#! /usr/bin/env python
"""
adbfs Virtual filesystem for Midnight Commander

* Copyright (c) 2016, Roman Dobosz,
* Published under 3-clause BSD-style license (see LICENSE file)
"""

import ConfigParser
import argparse
from datetime import datetime
import errno
import json
import os
import re
import subprocess
import sys

__version__ = 0.9

XDG_CONFIG_HOME = os.getenv('XDG_CONFIG_HOME', os.path.expanduser('~/.config'))


class NoBoxFoundException(OSError):
    """
    Exception raised in case of not found either toolbox or busybox on remote
    filesystem accessed via adb
    """
    pass


class Conf(object):
    """Simple config parser"""
    boxes = {'busybox': {'ls': 'busybox ls -anel',
                         'rls':  'busybox ls -Ranel {}',
                         'file_re': r'^(?P<perms>[-bcdlps][-rwxsStT]{9})\s+'
                                    r'(?P<links>\d+)\s'
                                    r'(?P<uid>\d+)\s+'
                                    r'(?P<gid>\d+)\s+'
                                    r'(?P<size>\d+)\s[A-Z,a-z]{3}\s'
                                    r'(?P<date_time>[A-Z,a-z]{3}\s+'
                                    r'\d+\s\d{2}:\d{2}:\d{2}\s+\d{4})\s'
                                    r'(?P<name>.*)'},
             'toolbox': {'ls': 'toolbox ls -anl',
                         'rls':  'toolbox ls -Ranl {}',
                         'file_re': r'^(?P<perms>[-bcdlps][-rwxsStT]{9})\s+'
                                    r'(?P<uid>\d+)\s+'
                                    r'(?P<gid>\d+)\s+'
                                    r'(?P<size>\d+)?\s'
                                    r'(?P<date>\d{4}-\d{2}-\d{2}\s'
                                    r'\d{2}:\d{2})\s'
                                    r'(?P<name>.*)'}}

    def __init__(self):
        self.box = None
        self.debug = False
        self.dirs_to_skip = ['acct', 'charger', 'd', 'dev', 'proc', 'sys']
        self.root = None
        self.suppress_colors = False

        self.read()
        self.get_the_box()

    def get_the_box(self):
        """Detect if we dealing with busybox or toolbox"""
        try:
            with open(os.devnull, 'w') as fnull:
                result = subprocess.check_output('adb shell which '
                                                 'busybox'.split(),
                                                 stderr=fnull)
            if 'busybox' in result:
                self.box = Conf.boxes['busybox']
                if self.suppress_colors:
                    self.box.update({'ls': 'busybox ls --color=none -anel',
                                     'rls': 'busybox ls --color=none '
                                            '-Ranel {}'})
                Adb.file_re = re.compile(self.box['file_re'])
                return
        except subprocess.CalledProcessError:
            pass

        try:
            with open(os.devnull, 'w') as fnull:
                result = subprocess.check_output('adb shell which '
                                                 'toolbox'.split(),
                                                 stderr=fnull)

            if 'toolbox' in result:
                self.box = Conf.boxes['toolbox']
                Adb.file_re = re.compile(self.box['file_re'])
                return
        except subprocess.CalledProcessError:
            pass

        raise NoBoxFoundException(errno.ENOENT,
                                  'There is no toolbox or busybox available')

    def read(self):
        """
        Read config file and change the options according to values from that
        file.
        """
        if not os.path.exists(XDG_CONFIG_HOME):
            return

        conf_fname = os.path.join(XDG_CONFIG_HOME, 'mc', 'adbfs.ini')
        if not os.path.exists(conf_fname):
            return

        cfg = ConfigParser.SafeConfigParser()
        cfg_map = {'debug': (cfg.getboolean, 'debug'),
                   'dirs_to_skip': (cfg.get, 'dirs_to_skip'),
                   'suppress_colors': (cfg.get, 'suppress_colors'),
                   'root': (cfg.get, 'root')}
        cfg.read(conf_fname)

        for key, (function, attr) in cfg_map.items():
            try:
                setattr(self, attr, function('adbfs', key))
            except (ConfigParser.NoSectionError, ConfigParser.NoOptionError):
                pass

        if self.dirs_to_skip and isinstance(self.dirs_to_skip, str):
            self.dirs_to_skip = json.loads(self.dirs_to_skip, encoding='ascii')
            self.dirs_to_skip = [x.encode('utf-8') for x in self.dirs_to_skip]
        else:
            self.dirs_to_skip = []


