# CS1300 Fall 2017
# Author: Gerald Robinson
# Recitation: Ganesh 123
# Assignment 10


#PART_1 functions here
def read_books(file_name):
    try:
        file=open(file_name)
        if file =="":
            return []
        else:
            result=[]
            for line in file:
                temp = line.strip().split(',')
                author = temp[0]
                book = temp[1]
                list = [book, author]
                result.append(list)
            return result
    except:
        return None


def read_users(file_name):
    try:
        file=open(file_name)
        if file == "":
            return {}
        else:
            mydict={}
            listofratings=[]
            for line in file:
                read = []
                line = line.strip().split()
                user=line[0]
                for i in range(1, len(line)):
                    listofratings.append(line[i])
                read = [user, listofratings]
                mydict[read[0]]=list(map(int,line[1:]))
        return mydict
    except:
        return None

def calculate_average_rating(ratings_dict):
    ratings_list = ratings_dict.values()
    rateNumbers = len(ratings_list)
    numBooks = len(ratings_list)

    avg_rates=[]

    for i in range(numBooks):
        index = 0
        num = 0.0
        for listofratings in ratings_list:
            num=num+float(listofratings[i])
            if listofratings!=0:
                index = index+1.0
        if num != 0:
            avg=num/index
        avg_rates.append(avg)

    return avg_rates

def lookup_average_rating(index, book_dict, avg_ratings_dict):
    books = book_dict[index]
    rate = "{0: .2f}".format(avg_ratings_dict[index])
    titles=books[0]
    authors=books[1]
    return "(%s) %s by %s"%(rating, titles, authors)





#PART_2 follow here


class Recommender:
    #Constructor here
    def __init__(self, book_filename, ratings_filename):
        self.book_list = []
        self.user_dictionary = {}
        self.average_rating_list = []
        self.read_books(book_filename)
        self.read_users(ratings_filename)
        self.calculate_average_rating()


    def read_books(self, file_name):
        try:
            file=open(file_name)
            if file =="":
                return []
            else:
                for line in file:
                    temp = line.strip().split(',')
                    authors = temp[0]
                    books = temp[1]
                    list = [books, authors]
                    self.book_list.append(list)
                return self.book_list
        except:
            return None

    def read_users(self, file_name):
        try:
            file=open(file_name,'r')
            if file == "":
                return {}
            else:
                listofratings=[]
                for line in file:
                    read = []
                    line = line.strip().split()
                    user=line[0]
                    for i in range(1, len(line)):
                        listofratings.append(line[i])
                        read = [user, listofratings]
                        self.user_dictionary[read[0]]=list(map(int,line[1:]))
                return self.user_dictionary
        except:
            return None


    def calculate_average_rating(self):
        ratings_list = self.user_dictionary.values()
        rateNumbers = len(ratings_list)
        numBooks = len(ratings_list)
        for i in range(numBooks):
            index = 0
            num = 0.0
            for listofratings in ratings_list:
                num=num+float(listofratings[i])
                if listofratings!=0:
                    index = index+1.0
            if num != 0:
                avg=num/index
            self.average_rating_list.append(avg)
        return self.average_rating_list

    def lookup_average_rating(self, book_index):
        books = self.book_list[book_index]
        rate = "{0: .2f}".format(self.average_rating_list[book_index])
        titles=books[0]
        authors=books[1]
        average_rating_string="(%s) %s by %s"%(rating, titles, authors)
        return average_rating_string
        self.average_rating_string = "(%s) %s by %s"%(rating, titles, authors)
        return self.average_rating_string

    def calc_similarity(self, user1, user2):
        similar=0
        for i in range(1,len(self.user_dictionary[user1])):
            similar=similar+(self.user_dictionary[user1[i]]*self.user_dictionary[user2][i])
        return similar

    def get_most_similar_user(self, current_user_id):
        highScore=0
        best_user_match_id=""
        for i in range(1, len(self.user_dictionary)):
            if current_user_id == self.user_dictionary.keys()[i]:
                continue
            similarity=self.calc_similarity(current_user_id, self.user_dictionary.keys()[i])
            if similarity>highScore:
                highScore=similarity
                best_user_match_id=self.user_dictionary.keys()[i]
        return best_user_match_id

    def recommend_books(self, current_user_id):
        list=[]
        similarUser=self.get_most_similar_user(current_user_id)
        for i, rating in enumerate(self.user_dictionary[similarUser]):
            if rating and self.user_dictionary[current_user_id][i]==0:
                list.append(self.lookup_average_rating(i))
        return list


def main():
    name=Recommender("book.txt","ratings.txt")
    mylist=name.read_books("book.txt")
    print mylist
    # print lookup_average_rating(0, read_books('books.txt'),calculate_average_rating('ratings.txt'))
    #test your functions and classes here


if __name__ == "__main__":

    main()