# coding: utf-8
#__author__ = 'Ravi: https://kaggle.com/company'


# Required Libraries
library(data.table)
library(readr)
library(caret)
library(stringdist)

# Read in data
location <- fread("../input/Location.csv")
itemPairsTest <- fread("../input/ItemPairs_test.csv")
itemPairsTrain <- fread("../input/ItemPairs_train.csv")
itemInfoTest <- read_csv("../input/ItemInfo_test.csv")
itemInfoTrain <- read_csv("../input/ItemInfo_train.csv")
itemInfoTest <- data.table(itemInfoTest)
itemInfoTrain <- data.table(itemInfoTrain)

setkey(location, locationID)
setkey(itemInfoTrain, itemID)
setkey(itemInfoTest, itemID)

# Drop unused factors
dropAndNumChar <- function(itemInfo){
  itemInfo[, ':=' (ncharTitle = nchar(title),
                   ncharDescription = nchar(description),
                   description = NULL,
                   images_array = NULL,
                   attrsJSON = NULL)]
}

dropAndNumChar(itemInfoTest)
dropAndNumChar(itemInfoTrain)


# Merge
mergeInfo <- function(itemPairs, itemInfo){
  # merge on itemID_1
  setkey(itemPairs, itemID_1)
  itemPairs <- itemInfo[itemPairs]
  setnames(itemPairs, names(itemInfo), paste0(names(itemInfo), "_1"))
  # merge on itemID_2
  setkey(itemPairs, itemID_2)
  itemPairs <- itemInfo[itemPairs]
  setnames(itemPairs, names(itemInfo), paste0(names(itemInfo), "_2"))
  # merge on locationID_1
  setkey(itemPairs, locationID_1)
  itemPairs <- location[itemPairs]
  setnames(itemPairs, names(location), paste0(names(location), "_1"))
  # merge on locationID_2
  setkey(itemPairs, locationID_2)
  itemPairs <- location[itemPairs]
  setnames(itemPairs, names(location), paste0(names(location), "_2"))
  return(itemPairs)
}

itemPairsTrain <- mergeInfo(itemPairsTrain, itemInfoTrain)
itemPairsTest <- mergeInfo(itemPairsTest, itemInfoTest)

rm(list=c("itemInfoTest", "itemInfoTrain", "location"))