class File(object):
    """Item in filesystem representation"""
    def __init__(self, perms=None, links=1, uid=0, gid=0, size=None,
                 date_time=None, date=None, name=None):
        """initialize file"""
        self.perms = perms
        self.links = links
        self.uid = uid
        self.gid = gid
        self.size = size if size else 0
        self.date_time = date_time  # as string
        self.name = name
        self.date = date  # as string

        self.dirname = ''
        self.type = None
        self.string = None
        self.link_target = None
        self.filepath = None

    def _correct_link(self):
        """Canonize filename and fill the link attr"""
        try:
            name, target = self.name.split(' -> ')
        except ValueError:
            return

        self.name = name

        if not self.size:
            self.size = 0

        if target.startswith('/'):
            self.link_target = target
        else:
            self.link_target = os.path.abspath(os.path.join(self.dirname,
                                                            target))

    def update(self, dirname):
        """update object fields"""
        month_num = {'Jan': 1,
                     'Feb': 2,
                     'Mar': 3,
                     'Apr': 4,
                     'May': 5,
                     'Jun': 6,
                     'Jul': 7,
                     'Aug': 8,
                     'Sep': 9,
                     'Oct': 10,
                     'Nov': 11,
                     'Dec': 12}
        self.dirname = dirname
        if self.date_time:
            date = self.date_time.split()
            date = '%s-%02d-%s %s' % (date[1],
                                      month_num[date[0]],
                                      date[3],
                                      date[2])
            date = datetime.strptime(date, '%d-%m-%Y %H:%M:%S')
        elif self.date:
            date = datetime.strptime(self.date, '%Y-%m-%d %H:%M')

        self.date_time = date.strftime('%m/%d/%Y %H:%M:01')

        self.type = self.perms[0] if self.perms else None

        if self.type == 'l' and ' -> ' in self.name:
            self._correct_link()

        self.filepath = os.path.join(self.dirname, self.name)

    def mk_link_relative(self):
        """Convert links to relative"""
        self.link_target = os.path.relpath(self.link_target, self.dirname)

    def __repr__(self):
        """represent the file/entire node"""
        fullname = os.path.join(self.dirname, self.name)
        if self.link_target:
            fullname += ' -> ' + self.link_target
        return '<File {type} {name} {id}>'.format(type=self.type,
                                                  name=fullname,
                                                  id=hex(id(self)))

    def __str__(self):
        """display the file/entire node"""
        template = ('{perms} {links:>4} {uid:<8} {gid:<8} {size:>8} '
                    '{date_time} {fullname}\n')

        if not self.name:
            return ''

        fullname = os.path.join(self.dirname, self.name)
        if self.link_target:
            fullname += ' -> ' + self.link_target

        return template.format(perms=self.perms,
                               links=self.links,
                               uid=self.uid,
                               gid=self.gid,
                               size=self.size,
                               date_time=self.date_time,
                               fullname=fullname)


class Adb(object):
    """Class for interact with android rooted device through adb"""
    file_re = None
    current_re = re.compile(r'^(\./)?(?P<dir>.+):$')

    def __init__(self):
        """Prepare archive content for operations"""
        super(Adb, self).__init__()
        self.conf = Conf()
        self.error = ''
        self._entries = []
        self._links = {}
        self._got_root = False

        self.__su_check()

    def __su_check(self):
        """Check if we are able to get elevated privileges"""
        try:
            with open(os.devnull, 'w') as fnull:
                result = subprocess.check_output('adb shell su -c '
                                                 'whoami'.split(),
                                                 stderr=fnull)

        except subprocess.CalledProcessError:
            return

        if 'root' in result:
            self._got_root = True

    def _find_target(self, needle):
        """Find link target"""

        if needle in self._links:
            elem = self._links[needle]
            target = os.path.abspath(os.path.join(elem.dirname,
                                                  elem.link_target))
            return self._find_target(target)

        for entry in self._entries:
            if entry.filepath == needle:
                return entry

        return None

    def _normalize_links(self):
        """
        There might be a case of a chain of linked files, like:

