"""Manage Network Application files."""
import json
import logging
import os
import pathlib
import re
import sys
import tarfile
import urllib
from http import HTTPStatus

# Disable pylint import checks that conflict with isort
# pylint: disable=ungrouped-imports,wrong-import-order
import pathspec
from jinja2 import Environment, FileSystemLoader
from ruamel.yaml import YAML

from kytos.utils.client import NAppsClient
from kytos.utils.config import KytosConfig
from kytos.utils.exceptions import KytosException
from kytos.utils.openapi import OpenAPI
from kytos.utils.settings import SKEL_PATH

LOG = logging.getLogger(__name__)


# pylint: disable=too-many-instance-attributes,too-many-public-methods
class NAppsManager:
    """Deal with NApps at filesystem level and ask Kytos to (un)load NApps."""

    _NAPP_ENABLE = "api/kytos/core/napps/{}/{}/enable"
    _NAPP_DISABLE = "api/kytos/core/napps/{}/{}/disable"
    _NAPP_INSTALL = "api/kytos/core/napps/{}/{}/install"
    _NAPP_UNINSTALL = "api/kytos/core/napps/{}/{}/uninstall"
    _NAPPS_INSTALLED = "api/kytos/core/napps_installed"
    _NAPPS_ENABLED = "api/kytos/core/napps_enabled"
    _NAPP_METADATA = "api/kytos/core/napps/{}/{}/metadata/{}"

    def __init__(self):
        """Instance a new NAppsManager.

        This method do not need parameters.
        """
        self._config = KytosConfig().config
        self._kytos_api = self._config.get('kytos', 'api')

        self.user = None
        self.napp = None
        self.version = None

        # Automatically get from kytosd API when needed
        self.__local_enabled = None
        self.__local_installed = None

    @property
    def _enabled(self):
        if self.__local_enabled is None:
            self.__require_kytos_config()
        return self.__local_enabled

    @property
    def _installed(self):
        if self.__local_installed is None:
            self.__require_kytos_config()
        return self.__local_installed

    def __require_kytos_config(self):
        """Set path locations from kytosd API.

        It should not be called directly, but from properties that require a
        running kytosd instance.
        """
        if self.__local_enabled is None:
            uri = self._kytos_api + 'api/kytos/core/config/'
            try:
                ops = json.loads(urllib.request.urlopen(uri).read())
            except urllib.error.URLError as err:
                msg = f'Error connecting to Kytos daemon: {uri} {err.reason}'
                print(msg)
                sys.exit(1)
            self.__local_enabled = pathlib.Path(ops.get('napps'))
            self.__local_installed = pathlib.Path(ops.get('installed_napps'))

    def set_napp(self, user, napp, version=None):
        """Set info about NApp.

        Args:
            user (str): NApps Server username.
            napp (str): NApp name.
            version (str): NApp version.

        """
        self.user = user
        self.napp = napp
        self.version = version or 'latest'

    @property
    def napp_id(self):
        """Return a Identifier of NApp."""
        return '/'.join((self.user, self.napp))

    @staticmethod
    def _get_napps(napps_dir):
        """List of (username, napp_name) found in ``napps_dir``.

        Ex: [('kytos', 'of_core'), ('kytos', 'of_lldp')]
        """
        jsons = napps_dir.glob('*/*/kytos.json')
        return sorted(j.parts[-3:-1] for j in jsons)

    def get_enabled_local(self):
        """Sorted list of (username, napp_name) of enabled napps."""
        return self._get_napps(self._enabled)

    def get_installed_local(self):
        """Sorted list of (username, napp_name) of installed napps."""
        return self._get_napps(self._installed)

    def get_enabled(self):
        """Sorted list of (username, napp_name) of enabled napps."""
        uri = self._kytos_api + self._NAPPS_ENABLED

        try:
            response = urllib.request.urlopen(uri)
            if response.getcode() != 200:
                msg = "Error calling Kytos to check enabled NApps."
                raise KytosException(msg)

            content = json.loads(response.read())
            return sorted((c[0], c[1]) for c in content['napps'])
        except urllib.error.URLError as exception:
            LOG.error("Error checking installed NApps. Is Kytos running?")
            raise KytosException(exception)

    def get_installed(self):
        """Sorted list of (username, napp_name) of installed napps."""
        uri = self._kytos_api + self._NAPPS_INSTALLED

        try:
            response = urllib.request.urlopen(uri)
            if response.getcode() != 200:
                msg = "Error calling Kytos to check installed NApps."
                raise KytosException(msg)

            content = json.loads(response.read())
            return sorted((c[0], c[1]) for c in content['napps'])
        except urllib.error.URLError as exception:
            LOG.error("Error checking installed NApps. Is Kytos running?")
            raise KytosException(exception)

    def is_installed(self):
        """Whether a NApp is installed."""
        return (self.user, self.napp) in self.get_installed()

    def get_disabled(self):
        """Sorted list of (username, napp_name) of disabled napps.

