#!/usr/bin/python

############################################################
# Main Program
############################################################

if __name__ == '__main__':
    import sys
    import string
    try:
        import psyco
        psyco.full()
    except:
        print >> sys.stderr, 'Warning: No psyco available'
    # COMMANDLINE: tagger.py training_file test_file
    if len(sys.argv) > 2:
        training_file = sys.argv[1]
        test_file = sys.argv[2]
    elif len(sys.argv) > 1:
	training_file = sys.argv[1]
        print >> sys.stderr, 'No test file!\n' 
    else: print >> sys.stderr, 'Usage: tagger.py <training_file> <test_file>'
    # sys.stderr is the file like object that corresponds to STDERR
    # Reading training data
    best_tag={}  ## best tag for word: = most frequent tag
    default_tag='' ## tag with best overall count
    try:
        fsock_train=open(training_file,'r',0)
        print >> sys.stderr, 'Reading %s' % training_file
        word_tag_matrix={}  ## word tag pair counts
        ## For word tag pairs, each key-value pair: a pair of a word and a tag
        ## 
        ## word_tag_matrix.get(('all','DET0'),0) = the number of 'all' tokens tagged as DET0
        ##               0 is what to return if (key,val) does not occurr in matrix...
        ##               safe when ('all','DET0') has never been seen
        ## incrementing (safe for 1st occurrence of key,val)
        ## word_tag_matrix['all','DET0'] = word_tag_matrix.get(('all','DET0'),0) +1
        tag_count={}   ##  tag counts
        ## NB: the 'get' method on dictionaries works for singleton keys as well as pair keys...
        ## tag_count[tag]=tag_count.get(tag,0)+1
        best_tag_count={} ## store count of best tag for word
        for line in fsock_train:
             splitline=line.rstrip().split()
             # split(' ') differs from split().
             # The latter handles consecutive spaces as we'd like
             if len(splitline)>0:
                 for elem in splitline:  ## Each elem shd be a word_tag pair connected by "_" 
                     wt_pair=elem.split('_')
                     if len(wt_pair)==2:
                         (word,tag)=wt_pair
                         word_tag_matrix[word,tag]=word_tag_matrix.get((word,tag),0) + 1
                         tag_count[tag]=tag_count.get(tag,0)+1
                         # print (word,tag)
                     else: print >> sys.stderr, 'Ill formed word/tag pair ', wt_pair
             else: continue
        fsock_train.close()
        print >> sys.stderr, 'Computing best tags'
        for wt_pair in word_tag_matrix.keys():
            (word,tag)=wt_pair
            word_tag_count=word_tag_matrix[word,tag]
            if word_tag_count > best_tag_count.get(word,0):
                best_tag_count[word]=word_tag_count
                best_tag[word]=tag
                # print (word,tag)
                default_tag_count=0
        for tag in tag_count.keys():
            if tag_count[tag] > default_tag_count:
                default_tag_count=tag_count[tag]
                default_tag=tag
            else: continue
    except IOError:
        print >> sys.stderr, "Unable to open %s" % training_file
    try:
        fsock_test=open(test_file,'r',0)
        print >> sys.stderr, 'Reading %s' % test_file
        for line in fsock_test:
             splitline=line.rstrip().split(' ')
             if len(splitline)>0:
                 for word in splitline:  ## Each word shd be an untagged word
                     tag=best_tag.get(word,0)
                     if tag:
                         print '%s_%s' % (word, tag),
                         # print "%s_%s" % (word, tag) adds a carriage return each time
                         # Python string magic:  '%s_%s ' % (word, tag) evaluates  to the string we want.
                         # print word + '_' + tag + ' ' # '+': concatenate operator, alt syntax
                         # See Dive into Python, Section 3.5
                         # Alternative: 
                         # sys.stdout.write('%s_%s ' % (word, tag)) 
                         # sys.stdout is the Python filelike object corresponding to STDOUT
                     elif default_tag:
                         print '%s_%s ' % (word, default_tag),
                     else: print '%s_dunno ' % word, # we didnt find the training file.
                 print '\n',
        fsock_test.close()
    except IOError:
        print >> sys.stderr, "Unable to open %s" % test_file