import abc
import copy
import logging
import re
from os.path import exists
from typing import Any, Dict, List, Optional, Tuple, Union

from uaclient import (
    apt,
    contract,
    event_logger,
    exceptions,
    messages,
    system,
    util,
)
from uaclient.entitlements import base
from uaclient.entitlements.entitlement_status import ApplicationStatus

event = event_logger.get_event_logger()


class RepoEntitlement(base.UAEntitlement):

    repo_list_file_tmpl = "/etc/apt/sources.list.d/ubuntu-{name}.list"
    repo_pref_file_tmpl = "/etc/apt/preferences.d/ubuntu-{name}"

    # The repo Origin value for setting pinning
    origin = None  # type: Optional[str]

    # GH: #1084 call apt in noninteractive mode
    apt_noninteractive = False

    # Optional repo pin priority in subclass
    @property
    def repo_pin_priority(self) -> Union[int, str, None]:
        return None

    @property
    def packages(self) -> List[str]:
        """debs to install on enablement"""
        packages = []

        entitlement = self.cfg.machine_token_file.entitlements.get(
            self.name, {}
        ).get("entitlement", {})

        if entitlement:
            directives = entitlement.get("directives", {})
            additional_packages = copy.copy(
                directives.get("additionalPackages", [])
            )

            packages = additional_packages

        return packages

    def _check_for_reboot(self) -> bool:
        """Check if system needs to be rebooted."""
        reboot_required = system.should_reboot(
            installed_pkgs=set(self.packages)
        )
        event.needs_reboot(reboot_required)
        return reboot_required

    @property
    @abc.abstractmethod
    def repo_key_file(self) -> str:
        pass

    def _perform_enable(self, silent: bool = False) -> bool:
        """Enable specific entitlement.

        @return: True on success, False otherwise.
        @raises: UserFacingError on failure to install suggested packages
        """
        self.setup_apt_config(silent=silent)

        if self.supports_access_only and self.access_only:
            packages_str = (
                ": " + " ".join(self.packages)
                if len(self.packages) > 0
                else ""
            )
            event.info("Skipping installing packages{}".format(packages_str))
            event.info(messages.ACCESS_ENABLED_TMPL.format(title=self.title))
        else:
            self.install_packages()
            event.info(messages.ENABLED_TMPL.format(title=self.title))
            self._check_for_reboot_msg(operation="install")
        return True

    def _perform_disable(self, silent=False):
        if hasattr(self, "remove_packages"):
            self.remove_packages()
        self.remove_apt_config(silent=silent)
        return True

    def application_status(
        self,
    ) -> Tuple[ApplicationStatus, Optional[messages.NamedMessage]]:
        entitlement_cfg = self.cfg.machine_token_file.entitlements.get(
            self.name, {}
        )
        directives = entitlement_cfg.get("entitlement", {}).get(
            "directives", {}
        )
        repo_url = directives.get("aptURL")
        if not repo_url:
            return (
                ApplicationStatus.DISABLED,
                messages.NO_APT_URL_FOR_SERVICE.format(title=self.title),
            )
        policy = apt.get_apt_cache_policy(
            error_msg=messages.APT_POLICY_FAILED.msg
        )
        match = re.search(r"{}/ubuntu".format(repo_url), policy)
        if match:
            return (
                ApplicationStatus.ENABLED,
                messages.SERVICE_IS_ACTIVE.format(title=self.title),
            )
        return (
            ApplicationStatus.DISABLED,
            messages.SERVICE_NOT_CONFIGURED.format(title=self.title),
        )

    def _check_apt_url_is_applied(self, apt_url):
        """Check if apt url delta should be applied.

        :param apt_url: string containing the apt url to be used.

        :return: False if apt url is already found on the source file.
                 True otherwise.
        """
        apt_file = self.repo_list_file_tmpl.format(name=self.name)
        # If the apt file is commented out, we will assume that we need
        # to regenerate the apt file, regardless of the apt url delta
        if all(
            line.startswith("#")
            for line in system.load_file(apt_file).strip().split("\n")
        ):
            return False

        # If the file is not commented out and we don't have delta,
        # we will not do anything
        if not apt_url:
            return True

        # If the delta is already in the file, we won't reconfigure it
        # again
        return bool(apt_url in system.load_file(apt_file))

    def process_contract_deltas(
        self,
        orig_access: Dict[str, Any],
        deltas: Dict[str, Any],
        allow_enable: bool = False,
    ) -> bool:
        """Process any contract access deltas for this entitlement.

