# SPDX-License-Identifier: GPL-2.0-or-later
#
# Copyright (C) 2011-2016 Red Hat, Inc.
#
# Authors:
# Thomas Woerner <twoerner@redhat.com>

"""ifcfg file parser"""

import os.path
import io
import tempfile
import shutil

from firewall.core.logger import log


class ifcfg:
    def __init__(self, filename):
        self._config = {}
        self._deleted = []
        self.filename = filename
        self.clear()

    def clear(self):
        self._config = {}
        self._deleted = []

    def cleanup(self):
        self._config.clear()

    def get(self, key):
        return self._config.get(key.strip())

    def set(self, key, value):
        _key = key.strip()
        self._config[_key] = value.strip()
        if _key in self._deleted:
            self._deleted.remove(_key)

    def __str__(self):
        s = ""
        for key, value in self._config.items():
            if s:
                s += "\n"
            s += "%s=%s" % (key, value)
        return s

    # load self.filename
    def read(self):
        self.clear()
        try:
            f = open(self.filename, "r")
        except Exception as msg:
            log.error("Failed to load '%s': %s", self.filename, msg)
            raise

        for line in f:
            if not line:
                break
            line = line.strip()
            if len(line) < 1 or line[0] in ["#", ";"]:
                continue
            # get key/value pair
            pair = [x.strip() for x in line.split("=", 1)]
            if len(pair) != 2:
                continue
            if len(pair[1]) >= 2 and pair[1].startswith('"') and pair[1].endswith('"'):
                pair[1] = pair[1][1:-1]
            if pair[1] == "":
                continue
            elif self._config.get(pair[0]) is not None:
                log.warning(
                    "%s: Duplicate option definition: '%s'", self.filename, line.strip()
                )
                continue
            self._config[pair[0]] = pair[1]
        f.close()

    def write(self):
        if len(self._config) < 1:
            # no changes: nothing to do
            return

        # handled keys
        done = []

        try:
            temp_file = tempfile.NamedTemporaryFile(
                mode="wt",
                prefix="%s." % os.path.basename(self.filename),
                dir=os.path.dirname(self.filename),
                delete=False,
            )
        except Exception as msg:
            log.error("Failed to open temporary file: %s" % msg)
            raise

        modified = False
        empty = False
        try:
            f = io.open(self.filename, mode="rt", encoding="UTF-8")
        except Exception as msg:
            if os.path.exists(self.filename):
                log.error("Failed to open '%s': %s" % (self.filename, msg))
                raise
            else:
                f = None
        else:
            for line in f:
                if not line:
                    break
                # remove newline
                line = line.strip("\n")

                if len(line) < 1:
                    if not empty:
                        temp_file.write("\n")
                        empty = True
                elif line[0] == "#":
                    empty = False
                    temp_file.write(line)
                    temp_file.write("\n")
                else:
                    p = line.split("=", 1)
                    if len(p) != 2:
                        empty = False
                        temp_file.write(line + "\n")
                        continue
                    key = p[0].strip()
                    value = p[1].strip()
                    if (
                        len(value) >= 2
                        and value.startswith('"')
                        and value.endswith('"')
                    ):
                        value = value[1:-1]
                    # check for modified key/value pairs
                    if key not in done:
                        if key in self._config and self._config[key] != value:
                            empty = False
                            temp_file.write("%s=%s\n" % (key, self._config[key]))
                            modified = True
                        elif key in self._deleted:
                            modified = True
                        else:
                            empty = False
                            temp_file.write(line + "\n")
                        done.append(key)
                    else:
                        modified = True

        # write remaining key/value pairs
        if len(self._config) > 0:
            for key, value in self._config.items():
                if key in done:
                    continue
                if not empty:
                    empty = True
                temp_file.write("%s=%s\n" % (key, value))
                modified = True

        if f:
            f.close()
        temp_file.close()

        if not modified:  # not modified: remove tempfile
            os.remove(temp_file.name)
            return
        # make backup
        if os.path.exists(self.filename):
            try:
                shutil.copy2(self.filename, "%s.bak" % self.filename)
            except Exception as msg:
                os.remove(temp_file.name)
                raise IOError("Backup of '%s' failed: %s" % (self.filename, msg))

        # copy tempfile
        try:
            shutil.move(temp_file.name, self.filename)
        except Exception as msg:
            os.remove(temp_file.name)
            raise IOError("Failed to create '%s': %s" % (self.filename, msg))
        else:
            os.chmod(self.filename, 0o600)