# -*- coding: utf-8 -*-

# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2019 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT

from __future__ import print_function
from __future__ import absolute_import
from __future__ import division
import json
import os
import sys
import uuid
import signal
import secureio
from future.moves import configparser as ConfigParser
from stat import S_IRUSR, S_IWUSR, S_IRGRP, S_IROTH
from future.utils import iteritems
from pathlib import Path
import psutil

from .clselect import ClSelect
from .clselectexcept import ClSelectExcept
from clcommon import ClPwd, clcaptain
from .clselectprint import clprint
from . import utils
from clcommon.utils import ExternalProgramFailed
try:
    from clcagefslib.const import BASEDIR
    from clcagefslib.fs import get_user_prefix
    from clcagefslib.selector.configure import is_ea4_enabled, read_cpanel_ea4_php_conf, configure_alt_php
    from clcagefslib.selector.panel.da import da_change_user_php_ini
    from clcagefslib.selector.panel.isp import ispmanager_create_user_wrapper
except ImportError:
    pass


class ClUserSelect(ClSelect):
    CAGEFS_PATH = '/var/cagefs'
    SELECTOR_PATH = '/usr/selector'
    NATIVE_PATH = SELECTOR_PATH if utils.in_cagefs() else '/usr/share/cagefs-skeleton/usr/selector'
    CAGEFS_EXCLUDE = '/etc/cagefs/exclude'
    SELECTOR2_DIR = '.cl.selector/selector.path'


    def clean_crui_images(self, users=None):
        """
        Creates flags mod_lsapi_reset_me in users' home directories in order
        to recreate CRIU images when php version/extensions/options have changed
        For details see LVEMAN-1210
        :param users: list of usernames (strings)
        """

        # There is not reliable way to check if CRIU is enabled inside CageFS
        # So let's always create the "mod_lsapi_reset_me" flag
        if not utils.in_cagefs() and not os.path.isfile('/var/run/mod_lsapi/criu.enabled'):
            return
        for user in users:
            pw = self._clpwd.get_pw_by_name(user)
            path = os.path.join(pw.pw_dir, 'mod_lsapi_reset_me')
            if not os.path.isfile(path):
                previous_user_data = self._change_uid(user)
                try:
                    clcaptain.write(path)
                except (OSError, ExternalProgramFailed) as e:
                    raise ClSelectExcept.UnableToSaveData(path, e)
                finally:
                    ClUserSelect._restore_uid(previous_user_data)


    @staticmethod
    def switch_symlink_for_alt_php(version, pw, exit_on_error=True, configure_multiphp = True):
        """
        Switch symlink for alt php.
        Create .cagefs directory if not created
        Rerurn True if error has occured
        """
        if not os.path.isdir(BASEDIR) and not utils.in_cagefs():
            print('ERROR: CageFS not installed.')
            if exit_on_error:
                sys.exit(1)
            else:
                return True

        if configure_multiphp and is_ea4_enabled():
            conf = read_cpanel_ea4_php_conf()
            if conf:
                try:
                    # get default system php version selected via MultiPHP Manager in cPanel WHM
                    default_php = conf['default']
                    # LVEMAN-1170: do not configure PHP Selector when system default version is alt-php
                    if not default_php.startswith('ea-php'):
                        print('ERROR: system default PHP version is alt-php. '
                              'PHP Selector is disabled. Use cPanel MultiPHP manager instead.')
                        if exit_on_error:
                            sys.exit(1)
                        else:
                            return True
                except KeyError:
                    pass

