# eval recommendations from MovieLens data
# tested it on DSSTNE, because it has straightforward steps to getting recommendations
# to use to test this
# fills in rec_titles and data_titles - a sorted list of recommended titles and original titles popularity
# missing_titles is the list of movies not recommended from the original dataset

RECS_FILE = '[your path to "recs" file from DSSTNE]'
TITLES_FILE = '[your path to "movies.csv" from the MovieLens .zip file]'
ORIGINAL_DATA = '[your path to "ml-20m_ratings.csv" from MovieLens .zip file]'

data = {}
with open(ORIGINAL_DATA, 'r') as file:
    line = file.readline()  # skip header
    line = file.readline()
    while line:
        line = line[line.index(',')+1:]
        index = int(line[:line.index(',')])
        data[index] = data.get(index, 0) + 1
        line = file.readline()

recs = {}
with open(RECS_FILE, 'r') as file:
    line = file.readline()
    while line:
        #usr_id = line[:line.index('\t')]
        line = line[line.index('\t')+1:]

        for _ in range(10):
            index = int(line[:line.index(',')])
            recs[index] = recs.get(index, 0) + 1
            line = line[line.index(':')+1:]

        line = file.readline()


movies = {}
with open(TITLES_FILE, 'r') as file:
    line = file.readline()  # skip header
    line = file.readline()
    while line:
        index = line[:line.index(',')]
        index = int(index)
        line = line[line.index(',')+1:]
        if line[0] == '"':
            line = line[1:]
            title = line[:line.index('"')]
        else:
            title = line[:line.index(',')]
        movies[index] = title
        line = file.readline()

rec_titles = []
for k,v in recs.items():
    rec_titles.append( (v, data[k], movies[k]) )
rec_titles.sort(reverse=True)

data_titles = []
for k,v in data.items():
    data_titles.append( (v, movies[k]) )
data_titles.sort(reverse=True)

missing_titles = []
for k,v in data.items():
    if k not in recs:
        missing_titles.append( (v, movies[k]) )
missing_titles.sort(reverse=True)