# Copyright 2020 Canonical, Ltd.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
import os
import shutil
import logging
import re
from typing import Tuple, List
import apt
import apt_pkg

from subiquity.common.errorreport import ErrorReportKind
from subiquity.common.types import ApplicationState
from subiquity.common.resources import get_users_and_groups
from subiquity.server.controller import SubiquityController
from subiquitycore.context import with_context
from subiquitycore.utils import arun_command
from system_setup.common.wsl_conf import wsl_config_update

log = logging.getLogger("system_setup.server.controllers.configure")


class ConfigureController(SubiquityController):

    def __init__(self, app):
        super().__init__(app)
        self.app = app
        self.model = app.base_model

    def start(self):
        self.install_task = self.app.aio_loop.create_task(self.configure())

    def __locale_gen_cmd(self) -> Tuple[str, bool]:
        """ Return a tuple of the locale-gen command path and True for
        validity. In dry-run, copy the locale-gen script, altering the
        localedef command line to output into a specified directory.
        """
        cmd = "usr/sbin/locale-gen"
        if self.app.opts.dry_run is False or self.app.opts.dry_run is None:
            return (os.path.join("/", cmd), True)

        outDir = os.path.join(self.model.root, "usr/lib/locale")
        usrSbinDir = os.path.join(self.model.root, "usr/sbin")
        os.makedirs(outDir, exist_ok=True)
        os.makedirs(usrSbinDir, exist_ok=True)
        cmdFile = os.path.join(self.model.root, cmd)
        shutil.copy(os.path.join("/", cmd), cmdFile)
        # Supply LC_* definition files to avoid complains from localedef.
        shutil.copytree("/usr/lib/locale/C.UTF-8/", outDir,
                        dirs_exist_ok=True)
        try:
            # Altering locale-gen script to output to the desired folder.
            with open(cmdFile, "r+") as f:
                script = f.read()
                pattern = r'(localedef .+) (\|\| :; \\)'
                localeDefRe = re.compile(pattern)
                replacement = r'\1 "{}/" \2'.format(outDir)
                (fileContents, n) = localeDefRe.subn(replacement, script,
                                                     count=1)
                if n != 1:
                    log.error("locale-gen script contents were unexpected."
                              " Aborting mock creation")
                    return ("", False)

                f.seek(0)
                f.write(fileContents)

            return (cmdFile, True)

        except IOError as err:
            log.error("Failed to modify %s file. %s", cmdFile, err)
            return ("", False)

    def __update_locale_cmd(self, lang) -> List[str]:
        """ Add mocking cli to update-locale if in dry-run."""
        updateLocCmd = ["update-locale", "LANG={}".format(lang)]
        if not self.app.opts.dry_run:
            return updateLocCmd

        defaultLocDir = os.path.join(self.model.root,
                                     "etc/default/")
        os.makedirs(defaultLocDir, exist_ok=True)
        updateLocCmd += ["--locale-file",
                         os.path.join(defaultLocDir, "locale"),
                         "--no-checks"]
        return updateLocCmd

    async def _activate_locale(self, lang, env) -> bool:
        """ Return true if succeed in running the last commands
        to set the locale.
        """
        (locGenCmd, ok) = self.__locale_gen_cmd()
        if not ok:
            log.error("Locale generation failed.")
            return False

        updateCmd = self.__update_locale_cmd(lang)
        cmds = [[locGenCmd], updateCmd]
        for cmd in cmds:
            cp = await arun_command(cmd, env=env)
            if cp.returncode != 0:
                log.error('Command "{}" failed with return code {}'
                          .format(cp.args, cp.returncode))
                return False

        return True

    async def _install_check_lang_support_packages(self, lang, env) -> bool:
        """ Install packages recommended by check-language-support
        command. lang is expected to be one single language/locale.
        """
        clsCommand = "check-language-support"
        # lang code may be separated by @, dot or spaces.
        # clsLang = lang.split('@')[0].split('.')[0].split(' ')[0]
        pattern = re.compile(r'([^.@\s]+)', re.IGNORECASE)
        matches = pattern.match(lang)
        if matches is None:
            log.error("Failed to match expected language format: %s", lang)
            return False

