#
# ipachangeconf - configuration file manipulation classes and functions
# partially based on authconfig code
# Copyright (c) 1999-2007 Red Hat, Inc.
# Author: Simo Sorce <ssorce@redhat.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 fcntl
import os
import shutil

import six

if six.PY3:
    unicode = str

def openLocked(filename, perms):
    fd = -1
    try:
        fd = os.open(filename, os.O_RDWR | os.O_CREAT, perms)

        fcntl.lockf(fd, fcntl.LOCK_EX)
    except OSError as e:
        if fd != -1:
            try:
                os.close(fd)
            except OSError:
                pass
        raise IOError(e.errno, e.strerror)
    return os.fdopen(fd, "r+")


    #TODO: add subsection as a concept
    #      (ex. REALM.NAME = { foo = x bar = y } )
    #TODO: put section delimiters as separating element of the list
    #      so that we can process multiple sections in one go
    #TODO: add a comment all but provided options as a section option
class IPAChangeConf:

    def __init__(self, name):
        self.progname = name
        self.indent = ("", "", "")
        self.assign = (" = ", "=")
        self.dassign = self.assign[0]
        self.comment = ("#",)
        self.dcomment = self.comment[0]
        self.eol = ("\n",)
        self.deol = self.eol[0]
        self.sectnamdel = ("[", "]")
        self.subsectdel = ("{", "}")
        self.case_insensitive_sections = True

    def setProgName(self, name):
        self.progname = name

    def setIndent(self, indent):
        if type(indent) is tuple:
            self.indent = indent
        elif type(indent) is str:
            self.indent = (indent, )
        else:
            raise ValueError('Indent must be a list of strings')

    def setOptionAssignment(self, assign):
        if type(assign) is tuple:
            self.assign = assign
        else:
            self.assign = (assign, )
        self.dassign = self.assign[0]

    def setCommentPrefix(self, comment):
        if type(comment) is tuple:
            self.comment = comment
        else:
            self.comment = (comment, )
        self.dcomment = self.comment[0]

    def setEndLine(self, eol):
        if type(eol) is tuple:
            self.eol = eol
        else:
            self.eol = (eol, )
        self.deol = self.eol[0]

    def setSectionNameDelimiters(self, delims):
        self.sectnamdel = delims

    def setSubSectionDelimiters(self, delims):
        self.subsectdel = delims

    def matchComment(self, line):
        for v in self.comment:
            if line.lstrip().startswith(v):
                return line.lstrip()[len(v):]
        return False

    def matchEmpty(self, line):
        if line.strip() == "":
            return True
        return False

    def matchSection(self, line):
        cl = "".join(line.strip().split())
        cl = cl.lower() if self.case_insensitive_sections else cl

        if len(self.sectnamdel) != 2:
            return False
        if not cl.startswith(self.sectnamdel[0]):
            return False
        if not cl.endswith(self.sectnamdel[1]):
            return False
        return cl[len(self.sectnamdel[0]):-len(self.sectnamdel[1])]

    def matchSubSection(self, line):
        if self.matchComment(line):
            return False

        parts = line.split(self.dassign, 1)
        if len(parts) < 2:
            return False

        if parts[1].strip() == self.subsectdel[0]:
            return parts[0].strip()

        return False

    def matchSubSectionEnd(self, line):
        if self.matchComment(line):
            return False

        if line.strip() == self.subsectdel[1]:
            return True

        return False

    def getSectionLine(self, section):
        if len(self.sectnamdel) != 2:
            return section
        return self._dump_line(self.sectnamdel[0],
                               section,
                               self.sectnamdel[1],
                               self.deol)

    def _dump_line(self, *args):
        return u"".join(unicode(x) for x in args)

    def dump(self, options, level=0):
        output = []
        if level >= len(self.indent):
            level = len(self.indent) - 1

        for o in options:
            if o['type'] == "section":
                output.append(self._dump_line(self.sectnamdel[0],
                                              o['name'],
                                              self.sectnamdel[1]))
                output.append(self.dump(o['value'], (level + 1)))
                continue
            if o['type'] == "subsection":
                output.append(self._dump_line(self.indent[level],
                                              o['name'],
                                              self.dassign,
                                              self.subsectdel[0]))
                output.append(self.dump(o['value'], (level + 1)))
                output.append(self._dump_line(self.indent[level],
                                              self.subsectdel[1]))
                continue
            if o['type'] == "option":
                delim = o.get('delim', self.dassign)
                if delim not in self.assign:
                    raise ValueError('Unknown delim "%s" must be one of "%s"' % (delim, " ".join([d for d in self.assign])))
                output.append(self._dump_line(self.indent[level],
                                              o['name'],
                                              delim,
                                              o['value']))
                continue
            if o['type'] == "comment":
                output.append(self._dump_line(self.dcomment, o['value']))
                continue
            if o['type'] == "empty":
                output.append('')
                continue
            raise SyntaxError('Unknown type: [%s]' % o['type'])