        # configure alt php - create .cagefs dir and create symlink
        error = configure_alt_php(pw, version, write_log=False, drop_perm=(os.geteuid() == 0), configure_multiphp = configure_multiphp)
        if error and exit_on_error:
            sys.exit(1)
        return error

    def apply_symlinks_rules(self):
        if self.without_cagefs:
            print('ERROR: this option does not work in "single user" mode (when CageFS is disabled)')
            sys.exit(1)
        if os.geteuid() != 0:
            print('ERROR: root privileges required')
            sys.exit(1)
        users_vers_dict = self.get_user_version_map()
        for user, version in iteritems(users_vers_dict):
            print('Processing user', user)
            pw = self._clpwd.get_pw_by_name(user)
            ClUserSelect.switch_symlink_for_alt_php(version, pw, exit_on_error=False, configure_multiphp=False)

    def __init__(self, item='php', exclude_pid_list=None):
        ClSelect.__init__(self, item)
        self._clpwd = ClPwd()
        self._user_excludes = set()
        if exclude_pid_list:
            self.exclude_pid_list = exclude_pid_list
        else:
            self.exclude_pid_list = []

    def get_version(self, user, show_native_version=False):
        """
        Returns alternative version for a user
        @param user: string
        @return: string
        """
        self._check_user_in_cagefs(user)
        alt_path = self._compose_user_alt_path(user)
        native = self._compose_native_info(show_native_version)
        if not os.path.isdir(alt_path):
            return native
        alternatives = self.get_all_alternatives_data()
        full_path = os.path.join(alt_path, self._item)
        if not os.path.islink(full_path):
            return native
        link_dst = os.readlink(full_path)
        if self.without_cagefs:
            if not self._native_contents:
                self._load_native_contents(self._item)
            if link_dst == self._native_contents[self._item]:
                return native
        if os.path.dirname(link_dst) == self.SELECTOR_PATH:
            return native
        try:
            version = list(filter(
                (lambda i: alternatives[i]['data'][self._item] ==
                    link_dst),
                list(alternatives.keys())))[0]
            return (version,
                    alternatives[version]['version'],
                    alternatives[version]['data'][self._item])
        except (IndexError, KeyError):
            return native


    def create_dir(self, path, user):
        if not os.path.isdir(path):
            previous_user_data = self._change_uid(user)
            try:
                clcaptain.mkdir(path)
            except (OSError, ExternalProgramFailed) as e:
                raise ClSelectExcept.UnableToSaveData(path, e)
            finally:
                ClUserSelect._restore_uid(previous_user_data)


    def create_selector_symlinks(self, user):
        """
        Creates additional directory and symlinks for use in "without CageFS" mode
        """
        homedir = self._clpwd.get_homedir(user)
        path_in_home = os.path.join(homedir, self.SELECTOR2_DIR)
        cur_user = self._change_uid(user)
        self.create_dir(path_in_home, user)
        self._create_symlink('../php-cli', path_in_home+'/php', check_existence=True)
        self._create_symlink('../php', path_in_home+'/php-cgi', check_existence=True)
        self._restore_uid(cur_user)


    def get_default_version(self):
        if os.path.isfile(ClSelect.DEFAULTS_PATH):
            try:
                return self._dh.get('versions', self._item)
            except (ConfigParser.Error, IOError, KeyError):
                return 'native'
        return 'native'


    def set_version_from_backup(self, user):
        user_backup_path = os.path.join(self._clpwd.get_homedir(user), '.cl.selector', 'defaults.cfg')
        if not os.path.isfile(user_backup_path):
            self.set_version(user, self.get_default_version())
        else:
            try:
                dh = self._get_default_config_handler(user_backup_path)
                self.set_version(user, dh.get('versions', self._item))
            except (ConfigParser.Error, IOError, KeyError) as e:
                print('Error while restoring settings from backup', str(e))
                sys.exit(1)

    def set_version(self, user, version, return_summary=False, show_native_version=False, exit_on_error=True):
        """
        Sets alternative version for a users with the same uid
        @param user: string
        @return: None
        """
        if os.geteuid() != 0 and (message := self.get_version_selection_disabled_msg(user)):
            raise ClSelectExcept.VersionModificationBlocked(message)

        data = utils.apply_for_at_least_one_user(
            self._set_version,
            self._clpwd.get_names(self._clpwd.get_uid(user)),
            ClSelectExcept.NoUserSelector,
            version, return_summary, show_native_version, exit_on_error
        )

