# -*- coding: utf-8 -*-
# filename： word_freq.py
#  注意：代码风格

from string import punctuation

def process_file(dst):     # 读文件到缓冲区
    try:     # 打开文件
        str = open("A_Tale_of_Two_Cities.txt", "r")
    except IOError, s:
        print s
        return None
    try:     # 读文件到缓冲区
        bvffer = str.read()
    except:
        print "Read File Error!"+bvffer
        return None
    str.close()
    return bvffer

def process_buffer(bvffer):
    if bvffer:
        word_freq = {}
        # 下面添加处理缓冲区 bvffer代码，统计每个单词的频率，存放在字典word_freq
        for i in range(97, 123):
            word_freq[chr(i)] = 0

        for line in bvffer:
         for character in line.lower():
            if ord(character) in range(97, 123):
                word_freq[character] += 1

        return word_freq

def output_result(word_freq):
    if word_freq:
        sorted_word_freq = sorted(word_freq.items(), key=lambda v: v[1], reverse=True)
        for item in sorted_word_freq[:10]:  # 输出 Top 10 的单词
            print item

if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument('dst',nargs='?')
    args = parser.parse_args()
    dst = args.dst
    bvffer = process_file(dst)
    word_freq = process_buffer(bvffer)
    output_result(word_freq)