"""
ldif - generate and parse LDIF data (see RFC 2849)
written by Michael Stroeder <michael@stroeder.com>

See http://python-ldap.sourceforge.net for details.

$Id: ldif.py,v 1.3 2008/02/11 16:35:43 dwelch Exp $

Python compability note:
Tested with Python 2.0+, but should work with Python 1.5.2+.

The python-ldap package is distributed under Python-style license.

Standard disclaimer:
   This software is made available by the author(s) to the public for free
   and "as is".  All users of this free software are solely and entirely
   responsible for their own choice and use of this software for their
   own purposes.  By using this software, each user agrees that the
   author(s) shall not be liable for damages of any kind in relation to
   its use or performance. The author(s) do not warrant that this software
   is fit for any purpose.

Note: This file is part of the python-ldap package. For the complete
  python-ldap package, please visit: http://sourceforge.net/projects/python-ldap/
  
  It has been modified for use in HPLIP.

"""

__version__ = '0.5.5'

__all__ = [
  # constants
  'ldif_pattern',
  # functions
  'AttrTypeandValueLDIF', 'CreateLDIF', 'ParseLDIF',
  # classes
  'LDIFWriter',
  'LDIFParser',
  'LDIFRecordList',
  'LDIFCopy',
]

import urlparse
import urllib # TODO: Replace with urllib2 (urllib is deprecated in Python 3.0)
import base64
import re
import types

try:
    from cStringIO import StringIO
except ImportError:
    from StringIO import StringIO

from base.g import *    

attrtype_pattern = r'[\w;.]+(;[\w_-]+)*'
attrvalue_pattern = r'(([^,]|\\,)+|".*?")'
rdn_pattern = attrtype_pattern + r'[ ]*=[ ]*' + attrvalue_pattern
dn_pattern   = rdn_pattern + r'([ ]*,[ ]*' + rdn_pattern + r')*[ ]*'
dn_regex   = re.compile('^%s$' % dn_pattern)

ldif_pattern = '^((dn(:|::) %(dn_pattern)s)|(%(attrtype_pattern)s(:|::) .*)$)+' % vars()

MOD_OP_INTEGER = {
  'add':0, 'delete':1, 'replace':2
}

MOD_OP_STR = {
  0:'add', 1:'delete', 2:'replace'
}

CHANGE_TYPES = ['add', 'delete', 'modify', 'modrdn']
valid_changetype_dict = {}
for c in CHANGE_TYPES:
    valid_changetype_dict[c]=None


SAFE_STRING_PATTERN = '(^(\000|\n|\r| |:|<)|[\000\n\r\200-\377]+|[ ]+$)'
safe_string_re = re.compile(SAFE_STRING_PATTERN)

def is_dn(s):
    """
    returns 1 if s is a LDAP DN
    """
    if s=='':
        return 1
    rm = dn_regex.match(s)
    return rm!=None and rm.group(0)==s


def needs_base64(s):
    """
    returns 1 if s has to be base-64 encoded because of special chars
    """
    return not safe_string_re.search(s) is None


def list_dict(l):
    """
    return a dictionary with all items of l being the keys of the dictionary
    """
    return dict([(i, None) for i in l])


class LDIFWriter:
    """
    Write LDIF entry or change records to file object
    Copy LDIF input to a file output object containing all data retrieved
    via URLs
    """

    def __init__(self, output_file, base64_attrs=None, cols=76, line_sep='\n'):
        """
        output_file
            file object for output
        base64_attrs
            list of attribute types to be base64-encoded in any case
        cols
            Specifies how many columns a line may have before it's
            folded into many lines.
        line_sep
            String used as line separator
        """
        self._output_file = output_file
        self._base64_attrs = list_dict([a.lower() for a in (base64_attrs or [])])
        self._cols = cols
        self._line_sep = line_sep
        self.records_written = 0

    def _unfoldLDIFLine(self, line):
        """
        Write string line as one or more folded lines
        """
        # Check maximum line length
        line_len = len(line)
        if line_len<=self._cols:
            self._output_file.write(line)
            self._output_file.write(self._line_sep)
        else:
            # Fold line
            pos = self._cols
            self._output_file.write(line[0:min(line_len, self._cols)])
            self._output_file.write(self._line_sep)
            while pos<line_len:
                self._output_file.write(' ')
                self._output_file.write(line[pos:min(line_len, pos+self._cols-1)])
                self._output_file.write(self._line_sep)
                pos = pos+self._cols-1
        return # _unfoldLDIFLine()

    def _unparseAttrTypeandValue(self, attr_type, attr_value):
        """
        Write a single attribute type/value pair

        attr_type
              attribute type
        attr_value
              attribute value
        """
        if self._base64_attrs.has_key(attr_type.lower()) or \
           needs_base64(attr_value):
            # Encode with base64
            self._unfoldLDIFLine(':: '.join([attr_type, base64.encodestring(attr_value).replace('\n', '')]))
        else:
            self._unfoldLDIFLine(': '.join([attr_type, attr_value]))
        return # _unparseAttrTypeandValue()