        # append an empty string to the output so that we add eol to the end
        # of the file contents in a single join()
        output.append('')
        return self.deol.join(output)

    def parseLine(self, line):

        if self.matchEmpty(line):
            return {'name': 'empty', 'type': 'empty'}

        value = self.matchComment(line)
        if value:
            return {'name': 'comment',
                    'type': 'comment',
                    'value': value.rstrip()}  # pylint: disable=E1103

        o = dict()
        parts = line.split(self.dassign, 1)
        if len(parts) < 2:
            # The default assign didn't match, try the non-default
            for d in self.assign[1:]:
                parts = line.split(d, 1)
                if len(parts) >= 2:
                    o['delim'] = d
                    break

            if 'delim' not in o:
                raise SyntaxError('Syntax Error: Unknown line format')

        o.update({'name':parts[0].strip(), 'type':'option', 'value':parts[1].rstrip()})
        return o

    def findOpts(self, opts, type, name, exclude_sections=False):

        num = 0
        for o in opts:
            if o['type'] == type and o['name'] == name:
                return (num, o)
            if exclude_sections and (o['type'] == "section" or
                                     o['type'] == "subsection"):
                return (num, None)
            num += 1
        return (num, None)

    def commentOpts(self, inopts, level=0):

        opts = []

        if level >= len(self.indent):
            level = len(self.indent) - 1

        for o in inopts:
            if o['type'] == 'section':
                no = self.commentOpts(o['value'], (level + 1))
                val = self._dump_line(self.dcomment,
                                      self.sectnamdel[0],
                                      o['name'],
                                      self.sectnamdel[1])
                opts.append({'name': 'comment',
                             'type': 'comment',
                             'value': val})
                for n in no:
                    opts.append(n)
                continue
            if o['type'] == 'subsection':
                no = self.commentOpts(o['value'], (level + 1))
                val = self._dump_line(self.indent[level],
                                      o['name'],
                                      self.dassign,
                                      self.subsectdel[0])
                opts.append({'name': 'comment',
                             'type': 'comment',
                             'value': val})
                opts.extend(no)
                val = self._dump_line(self.indent[level], self.subsectdel[1])
                opts.append({'name': 'comment',
                             'type': 'comment',
                             'value': val})
                continue
            if o['type'] == 'option':
                delim = o.get('delim', self.dassign)
                if delim not in self.assign:
                    val = self._dump_line(self.indent[level],
                                          o['name'],
                                          delim,
                                          o['value'])
                opts.append({'name':'comment', 'type':'comment', 'value':val})
                continue
            if o['type'] == 'comment':
                opts.append(o)
                continue
            if o['type'] == 'empty':
                opts.append({'name': 'comment',
                             'type': 'comment',
                             'value': ''})
                continue
            raise SyntaxError('Unknown type: [%s]' % o['type'])

        return opts

    def mergeOld(self, oldopts, newopts):

        opts = []

        for o in oldopts:
            if o['type'] == "section" or o['type'] == "subsection":
                (num, no) = self.findOpts(newopts, o['type'], o['name'])
                if not no:
                    opts.append(o)
                    continue
                if no['action'] == "set":
                    mo = self.mergeOld(o['value'], no['value'])
                    opts.append({'name': o['name'],
                                 'type': o['type'],
                                 'value': mo})
                    continue
                if no['action'] == "comment":
                    co = self.commentOpts(o['value'])
                    for c in co:
                        opts.append(c)
                    continue
                if no['action'] == "remove":
                    continue
                raise SyntaxError('Unknown action: [%s]' % no['action'])

            if o['type'] == "comment" or o['type'] == "empty":
                opts.append(o)
                continue

            if o['type'] == "option":
                (num, no) = self.findOpts(newopts, 'option', o['name'], True)
                if not no:
                    opts.append(o)
                    continue
                if no['action'] == 'comment' or no['action'] == 'remove':
                    if (no['value'] is not None and
                            o['value'] is not no['value']):
                        opts.append(o)
                        continue
                    if no['action'] == 'comment':
                        value = self._dump_line(self.dcomment,
                                                o['name'],
                                                self.dassign,
                                                o['value'])
                        opts.append({'name': 'comment',
                                     'type': 'comment',
                                     'value': value})
                    continue
                if no['action'] == 'set':
                    opts.append(no)
                    continue
                if no['action'] == 'addifnotset':
                    opts.append({'name': 'comment', 'type': 'comment',
                                'value': self._dump_line(no['name'],
                                                         self.dassign,
                                                         no['value'],
                                                         u' # modified by IPA'
                                                         )})
                    opts.append(o)
                    continue
                raise SyntaxError('Unknown action: [%s]' % no['action'])

            raise SyntaxError('Unknown type: [%s]' % o['type'])