        The difference of installed and enabled.
        """
        installed = set(self.get_installed())
        enabled = set(self.get_enabled())
        return sorted(installed - enabled)

    def dependencies(self, user=None, napp=None):
        """Get napp_dependencies from install NApp.

        Args:
            user(string)  A Username.
            napp(string): A NApp name.
        Returns:
            napps(list): List with tuples with Username and NApp name.
                         e.g. [('kytos'/'of_core'), ('kytos/of_l2ls')]

        """
        napps = self._get_napp_key('napp_dependencies', user, napp)
        return [tuple(napp.split('/')) for napp in napps]

    def get_description(self, user=None, napp=None):
        """Return the description from kytos.json."""
        return self._get_napp_key('description', user, napp)

    def get_version(self, user=None, napp=None):
        """Return the version from kytos.json."""
        return self._get_napp_key('version', user, napp) or 'latest'

    def _get_napp_key(self, key, user=None, napp=None):
        """Return a value from kytos.json.

        Args:
            user (string): A Username.
            napp (string): A NApp name
            key (string): Key used to get the value within kytos.json.

        Returns:
            meta (object): Value stored in kytos.json.

        """
        if user is None:
            user = self.user
        if napp is None:
            napp = self.napp

        uri = self._kytos_api + self._NAPP_METADATA
        uri = uri.format(user, napp, key)

        meta = json.loads(urllib.request.urlopen(uri).read())
        return meta[key]

    def disable(self):
        """Disable a NApp if it is enabled."""
        uri = self._kytos_api + self._NAPP_DISABLE
        uri = uri.format(self.user, self.napp)

        try:
            json.loads(urllib.request.urlopen(uri).read())
        except urllib.error.HTTPError as exception:
            if exception.code == HTTPStatus.BAD_REQUEST.value:
                LOG.error("NApp is not installed. Check the NApp list.")
            else:
                LOG.error("Error disabling the NApp")

    def enable(self):
        """Enable a NApp if not already enabled."""
        uri = self._kytos_api + self._NAPP_ENABLE
        uri = uri.format(self.user, self.napp)

        try:
            json.loads(urllib.request.urlopen(uri).read())
        except urllib.error.HTTPError as exception:
            if exception.code == HTTPStatus.BAD_REQUEST.value:
                LOG.error("NApp is not installed. Check the NApp list.")
            else:
                LOG.error("Error enabling the NApp")

    def enabled_dir(self):
        """Return the enabled dir from current napp."""
        return self._enabled / self.user / self.napp

    def installed_dir(self):
        """Return the installed dir from current napp."""
        return self._installed / self.user / self.napp

    def is_enabled(self):
        """Whether a NApp is enabled."""
        return (self.user, self.napp) in self.get_enabled()

    def remote_uninstall(self):
        """Delete code inside NApp directory, if existent."""
        uri = self._kytos_api + self._NAPP_UNINSTALL
        uri = uri.format(self.user, self.napp)

        try:
            json.loads(urllib.request.urlopen(uri).read())
        except urllib.error.HTTPError as exception:
            if exception.code == HTTPStatus.BAD_REQUEST.value:
                LOG.error("Check if the NApp is installed.")
            else:
                LOG.error("Error uninstalling the NApp")

    @staticmethod
    def valid_name(username):
        """Check the validity of the given 'name'.

        The following checks are done:
        - name starts with a letter
        - name contains only letters, numbers or underscores
        """
        return username and re.match(r'[a-zA-Z][a-zA-Z0-9_]{2,}$', username)

    @staticmethod
    def render_template(templates_path, template_filename, context):
        """Render Jinja2 template for a NApp structure."""
        template_env = Environment(
            autoescape=False, trim_blocks=False,
            loader=FileSystemLoader(str(templates_path)))
        return template_env.get_template(str(template_filename)) \
            .render(context)

    @staticmethod
    def search(pattern):
        """Search all server NApps matching pattern.

        Args:
            pattern (str): Python regular expression.