        if return_summary:
            return data

    def _set_version(self, user, version, return_summary=False, show_native_version=False, exit_on_error=True):
        """
        Sets alternative version for a user
        @param user: string
        @return: None
        """
        if self.without_cagefs:
            previous_user_data = self._change_uid(user)
        self._check_user_in_cagefs(user)
        alt_path = self._compose_user_alt_path(user)
        if not os.path.isdir(alt_path):
            if self.without_cagefs:
                self.create_dir(alt_path, user)
            else:
                raise ClSelectExcept.NoUserSelector(user)
        alternatives = self.get_all_alternatives_data()
        if version not in alternatives and version != 'native':
            raise ClSelectExcept.NoSuchAlternativeVersion(version)
        self._remove_alternatives_links(alt_path)
        pw = self._clpwd.get_pw_by_name(user)
        if version == 'native':
            if self.without_cagefs:
                if not self._native_contents:
                    self._load_native_contents(self._item)
                for item, native_path in iteritems(self._native_contents):
                    self._create_symlink(native_path, alt_path+'/'+item, user, version)
            else:
                ini = 'php.ini'
                new_ini_created = False
                new_ini_path = os.path.join("%s.etc" % (self.NATIVE_PATH,), ini)
                if os.path.exists(new_ini_path):
                    src = os.path.join("%s.etc" % self.SELECTOR_PATH, ini)
                    dst = os.path.join(alt_path, ini)
                    self._create_symlink(src, dst, user, version)
                    new_ini_created = True
                for filename in os.listdir(self.NATIVE_PATH):
                    if self._item not in filename:
                        continue
                    if filename.endswith('.ini') and new_ini_created:
                        continue
                    dst = os.path.join(alt_path, filename)
                    src = os.path.join(self.SELECTOR_PATH, filename)
                    self._create_symlink(src, dst, user, version)
        else:
            for item, path in iteritems(alternatives[version]['data']):
                self._create_symlink(path, os.path.join(alt_path, item), user, version)

        if self.without_cagefs:
            ClUserSelect._restore_uid(previous_user_data)
        else:
            ClUserSelect.switch_symlink_for_alt_php(version, pw, exit_on_error = exit_on_error)
            self._switch_php_da_isp(user, version)
        self._reload_processes(user)
        self._backup_settings(user)

        if return_summary:
            return self.get_summary(user, show_native_version)

    def get_version_selection_disabled_msg(self, username: str) -> str:
        """
        Returns a message indicating that the selection of the PHP version
        is disabled for the user, based on the configuration file.

        Args:
            username (str): The username for which to check the configuration.

        Returns:
            str: The message indicating that version selection is disabled,
                 or an empty string if the configuration file does not exist
                 or does not contain the message.
        """
        uid = self._clpwd.get_uid(username)
        config_file = Path(f'/var/cloudlinux/cl.selector/uids/{uid}/version_selection_conf.json')
        if not config_file.exists():
            return ''

        try:
            with config_file.open(encoding='utf-8') as f:
                config_data = json.load(f)
                return config_data.get('version_selection_disabled_msg', '')
        except (OSError, ValueError):
            return ''

    def get_summary(self, user, show_native_version=False):
        """
        Returns state of alternatives
        @param user: string
        @return: tuple
        """
        self._check_user_in_cagefs(user)
        alternatives = self.get_all_alternatives_data()
        native_info = self._compose_native_info(show_native_version)
        summary = {'native': {
            'enabled': True, 'default': False, 'selected': False}}
        alt_versions = sorted(alternatives.keys())
        alt_versions.append('native')
        selected_version = self.get_version(user)[0]
        for version in alt_versions:
            if version not in summary:
                summary[version] = {}
            summary[version]['enabled'] = not self._dh.has_option(
                "%s%s" % (self._item, version), 'state')
            summary[version]['default'] = False
            summary[version]['selected'] = False
        try:
            default_version = self._dh.get('versions', self._item)
        except (ConfigParser.NoSectionError, ConfigParser.NoOptionError):
            default_version = 'native'
        try:
            summary[default_version]['default'] = True
            summary[selected_version]['selected'] = True
        except KeyError:
            raise ClSelectExcept.NoSuchAlternativeVersion(default_version)
        summary[native_info[0]] = summary.pop('native')
        alt_versions.remove('native')
        alt_versions.append(native_info[0])
        for idx in range(len(alt_versions)):
            v = alt_versions[idx]
            alt_versions[idx] = (
                v,
                (summary[v]['enabled'],
                 summary[v]['default'],
                 summary[v]['selected']))
        return tuple(alt_versions)