    def _unparseEntryRecord(self, entry):
        """
        entry
            dictionary holding an entry
        """
        attr_types = entry.keys()[:]
        attr_types.sort()
        for attr_type in attr_types:
            for attr_value in entry[attr_type]:
                self._unparseAttrTypeandValue(attr_type, attr_value)

    def _unparseChangeRecord(self, modlist):
        """
        modlist
            list of additions (2-tuple) or modifications (3-tuple)
        """
        mod_len = len(modlist[0])
        if mod_len==2:
            changetype = 'add'
        elif mod_len==3:
            changetype = 'modify'
        else:
            raise ValueError, "modlist item of wrong length"
        self._unparseAttrTypeandValue('changetype', changetype)
        for mod in modlist:
            if mod_len==2:
                mod_type, mod_vals = mod
            elif mod_len==3:
                mod_op, mod_type, mod_vals = mod
                self._unparseAttrTypeandValue(MOD_OP_STR[mod_op], mod_type)
            else:
                raise ValueError, "Subsequent modlist item of wrong length"
            if mod_vals:
                for mod_val in mod_vals:
                    self._unparseAttrTypeandValue(mod_type, mod_val)
            if mod_len==3:
                self._output_file.write('-'+self._line_sep)

    def unparse(self, dn, record):
        """
        dn
              string-representation of distinguished name
        record
              Either a dictionary holding the LDAP entry {attrtype:record}
              or a list with a modify list like for LDAPObject.modify().
        """
        if not record:
            # Simply ignore empty records
            return
        # Start with line containing the distinguished name
        self._unparseAttrTypeandValue('dn', dn)
        # Dispatch to record type specific writers
        if isinstance(record, types.DictType):
            self._unparseEntryRecord(record)
        elif isinstance(record, types.ListType):
            self._unparseChangeRecord(record)
        else:
            raise ValueError, "Argument record must be dictionary or list"
        # Write empty line separating the records
        self._output_file.write(self._line_sep)
        # Count records written
        self.records_written = self.records_written+1
        return # unparse()


def CreateLDIF(dn, record, base64_attrs=None, cols=76):
    """
    Create LDIF single formatted record including trailing empty line.
    This is a compability function. Use is deprecated!

    dn
          string-representation of distinguished name
    record
          Either a dictionary holding the LDAP entry {attrtype:record}
          or a list with a modify list like for LDAPObject.modify().
    base64_attrs
          list of attribute types to be base64-encoded in any case
    cols
          Specifies how many columns a line may have before it's
          folded into many lines.
    """
    f = StringIO()
    ldif_writer = LDIFWriter(f, base64_attrs, cols, '\n')
    ldif_writer.unparse(dn, record)
    s = f.getvalue()
    f.close()
    return s


class LDIFParser:
    """
    Base class for a LDIF parser. Applications should sub-class this
    class and override method handle() to implement something meaningful.

    Public class attributes:
    records_read
          Counter for records processed so far
    """

    def _stripLineSep(self, s):
        """
        Strip trailing line separators from s, but no other whitespaces
        """
        return s.strip('\n').strip('\r')
        
##        if s[-2:] == '\r\n':
##            return s[:-2]
##        elif s[-1:] == '\n':
##            return s[:-1]
##        else:
##            return s

    def __init__(self, input_file, ignored_attr_types=None,
      max_entries=0, process_url_schemes=None, line_sep='\n'):
        """
        Parameters:
        input_file
            File-object to read the LDIF input from
        ignored_attr_types
            Attributes with these attribute type names will be ignored.
        max_entries
            If non-zero specifies the maximum number of entries to be
            read from f.
        process_url_schemes
            List containing strings with URLs schemes to process with urllib.
            An empty list turns off all URL processing and the attribute
            is ignored completely.
        line_sep
            String used as line separator
        """
        self._input_file = input_file
        self._max_entries = max_entries
        self._process_url_schemes = list_dict([s.lower() for s in (process_url_schemes or [])])
        self._ignored_attr_types = list_dict([a.lower() for a in (ignored_attr_types or [])])
        self._line_sep = line_sep
        self.records_read = 0

    def handle(self, dn, entry):
        """
        Process a single content LDIF record. This method should be
        implemented by applications using LDIFParser.
        """

    def _unfoldLDIFLine(self):
        """
        Unfold several folded lines with trailing space into one line
        """
        unfolded_lines = [ self._stripLineSep(self._line) ]
        self._line = self._input_file.readline()
        
        while self._line and self._line[0] == ' ':
            unfolded_lines.append(self._stripLineSep(self._line[1:]))
            self._line = self._input_file.readline()
        
        return ''.join(unfolded_lines)

    def _parseAttrTypeandValue(self):
        """
        Parse a single attribute type and value pair from one or
        more lines of LDIF data
        """
        # Reading new attribute line
        unfolded_line = self._unfoldLDIFLine()
        