        """
        def match(napp):
            """Whether a NApp metadata matches the pattern."""
            # WARNING: This will change for future versions, when 'author' will
            # be removed.
            username = napp.get('username', napp.get('author'))

            strings = ['{}/{}'.format(username, napp.get('name')),
                       napp.get('description')] + napp.get('tags')
            return any(pattern.match(string) for string in strings)

        napps = NAppsClient().get_napps()
        return [napp for napp in napps if match(napp)]

    def remote_install(self):
        """Ask kytos server to install NApp."""
        uri = self._kytos_api + self._NAPP_INSTALL
        uri = uri.format(self.user, self.napp)

        try:
            json.loads(urllib.request.urlopen(uri).read())
        except urllib.error.HTTPError as exception:
            if exception.code == HTTPStatus.BAD_REQUEST.value:
                LOG.error("NApp is not installed. Check the NApp list.")
            else:
                LOG.error("Error installing the NApp.")

    @classmethod
    def create_napp(cls, meta_package=False):
        """Bootstrap a basic NApp structure for you to develop your NApp.

        This will create, on the current folder, a clean structure of a NAPP,
        filling some contents on this structure.
        """
        templates_path = SKEL_PATH / 'napp-structure/username/napp'

        ui_templates_path = os.path.join(templates_path, 'ui')

        username = None
        napp_name = None

        print('--------------------------------------------------------------')
        print('Welcome to the bootstrap process of your NApp.')
        print('--------------------------------------------------------------')
        print('In order to answer both the username and the napp name,')
        print('You must follow this naming rules:')
        print(' - name starts with a letter')
        print(' - name contains only letters, numbers or underscores')
        print(' - at least three characters')
        print('--------------------------------------------------------------')
        print('')
        while not cls.valid_name(username):
            username = input('Please, insert your NApps Server username: ')

        while not cls.valid_name(napp_name):
            napp_name = input('Please, insert your NApp name: ')

        description = input('Please, insert a brief description for your'
                            'NApp [optional]: ')
        if not description:
            # pylint: disable=fixme
            description = '# TODO: <<<< Insert your NApp description here >>>>'
            # pylint: enable=fixme

        context = {'username': username, 'napp': napp_name,
                   'description': description}

        #: Creating the directory structure (username/napp_name)
        os.makedirs(username, exist_ok=True)

        #: Creating ``__init__.py`` files
        with open(os.path.join(username, '__init__.py'), 'w') as init_file:
            init_file.write(f'"""Napps for the user {username}.""""')

        os.makedirs(os.path.join(username, napp_name))

        #: Creating the other files based on the templates
        templates = os.listdir(templates_path)
        templates.remove('ui')
        templates.remove('openapi.yml.template')

        if meta_package:
            templates.remove('main.py.template')
            templates.remove('settings.py.template')

        for tmp in templates:
            fname = os.path.join(username, napp_name,
                                 tmp.rsplit('.template')[0])
            with open(fname, 'w') as file:
                content = cls.render_template(templates_path, tmp, context)
                file.write(content)

        if not meta_package:
            NAppsManager.create_ui_structure(username, napp_name,
                                             ui_templates_path, context)

        print()
        print(f'Congratulations! Your NApp has been bootstrapped!\nNow you '
              'can go to the directory {username}/{napp_name} and begin to '
              'code your NApp.')
        print('Have fun!')

    @classmethod
    def create_ui_structure(cls, username, napp_name, ui_templates_path,
                            context):
        """Create the ui directory structure."""
        for section in ['k-info-panel', 'k-toolbar', 'k-action-menu']:
            os.makedirs(os.path.join(username, napp_name, 'ui', section))

        templates = os.listdir(ui_templates_path)

        for tmp in templates:
            fname = os.path.join(username, napp_name, 'ui',
                                 tmp.rsplit('.template')[0])

            with open(fname, 'w') as file:
                content = cls.render_template(ui_templates_path, tmp,
                                              context)
                file.write(content)

    @staticmethod
    def _check_module(folder):
        """Create module folder with empty __init__.py if it doesn't exist.

        Args:
            folder (pathlib.pathlib.Path): Module path.

        """
        if not folder.exists():
            folder.mkdir(parents=True, exist_ok=True, mode=0o755)
            (folder / '__init__.py').touch()

    @staticmethod
    def build_napp_package(napp_name):
        """Build the .napp file to be sent to the napps server.

        Args:
            napp_identifier (str): Identifier formatted as
                <username>/<napp_name>

        Return:
            file_payload (binary): The binary representation of the napp
                package that will be POSTed to the napp server.

