package com.be.music.blast.musicBlast;

import org.springframework.stereotype.Service;

import java.sql.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.sql.Date;

import javax.sql.DataSource;

import org.apache.mahout.cf.taste.common.TasteException;
import org.apache.mahout.cf.taste.impl.common.FastByIDMap;
import org.apache.mahout.cf.taste.impl.model.GenericDataModel;
import org.apache.mahout.cf.taste.impl.model.GenericPreference;
import org.apache.mahout.cf.taste.impl.model.GenericUserPreferenceArray;
import org.apache.mahout.cf.taste.impl.neighborhood.NearestNUserNeighborhood;
import org.apache.mahout.cf.taste.impl.neighborhood.ThresholdUserNeighborhood;
import org.apache.mahout.cf.taste.impl.recommender.CachingRecommender;
import org.apache.mahout.cf.taste.impl.recommender.GenericUserBasedRecommender;
import org.apache.mahout.cf.taste.impl.similarity.PearsonCorrelationSimilarity;
import org.apache.mahout.cf.taste.model.DataModel;
import org.apache.mahout.cf.taste.model.Preference;
import org.apache.mahout.cf.taste.model.PreferenceArray;
import org.apache.mahout.cf.taste.neighborhood.UserNeighborhood;
import org.apache.mahout.cf.taste.recommender.RecommendedItem;
import org.apache.mahout.cf.taste.recommender.Recommender;
import org.apache.mahout.cf.taste.recommender.UserBasedRecommender;
import org.apache.mahout.cf.taste.similarity.UserSimilarity;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.Statement;
import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;

@Service
public class RecommendersService {


    public RecommendersService()
    {

    }

    public void generateStartingData(ResultSet rs, Connection con) throws SQLException {
        int id_product;
        int id_rate;
        int id_customer;
        float rateValue;
        long miliSeconds;
        String query2 = "INSERT INTO ps_product_comment "
                    + "(id_product_comment, id_product, id_customer, grade, content, title, customer_name, validate, deleted, date_add) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
        PreparedStatement prepStmt = con.prepareStatement(query2);
        try {
            while(rs.next()){
                 id_product  = rs.getInt("id_product");
                 id_customer = rs.getInt("id_customer");
                 rateValue =  rs.getFloat("rate");
                 id_rate = rs.getInt("id_rate");
                prepStmt.setInt(1, id_rate);
                prepStmt.setInt(2, id_product);
                prepStmt.setInt(3, id_customer);
                prepStmt.setFloat(4, rateValue);
                prepStmt.setString(5, "Random content");
                prepStmt.setString(6, "Random title");
                prepStmt.setString(7, "Random name");
                prepStmt.setBoolean(8, true);
                prepStmt.setBoolean(9, false);
                miliSeconds = (long)46* (long)365* (long)24* (long)60* (long)60* (long)1000;
                prepStmt.setDate(10, new Date(miliSeconds));
                prepStmt.execute();

                 System.out.print(id_product + " ");
                 System.out.print(id_customer + " ");
                 System.out.print(rateValue + " ");
                 System.out.println(id_rate + " ");
              }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public CachingRecommender getRecommender(Connection con, ResultSet rs, Statement stmt) throws SQLException, TasteException {
        String comment_stmt = "SELECT * FROM ps_product_comment";
        List<Preference> liOfRatePrefs = new ArrayList<Preference>();
        GenericUserPreferenceArray genUserRatePrefs;
        FastByIDMap<PreferenceArray> fastRatePrefsMap;
        GenericDataModel genericRatesModel;
        UserSimilarity userSimilarity;
        UserNeighborhood neighborhood;
        Recommender recommender, cachingRecommender;

        //Creating list of lists of rates for one customer
        ArrayList<ArrayList<Preference>> liOfliOfRatePref= new ArrayList<ArrayList<Preference>>();
        for (int i=0 ;i<getNumOfCustomers(con, rs, stmt) ;i++) {
            liOfliOfRatePref.add(new ArrayList<Preference>());
        }



        writePrefsToList(con, rs, stmt, liOfliOfRatePref);

        for (int i=0 ;i<getNumOfCustomers(con, rs, stmt) ;i++) {
             for (Preference arr : liOfliOfRatePref.get(i)) {
                // System.out.println(arr.getUserID() + " " + arr.getValue() + " " + arr.getItemID());
             }
        }

        fastRatePrefsMap = new FastByIDMap<PreferenceArray>();
        for (int i=0; i<liOfliOfRatePref.size(); i++){
            fastRatePrefsMap.put((long) i, new GenericUserPreferenceArray(liOfliOfRatePref.get(i)));
            GenericUserPreferenceArray gen = (GenericUserPreferenceArray) fastRatePrefsMap.get(i);
            for (int j = 0; j < gen.length(); j ++) {
            //  System.out.println(gen.get(j).getItemID() + " " + gen.get(j).getUserID() + " " + gen.get(j).getValue());
            }

        }

        genericRatesModel = new GenericDataModel(fastRatePrefsMap);
        userSimilarity = new PearsonCorrelationSimilarity(genericRatesModel);
        neighborhood = new ThresholdUserNeighborhood(0.1, userSimilarity, genericRatesModel);
        recommender = new GenericUserBasedRecommender(genericRatesModel, neighborhood, userSimilarity);

        return new CachingRecommender(recommender);
    }

    public void writePrefsToList(Connection con, ResultSet rs, Statement stmt, ArrayList<ArrayList<Preference>> liOfliOfRatePref) throws SQLException {
        int id_product = 0;
        int id_customer = 0;
        int id_rate = 0;
        float rateValue = (float) 0.0;
        String comment_stmt = "SELECT * FROM ps_product_comment";
        stmt = (Statement) con.createStatement();
        rs = stmt.executeQuery(comment_stmt);
        while(rs.next()){
             id_product  = rs.getInt("id_product");
             id_customer = rs.getInt("id_customer");
             rateValue =  rs.getFloat("grade");
             id_rate = rs.getInt("id_product_comment");

            // Adding preference to the list by correct id_customer (id_customer - 1, because in DB there are customers counted from 1)
            liOfliOfRatePref.get(id_customer - 1).add(new GenericPreference(id_customer,  id_product,  rateValue));
        }
    }

    public int getNumOfCustomers(Connection con, ResultSet rs, Statement stmt) throws SQLException  {
        String customers_stmt    = "SELECT * FROM ps_customer";
        stmt = (Statement) con.createStatement();
        rs = stmt.executeQuery(customers_stmt);
        int numOfCustomers = 0;
        while(rs.next()) {
             numOfCustomers++;
             System.out.println(numOfCustomers);
        }

        return numOfCustomers;
    }

    public String getItemIds(int idOfUser) throws TasteException
    {
        Connection conn = null;
        Connection con = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
          // Get connection from DataSource
            con = (Connection) DriverManager.getConnection("jdbc:mysql://172.22.0.2:3306/zabawa","root","szachownica");
            stmt = (Statement) con.createStatement();


            List<RecommendedItem> recommendations = getRecommender(con, rs, stmt).recommend(20, 3);
            String itemIDs = null;
            for(int i=0; i<recommendations.size(); i++) {
                itemIDs += recommendations.get(i).getItemID();
                if(i != recommendations.size()-1) itemIDs += ",";;
            }

            return itemIDs;


    }catch (SQLException e) {
        e.printStackTrace();
      } finally {
        try {
          if (rs != null) {
            rs.close();
          }
          if (stmt != null) {
            stmt.close();
          }
          if (conn != null) {
            conn.close();
          }
        } catch (Exception e) {
          e.printStackTrace();
        }
      }
        return null;
    }

}