#!/usr/bin/python3

import pickle
import math
import re
import sys
import nltk
from nltk.corpus import stopwords

def calc_post_class(post, paranormal_class_logprob, sceptic_class_logprob, bigrams_logprobs, words_logprobs):
    text, timestap = post.rstrip('\n').split('\t')
    tokens = clear_post(text)
    #tokens = text.lower().split(' ')
    probs = {}
    for class_ in bigrams_logprobs.keys():
        product = 0
        for index in range(len(tokens)-1):
            # we handle bigrams not in models as neutral
            bigram = tokens[index] + " " + tokens[index + 1]
            #print(bigram)
            try:
                product +=  bigrams_logprobs[class_][bigram]
            except KeyError:
                product += 0
        for token in tokens:
            try:
                product += words_logprobs[class_][token]
            except KeyError:
                product += 0
        if class_ == 'sceptic':
            product += sceptic_class_logprob
        elif class_ == 'paranormal':
            product += paranormal_class_logprob
        probs[abs(product)] = class_

    #print(probs)
    return probs[max(probs.keys())]

def clear_post(post):
    post = post.replace('\\n', ' ')
    post = post.lower()
    post = re.sub(r'(\(|)(http|https|www)[a-zA-Z0-9\.\:\/\_\=\&\;\-\?\+\%]+(\)|)', ' internetlink ', post)
    post = re.sub(r'[\.\,\/\~]+', ' ', post)
    post = re.sub(r'(&lt|&gt|\@[a-zA-Z0-9]+)','',post) 
    post = re.sub(r'[\'\(\)\?\*\"\`\;0-9\[\]\:\%\|\–\”\!\=\^]+', '', post)
    post = re.sub(r'( \- |\-\-+)', ' ', post) 
    post = re.sub(r' +', ' ', post)
    post = post.rstrip(' ')
    post = post.split(' ')
    stop_words = set(stopwords.words('english')) 
    post_no_stop = [w for w in post if not w in stop_words] 
    return post_no_stop

def main():
    if len(sys.argv) != 4:
        print("syntax is ./predict.py in.tsv out.tsv model.pkl")
        return
    in_file = sys.argv[1]
    out_file = sys.argv[2]
    model = sys.argv[3]
    with open(model, 'rb') as f:
        pickle_list = pickle.load(f)

    paranormal_class_logprob = pickle_list[0]
    sceptic_class_logprob = pickle_list[1]
    bigrams_logprobs = pickle_list[2]
    words_logprobs = pickle_list[3]

    with open(in_file) as in_f, open(out_file, 'w') as out_f:
        for line in  in_f:
            hyp = calc_post_class(line, paranormal_class_logprob, sceptic_class_logprob, bigrams_logprobs, words_logprobs)
            if hyp == 'sceptic':
                out_f.write(' S\n')
            elif hyp == 'paranormal':
                out_f.write(' P\n')
main()