        """
        def get_matches(path):
            """Return all NApp files matching any .gitignore pattern."""
            ignored_files = [".git"]
            with open(".gitignore", 'r') as kytosignore:
                ignored_files.extend(kytosignore.readlines())

            # Define Wildmatch pattern (default gitignore pattern)
            pattern = pathspec.patterns.GitWildMatchPattern
            spec = pathspec.PathSpec.from_lines(pattern, ignored_files)
            # Get tree containing all matching files
            match_tree = spec.match_tree(path)
            # Create list with all absolute paths of match tree
            return ["%s/%s" % (path, match) for match in match_tree]

        files = []
        path = os.getcwd()

        for dir_file in os.walk(path):
            dirname, _, arc = dir_file
            files.extend([os.path.join(dirname, f) for f in arc])

        # Allow the user to run `kytos napps upload` from outside the
        # napp directory.
        # Filter the files with the napp_name in their path
        # Example: home/user/napps/kytos/, napp_name = kronos
        # This filter will get all files from:
        # home/user/napps/kytos/kronos/*
        files = list(filter(lambda x: napp_name in x, files))

        matches = get_matches(path)

        for filename in files.copy():
            if filename in matches:
                files.remove(filename)

        # Create the '.napp' package
        napp_file = tarfile.open(napp_name + '.napp', 'x:xz')
        for local_f in files:
            # Add relative paths instead of absolute paths
            napp_file.add(pathlib.PurePosixPath(local_f).relative_to(path))
        napp_file.close()

        # Get the binary payload of the package
        file_payload = open(napp_name + '.napp', 'rb')

        # remove the created package from the filesystem
        os.remove(napp_name + '.napp')

        return file_payload

    @staticmethod
    def create_metadata(*args, **kwargs):  # pylint: disable=unused-argument
        """Generate the metadata to send the napp package."""
        json_filename = kwargs.get('json_filename', 'kytos.json')
        readme_filename = kwargs.get('readme_filename', 'README.rst')
        ignore_json = kwargs.get('ignore_json', False)
        metadata = {}

        if not ignore_json:
            try:
                with open(json_filename) as json_file:
                    metadata = json.load(json_file)
            except FileNotFoundError:
                print("ERROR: Could not access kytos.json file.")
                sys.exit(1)

        try:
            with open(readme_filename) as readme_file:
                metadata['readme'] = readme_file.read()
        except FileNotFoundError:
            metadata['readme'] = ''

        try:
            yaml = YAML(typ='safe')
            openapi_dict = yaml.load(pathlib.Path('openapi.yml').open())
            openapi = json.dumps(openapi_dict)
        except FileNotFoundError:
            openapi = ''
        metadata['OpenAPI_Spec'] = openapi

        return metadata

    def upload(self, *args, **kwargs):
        """Create package and upload it to NApps Server.

        Raises:
            FileNotFoundError: If kytos.json is not found.

        """
        self.prepare()
        metadata = self.create_metadata(*args, **kwargs)
        package = self.build_napp_package(metadata.get('name'))

        NAppsClient().upload_napp(metadata, package)

    def delete(self):
        """Delete a NApp.

        Raises:
            requests.HTTPError: When there's a server error.

        """
        client = NAppsClient(self._config)
        client.delete(self.user, self.napp)

    @classmethod
    def prepare(cls):
        """Prepare NApp to be uploaded by creating openAPI skeleton."""
        if cls._ask_openapi():
            napp_path = pathlib.Path()
            tpl_path = SKEL_PATH / 'napp-structure/username/napp'
            OpenAPI(napp_path, tpl_path).render_template()
            print('Please, update your openapi.yml file.')
            sys.exit()

    @staticmethod
    def _ask_openapi():
        """Return whether we should create a (new) skeleton."""
        if pathlib.Path('openapi.yml').exists():
            question = 'Override local openapi.yml with a new skeleton? (y/N) '
            default = False
        else:
            question = 'Do you have REST endpoints and wish to create an API' \
                ' skeleton in openapi.yml? (Y/n) '
            default = True

        while True:
            answer = input(question)
            if answer == '':
                return default
            if answer.lower() in ['y', 'yes']:
                return True
            if answer.lower() in ['n', 'no']:
                return False

    def reload(self, napps=None):
        """Reload a NApp or all NApps.

        Args:
            napps (list): NApp list to be reloaded.
        Raises:
            requests.HTTPError: When there's a server error.

        """
        client = NAppsClient(self._config)
        client.reload_napps(napps)


# pylint: enable=too-many-instance-attributes,too-many-public-methods