#!/usr/bin/python
# -*- coding=utf-8 -*-
"""
Utility functions used by to prepare an arabic text to search and index .
"""
import re
import tashaphyne.arabic_const as arabconst


######################################################################
#{ Indivudual Functions
######################################################################

#--------------------------------------
def strip_tashkeel(text):
    """Strip vowel from a text and return a result text.
    The striped marks are : 
        - FATHA, DAMMA, KASRA
        - SUKUN
        - SHADDA
        - FATHATAN, DAMMATAN, KASRATAN, , , .
    Example:
        >>> text=u"الْعَرَبِيّةُ"
        >>> strip_tashkeel(text)
        العربية

    @param text: arabic text.
    @type text: unicode.
    @return: return a striped text.
    @rtype: unicode.
    """
    return arabconst.HARAKAT_PAT.sub('', text)


#strip tatweel from a text and return a result text
#--------------------------------------
def strip_tatweel(text):
    """
    Strip tatweel from a text and return a result text.

    Example:
        >>> text=u"العـــــربية"
        >>> strip_tatweel(text)
        العربية

    @param text: arabic text.
    @type text: unicode.
    @return: return a striped text.
    @rtype: unicode.
    """
    return re.sub(u'[%s]' % arabconst.TATWEEL,    '', text)


#--------------------------------------
def normalize_hamza(text):
    """Normalize Hamza forms into one form, and return a result text.
    The converted letters are : 
        - The converted lettersinto HAMZA are: WAW_HAMZA,YEH_HAMZA 
        - The converted lettersinto ALEF are: ALEF_MADDA, ALEF_HAMZA_ABOVE, ALEF_HAMZA_BELOW ,HAMZA_ABOVE, HAMZA_BELOW 

    Example:
        >>> text=u"أهؤلاء من أولئكُ"
        >>> normalize_hamza(text)
        اهءلاء من اولءكُ

    @param text: arabic text.
    @type text: unicode.
    @return: return a converted text.
    @rtype: unicode.
    """
    text = arabconst.ALEFAT_PAT.sub(arabconst.ALEF, text)
    return arabconst.HAMZAT_PAT.sub(arabconst.HAMZA, text)

#--------------------------------------
def normalize_lamalef(text):
    """Normalize Lam Alef ligatures into two letters (LAM and ALEF), 
    and return a result text.
    Some systems present lamAlef ligature as a single letter, this function convert it into two letters,
    The converted letters into  LAM and ALEF are : 
        - LAM_ALEF, LAM_ALEF_HAMZA_ABOVE, LAM_ALEF_HAMZA_BELOW, LAM_ALEF_MADDA_ABOVE

    Example:
        >>> text=u"لانها لالئ الاسلام"
        >>> normalize_lamalef(text)
        لانها لالئ الاسلام

    @param text: arabic text.
    @type text: unicode.
    @return: return a converted text.
    @rtype: unicode.
    """
    return arabconst.LAMALEFAT_PAT.sub(\
      u'%s%s'%(arabconst.LAM, arabconst.ALEF), text)

#--------------------------------------
def normalize_spellerrors(text):
    """Normalize some spellerrors like, 
    TEH_MARBUTA into HEH,ALEF_MAKSURA into YEH,  and return a result text.
    In some context users omit the difference between TEH_MARBUTA and HEH, and ALEF_MAKSURA and YEh.
    The conversions are:
        - TEH_MARBUTA into HEH
        - ALEF_MAKSURA into YEH

    Example:
        >>> text=u"اشترت سلمى دمية وحلوى"
        >>> normalize_spellerrors(text)
        اشترت سلمي دميه وحلوي

    @param text: arabic text.
    @type text: unicode.
    @return: return a converted text.
    @rtype: unicode. 
    """
    text = re.sub(u'[%s]' % arabconst.TEH_MARBUTA,    arabconst.HEH, text)
    return re.sub(u'[%s]' % arabconst.ALEF_MAKSURA,    arabconst.YEH, text)

######################################################################
#{ Normalize One Function
######################################################################

def normalize_searchtext(text):
    """Normalize input text and return a result text.
    Normalize a text by :
        - strip tashkeel
        - strip tatweel
        - normalize  Hamza
        - normalize Lam Alef.
        - normalize Teh Marbuta and Alef Maksura
    Example:
        >>> text=u'أستشتري دمـــى آلية لأبنائك قبل الإغلاق'
        >>> normalize_searchtext(text)
        استشتري دمي اليه لابناءك قبل الاغلاق

    @param text: arabic text.
    @type text: unicode.
    @return: return a normalized text.
    @rtype: unicode. 
    """
    text = strip_tashkeel(text)
    text = strip_tatweel(text)
    text = normalize_lamalef(text)
    text = normalize_hamza(text)
    text = normalize_spellerrors(text)
    return text
