# This file is a part of sedbgmux, an open source DebugMux client.
# Copyright (c) 2023  Vadim Yanitskiy <fixeria@osmocom.org>
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU 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
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

import logging
import threading
import queue
import re

from typing import NewType, List, Tuple

from . import DbgMuxConnHandler
from . import DbgMuxConnState

# local logger for this module
log = logging.getLogger(__name__)

# a directory item type
DirItem = NewType('DirItem', Tuple[str, str])


class DbgMuxConnWalker(DbgMuxConnHandler):
    ''' A tool to build a hierarchy of 'Interactive Debug' DPs '''

    line_pattern = re.compile(r'^(\S+)\s+([<(]\S+[>)])')

    def __init__(self):
        super().__init__()
        self._connected = threading.Event()

    def _conn_established(self) -> None:
        ''' Called when a connection has been established '''
        self._connected.set()

    def _conn_terminated(self) -> None:
        ''' Called when a connection has been terminated '''
        self._connected.clear()

    def send_cmd(self, cmd: str) -> None:
        ''' Send a command '''
        self.send_data(cmd.encode() + b'\r')

    def read_rsp(self) -> List[str]:
        ''' Receive a response, return a list of (not empty) lines '''
        data: bytes = b''
        while self._connected.is_set():
            try:
                data += self._rx_data_queue.get(block=True, timeout=0.2)
                self._rx_data_queue.task_done()
            except queue.Empty:
                break
        rsp = data.decode('ascii').split('\r\n')
        return [l for l in rsp if l != '']

    def do_chdir(self, dirname: str) -> None:
        ''' List current directory contents '''
        self.send_cmd(f'cd {dirname}')
        self.read_rsp() # unused

    def do_list(self) -> List[DirItem]:
        ''' List current directory contents '''
        self.send_cmd('ls')
        rsp = self.read_rsp()
        items = []
        for line in rsp:
            m = self.line_pattern.match(line)
            if m is None:
                continue
            items.append(m.groups())
        return items

    def walk_dir(self, path: str = '') -> List[DirItem]:
        items: List[DirItem] = self.do_list()
        for item_name, item_type in items:
            print(f'{item_type}\t{path}/{item_name}')
            if item_type == '<DIR>':
                self.do_chdir(item_name)
                self.walk_dir(f'{path}/{item_name}')
                self.do_chdir('..')

    def walk(self) -> None:
        if not self._connected.wait(0.5):
            log.error('Connection is not established (yet?)')
            return
        # read the welcome message and prompt
        self.read_rsp()
        # get listing of the root directory
        self.do_chdir('/')
        self.walk_dir()