    def change_to_version(self, new_version, current_version):
        """
        Changes users of a supplied version to specified_version
        @param version: string
        @param current_version: string
        """
        users = self.list_users(current_version)
        for user in users:
            try:
                self.set_version(user, new_version, exit_on_error = False)
            except Exception as e:     #catch every errors, print it and go to the next user
                clprint.print_diag('text', {'status': 'ERROR', 'message': str(e)})
                pass
        self.clean_crui_images(users)

    def list_users(self, version):
        """
        Returns users of a certain alternative
        """
        data = self.get_version_user_map()
        if version in data:
            return data[version]
        return []

    def list_all_users(self):
        """
        Returns all valid system users
        @return: list
        """
        if self.without_cagefs:
            from .clselectctlphp import get_cpanel_user
            return [get_cpanel_user()]
        return list(self._get_system_users().difference(
            self._get_user_excludes()))

    def cagefs_copy_etc(self, user):
        config = dict()
        config['init'] = 0
        config['reinit'] = 0
        config['verbose'] = 0
        LIBDIR = '/usr/share/cagefs'
        sys.path.append(LIBDIR)

        try:
            import cagefsctl
        except ImportError:
            print('ERROR: CageFS not installed.')
            sys.exit(1)

        cagefs_etc_path = os.path.join(BASEDIR, get_user_prefix(user), user, 'etc')
        if not os.path.exists(cagefs_etc_path + '/cl.selector') or \
                not os.path.exists(cagefs_etc_path + '/cl.php.d'):
            cagefsctl.cpetc_for_user(user, config)

    def get_user_version_map(self):
        """
        Returns user version map as dict
        @return: dict
        """
        actual_users = self.list_all_users()
        data = {}
        for user in actual_users:
            try:
                data[user] = self.get_version(user, False)[0]
            except ClSelectExcept.NotCageFSUser:
                continue
        return data

    def get_version_user_map(self, user_names = None):
        """
        Returns users grouped by version
        @return: dict
        """
        actual_users = user_names or self.list_all_users()
        data = {}
        for user in actual_users:
            try:
                version = self.get_version(user, False)[0]
                if not version in data:
                    data[version] = []
                data[version].append(user)
            except ClSelectExcept.NotCageFSUser:
                continue
        return data

    def _create_symlink(src, dst, user=None, version=None, check_existence=False):
        """
        Creates symlink from src to dst
        @param src: string
        @param dst: string
        @param user: string
        @param version: string
        @param check_existence: bool
        @return: None
        """
        try:
            if check_existence:
                if os.path.islink(dst):
                    if os.readlink(dst) != src:
                        os.unlink(dst)
                    else:
                        return
                else:
                    utils.remove_file_or_dir(dst)
            clcaptain.symlink(src, dst)
        except Exception as e:
            if user is not None and version is not None:
                raise ClSelectExcept.UnableToSetAlternative(user, version, e)
            raise ClSelectExcept.SelectorException(
                "Cannot create symlink from %s to %s (%s)" % (src, dst, e))
    _create_symlink = staticmethod(_create_symlink)

    def _get_user_excludes(self):
        """
        Returns list of user excludes
        @return: list
        """
        if self._user_excludes:
            return self._user_excludes
        if not os.path.isdir(self.CAGEFS_EXCLUDE):
            return set()
        for item in os.listdir(self.CAGEFS_EXCLUDE):
            full_item_path = os.path.join(self.CAGEFS_EXCLUDE, item)
            self._user_excludes.update(
                set(
                    map((lambda x: x.strip()),
                        utils.read_file_as_string(full_item_path).splitlines())))
        return self._user_excludes

