database.py

# this file will be used in order to handle the database.txt and the logfile txt
# it is used by all modules
# the user has no direct contact with it
# last modified 12/12/2019 by Student ID: B915247

bookid = []
titles = []
authors = []
pdate = []
mid = []
# the lists used to categorize the data when we read the database


def accessor_of_data(database):
    # it is used to access data
    # line is temporary holding ground for the data extracted
    # the system reads the file and puts in the list line
    # then the function returns the list line

    line = []
    try:
        f = open(database, "r")
        # prepares to file in order to read it
        for line in f:
            line = f.readlines()
        f.close()
        # it reads all the values of the file indicated and returns a list of all the strings it contains
    except IOError:
        print("Failure in reading file")
    return line


def format_database():
    # to be used in order to reformat the database file in case a new blank file is needed
    f = open("database.txt", "w")
    line = "ID | Title | Author | Purchase Date | Member ID"
    f.write(line)
    f.close()


def sort_data_to_present_database(list_input):
    # sorts the data retrieved from the database.txt file
    # it breaks it down to lists that comprise all the data of each individual book
    # it breaks the string into smaller elements

    for i in range(0, len(list_input)):
        now_list = str(list_input[i]).split("|")
        if len(now_list) > 1:
            print(now_list)
            bookid.append(now_list[0])
            titles.append(now_list[1])
            authors.append(now_list[2])
            pdate.append(now_list[3])
            mid.append(now_list[4].strip("\n"))


def module_check_for_presenter_and_accessor():
    # this function will test if the presenter sorting the data of the database as expected
    sort_data_to_present_database(accessor_of_data("database.txt"))
    print(bookid)
    print(authors_list())
    print(titles)
    print(mid)


def database_modifier(database, message):
    # it is used to add new strings in the file
    f = open(database, "a")
    f.write(message)
    f.close()


def book_id_giver():
    # returns a list of all books' ids stored
    return bookid


def book_titles():
    # returns a list of all books' titles stored
    return titles


def authors_list():
    # returns a list of all books' authors stored
    return authors


def purchase_date():
    # returns a list of all stored books' purchase date
    return pdate


def member_id():
    # returns a list of all stored books' member id, 0 if free, the member's id if taken
    return mid


def test_data():
    # it generates test data in the database in order to check the functions
    f = open("database.txt", "w")
    line = "ID | Title | Author | Purchase Date | Member ID \n"
    f.write(line)
    line1 = "01 | The Art of War | Sun Tzu | 09/08/2019| 0 \n"
    f.write(line1)
    f.close()


def data_terminator(line, database):
    # this function deletes certain lines from the a file given
    o = open(database, "r")
    lines = o.readlines()
    # creates a file of all the lines in the file
    o.close()
    for i in range(len(lines)):
        try:
            print(lines[i])
            if str(lines[i]).strip("\n").strip(" ") == str(line).strip("\n").strip(' '):
                # finds the line needed
                lines.pop(i)
                # pops it
                f = open(database, "w")
                f.writelines(lines)
                f.close()
                # it opens and overwrites the entire file.
                break
            else:
                print("Line not found")
        except ValueError:
            print("System Malfunction")


def database_overwrite(database, origvalue, aftvalue):
    # this function is used to replace a line with a new line at the end of the file
    # reads the entire file and produces a list of all the lines
    # checks that the line that we are looking for exists
    # removes that line
    # then rewrites the entire file

    o = open(database, "r")
    lines = o.readlines()
    o.close()
    for i in range(len(lines)):
        try:
            if str(lines[i]).strip("\n").strip(" ") == origvalue.strip("\n").strip(" "):
                # finds the value that needs to be overwritten
                lines.pop(i)
                # removes it
                lines.append(aftvalue)
                # and replaces it
                f = open(database, "w")
                f.writelines(lines)
                f.close()
                # and then overwrites the file
                break
        except RuntimeError:
            print("System Malfunction")


def overwrite_test():
    # tests that the overwrite function works
    database_overwrite("database.txt", "  1 | The Art of War | Sun Tzu | 09/08/2019| 1234\n",
                       "   1 | The Art of War | Sun Tzu | 09/08/2019| 0\n")


def test_data_removal():
    # it used a value that no longer exists
    data_terminator(" 1 | The Art of War | Sun Tzu | 09/08/2019| 0", "database.txt")


def resetdata():
    # resets all the lists of the entire file
    bookid = []
    titles = []
    authors = []
    pdate = []
    mid = []
    sort_data_to_present_database(accessor_of_data("database.txt"))


if __name__ == "__main__":
    overwrite_test()
    test_data_removal()