        langCodes = matches.groups()
        if len(langCodes) != 1:
            log.error("Only one match was expected for: %s", lang)
            return False

        clsLang = langCodes[0]
        # Running that command doesn't require root.
        cp = await arun_command([clsCommand, "-l", clsLang], env=env)
        if cp.returncode != 0:
            log.error('Command "%s" failed with return code %d',
                      cp.args, cp.returncode)
            return False

        packages = cp.stdout.strip('\n').split(' ')
        if len(packages) == 0:
            log.debug("%s didn't recommend any packages. Nothing to do.",
                      clsCommand)
            return True

        cache = apt.Cache()
        if self.app.opts.dry_run:
            packs_dir = os.path.join(self.model.root,
                                     apt_pkg.config
                                     .find_dir("Dir::Cache::Archives")[1:])
            os.makedirs(packs_dir, exist_ok=True)
            try:
                for package in packages:
                    # Just write the package uri to a file.
                    archive = os.path.join(packs_dir, cache[package].fullname)
                    with open(archive, "wt") as f:
                        f.write(cache[package].candidate.uri)
            except IOError:
                log.error("Failed to write %s file.", archive)
                return False

            return True

        cache.update()
        cache.open(None)
        with cache.actiongroup():
            for package in packages:
                cache[package].mark_install()

            cache.commit()

        return True

    def _update_locale_gen_file(self, localeGenPath, lang) -> bool:
        """ Uncomment the line in locale.gen file matching lang,
        if found commented. A fully qualified language is expected,
        since that would have passed thru the Locale controller
        validation. e.g. en_UK.UTF-8. Return True for success.
        """
        fileContents: str
        try:
            with open(localeGenPath, "r+") as f:
                fileContents = f.read()
                lineFound = fileContents.find(lang)
                if lineFound == -1:
                    # An unsupported locale coming from our UI is a bug
                    log.error("Selected language %s not supported.", lang)
                    return False

                pattern = r'[# ]*({}.*)'.format(lang)
                commented = re.compile(pattern)
                (fileContents, n) = commented.subn(r'\1', fileContents,
                                                   count=1)
                if n != 1:
                    log.error("Unexpected locale.gen file contents. Aborting.")
                    return False

                f.seek(0)
                f.write(fileContents)
                return True

        except IOError as err:
            log.error("Failed to modify %s file. %s", localeGenPath, err)
            return False

    def _locale_gen_file_path(self):
        """ Return the proper locale.gen path for dry or live-run."""
        localeGenPath = "/etc/locale.gen"
        if self.app.opts.dry_run is False or self.app.opts.dry_run is None:
            return localeGenPath

        # For testing purposes.
        etc_dir = os.path.join(self.model.root, "etc")
        testLocGenPath = os.path.join(etc_dir,
                                      os.path.basename(localeGenPath))
        shutil.copy(localeGenPath, testLocGenPath)
        shutil.copy(localeGenPath, "{}.test".format(testLocGenPath))
        return testLocGenPath

    async def apply_locale(self, lang):
        """ Effectively apply the locale setup to the new system."""
        env = os.environ.copy()
        localeGenPath = self._locale_gen_file_path()
        if self._update_locale_gen_file(localeGenPath, lang) is False:
            log.error("Failed to update locale.gen")
            return

        ok = await self._install_check_lang_support_packages(lang, env)
        if not ok:
            log.error("Failed to install recommended language packs.")
            return

        ok = await self._activate_locale(lang, env)
        if not ok:
            log.error("Failed to run locale activation commands.")
            return

