import re
import pandas as pd
import math
from functools import reduce

df1 = pd.read_csv('教典例句.csv', header=0, names=['漢字', '羅馬字'])
df2 = pd.read_csv('教典發音詞.csv',header=0, names=['漢字', '羅馬字'])


df = pd.concat([df1, df2]) # combine 2 csv dataframe

df['羅馬字'] = df['羅馬字'].str.lower()

new_data = []

for index, row in df.iterrows():
    hanji = list(filter(lambda x : re.match("[^、（）；：，。！？「」『』]", x), list(row['漢字'])))
    tl = re.split(r'(:?[!?;,.\"\'\(\):]|[-]+|\s+)', row['羅馬字'])
    tl2 = list(filter(lambda x : re.match(r"([^\(\)^!:?; \'\",.\-\u3000])", x), tl))
    new_data.append((hanji, tl2))
    #if (len(hanji) != len(tl2)):
        #print(tl2, hanji)
    #print(tl2, hanji)


# char-To-Pronounciation Prossibility dict

char_to_pronounce = {}

for i in new_data:
    hanji = i[0]
    lomaji = i[1]
    for j in range(len(i[0])):
        if not hanji[j] in char_to_pronounce:
            char_to_pronounce[hanji[j]] = {lomaji[j] : 1}
        elif not lomaji[j] in char_to_pronounce[hanji[j]]:
            char_to_pronounce[hanji[j]][lomaji[j]] = 1
        else:
            char_to_pronounce[hanji[j]][lomaji[j]] += 1

for char, char_reading in char_to_pronounce.items():
    total_count = reduce((lambda x, y : x + y), list(char_reading.values()))

    for i in char_reading.keys():
        char_reading[i] = char_reading[i] / float(total_count)

#print(char_to_pronounce)

all_chars = char_to_pronounce.keys()

'''{'提': 45, '宋': 7, '完': 18, '刻': 7, '局': 9,
 '巡': 8, '畫': 25, '青': 56, '尪': 13}'''
init_freq = {} #詞kap句開始ê字出現次數

for i in new_data:
    head_hanji = i[0][0]

    if head_hanji in init_freq:
        init_freq[head_hanji] += 1
    else:
        init_freq[head_hanji] = 1

#補字
min_weight = 0.1

for i in all_chars:
    if not i in init_freq.keys():
        init_freq[i] = 0.1
        
#print(init_freq)
    



# probability of P(next=c2|this=c1)
char_transition = {}

for i in new_data:
    hanji = i[0]
    for j in range(len(i[0])-1):
        this_hanji = hanji[j]
        next_hanji = hanji[j+1]
        if not this_hanji in char_transition:
            char_transition[this_hanji] = {next_hanji : 1}
        elif not next_hanji in char_transition[this_hanji]:
            char_transition[this_hanji][next_hanji] = 1
        else:
            char_transition[this_hanji][next_hanji] += 1

#print(char_transition)

#補字
for i in all_chars:
    if not i in char_transition.keys():
        char_transition[i] = {}
        for j in all_chars:
            char_transition[i][j] = init_freq[j]
    else:
        pass

for i in char_transition.keys():
    for j in all_chars:
        if not j in char_transition[i].keys():
            char_transition[i][j] = min_weight * (0.03+math.log(init_freq[j]))


for char, next_char in char_transition.items():
    total_count = 0
    [total_count := total_count + x for x in list(next_char.values())]

    for i in next_char.keys():
        next_char[i] = next_char[i] / float(total_count)




def get_homophones(pron):
    homophones = []
    for i in char_to_pronounce.keys():
        if pron in char_to_pronounce[i].keys():
            homophones.append(i)
        else:
            pass

    return homophones

input_lomaji = ["guá", "kap", "tshit", "á", "lâi", "khì", "tâi", "tiong", "tshit", "thô", "sūn", "suà", "tsē", "ko", "thih"]

char_candidates = []

for i in input_lomaji:
    homophones = list(map(lambda x : {"char": x,
                                      "prev_char": None,
                                      "prob" : None}, # probibility
                          get_homophones(i)))
    char_candidates.append(homophones)

#print(char_candidates)
def get_max_prob(input_lmj, char_cand):
    for i in range(len(input_lmj)):
        if i == 0:
            for j in char_cand[i]:
                init_freq_sum = reduce(lambda x, y : x + y,
                                       list(
                                           map(lambda x : init_freq[x["char"]] ,
                                               char_cand[0])))
                print(init_freq_sum)
                ch = j["char"]
                init_to_char_prob = init_freq[ch] / init_freq_sum # get the ratio
                char_reading_prob = char_to_pronounce[ch][input_lmj[0]]
            
                j["prob"] = init_to_char_prob * char_reading_prob
        
            result = ""
            max_num = -math.inf

            for i in char_cand[0]:
                if i["prob"] >= max_num:
                    max_num = i["prob"]
                    result = i["char"]

            #print(result)
        else:
            for j in char_cand[i]:
                prob = -math.inf
                prev_char = ""
                for k in char_cand[i-1]:
                    k_prob = k["prob"]
                    #print(k["char"], "k_prob:", k_prob)
                    k_to_j_prob = char_transition[k["char"]][j["char"]]
                    #print(k["char"], "->",j["char"] ,"k_to_j_prob:", k_to_j_prob)
                    j_to_pron_prob = char_to_pronounce[j["char"]][input_lmj[i]]
                    total_tmp_prob = k_prob * k_to_j_prob * j_to_pron_prob 
                    if prob < total_tmp_prob:
                        prob = total_tmp_prob
                        prev_char = k

                j["prev_char"] = prev_char["char"]
                j["prob"] = prob

    real_last_char = ""
    prev_char = ""
    prob = -math.inf
    for i in char_cand[-1]:
        if i["prob"] > prob:
            prob = i["prob"]
            real_last_char = i["char"]
            prev_char = i["prev_char"]

    print(real_last_char)

    result_hanji = [real_last_char]
    for i in range(len(input_lmj)-2, -1, -1):
        current = list(filter(lambda x : x["char"] == prev_char,
                              char_cand[i]))[0]
        result_hanji.append(current["char"])
        prev_char = current["prev_char"]
        

    result_hanji.reverse()
    
    result_hanji_string = "".join(result_hanji)
    print("輸入ê羅馬字陣列(array)：", input_lomaji)
    print("輸出ê漢字：", result_hanji_string)
                
    
get_max_prob(input_lomaji, char_candidates)