            /foo -> /mnt/foo
            /bar -> /foo

        If one want to follow such 'bar' link - MC in extfs mode will fail to
        figure out the right target. This helper will correct the thing.
        """
        elems_to_remove = []
        for entry in self._links.values():
            target_entry = self._find_target(entry.link_target)
            if target_entry:
                entry.link_target = target_entry.filepath
                entry.mk_link_relative()
            else:
                elems_to_remove.append(self._entries.index(entry))

        for idx in sorted(elems_to_remove, reverse=True):
            del self._entries[idx]

    def _retrieve_single_dir_list(self, dir_):
        """Retrieve file list using adb"""
        if self._got_root:
            command = ['adb', 'shell', 'su', '-c',
                       self.conf.box['rls'].format(dir_)]
        else:
            command = ['adb', 'shell']
            command += self.conf.box['rls'].format(dir_).split(' ')

        try:
            if self.conf.debug:
                print 'executing', ' '.join(command)

            lines = subprocess.check_output(command)
        except subprocess.CalledProcessError:
            sys.stderr.write('Cannot read directory. Is device connected?\n')
            return 1

        lines = [l.strip() for l in lines.split('\n') if l.strip()]
        if len(lines) == 1:
            reg_match = self.file_re.match(lines[0])
            entry = File(**reg_match.groupdict())
            entry.update('/')

            if entry.filepath in self.conf.dirs_to_skip:
                return

            self._entries.append(entry)
            if entry.type == 'l':
                self._links[entry.filepath] = entry
                self._retrieve_single_dir_list(entry.link_target)
        else:
            for line in lines:
                current_dir_re = self.current_re.match(line)
                if current_dir_re:
                    current_dir = current_dir_re.groupdict()['dir']
                    if not current_dir:
                        current_dir = '/'
                    continue

                reg_match = self.file_re.match(line)
                if not reg_match:
                    continue

                entry = File(**reg_match.groupdict())
                if entry.name in ('.', '..'):
                    continue

                entry.update(current_dir)

                if entry.filepath in self.conf.dirs_to_skip:
                    continue

                self._entries.append(entry)

                if entry.type == 'l':
                    self._links[entry.filepath] = entry

    def _retrieve_file_list(self, root=None):
        """Retrieve file list using adb"""

        if not root:
            lscmd = self.conf.box['ls']
        else:
            lscmd = self.conf.box['rls'].format(root.filepath)

        if self._got_root:
            command = ['adb', 'shell', 'su', '-c', lscmd]
        else:
            command = ['adb', 'shell'] + lscmd.split()

        try:
            if self.conf.debug:
                print 'executing', ' '.join(command)

            lines = subprocess.check_output(command)
        except subprocess.CalledProcessError:
            sys.stderr.write('Cannot read directory. Is device connected?\n')
            return 1

        current_dir = root.dirname if root else '/'
        for line in lines.split('\n'):
            line = line.strip()
            current_dir_re = self.current_re.match(line)
            if current_dir_re:
                current_dir = current_dir_re.groupdict()['dir']
                if not current_dir:
                    current_dir = '/'
                continue

            reg_match = self.file_re.match(line)
            if not reg_match:
                continue

            entry = File(**reg_match.groupdict())
            if entry.name in ('.', '..'):
                continue

            entry.update(current_dir)

            if entry.filepath in self.conf.dirs_to_skip:
                continue

            self._entries.append(entry)
            if root is None and entry.type == 'd':
                self._retrieve_file_list(entry)

            if entry.type == 'l':
                self._links[entry.filepath] = entry

    def run(self, fname):
        """Not supported"""
        sys.stderr.write('Not supported - or maybe you are on compatible '
                         'architecture?\n')
        return 1

    def list(self):
        """Output list contents directory"""
        if self.error:
            sys.stderr.write(self.error)
            return 1

        if self.conf.root:
            self._retrieve_single_dir_list(self.conf.root)
        else:
            self._retrieve_file_list()

        self._normalize_links()
        sys.stdout.write(''.join([str(entry) for entry in self._entries]))
        return 0

    def copyout(self, src, dst):
        """Copy file form the device using adb."""
        if self.error:
            sys.stderr.write(self.error)
            return 1

        cmd = ['adb', 'pull', src, dst]
        if self.conf.debug:
            sys.stderr.write(' '.join(cmd) + '\n')

        with open(os.devnull, 'w') as fnull:
            try:
                err = subprocess.call(cmd, stdout=fnull, stderr=fnull)
            except subprocess.CalledProcessError:
                sys.stderr.write('Error executing adb shell')
                return 1

