const defdir = joinpath(dirname(@__FILE__), "..", "datasets")

function getmovielensdata(dir)
   	mkpath(dir)
   	path = download("http://files.grouplens.org/datasets/movielens/ml-100k.zip")
   	run(unpack_cmd(path, dir, ".zip", ""))
end

function getmovielensdata1m(dir)
   	mkpath(dir)
   	path = download("http://files.grouplens.org/datasets/movielens/ml-1m.zip")
   	run(unpack_cmd(path, dir, ".zip", ""))
end

"""
    MovieLens()::Persa.Dataset

Return MovieLens 100k dataset.
"""
function MovieLens()::Persa.Dataset
   	filename = "$(defdir)/ml-100k/u.data"

   	isfile(filename) || getmovielensdata(defdir)

   	file = CSV.read(filename, DataFrame, delim = '\t',
					header = [:user, :item, :rating, :timestamp],
					types = [Int, Int, Int, Int])

   	return Persa.Dataset(file)
end

"""
    MovieLens1M()::Persa.Dataset

Return MovieLens 1M dataset.
"""
function MovieLens1M()::Persa.Dataset
    filename = "$(defdir)/ml-1m/ratings.dat"

    isfile(filename) || getmovielensdata1m(defdir)

    file = CSV.read(filename, DataFrame, delim = "::",
						header = [:user, :item, :rating, :timestamp],
						types = [Int, Int, Int, Int])

    df = DataFrame()

   	df[!, :user] = convert(Array{Int}, file[!, :user])
   	df[!, :item] = convert(Array{Int}, file[!, :item])
   	df[!, :item] = labelencode(labelmap(df[!, :item]), df[!, :item])
   	df[!, :rating] = convert(Array{Int}, file[!, :rating])
   	df[!, :timestamp] = convert(Array{Int}, file[!, :timestamp])

    return Persa.Dataset(df)
end
