# Map 1-based optional input ports to variables
data.songs <- maml.mapInputPort(1) # class: data.frame

data.toUse <- (data.songs[,!(names(data.songs) %in% c("user"))])

getCosine <- function(x,y)
{
  this.cosine <- sum(x*y) / (sqrt(sum(x*x)) * sqrt(sum(y*y)))
  return(this.cosine)
}

data.similarity  <- matrix(NA, nrow=ncol(data.toUse),
                           ncol=ncol(data.toUse),
                           dimnames=list(colnames(data.toUse),
                                         colnames(data.toUse)))


for(i in 1:ncol(data.toUse)) {
  # Loop through the columns for each column
  for(j in 1:ncol(data.toUse)) {
    # Fill in placeholder with cosine similarities
    data.similarity[i,j] <- getCosine(as.matrix(data.toUse[i]),
                                      as.matrix(data.toUse[j]))
  }
}

data.neighbours <- matrix(NA, nrow=ncol(data.similarity),
                          ncol=11,dimnames=list(colnames(data.similarity)))

for(i in 1:ncol(data.toUse))
{
  data.neighbours[i,] <-
    t(head(n=11,
           rownames(as.matrix((data.similarity[order(data.similarity[,i],
                                                     decreasing = TRUE),][,i])))))
}


data.neighbours = as.data.frame(data.neighbours)
# Select data.frame to be sent to the output Dataset port
maml.mapOutputPort("data.neighbours");