""" IMDB database (https://www.imdb.com/interfaces/) is not clean, which can be improved by some heuristic rules
rule 1. titleType == 'movie' (from ['short', 'movie', 'tvShort', 'tvMovie', 'tvSeries', 'tvEpisode', 'tvMiniSeries', 'tvSpecial', 'video', 'videoGame', 'tvPilot'])
rule 2. runtimeMinutes == '60' - '360' (1h - 6h)
rule 3. sorted by numVotes (descending)
the cleaned dataset is called “imdb/movie_clean.tsv”
"""

import pandas as pd

df_basics = pd.read_csv("title.basics.tsv", sep="\t")
df_ratings = pd.read_csv("title.ratings.tsv", sep="\t")

print("Before merging: ", df_basics.shape, df_ratings.shape)

# merge
df = pd.merge(df_basics, df_ratings, on="tconst", how="left")

# Fill missing values with -1
df.fillna(-1, inplace=True)

print("Before cleaning: ", df.shape)

# rule 1
df = df[df['titleType'] == 'movie']

print("After Rule 1: ", df.shape)

# rule 2
df = df[df['runtimeMinutes'].apply(lambda x: x.isnumeric() and 60 <= int(x) <= 360)]

print("After Rule 2: ", df.shape)

# rule 3
df = df.sort_values(by="numVotes", ascending=False)

# save
df.to_csv("movie_clean.tsv", sep="\t", index=False)