        # Ignore comments which can also be folded
        while unfolded_line and unfolded_line[0] == '#':
            unfolded_line = self._unfoldLDIFLine()
        
        if not unfolded_line or unfolded_line == '\n' or unfolded_line == '\r\n':
            return None, None
        
        try:
            colon_pos = unfolded_line.index(':')
        except ValueError:
            # Treat malformed lines without colon as non-existent
            log.error("Malformed line: %s" % unfolded_line)
            #return None, None
            return '', ''
        
        attr_type = unfolded_line[0:colon_pos]
        
        # if needed attribute value is BASE64 decoded
        value_spec = unfolded_line[colon_pos:colon_pos+2]
        
        if value_spec=='::':
            # attribute value needs base64-decoding
            attr_value = base64.decodestring(unfolded_line[colon_pos+2:])
        
        elif value_spec==':<':
            # fetch attribute value from URL
            url = unfolded_line[colon_pos+2:].strip()
            attr_value = None
            if self._process_url_schemes:
                u = urlparse.urlparse(url)
                if self._process_url_schemes.has_key(u[0]):
                    attr_value = urllib.urlopen(url).read()
        
        elif value_spec==':\r\n' or value_spec=='\n':
            attr_value = ''
        
        else:
            attr_value = unfolded_line[colon_pos+2:].lstrip()
        
        return attr_type, attr_value

    def parse(self):
        """
        Continously read and parse LDIF records
        """
        self._line = self._input_file.readline()

        while self._line and \
              (not self._max_entries or self.records_read<self._max_entries):

            # Reset record
            version = None
            dn = None 
            changetype = None
            modop = None
            entry = {}

            attr_type, attr_value = self._parseAttrTypeandValue()
            
            while attr_type is not None and attr_value is not None:
                attr_type = attr_type.lower()
                log.debug("%s ---> %s" % (repr(attr_type), repr(attr_value)))
                
                if not attr_type or not attr_value:
                    attr_type, attr_value = self._parseAttrTypeandValue()
                    continue
                
                if attr_type == 'dn':
                    
                    # attr type and value pair was DN of LDIF record
                    if dn is not None:
                        raise ValueError, 'Two lines starting with dn: in one record.'
                    
                    if not is_dn(attr_value):
                        raise ValueError, 'No valid string-representation of distinguished name %s.' % (repr(attr_value))
                    dn = attr_value
                
                elif attr_type == 'version' and dn is None:
                    version = 1
                
                elif attr_type == 'changetype':
                    # attr type and value pair was DN of LDIF record
                    if dn is None:
                        raise ValueError, 'Read changetype: before getting valid dn: line.'
                    
                    if changetype is not None:
                        raise ValueError, 'Two lines starting with changetype: in one record.'
                    
                    if not attr_value in valid_changetype_dict:
                        raise ValueError, 'changetype value %s is invalid.' % (repr(attr_value))
                    
                    changetype = attr_value
                
                elif attr_value is not None and \
                     not self._ignored_attr_types.has_key(attr_type.lower()):
                    
                    # Add the attribute to the entry if not ignored attribute
                    if attr_type in entry:
                        entry[attr_type].append(attr_value)
                    else:
                        entry[attr_type]=[attr_value]

                # Read the next line within an entry
                attr_type, attr_value = self._parseAttrTypeandValue()
            
            if entry:
                # append entry to result list
                self.handle(dn, entry)
                self.records_read += 1

        return # parse()


class LDIFRecordList(LDIFParser):
    """
    Collect all records of LDIF input into a single list.
    of 2-tuples (dn, entry). It can be a memory hog!
    """

    def __init__(self, input_file, ignored_attr_types=None,
        max_entries=0, process_url_schemes=None):
        """
        See LDIFParser.__init__()

        Additional Parameters:
        all_records
            List instance for storing parsed records
        """
        LDIFParser.__init__(self, input_file, ignored_attr_types, max_entries, process_url_schemes)
        self.all_records = []

    def handle(self, dn, entry):
        """
        Append single record to dictionary of all records.
        """
        self.all_records.append((dn, entry))


class LDIFCopy(LDIFParser):
    """
    Copy LDIF input to LDIF output containing all data retrieved
    via URLs
    """

    def __init__(self, input_file, output_file, ignored_attr_types=None,
        max_entries=0, process_url_schemes=None, base64_attrs=None,
        cols=76, line_sep='\n'):
        """
        See LDIFParser.__init__() and LDIFWriter.__init__()
        """
        LDIFParser.__init__(self, input_file, ignored_attr_types, max_entries, process_url_schemes)
        self._output_ldif = LDIFWriter(output_file, base64_attrs, cols, line_sep)

    def handle(self, dn, entry):
        """
        Write single LDIF record to output file.
        """
        self._output_ldif.unparse(dn, entry)


def ParseLDIF(f, ignore_attrs=None, maxentries=0):
    """
    Parse LDIF records read from file.
    This is a compability function. Use is deprecated!
    """
    ldif_parser = LDIFRecordList(f, ignored_attr_types=ignore_attrs,
        max_entries=maxentries, process_url_schemes=0)
    ldif_parser.parse()
    return ldif_parser.all_records