        :param orig_access: Dictionary containing the original
            resourceEntitlement access details.
        :param deltas: Dictionary which contains only the changed access keys
        and values.
        :param allow_enable: Boolean set True if allowed to perform the enable
            operation. When False, a message will be logged to inform the user
            about the recommended enabled service.

        :return: True when delta operations are processed; False when noop.
        """
        if super().process_contract_deltas(orig_access, deltas, allow_enable):
            return True  # Already processed parent class deltas

        delta_entitlement = deltas.get("entitlement", {})
        delta_directives = delta_entitlement.get("directives", {})
        delta_apt_url = delta_directives.get("aptURL")
        delta_packages = delta_directives.get("additionalPackages")
        status_cache = self.cfg.read_cache("status-cache")

        if delta_directives and status_cache:
            application_status = self._check_application_status_on_cache()
        else:
            application_status, _ = self.application_status()

        if application_status == ApplicationStatus.DISABLED:
            return False

        if not self._check_apt_url_is_applied(delta_apt_url):
            logging.info(
                "Updating '%s' apt sources list on changed directives.",
                self.name,
            )

            orig_entitlement = orig_access.get("entitlement", {})
            old_url = orig_entitlement.get("directives", {}).get("aptURL")
            if old_url:
                # Remove original aptURL and auth and rewrite
                repo_filename = self.repo_list_file_tmpl.format(name=self.name)
                apt.remove_auth_apt_repo(repo_filename, old_url)

            self.remove_apt_config()
            self.setup_apt_config()

        if delta_packages:
            logging.info(
                "Installing packages on changed directives: {}".format(
                    ", ".join(delta_packages)
                )
            )
            self.install_packages(package_list=delta_packages)

        return True

    def install_packages(
        self,
        package_list: Optional[List[str]] = None,
        cleanup_on_failure: bool = True,
        verbose: bool = True,
    ) -> None:
        """Install contract recommended packages for the entitlement.

        :param package_list: Optional package list to use instead of
            self.packages.
        :param cleanup_on_failure: Cleanup apt files if apt install fails.
        :param verbose: If true, print messages to stdout
        """

        if not package_list:
            package_list = self.packages

        if not package_list:
            return

        msg_ops = self.messaging.get("pre_install", [])
        if not util.handle_message_operations(msg_ops):
            return

        if verbose:
            event.info("Installing {title} packages".format(title=self.title))

        if self.apt_noninteractive:
            env = {"DEBIAN_FRONTEND": "noninteractive"}
            apt_options = [
                "--allow-downgrades",
                '-o Dpkg::Options::="--force-confdef"',
                '-o Dpkg::Options::="--force-confold"',
            ]
        else:
            env = {}
            apt_options = []

        try:
            msg = messages.ENABLED_FAILED.format(title=self.title)
            apt.run_apt_install_command(
                packages=package_list,
                apt_options=apt_options,
                error_msg=msg.msg,
                env=env,
            )
        except exceptions.UserFacingError:
            if cleanup_on_failure:
                self.remove_apt_config()
            raise

    def setup_apt_config(self, silent: bool = False) -> None:
        """Setup apt config based on the resourceToken and directives.
        Also sets up apt proxy if necessary.

        :raise UserFacingError: on failure to setup any aspect of this apt
           configuration
        """
        http_proxy = None  # type: Optional[str]
        https_proxy = None  # type: Optional[str]
        scope = None  # type: Optional[apt.AptProxyScope]
        if self.cfg.global_apt_http_proxy or self.cfg.global_apt_https_proxy:
            http_proxy = util.validate_proxy(
                "http",
                self.cfg.global_apt_http_proxy,
                util.PROXY_VALIDATION_APT_HTTP_URL,
            )
            https_proxy = util.validate_proxy(
                "https",
                self.cfg.global_apt_https_proxy,
                util.PROXY_VALIDATION_APT_HTTPS_URL,
            )
            scope = apt.AptProxyScope.GLOBAL
        elif self.cfg.ua_apt_http_proxy or self.cfg.ua_apt_https_proxy:
            http_proxy = util.validate_proxy(
                "http",
                self.cfg.ua_apt_http_proxy,
                util.PROXY_VALIDATION_APT_HTTP_URL,
            )
            https_proxy = util.validate_proxy(
                "https",
                self.cfg.ua_apt_https_proxy,
                util.PROXY_VALIDATION_APT_HTTPS_URL,
            )
            scope = apt.AptProxyScope.UACLIENT

