# -*- coding: utf-8 -*-
"""
OnionShare | https://onionshare.org/

Copyright (C) 2014-2021 Micah Lee, et al. <micah@micahflee.com>

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 base64
import hashlib
import os
import platform
import random
import socket
import sys
import threading
import time
import shutil
from pkg_resources import resource_filename

from .settings import Settings


class CannotFindTor(Exception):
    """
    OnionShare can't find a tor binary
    """


class Common:
    """
    The Common object is shared amongst all parts of OnionShare.
    """

    def __init__(self, verbose=False):
        self.verbose = verbose

        # The platform OnionShare is running on
        self.platform = platform.system()
        if self.platform.endswith("BSD") or self.platform == "DragonFly":
            self.platform = "BSD"

        # The current version of OnionShare
        with open(self.get_resource_path("version.txt")) as f:
            self.version = f.read().strip()

    def load_settings(self, config=None):
        """
        Loading settings, optionally from a custom config json file.
        """
        self.settings = Settings(self, config)
        self.settings.load()

    def log(self, module, func, msg=None):
        """
        If verbose mode is on, log error messages to stdout
        """
        if self.verbose:
            timestamp = time.strftime("%b %d %Y %X")

            final_msg = f"[{timestamp}] {module}.{func}"
            if msg:
                final_msg = f"{final_msg}: {msg}"
            print(final_msg)

    def get_resource_path(self, filename):
        """
        Returns the absolute path of a resource
        """
        self.log("Common", "get_resource_path", f"filename={filename}")
        path = resource_filename("onionshare_cli", os.path.join("resources", filename))
        self.log("Common", "get_resource_path", f"filename={filename}, path={path}")
        return path

    def get_tor_paths(self):
        if self.platform == "Linux":
            tor_path = shutil.which("tor")
            if not tor_path:
                raise CannotFindTor()
            obfs4proxy_file_path = shutil.which("obfs4proxy")
            prefix = os.path.dirname(os.path.dirname(tor_path))
            tor_geo_ip_file_path = os.path.join(prefix, "share/tor/geoip")
            tor_geo_ipv6_file_path = os.path.join(prefix, "share/tor/geoip6")
        elif self.platform == "Windows":
            base_path = self.get_resource_path("tor")
            tor_path = os.path.join(base_path, "Tor", "tor.exe")
            obfs4proxy_file_path = os.path.join(base_path, "Tor", "obfs4proxy.exe")
            tor_geo_ip_file_path = os.path.join(base_path, "Data", "Tor", "geoip")
            tor_geo_ipv6_file_path = os.path.join(base_path, "Data", "Tor", "geoip6")
        elif self.platform == "Darwin":
            tor_path = shutil.which("tor")
            if not tor_path:
                raise CannotFindTor()
            obfs4proxy_file_path = shutil.which("obfs4proxy")
            prefix = os.path.dirname(os.path.dirname(tor_path))
            tor_geo_ip_file_path = os.path.join(prefix, "share/tor/geoip")
            tor_geo_ipv6_file_path = os.path.join(prefix, "share/tor/geoip6")
        elif self.platform == "BSD":
            tor_path = "/usr/local/bin/tor"
            tor_geo_ip_file_path = "/usr/local/share/tor/geoip"
            tor_geo_ipv6_file_path = "/usr/local/share/tor/geoip6"
            obfs4proxy_file_path = "/usr/local/bin/obfs4proxy"

        return (
            tor_path,
            tor_geo_ip_file_path,
            tor_geo_ipv6_file_path,
            obfs4proxy_file_path,
        )

    def build_data_dir(self):
        """
        Returns the path of the OnionShare data directory.
        """
        if self.platform == "Windows":
            try:
                appdata = os.environ["APPDATA"]
                onionshare_data_dir = f"{appdata}\\OnionShare"
            except:
                # If for some reason we don't have the 'APPDATA' environment variable
                # (like running tests in Linux while pretending to be in Windows)
                onionshare_data_dir = os.path.expanduser("~/.config/onionshare")
        elif self.platform == "Darwin":
            onionshare_data_dir = os.path.expanduser(
                "~/Library/Application Support/OnionShare"
            )
        else:
            onionshare_data_dir = os.path.expanduser("~/.config/onionshare")