    def _check_user_in_cagefs(self, user):
        """
        Check that cagefs enabled for user
        """
        if self.without_cagefs:
            return

        if utils.in_cagefs():
            return

        LIBDIR = '/usr/share/cagefs'
        sys.path.append(LIBDIR)
        try:
            import cagefsctl
        except ImportError:
            print('ERROR: CageFS not installed.')
            sys.exit(1)
        try:
            if not cagefsctl.is_user_enabled(user):
                raise ClSelectExcept.NotCageFSUser(user)
        except AttributeError:
            print('ERROR: CageFS version is unsupported. Please update CageFS.')
            sys.exit(1)

    def _remove_alternatives_links(self, path):
        """
        Removes all symlinks from directory
        @param path: string
        @return: None
        """
        for filename in os.listdir(path):
            if self._item not in filename:
                continue
            full_path = os.path.join(path, filename)
            if not os.path.islink(full_path):
                continue
            os.unlink(full_path)

    def _compose_user_alt_path(self, user):
        """
        Composes and returns user alternative directory path
        @param user: string
        @return: string
        """
        if self.without_cagefs:
            homedir = self._clpwd.get_homedir(user)
            return homedir + '/.cl.selector'
        uid = str(self._clpwd.get_uid(user))
        return (
            '/etc/cl.selector'
            if utils.in_cagefs() else
            os.path.join(self.CAGEFS_PATH, uid[-2:], user, 'etc', 'cl.selector')
        )

    def _get_system_users(self):
        """
        Returns set of system users
        @return: set
        """
        users_dict = self._clpwd.get_user_dict()
        return set(users_dict.keys())

    def _delete_if_symlink(file_path):
        """
        Deletes file to be written if it is a symlink
        """
        if os.path.islink(file_path):
            try:
                os.unlink(file_path)
            except OSError:
                raise ClSelectExcept.UnableToSaveData(
                    file_path,
                    "Cannot delete symlink while saving data")
    _delete_if_symlink = staticmethod(_delete_if_symlink)

    def _change_uid(self, user):
        """
        Changes to another uid and returns tuple of previous euid and egid
        @param user: string
        @return: tuple
        """
        entry = self._clpwd.get_pw_by_name(user)
        new_uid = entry.pw_uid
        new_gid = entry.pw_gid
        cur_euid = os.geteuid()
        cur_egid = os.getegid()
        if cur_euid == new_uid:
            return cur_euid, cur_egid
        try:
            os.setegid(new_gid)
            os.seteuid(new_uid)
            secureio.set_capability()
            return cur_euid, cur_egid
        except OSError as e:
            raise ClSelectExcept.UnableToChangeToAnotherUser(user, e)

    def _restore_uid(uid_and_gid):
        """
        Restores changed uid and gid to original ones
        @param uid_and_gid: tuple
        @return: None
        """
        if uid_and_gid[0] != os.geteuid():
            secureio.set_capability(clear=True)
            try:
                os.setegid(uid_and_gid[1])
                os.seteuid(uid_and_gid[0])
            except OSError as e:
                raise ClSelectExcept.UnableToChangeToAnotherUser(str(uid_and_gid[0]), e)
    _restore_uid = staticmethod(_restore_uid)

    def _write_to_file(self, user, file_contents, file_path, create=True):
        """
        Saves data to file
        @param user: string
        @param file_contents: string
        @param file_path: string
        @return: None
        """
        if not create and not os.path.exists(file_path):
            return
        self._delete_if_symlink(file_path)
        previous_user_data = self._change_uid(user)
        file_directory = os.path.dirname(file_path)
        try:
            # Replace tempfile.mkstemp with str(uuid.uuid4())
            dirname = 'clseltmp_%s' % str(uuid.uuid4())
            temp_path = os.path.join(file_directory, dirname)
            clcaptain.write(temp_path, "%s\n" % (file_contents,))
        except (IOError, OSError, ExternalProgramFailed) as e:
            try:
                if os.path.exists(temp_path):
                    os.unlink(temp_path)
            except:
                pass
            ClUserSelect._restore_uid(previous_user_data)
            raise ClSelectExcept.UnableToSaveData(file_path, e)
        else:
            try:
                mask = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH
                os.rename(temp_path, file_path)
                os.chmod(file_path, mask)
            except OSError:
                pass
        ClUserSelect._restore_uid(previous_user_data)

