
        else:
            command = [os.environ.get('CDIST_LOCAL_SHELL', "/bin/sh"), "-e"]
            self.log.debug('%s is NOT executable, running it with %s',
                           script, " ".join(command))
            command.append(script)

        return self.run(command=command, env=env, return_output=return_output,
                        message_prefix=message_prefix, save_output=save_output)

    def _cache_subpath_repl(self, matchobj):
        if matchobj.group(2) == '%P':
            repl = str(os.getpid())
        elif matchobj.group(2) == '%h':
            repl = self.hostdir
        elif matchobj.group(2) == '%N':
            repl = self.target_host[0]

        return matchobj.group(1) + repl

    def _cache_subpath(self, start_time=time.time(), path_format=None):
        if path_format:
            repl_func = self._cache_subpath_repl
            cache_subpath = re.sub(r'([^%]|^)(%h|%P|%N)', repl_func,
                                   path_format)
            dt = datetime.datetime.fromtimestamp(start_time)
            cache_subpath = dt.strftime(cache_subpath)
        else:
            cache_subpath = self.hostdir

        i = 0
        while i < len(cache_subpath) and cache_subpath[i] == os.sep:
            i += 1
        cache_subpath = cache_subpath[i:]
        if not cache_subpath:
            cache_subpath = self.hostdir
        return cache_subpath

    def save_cache(self, start_time=time.time()):
        self.log.trace("cache subpath pattern: {}".format(
            self.cache_path_pattern))
        cache_subpath = self._cache_subpath(start_time,
                                            self.cache_path_pattern)
        self.log.debug("cache subpath: {}".format(cache_subpath))
        destination = os.path.join(self.cache_path, cache_subpath)
        self.log.trace(("Saving cache: " + self.base_path + " to " +
                        destination))

        if not os.path.exists(destination):
            shutil.move(self.base_path, destination)
        else:
            for direntry in os.listdir(self.base_path):
                srcentry = os.path.join(self.base_path, direntry)
                destentry = os.path.join(destination, direntry)
                try:
                    if os.path.isdir(destentry):
                        shutil.rmtree(destentry)
                    elif os.path.exists(destentry):
                        os.remove(destentry)
                except (PermissionError, OSError) as e:
                    raise cdist.Error(
                            "Cannot delete old cache entry {}: {}".format(
                                destentry, e))
                shutil.move(srcentry, destentry)

        # add target_host since cache dir can be hash-ed target_host
        host_cache_path = os.path.join(destination, "target_host")
        with open(host_cache_path, 'w') as hostf:
            print(self.target_host[0], file=hostf)

    def _create_messages(self):
        """Create empty messages"""
        with open(self.messages_path, "w"):
            pass

    def _create_conf_path_and_link_conf_dirs(self):
        # Create destination directories
        for sub_dir in CONF_SUBDIRS_LINKED:
            self.mkdir(os.path.join(self.conf_path, sub_dir))

        # Iterate over all directories and link the to the output dir
        for conf_dir in self.conf_dirs:
            self.log.debug("Checking conf_dir %s ..." % (conf_dir))
            for sub_dir in CONF_SUBDIRS_LINKED:
                current_dir = os.path.join(conf_dir, sub_dir)

                # Allow conf dirs to contain only partial content
                if not os.path.exists(current_dir):
                    continue

                for entry in os.listdir(current_dir):
                    src = os.path.abspath(os.path.join(conf_dir,
                                                       sub_dir,
                                                       entry))
                    dst = os.path.join(self.conf_path, sub_dir, entry)

                    # Already exists? remove and link
                    if os.path.exists(dst):
                        os.unlink(dst)

                    self.log.trace("Linking %s to %s ..." % (src, dst))
                    try:
                        os.symlink(src, dst)
                    except OSError as e:
                        raise cdist.Error("Linking %s %s to %s failed: %s" % (
                            sub_dir, src, dst, e.__str__()))

    def _link_types_for_emulator(self):
        """Link emulator to types"""
        src = os.path.abspath(self.exec_path)
        for cdist_type in core.CdistType.list_types(self.type_path):
            dst = os.path.join(self.bin_path, cdist_type.name)
            self.log.trace("Linking emulator: %s to %s", src, dst)

            try:
                os.symlink(src, dst)
            except OSError as e:
                raise cdist.Error(
                        "Linking emulator from %s to %s failed: %s" % (
                            src, dst, e.__str__()))