        # Modify the data dir if running tests
        if getattr(sys, "onionshare_test_mode", False):
            onionshare_data_dir += "-testdata"

        os.makedirs(onionshare_data_dir, 0o700, True)
        return onionshare_data_dir

    def build_tmp_dir(self):
        """
        Returns path to a folder that can hold temporary files
        """
        tmp_dir = os.path.join(self.build_data_dir(), "tmp")
        os.makedirs(tmp_dir, 0o700, True)
        return tmp_dir

    def build_persistent_dir(self):
        """
        Returns the path to the folder that holds persistent files
        """
        persistent_dir = os.path.join(self.build_data_dir(), "persistent")
        os.makedirs(persistent_dir, 0o700, True)
        return persistent_dir

    def build_tor_dir(self):
        """
        Returns path to the tor data directory
        """
        tor_dir = os.path.join(self.build_data_dir(), "tor_data")
        os.makedirs(tor_dir, 0o700, True)
        return tor_dir

    def build_password(self, word_count=2):
        """
        Returns a random string made of words from the wordlist, such as "deter-trig".
        """
        with open(self.get_resource_path("wordlist.txt")) as f:
            wordlist = f.read().split()

        r = random.SystemRandom()
        return "-".join(r.choice(wordlist) for _ in range(word_count))

    def build_username(self, word_count=2):
        """
        Returns a random string made of words from the wordlist, such as "deter-trig".
        """
        with open(self.get_resource_path("wordlist.txt")) as f:
            wordlist = f.read().split()

        r = random.SystemRandom()
        return "-".join(r.choice(wordlist) for _ in range(word_count))

    @staticmethod
    def random_string(num_bytes, output_len=None):
        """
        Returns a random string with a specified number of bytes.
        """
        b = os.urandom(num_bytes)
        h = hashlib.sha256(b).digest()[:16]
        s = base64.b32encode(h).lower().replace(b"=", b"").decode("utf-8")
        if not output_len:
            return s
        return s[:output_len]

    @staticmethod
    def human_readable_filesize(b):
        """
        Returns filesize in a human readable format.
        """
        thresh = 1024.0
        if b < thresh:
            return "{:.1f} B".format(b)
        units = ("KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB")
        u = 0
        b /= thresh
        while b >= thresh:
            b /= thresh
            u += 1
        return "{:.1f} {}".format(b, units[u])

    @staticmethod
    def format_seconds(seconds):
        """Return a human-readable string of the format 1d2h3m4s"""
        days, seconds = divmod(seconds, 86400)
        hours, seconds = divmod(seconds, 3600)
        minutes, seconds = divmod(seconds, 60)

        human_readable = []
        if days:
            human_readable.append("{:.0f}d".format(days))
        if hours:
            human_readable.append("{:.0f}h".format(hours))
        if minutes:
            human_readable.append("{:.0f}m".format(minutes))
        if seconds or not human_readable:
            human_readable.append("{:.0f}s".format(seconds))
        return "".join(human_readable)

    @staticmethod
    def estimated_time_remaining(bytes_downloaded, total_bytes, started):
        now = time.time()
        time_elapsed = now - started  # in seconds
        download_rate = bytes_downloaded / time_elapsed
        remaining_bytes = total_bytes - bytes_downloaded
        eta = remaining_bytes / download_rate
        return Common.format_seconds(eta)

    @staticmethod
    def get_available_port(min_port, max_port):
        """
        Find a random available port within the given range.
        """
        with socket.socket() as tmpsock:
            while True:
                try:
                    tmpsock.bind(("127.0.0.1", random.randint(min_port, max_port)))
                    break
                except OSError as e:
                    pass
            _, port = tmpsock.getsockname()
        return port

    @staticmethod
    def dir_size(start_path):
        """
        Calculates the total size, in bytes, of all of the files in a directory.
        """
        total_size = 0
        for dirpath, dirnames, filenames in os.walk(start_path):
            for f in filenames:
                fp = os.path.join(dirpath, f)
                if not os.path.islink(fp):
                    total_size += os.path.getsize(fp)
        return total_size


class AutoStopTimer(threading.Thread):
    """
    Background thread sleeps t hours and returns.
    """

    def __init__(self, common, time):
        threading.Thread.__init__(self)

        self.common = common

        self.setDaemon(True)
        self.time = time

    def run(self):
        self.common.log(
            "AutoStopTimer", f"Server will shut down after {self.time} seconds"
        )
        time.sleep(self.time)
        return 1