import sys, re, string, sqlite3

#
# The relational database of this problem consists of 3 tables:
# documents, words, characters
#
def create_db_schema(connection):
    c = connection.cursor()
    c.execute('''CREATE TABLE documents (id INTEGER PRIMARY KEY AUTOINCREMENT, name)''')
    c.execute('''CREATE TABLE words (id, doc_id, value)''')
    c.execute('''CREATE TABLE characters (id, word_id, value)''')
    connection.commit()
    c.close()

def load_file_into_database(path_to_file, connection):
    """ Takes the path to a file and loads the contents into the database """
    def _read_file(path_to_file):
        """
        Takes a path to a file and returns the entire contents of the 
        file as a string
        """
        f = open(path_to_file)
        data = f.read()
        f.close()
        return data

    def _filter_chars_and_normalize(str_data):
        """
        Takes a string and returns a copy with all nonalphanumeric chars
        replaced by white space, and all characters lower-cased
        """
        pattern = re.compile('[\W_]+')
        return pattern.sub(' ', str_data).lower()

    def _scan(str_data):
        """ Takes a string and scans for words, returning a list of words. """
        return str_data.split()

    def _remove_stop_words(word_list):
        f = open('../stop_words.txt')
        stop_words = f.read().split(',')
        f.close()
        # add single-letter words
        stop_words.extend(list(string.ascii_lowercase))
        return [w for w in word_list if not w in stop_words]

    # The actual work of splitting the input into words
    words = _remove_stop_words(_scan(_filter_chars_and_normalize(_read_file(path_to_file))))

    # Now let's add data to the database
    # Add the document itself to the database
    c = connection.cursor()
    c.execute("INSERT INTO documents (name) VALUES (?)", (path_to_file,))
    c.execute("SELECT id from documents WHERE name=?", (path_to_file,))
    doc_id = c.fetchone()[0]

    # Add the words to the database
    c.execute("SELECT MAX(id) FROM words")
    row = c.fetchone()
    word_id = row[0]
    if word_id == None:
        word_id = 0
    for w in words:
        c.execute("INSERT INTO words VALUES (?, ?, ?)", (word_id, doc_id, w))
        # Add the characters to the database
        char_id = 0
        for char in w:
            c.execute("INSERT INTO characters VALUES (?, ?, ?)", (char_id, word_id, char))
            char_id += 1
        word_id += 1
    connection.commit()
    c.close()

#
# The main function
#
connection = sqlite3.connect(':memory:')
create_db_schema(connection)
load_file_into_database(sys.argv[1], connection)

# Now, let's query
c = connection.cursor()
c.execute("SELECT value, COUNT(*) as C FROM words GROUP BY value ORDER BY C DESC")
for i in range(25):
    row = c.fetchone()
    if row != None:
        print row[0] + ' - '  + str(row[1])

connection.close()