    @with_context(
        description="final system configuration", level="INFO",
        childlevel="DEBUG")
    async def configure(self, *, context):
        """ Apply the installation steps submitted by the user."""
        context.set('is-install-context', True)
        try:

            self.app.update_state(ApplicationState.WAITING)

            await self.model.wait_install()

            self.app.update_state(ApplicationState.NEEDS_CONFIRMATION)

            self.app.update_state(ApplicationState.RUNNING)

            await self.model.wait_postinstall()

            self.app.update_state(ApplicationState.POST_WAIT)

            self.app.update_state(ApplicationState.POST_RUNNING)

            dryrun = self.app.opts.dry_run
            variant = self.app.variant
            root_dir = self.model.root
            username = None
            if variant == "wsl_setup":
                wsl_id = self.model.identity.user
                username = wsl_id.username
                create_user_base = []
                assign_grp_base = []
                usergroups_list = get_users_and_groups()
                lang = self.model.locale.selected_language
                if dryrun:
                    log.debug("creating a mock-up env for user %s", username)
                    # creating folders and files for dryrun
                    etc_dir = os.path.join(root_dir, "etc")
                    os.makedirs(etc_dir, exist_ok=True)
                    home_dir = os.path.join(root_dir, "home")
                    os.makedirs(home_dir, exist_ok=True)
                    pseudo_files = ["passwd", "shadow", "gshadow", "group",
                                    "subgid", "subuid"]
                    for file in pseudo_files:
                        filepath = os.path.join(etc_dir, file)
                        open(filepath, "a").close()

                    # mimic groupadd
                    group_id = 1000
                    for group in usergroups_list:
                        group_filepath = os.path.join(etc_dir, "group")
                        gshadow_filepath = os.path.join(etc_dir, "gshadow")
                        shutil.copy(group_filepath,
                                    "{}-".format(group_filepath))
                        with open(group_filepath, "a") as group_file:
                            group_file.write("{}:x:{}:\n".
                                             format(group, group_id))
                        group_id += 1
                        shutil.copy(gshadow_filepath,
                                    "{}-".format(gshadow_filepath))
                        with open(gshadow_filepath, "a") as gshadow_file:
                            gshadow_file.write("{}:!::\n".format(group))

                    create_user_base = ["-P", root_dir]
                    assign_grp_base = ["-P", root_dir]

                create_user_cmd = ["useradd"] + create_user_base + \
                                  ["-m", "-s", "/bin/bash",
                                   "-c", wsl_id.realname,
                                   "-p", wsl_id.password, username]
                assign_grp_cmd = ["usermod"] + assign_grp_base + \
                                 ["-a", "-G", ",".join(usergroups_list),
                                  username]

                create_user_proc = await arun_command(create_user_cmd)
                if create_user_proc.returncode != 0:
                    raise Exception("Failed to create user %s: %s"
                                    % (username, create_user_proc.stderr))
                log.debug("created user %s", username)

                assign_grp_proc = await arun_command(assign_grp_cmd)
                if assign_grp_proc.returncode != 0:
                    raise Exception(("Failed to assign group to user %s: %s")
                                    % (username, assign_grp_proc.stderr))

                await self.apply_locale(lang)

            else:
                wsl_config_update(self.model.wslconfadvanced.wslconfadvanced,
                                  root_dir)

            # update advanced config when it is in autoinstall mode
            if self.app.opts.autoinstall is not None and \
               self.model.wslconfadvanced.wslconfadvanced is not None:
                wsl_config_update(self.model.wslconfadvanced.wslconfadvanced,
                                  root_dir)

            wsl_config_update(self.model.wslconfbase.wslconfbase, root_dir,
                              default_user=username)

            self.app.update_state(ApplicationState.DONE)

        except Exception:
            kw = {}
            self.app.make_apport_report(
                ErrorReportKind.INSTALL_FAIL, "configuration failed", **kw)
            raise

    def stop_uu(self):
        # This is a no-op to allow Shutdown controller to depend on this one
        pass