# -*- coding: utf-8 -*-

import cjson
import time
import nltk

def handler(function,data,callback):    
    try:
        data = cjson.decode(data)
    except:
        return fail("invalid input json for <data>: %s" % data,callback)
    if(function == 'sentences'):
        if isinstance(data, basestring):
            result = sentences_function(data)
        else:
            return fail('invalid input, string expected',callback)
        
    elif(function == 'tokens'):
        if isinstance(data,list):
            result = tokens_function(data)
        else:
            return fail('invalid input, string expected',callback)
        
    elif(function == 'tags'):
        if isinstance(data,list):
            result = tags_function(data)
        else:
            return fail('invalid input, list expected',callback)
    else:
        return fail('unknown function: %s' % function,callback)
    return response(result,callback)

def fail(message,callback):
    result = json_fail(message)
    return response(result,callback)        

def response(result,callback):
    if callback != '':
        return callback +'(' + result + ');'            
    else:
        return result

def json_envelope(data, start_time):
    envelope =  '{"success":true, "time":%f, "result":%s}' % (time.clock()-start_time,data) 
    return envelope.encode('UTF-8')

def json_list(lst):
    return '[' + ", ".join(['"' + s + '"' for s in lst]) + ']'

def json_fail(message):
    envelope =  '{"success":false, "message":"%s"}' % (message) 
    return envelope.encode('UTF-8')    

def sentences_function(text):
    start_time = time.clock()
    tokens = nltk.sent_tokenize(text)
    result = json_envelope(json_list(tokens),start_time)
    return (result)

def tokens_function(sentences):
    start_time = time.clock()
    tokens_list = [nltk.word_tokenize(sentence) for sentence in sentences]
    json = '[' + ", ".join([json_list(tokens) for tokens in tokens_list]) + ']' 
    result = json_envelope(json,start_time)
    return (result)

def tags_function(tokens_list):
    start_time = time.clock()
    tagged_tokens = [nltk.pos_tag(tokens) for tokens in tokens_list]
    json = '[' + ", ".join([render_json(tokens) for tokens in tagged_tokens]) + ']' 
    result = json_envelope(json,start_time)
    return (result)

def render_json(result):
    return '[' + ", ".join(['{"token":"%s","pos":"%s"}' % (w,f) for (w,f) in result])  + ']'