    def _reload_processes(self, user):
        """
        Reloads user process
        """
        try:
            next_parent = psutil.Process()
            for i in range(2):
                next_parent = next_parent.parent()
                if next_parent is not None:
                    self.exclude_pid_list.append(next_parent.pid)
                else:
                    break
        except psutil.NoSuchProcess:
            pass
        try:
            uid = ClPwd().get_uid(user)
        except (ClPwd.NoSuchUserException, ):
            # no such user
            return
        try:
            for proc in psutil.process_iter():
                try:
                    if uid not in [proc.uids().real, proc.uids().effective] or proc.name().find(self._item) == -1:
                        continue
                    pid = proc.pid
                except psutil.NoSuchProcess:
                    continue
                try:
                    if pid not in self.exclude_pid_list:
                        os.kill(pid, signal.SIGHUP)
                except (OSError, ):
                    continue
        except (OSError, IOError):
            # psutil reads /proc FS as usual FS, skip read errors
            pass

    def _skim_over_extensions(path):
        """
        Get extension names from user extensions file comments
        """
        extensions = []
        try:
            ini = open(path)
            for line in ini:
                if line.startswith(';---'):
                    ext = line[4:line.rfind('---')]
                    extensions.append(ext)
            ini.close()
        except (OSError, IOError):
            pass
        return extensions
    _skim_over_extensions = staticmethod(_skim_over_extensions)

    def _backup_settings(self, user):
        """
        Scans all user settings and backups'em in homedir as INI file
        @param user: string
        """
        self._check_user_in_cagefs(user)
        backup_contents = []
        user_alt_path = self._compose_user_alt_path(user)
        user_ext_path = os.path.join(os.path.dirname(user_alt_path), 'cl.php.d')
        alternatives = self.get_all_alternatives_data()
        user_backup_path = os.path.join(
            self._clpwd.get_homedir(user), '.cl.selector')
        if not os.path.isdir(user_backup_path):
            previous_user_data = self._change_uid(user)
            try:
                clcaptain.mkdir(user_backup_path)
            except (OSError, ExternalProgramFailed) as e:
                ClUserSelect._restore_uid(previous_user_data)
                raise ClSelectExcept.UnableToSaveData(user_backup_path, e)
            ClUserSelect._restore_uid(previous_user_data)
        user_backup_file = os.path.join(
            user_backup_path, 'defaults.cfg')
        if os.path.isdir(user_alt_path):
            version = '[versions]\n%s = %s\n' % (
                self._item, self.get_version(user)[0])
        else:
            version = '[versions]\n%s = native\n' % (self._item,)
        backup_contents.append(version)
        for alt in sorted(alternatives.keys()):
            if self.without_cagefs:
                curr_ext_path = user_alt_path + "/alt_php" + alt.replace('.', '') + '.ini'
            else:
                curr_ext_path = os.path.join(
                    user_ext_path, "alt-php%s" % (
                        (alt.replace('.', ''),)), 'alt_php.ini')
            extensions = self._skim_over_extensions(curr_ext_path)
            backup_contents.append(
                "[%s%s]\nmodules = %s\n" % (
                    self._item, alt, ','.join(sorted(extensions))))
        self._write_to_file(
            user, '\n'.join(backup_contents), user_backup_file)

    def _switch_php_da_isp(self, user, version):
        if self.without_cagefs:
            return
        da_change_user_php_ini(user, version)
        ispmanager_create_user_wrapper(user, version)