##############################################################################
#
# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE
#
##############################################################################
__doc__='''Class for reading RDB files


$Id: RDB.py,v 1.33 2002/08/14 21:50:59 mj Exp $'''
__version__='$Revision: 1.33 $'[11:-2]

from string import split, strip, lower, upper, atof, atoi, atol, find, join,find
import DateTime,re
from Missing import MV
from array import array
from Record import Record
from Acquisition import Implicit
import ExtensionClass

def parse_text(s):
    if find(s,'\\') < 0 and (find(s,'\\t') < 0 and find(s,'\\n') < 0): return s
    r=[]
    for x in split(s,'\\\\'):
        x=join(split(x,'\\n'),'\n')
        r.append(join(split(x,'\\t'),'\t'))
    return join(r,'\\')


Parsers={'n': atof,
         'i': atoi,
         'l': atol,
         'd': DateTime.DateTime,
         't': parse_text,
         }

class SQLAlias(ExtensionClass.Base):
    def __init__(self, name): self._n=name
    def __of__(self, parent): return getattr(parent, self._n)

class NoBrains: pass

class DatabaseResults:
    """Class for reading RDB files
    """
    _index=None

    # We need to allow access to not-explicitly-protected
    # individual record objects contained in the result.
    __allow_access_to_unprotected_subobjects__=1

    def __init__(self,file,brains=NoBrains, parent=None, zbrains=None):

        self._file=file
        readline=file.readline
        line=readline()
        self._parent=parent
        if zbrains is None: zbrains=NoBrains


        while line and line.find('#') != -1 : line=readline()

        line=line[:-1]
        if line and line[-1:] in '\r\n': line=line[:-1]
        self._names=names=split(line,'\t')
        if not names: raise ValueError, 'No column names'

        aliases=[]
        self._schema=schema={}
        i=0
        for name in names:
            name=strip(name)
            if not name:
                raise ValueError, 'Empty column name, %s' % name
            if schema.has_key(name):
                raise ValueError, 'Duplicate column name, %s' % name
            schema[name]=i
            n=lower(name)
            if n != name: aliases.append((n, SQLAlias(name)))
            n=upper(name)
            if n != name: aliases.append((n, SQLAlias(name)))
            i=i+1

        self._nv=nv=len(names)
        line=readline()
        line=line[:-1]
        if line[-1:] in '\r\n': line=line[:-1]

        self._defs=defs=split(line,'\t')
        if not defs: raise ValueError, 'No column definitions'
        if len(defs) != nv:
            raise ValueError, (
                """The number of column names and the number of column
                definitions are different.""")

        i=0
        self._parsers=parsers=[]
        defre=re.compile(r'([0-9]*)([a-zA-Z])?')
        self._data_dictionary=dd={}
        self.__items__=items=[]
        for _def in defs:
            _def=strip(_def)
            if not _def:
                raise ValueError, ('Empty column definition for %s' % names[i])

            mo = defre.match(_def)
            if mo is None:
                raise ValueError, (
                    'Invalid column definition for, %s, for %s'
                    % _def, names[i])
            type  = mo.group(2).lower()
            width = mo.group(1)
            if width: width=atoi(width)
            else: width=8

            try: parser=Parsers[type]
            except: parser=str

            name=names[i]
            d={'name': name, 'type': type, 'width': width, 'parser': parser}
            items.append(d)
            dd[name]=d

            parsers.append((i,parser))
            i=i+1

        # Create a record class to hold the records.
        names=tuple(names)

        class r(Record, Implicit, brains, zbrains):
            'Result record class'

        r.__record_schema__=schema
        for k in filter(lambda k: k[:2]=='__', Record.__dict__.keys()):
            setattr(r,k,getattr(Record,k))

        # Add SQL Aliases
        d=r.__dict__
        for k, v in aliases:
            if not hasattr(r,k): d[k]=v

        if hasattr(brains, '__init__'):
            binit=brains.__init__
            if hasattr(binit,'im_func'): binit=binit.im_func
            def __init__(self, data, parent, binit=binit):
                Record.__init__(self,data)
                binit(self.__of__(parent))

            r.__dict__['__init__']=__init__


        self._class=r

        # OK, we've read meta data, now get line indexes

        p=file.tell()
        save=self._lines=array('i')
        save=save.append
        l=readline()
        while l:
            save(p)
            p=p+len(l)
            l=readline()

    def _searchable_result_columns(self): return self.__items__
    def names(self): return self._names
    def data_dictionary(self): return self._data_dictionary

    def __len__(self): return len(self._lines)

    def __getitem__(self,index):
        if index==self._index: return self._row
        file=self._file
        file.seek(self._lines[index])
        line=file.readline()
        line=line[:-1]
        if line and line[-1:] in '\r\n': line=line[:-1]
        fields=split(line,'\t')
        l=len(fields)
        nv=self._nv
        if l != nv:
            if l < nv:
                fields=fields+['']*(nv-l)
            else:
                raise ValueError, (
                    """The number of items in record %s is invalid
                    <pre>%s\n%s\n%s\n%s</pre>
                    """
                    % (index, ('='*40), line, ('='*40), fields))
        for i, parser in self._parsers:
            try: v=parser(fields[i])
            except:
                if fields[i]:
                    raise ValueError, (
                        """Invalid value, %s, for %s in record %s"""
                        % (fields[i], self._names[i], index))
                else: v=MV
            fields[i]=v

        parent=self._parent
        fields=self._class(fields, parent)
        self._index=index
        self._row=fields
        if parent is None: return fields
        return fields.__of__(parent)

File=DatabaseResults
