import sys
import csv


COUNTRY_IDX = 0
INDICATOR_IDX = 1


def get_data_for(csvreader, indicator):
    all_data = []
    for row in csvreader:
        if row[INDICATOR_IDX] == indicator:
            all_data.append((row[COUNTRY_IDX],
                            [int(num.replace('.', ''))
                             if len(num.strip()) != 0 else None for num in row[2:]]))
    return all_data


def output_data(filename, data):
    with open(filename, 'w') as f:
        f.write("Year {}\n".format(" ".join(list([('"' + country + '"') for country, _ in data]))))
        for idx, year in enumerate(range(1970, 2016)):
            values = (data_set[idx] if data_set[idx] is not None else 0 for _, data_set in data)
            f.write("{} {}\n".format(year, ' '.join(str(v) for v in values)))
            

def main(args):
    with open('GDP-Countries-USD.csv', newline='') as csvfile:
        csvreader = csv.reader(csvfile, delimiter=';')
        data = get_data_for(csvreader, 'Gross Domestic Product (GDP)')
        output_data('data_out.txt', data)
        
    print("File generated")

if __name__ == '__main__':
    main(sys.argv[1:])