        apt.setup_apt_proxy(
            http_proxy=http_proxy, https_proxy=https_proxy, proxy_scope=scope
        )
        repo_filename = self.repo_list_file_tmpl.format(name=self.name)
        resource_cfg = self.cfg.machine_token_file.entitlements.get(self.name)
        directives = resource_cfg["entitlement"].get("directives", {})
        obligations = resource_cfg["entitlement"].get("obligations", {})
        token = resource_cfg.get("resourceToken")
        if not token:
            machine_token = self.cfg.machine_token["machineToken"]
            if not obligations.get("enableByDefault"):
                # services that are not enableByDefault need to obtain specific
                # resource access for tokens. We want to refresh this every
                # enable call because it is not refreshed by `pro refresh`.
                client = contract.UAContractClient(self.cfg)
                machine_access = client.request_resource_machine_access(
                    machine_token, self.name
                )
                if machine_access:
                    token = machine_access.get("resourceToken")
            if not token:
                token = machine_token
                logging.warning(
                    "No resourceToken present in contract for service %s."
                    " Using machine token as credentials",
                    self.title,
                )
        aptKey = directives.get("aptKey")
        if not aptKey:
            raise exceptions.UserFacingError(
                "Ubuntu Pro server provided no aptKey directive for"
                " {}.".format(self.name)
            )
        repo_url = directives.get("aptURL")
        if not repo_url:
            raise exceptions.MissingAptURLDirective(self.name)
        repo_suites = directives.get("suites")
        if not repo_suites:
            raise exceptions.UserFacingError(
                "Empty {} apt suites directive from {}".format(
                    self.name, self.cfg.contract_url
                )
            )
        if self.repo_pin_priority:
            if not self.origin:
                raise exceptions.UserFacingError(
                    "Cannot setup apt pin. Empty apt repo origin value '{}'.\n"
                    "{}".format(
                        self.origin,
                        messages.ENABLED_FAILED.format(title=self.title).msg,
                    )
                )
            repo_pref_file = self.repo_pref_file_tmpl.format(name=self.name)
            apt.add_ppa_pinning(
                repo_pref_file,
                repo_url,
                self.origin,
                self.repo_pin_priority,
            )

        prerequisite_pkgs = []
        if not exists(apt.APT_METHOD_HTTPS_FILE):
            prerequisite_pkgs.append("apt-transport-https")
        if not exists(apt.CA_CERTIFICATES_FILE):
            prerequisite_pkgs.append("ca-certificates")

        if prerequisite_pkgs:
            if not silent:
                event.info(
                    "Installing prerequisites: {}".format(
                        ", ".join(prerequisite_pkgs)
                    )
                )
            try:
                apt.run_apt_install_command(packages=prerequisite_pkgs)
            except exceptions.UserFacingError:
                self.remove_apt_config()
                raise
        apt.add_auth_apt_repo(
            repo_filename, repo_url, token, repo_suites, self.repo_key_file
        )
        # Run apt-update on any repo-entitlement enable because the machine
        # probably wants access to the repo that was just enabled.
        # Side-effect is that apt policy will now report the repo as accessible
        # which allows pro status to report correct info
        if not silent:
            event.info(messages.APT_UPDATING_LISTS)
        try:
            apt.run_apt_update_command()
        except exceptions.UserFacingError:
            self.remove_apt_config(run_apt_update=False)
            raise

    def remove_apt_config(
        self, run_apt_update: bool = True, silent: bool = False
    ):
        """Remove any repository apt configuration files.

        :param run_apt_update: If after removing the apt update
            command after removing the apt files.
        """
        series = system.get_platform_info()["series"]
        repo_filename = self.repo_list_file_tmpl.format(name=self.name)
        entitlement = self.cfg.machine_token_file.entitlements[self.name].get(
            "entitlement", {}
        )
        access_directives = entitlement.get("directives", {})
        repo_url = access_directives.get("aptURL")
        if not repo_url:
            raise exceptions.MissingAptURLDirective(self.name)

        apt.remove_auth_apt_repo(repo_filename, repo_url, self.repo_key_file)
        apt.remove_apt_list_files(repo_url, series)

        if self.repo_pin_priority:
            repo_pref_file = self.repo_pref_file_tmpl.format(name=self.name)
            system.ensure_file_absent(repo_pref_file)

        if run_apt_update:
            if not silent:
                event.info(messages.APT_UPDATING_LISTS)
            apt.run_apt_update_command()
