#!/usr/bin/env python3
"""
Read only, Amiga LZX[1] archiver Virtual filesystem executive for Midnight
Commander.

Tested against python 3.6, unlzx[1] 1.1 and mc 4.8.22

[1] ftp://us.aminet.net/pub/aminet/misc/unix/unlzx.c.gz.readme

Changelog:
    1.2 Use python3
    1.1 Moved common code into extfslib library
    1.0 Initial release

Author: Roman 'gryf' Dobosz <gryf73@gmail.com>
Date: 2019-06-30
Version: 1.2
Licence: BSD
"""
import os
import sys
import re
import shutil
from subprocess import call, CalledProcessError
from tempfile import mkdtemp, mkstemp

from extfslib import Archive, parse_args


class ULzx(Archive):
    """Archive handle. Provides interface to MC's extfs subsystem"""
    LINE_PAT = re.compile(b"^\s+(?P<size>\d+)\s+"
                          b"((n/a)|\d+)\s"
                          b"(?P<time>\d{2}:\d{2}:\d{2})\s+"
                          b"(?P<date>\d+-[a-z]{3}-\d{4})\s"
                          b"(?P<perms>[h-][s-][p-][a-][r-][w-][e-][d-])\s"
                          b"\"(?P<fpath>.*)\"")
    ARCHIVER = b"unlzx"
    CMDS = {"list": b"-v",
            "read": b"-x"}
    DATETIME = b"%02d-%02d-%s %02d:%02d"

    def _get_date(self, time, date):
        """Return MM-DD-YYYY hh:mm formatted date out of time and date
        strings"""
        month_list = [b"jan", b"feb", b"mar", b"apr", b"may", b"jun", b"jul",
                      b"aug", b"sep", b"oct", b"nov", b"dec"]
        day, month, year = date.split(b"-")
        month = month_list.index(month) + 1
        hours, minutes, dummy = time.split(b":")
        return self.DATETIME % (month, int(day), year, int(hours),
                                int(minutes))

    def _get_dir(self):
        """Prepare archive file listing"""
        contents = []

        out = self._call_command("list")
        if not out:
            return

        for line in out.split(b"\n"):
            match = self.LINE_PAT.match(line)
            if not match:
                continue

            match_entry = match.groupdict()
            entry = {}
            for key in match_entry:
                entry[bytes(key, 'utf-8')] = match_entry[key]
            del match_entry

            entry[b'datetime'] = self._get_date(entry[b'time'], entry[b'date'])
            entry[b'display_name'] = self._map_name(entry[b'fpath'])
            entry[b'perms'] = b"-rw-r--r--"  # lzx doesn't store empty dirs
            entry[b'uid'] = bytes(str(self._uid), 'utf-8')
            entry[b'gid'] = bytes(str(self._gid), 'utf-8')
            contents.append(entry)

        return contents

    def list(self):
        """Output contents of the archive to stdout"""
        for entry in self._contents:
            sys.stdout.buffer.write(self.ITEM % entry)
        return 0

    def run(self, dst):
        """Execute file out of archive"""
        fdesc, tmp_file = mkstemp()
        os.close(fdesc)
        result = 0

        if self.copyout(dst, tmp_file) != 0:
            result = 1

        os.chmod(tmp_file, int("700", 8))

        try:
            result = call([tmp_file])
        finally:
            try:
                os.unlink(tmp_file)
            except OSError:
                pass

        return result

    def copyout(self, src, dst):
        """Unfortunately, to copy one file out entire LZX archive have to be
        extracted. For small archives is not a problem, but in relatively big
        one it could be a performance issue."""
        tmp_dir = mkdtemp()
        src = self._get_real_name(src)
        current_dir = os.path.abspath(os.curdir)
        os.chdir(tmp_dir)

        try:
            with open(os.devnull, "w") as fnull:
                result = call([self.ARCHIVER, self.CMDS['read'],
                               os.path.join(current_dir, self._arch)],
                              stdout=fnull, stderr=fnull)
            if result == 0:
                shutil.copy2(src, dst)
        except CalledProcessError:
            return 1
        finally:
            shutil.rmtree(tmp_dir)
            os.chdir(current_dir)

        return result


if __name__ == "__main__":
    sys.exit(parse_args(ULzx))