/*
  This is a JavaScript script for mongodb.
  It constructs a new version of the Artists collection of the moma
  database from the one created by mongoimport and the Artists.json
  files downloaded from the Museum of Modern Art:

  https://github.com/MuseumofModernArt/collection

  It makes the following changes:

  The auto-generated _id field is replaced by the ConstituentID in Artists

  For each artist document, we add an array field which is an array of
  the ObjectIDs of the artist's artworks
*/
conn = new Mongo("mongodb.cs.oberlin.edu")
db1 = conn.getDB("moma1")
db2 = conn.getDB("moma2")
db2.Artists.drop()
db2.createCollection("Artists")
cursor1 = db1.Artists.find()
docs = []
n = 0
while(cursor1.hasNext()){
    doc = cursor1.next()
    doc._id = doc.ConstituentID
    cursor2 = db1.Artworks.find({ "Artist.ConstituentID" : doc.ConstituentID })
    doc.Artworks = []
    while(cursor2.hasNext()){
	doc.Artworks.push(cursor2.next().ObjectID)
    }
    docs.push(doc)
    n++
    if(n%1000==0){
	print("processed "+n+" artists")
    }
}
    print("inserting "+n+" documents into Artists collection")
db2.Artists.insertMany(docs)