        return err

    def copyin(self, src, dst):
        """Copy file to the device through adb."""
        if self.error:
            sys.stderr.write(self.error)
            return 1
        if not dst.startswith('/'):
            dst = '/' + dst

        cmd = ['adb', 'push', src, dst]
        if self.conf.debug:
            sys.stderr.write(' '.join(cmd) + '\n')

        with open(os.devnull, 'w') as fnull:
            try:
                err = subprocess.call(cmd, stdout=fnull, stderr=fnull)
            except subprocess.CalledProcessError:
                sys.stderr.write('Error executing adb shell')
                return 1

        if err != 0:
            sys.stderr.write('Cannot push the file, '
                             '%s, error %d' % (dst, err))
            return 1
        return 0

    def rm(self, dst):
        """Remove file from device."""
        if self.error:
            sys.stderr.write(self.error)
            return 1

        cmd = ['adb', 'shell', 'rm', dst]
        try:
            err = subprocess.check_output(cmd)
        except subprocess.CalledProcessError:
            sys.stderr.write('Error executing adb shell')
            return 1

        if err != '':
            sys.stderr.write(err)
            return 1
        return 0

    def rmdir(self, dst):
        """Remove directory from device."""
        if self.error:
            sys.stderr.write(self.error)
            return 1

        cmd = ['adb', 'shell', 'rm', '-r', dst]
        try:
            err = subprocess.check_output(cmd)
        except subprocess.CalledProcessError:
            sys.stderr.write('Error executing adb shell')
            return 1

        if err != '':
            sys.stderr.write(err)
            return 1
        return 0

    def mkdir(self, dst):
        """Make directory on the device through adb."""
        if self.error:
            sys.stderr.write(self.error)
            return 1

        if not dst.startswith('/'):
            dst = '/' + dst

        cmd = ['adb', 'shell', 'mkdir', dst]
        try:
            err = subprocess.check_output(cmd)
        except subprocess.CalledProcessError:
            sys.stderr.write('Error executing adb shell')
            return 1

        if err != '':
            sys.stderr.write(err)
            return 1
        return 0


CALL_MAP = {'list': lambda a: Adb().list(),
            'copyin': lambda a: Adb().copyin(a.src, a.dst),
            'copyout': lambda a: Adb().copyout(a.src, a.dst),
            'mkdir': lambda a: Adb().mkdir(a.dst),
            'rmdir': lambda a: Adb().rmdir(a.dst),
            'rm': lambda a: Adb().rm(a.dst),
            'run': lambda a: Adb().run(a.dst)}


def main():
    """parse commandline"""
    parser = argparse.ArgumentParser()
    subparsers = parser.add_subparsers(help='supported commands')
    parser_list = subparsers.add_parser('list')
    parser_copyin = subparsers.add_parser('copyin')
    parser_copyout = subparsers.add_parser('copyout')
    parser_rm = subparsers.add_parser('rm')
    parser_mkdir = subparsers.add_parser('mkdir')
    parser_rmdir = subparsers.add_parser('rmdir')
    parser_run = subparsers.add_parser('run')

    parser_list.add_argument('arch')
    parser_list.set_defaults(func=CALL_MAP['list'])

    parser_copyin.add_argument('arch')
    parser_copyin.add_argument('dst')
    parser_copyin.add_argument('src')
    parser_copyin.set_defaults(func=CALL_MAP['copyin'])

    parser_copyout.add_argument('arch')
    parser_copyout.add_argument('src')
    parser_copyout.add_argument('dst')
    parser_copyout.set_defaults(func=CALL_MAP['copyout'])

    parser_rm.add_argument('arch')
    parser_rm.add_argument('dst')
    parser_rm.set_defaults(func=CALL_MAP['rm'])

    parser_mkdir.add_argument('arch')
    parser_mkdir.add_argument('dst')
    parser_mkdir.set_defaults(func=CALL_MAP['mkdir'])

    parser_rmdir.add_argument('arch')
    parser_rmdir.add_argument('dst')
    parser_rmdir.set_defaults(func=CALL_MAP['rmdir'])

    parser_run.add_argument('arch')
    parser_run.add_argument('dst')
    parser_run.set_defaults(func=CALL_MAP['run'])

    parser.add_argument('--version', action='version',
                        version='%(prog)s ' + str(__version__))

    args = parser.parse_args()

    return args.func(args)


if __name__ == '__main__':
    sys.exit(main())