        return opts

    def mergeNew(self, opts, newopts):

        cline = 0

        for no in newopts:

            if no['type'] == "section" or no['type'] == "subsection":
                (num, o) = self.findOpts(opts, no['type'], no['name'])
                if not o:
                    if no['action'] == 'set':
                        opts.append(no)
                    continue
                if no['action'] == "set":
                    self.mergeNew(o['value'], no['value'])
                    continue
                cline = num + 1
                continue

            if no['type'] == "option":
                (num, o) = self.findOpts(opts, no['type'], no['name'], True)
                if not o:
                    if no['action'] == 'set' or no['action'] == 'addifnotset':
                        opts.append(no)
                    continue
                cline = num + 1
                continue

            if no['type'] == "comment" or no['type'] == "empty":
                opts.insert(cline, no)
                cline += 1
                continue

            raise SyntaxError('Unknown type: [%s]' % no['type'])

    def merge(self, oldopts, newopts):

        #Use a two pass strategy
        #First we create a new opts tree from oldopts removing/commenting
        #  the options as indicated by the contents of newopts
        #Second we fill in the new opts tree with options as indicated
        #  in the newopts tree (this is becaus eentire (sub)sections may
        #  in the newopts tree (this is becaus entire (sub)sections may
        #  exist in the newopts that do not exist in oldopts)

        opts = self.mergeOld(oldopts, newopts)
        self.mergeNew(opts, newopts)
        return opts

    #TODO: Make parse() recursive?
    def parse(self, f):

        opts = []
        sectopts = []
        section = None
        subsectopts = []
        subsection = None
        curopts = opts
        fatheropts = opts

        # Read in the old file.
        for line in f:

            # It's a section start.
            value = self.matchSection(line)
            if value:
                if section is not None:
                    opts.append({'name': section,
                                 'type': 'section',
                                 'value': sectopts})
                sectopts = []
                curopts = sectopts
                fatheropts = sectopts
                section = value
                continue

            # It's a subsection start.
            value = self.matchSubSection(line)
            if value:
                if subsection is not None:
                    raise SyntaxError('nested subsections are not '
                                      'supported yet')
                subsectopts = []
                curopts = subsectopts
                subsection = value
                continue

            value = self.matchSubSectionEnd(line)
            if value:
                if subsection is None:
                    raise SyntaxError('Unmatched end subsection terminator '
                                      'found')
                fatheropts.append({'name': subsection,
                                   'type': 'subsection',
                                   'value': subsectopts})
                subsection = None
                curopts = fatheropts
                continue

            # Copy anything else as is.
            try:
                curopts.append(self.parseLine(line))
            except SyntaxError as e:
                raise SyntaxError('{error} in file {fname}: [{line}]'.format(
                    error=e, fname=f.name, line=line.rstrip()))

        #Add last section if any
        if len(sectopts) is not 0:
            opts.append({'name': section,
                         'type': 'section',
                         'value': sectopts})

        return opts

    # Write settings to configuration file
    # file is a path
    # options is a set of dictionaries in the form:
    #     [{'name': 'foo', 'value': 'bar', 'action': 'set/comment'}]
    # section is a section name like 'global'
    def changeConf(self, file, newopts):
        autosection = False
        savedsection = None
        done = False
        output = ""
        f = None
        try:
            # Do not catch an unexisting file error
            # we want to fail in that case
            shutil.copy2(file, (file + ".ipabkp"))

            f = openLocked(file, 0o644)

            oldopts = self.parse(f)

            options = self.merge(oldopts, newopts)

            output = self.dump(options)

            # Write it out and close it.
            f.seek(0)
            f.truncate(0)
            f.write(output)
        finally:
            try:
                if f:
                    f.close()
            except IOError:
                pass
        return True

    # Write settings to new file, backup old
    # file is a path
    # options is a set of dictionaries in the form:
    #     [{'name': 'foo', 'value': 'bar', 'action': 'set/comment'}]
    def newConf(self, file, options):
        autosection = False
        savedsection = None
        done = False
        output = ""
        f = None
        try:
            try:
                shutil.copy2(file, (file + ".ipabkp"))
            except IOError as err:
                if err.errno == 2:
                    # The orign file did not exist
                    pass

            f = openLocked(file, 0o644)

            # Trunkate
            f.seek(0)
            f.truncate(0)

            output = self.dump(options)

            f.write(output)
        finally:
            try:
                if f:
                    f.close()
            except IOError:
                pass
        return True

    @staticmethod
    def setOption(name, value):
        return {'name': name,
                'type': 'option',
                'action': 'set',
                'value': value}

    @staticmethod
    def rmOption(name):
        return {'name': name,
                'type': 'option',
                'action': 'remove',
                'value': None}

    @staticmethod
    def setSection(name, options):
        return {'name': name,
                'type': 'section',
                'action': 'set',
                'value': options}