# -*- coding: utf-8 -*-
"""
u.data     -- The full u data set, 100000 ratings by 943 users on 1682 items.
              Each user has rated at least 20 movies.  Users and items are
              numbered consecutively from 1.  The data is randomly
              ordered. This is a tab separated list of
             user id | item id | rating | timestamp.
              The time stamps are unix seconds since 1/1/1970 UTC

"""
import numpy as np
import math



def srednia_filmu(movie_id, in_array):
    suma=0
    ilosc=0
    for x in in_array:
        if x[1]==movie_id:
            ilosc+=1
            suma+=x[2]
    return suma/ilosc;

def srednia_uzytkownika(user_id,in_array):
    suma=0
    ilosc=0
    for x in in_array:
        if x[0]==user_id:
            ilosc+=1
            suma+=x[2]
    print('Suma %s (%f)' % (suma))
    return suma/ilosc;


def select(parameter_index,value,in_array):
    out_list=[]
    for x in in_array:
        if x[parameter_index]==value:
            out_list.append(x)
    return out_list;

def sim(a,b):
    P=[]
    P1=select(0,a,arr)
    P2=select(0,b,arr)
    for x in P1:
        for y in P2:
            if y[1]==x[1]:
                P.append([x[1], x[2], y[2]])
            break
    if not P:
        return 0
    sr_a=srednia_uzytkownika(a,arr)
    sr_b=srednia_uzytkownika(b,arr)
    dzielna=0
    for p in P:
        dzielna+=(p[1]-sr_a)*(p[2]-sr_b)
    s1=0
    for p in P:
        s1+=(p[1]-sr_a)*(p[1]-sr_a)
    s2=0
    for p in P:
        s2+=(p[2]-sr_b)*(p[2]-sr_b)

    dzielnik=math.sqrt(s1)*math.sqrt(s2)
    return dzielna/dzielnik;
def users():
    print("Generowanie słownika użytkownikow")
    users_dictionary={}
    size=0
    for x in arr:
        if x[0] not in users_dictionary:
            users_dictionary[x[0]]=select(0,x[0],arr)
            size+=1
            if size % 20 ==0:
                print("Ilość użytkownikow: "+str(size))
    return users_dictionary;
def users1():
    print("Generowanie słownika użytkownikow")
    users_dictionary={}
    size=0
    for x in arr:
        if x[0] not in users_dictionary:
            l=select(0,x[0],arr)
            node={}
            for y in l:
                node[y[1]]=y[2]
            users_dictionary[x[0]]=node
            size+=1
            if size % 20 ==0:
                print("Ilość użytkownikow: "+str(size))
    return users_dictionary;

def pred(a,p):
    sr_a=srednia_uzytkownika(a,arr)
    dzielna=0
    for k,value in users_movies_rate.items():
        if k!= a:
            if p in value:
                r_k_p=value[p]
            else:
                r_k_p=0
            dzielna+=sim(a,k)*(r_k_p-srednia_uzytkownika(k,arr))
    dzielnik=0
    for k in users_movies_rate:
        if k!=a:
            dzielnik+=sim(a,k)
    return sr_a+dzielna/dzielnik;



f=open("c:\\Users\\Computer\\Desktop\\System_rekomendacyjny-master\\System_rekomendacyjny-master\\DB\\u.data")
lista=[]


for line in f:
        splited=line.split("\t",4)
        lista.append([int(splited[0]),int(splited[1]),\
        int(splited[2]),int(splited[3])])

arr=np.array(lista)
users_movies_rate=users1()

ar = []
#print('Najbardziej podobny %s (%f)' % (srednia_filmu(1, ar)))