# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
# All Rights Reserved. See LICENSE file for details.

from os.path import isfile, join, relpath, exists, isdir, realpath
from glob import glob
from fnmatch import fnmatchcase
from collections import Iterable

from tfw import TriggerlessEventHandler
from tfw.config.logs import logging
from .directory_monitor import DirectoryMonitor

LOG = logging.getLogger(__name__)


class FileManager:  # pylint: disable=too-many-instance-attributes
    def __init__(self, working_directory, allowed_directories, selected_file=None, exclude=None):
        self._exclude, self.exclude = None, exclude
        self._allowed_directories, self.allowed_directories = None, allowed_directories
        self._workdir, self.workdir = None, working_directory
        self._filename, self.filename = None, selected_file or self.files[0]

    @property
    def exclude(self):
        return self._exclude

    @exclude.setter
    def exclude(self, exclude):
        if exclude is None:
            return
        if not isinstance(exclude, Iterable):
            raise TypeError('Exclude must be Iterable!')
        self._exclude = exclude

    @property
    def workdir(self):
        return self._workdir

    @workdir.setter
    def workdir(self, directory):
        if not exists(directory) or not isdir(directory):
            raise EnvironmentError('"{}" is not a directory!'.format(directory))
        if not self._is_whitelisted(directory):
            raise EnvironmentError('Directory "{}" is not in whitelist!'.format(directory))
        self._workdir = directory

    @property
    def allowed_directories(self):
        return self._allowed_directories

    @allowed_directories.setter
    def allowed_directories(self, directories):
        self._allowed_directories = directories

    @property
    def filename(self):
        return self._filename

    @filename.setter
    def filename(self, filename):
        if not filename in self.files:
            raise EnvironmentError('No such file in workdir!')
        self._filename = filename

    @property
    def files(self):
        return [self._relpath(file) for file in glob(join(self._workdir, '**/*'), recursive=True)
                if isfile(file)
                    and self._is_whitelisted(file)
                    and not any(fnmatchcase(file, blacklisted) for blacklisted in self.exclude)]

    @property
    def file_contents(self):
        with open(self._filepath(self.filename), 'r', errors='surrogateescape') as ifile:
            return ifile.read()

    @file_contents.setter
    def file_contents(self, value):
        with open(self._filepath(self.filename), 'w', errors='surrogateescape') as ofile:
            ofile.write(value)

    def _is_whitelisted(self, file):
        return any(realpath(file).startswith(allowed_dir) for allowed_dir in self.allowed_directories)

    def _filepath(self, filename):
        return join(self._workdir, filename)

    def _relpath(self, filename):
        return relpath(self._filepath(filename), start=self._workdir)


class SourceCodeEventHandler(TriggerlessEventHandler):
    # pylint: disable=too-many-arguments
    def __init__(self, key, directory, allowed_directories, selected_file=None, exclude=None):
        super().__init__(key)
        self.filemanager = FileManager(allowed_directories=allowed_directories, working_directory=directory,
                                       selected_file=selected_file, exclude=exclude)

        self.commands = {'read':      self.read,
                         'write':     self.write,
                         'select':    self.select,
                         'selectdir': self.select_dir,
                         'exclude':   self.exclude}

        self._monitor = None
        self.reload_monitor()

    @property
    def monitor(self):
        return self._monitor

    def reload_monitor(self):
        if self._monitor:
            try:
                self._monitor.stop()
            except KeyError:
                logging.debug('Working directory was removed – ignoring...')
        self._monitor = DirectoryMonitor(self.filemanager.workdir)
        self._monitor.watch()   # This runs on a separate thread

    def read(self, data):
        try:
            data['content'] = self.filemanager.file_contents
        except PermissionError:
            data['content'] = 'You have no permission to open that file :('
        except FileNotFoundError:
            data['content'] = 'This file was removed :('
        except Exception: # pylint: disable=broad-except
            data['content'] = 'Failed to read file :('
        return data

    def write(self, data):
        self.monitor.ignore = self.monitor.ignore + 1
        try:
            self.filemanager.file_contents = data['content']
        except Exception: # pylint: disable=broad-except
            LOG.exception('Error writing file!')
        del data['content']
        return data

    def select(self, data):
        try:
            self.filemanager.filename = data['filename']
        except EnvironmentError:
            LOG.exception('Failed to select file "%s"', data['filename'])
        return data

    def select_dir(self, data):
        try:
            self.filemanager.workdir = data['directory']
            self.reload_monitor()
            try:
                self.filemanager.filename = self.filemanager.files[0]
                self.read(data)
            except IndexError:
                data['content'] = 'No files in this directory :('
        except EnvironmentError as err:
            LOG.error('Failed to select directory "%s". Reason: %s', data['directory'], str(err))
        return data

    def exclude(self, data):
        try:
            self.filemanager.exclude = list(data['exclude'])
        except TypeError:
            LOG.error('Exclude must be Iterable!')
        return data

    def attach_fileinfo(self, data):
        data['filename'] = self.filemanager.filename
        data['files'] = self.filemanager.files
        data['directory'] = self.filemanager.workdir

    def handle_event(self, key, message):
        try:
            data = message['data']
            message['data'] = self.commands[data['command']](data)
            self.attach_fileinfo(data)
            return message
        except KeyError:
            LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)

    def cleanup(self):
        self.monitor.stop()