"""
To run:
    1. If csv files are downloaded to 'slcsp' directory in the same hierarchy this file exists
    >>> python calculate_slcsp.py

    (OR)
    2. To give custom paths to csv files
    >>> python calculate_slcsp.py <SLCSP_CSV_FILE_PATH> <ZIPS_CSV_FILE_PATH> <PLANS_CSV_FILE_PATH>
"""

from collections import OrderedDict
import csv
import sys

DEFAULT_SLCSP_CSV_FILEPATH = 'slcsp/slcsp.csv'
DEFAULT_ZIPS_CSV_FILEPATH = 'slcsp/zips.csv'
DEFAULT_PLANS_CSV_FILEPATH = 'slcsp/plans.csv'


def calculate_slcsp(slcsp_csv, zips_csv, plans_csv):
    slcsp = read_csv(slcsp_csv)
    zips = read_csv(zips_csv)
    plans = read_csv(plans_csv)
    silver_plans = get_silver_plans(plans)

    zipcode_rate_dict = get_zipcode_rate_area(slcsp, zips)
    slcsp_plans = get_plans_for_zipcode(zipcode_rate_dict, silver_plans)
    write_csv(slcsp_plans)

    return


def get_zipcode_rate_area(slcsp, zips):
    zipcode_rate_dict = OrderedDict()
    for slcsp_row in slcsp:
        slcsp_zipcode = slcsp_row['zipcode']

        for zip_row in zips:
            zipcode = zip_row['zipcode']
            rate_area = zip_row['rate_area']
            state = zip_row['state']

            if slcsp_zipcode != zipcode:
                continue

            if zipcode in zipcode_rate_dict:
                if zipcode_rate_dict[zipcode]['rate_area'] != rate_area:
                    # Handling case when zipcode has different multiple rates
                    zipcode_rate_dict[zipcode] = None
                break
            else:
                zipcode_rate_dict[zipcode] = {'rate_area': rate_area,
                                              'state': state}

        if slcsp_zipcode not in zipcode_rate_dict:
            zipcode_rate_dict[slcsp_zipcode] = None

    return zipcode_rate_dict


def get_plans_for_zipcode(zipcode_rate_dict, plans):
    slcsp_plans = OrderedDict()
    for zipcode in zipcode_rate_dict:

        if zipcode_rate_dict[zipcode]:
            rate_area = zipcode_rate_dict[zipcode]['rate_area']
            state = zipcode_rate_dict[zipcode]['state']

            for plan in plans:
                if rate_area == plan['rate_area'] and state == plan['state']:
                    if zipcode not in slcsp_plans:
                        slcsp_plans[zipcode] = []
                    slcsp_plans[zipcode].append(plan['rate'])
        else:
            slcsp_plans[zipcode] = []

        if zipcode not in slcsp_plans:
            slcsp_plans[zipcode] = []

    return slcsp_plans


def read_csv(file_name):
    content = []
    csv_dict_reader = csv.DictReader(open(file_name, 'r'))
    for row in csv_dict_reader:
        content.append(row)
    return content


def write_csv(slcsp_plans):
    csv_rows = []
    csv_rows.append('zipcode,rate')
    for zipcode in slcsp_plans:
        rates = list(set(slcsp_plans[zipcode]))
        sorted_rates = sorted(rates)
        if len(sorted_rates) > 1:
            # Selecting 2nd lowest plan and rounding to two digits
            csv_rows.append('{},{}'.format(zipcode, round(float(sorted_rates[1]),2)))
        else:
            # Handling case when zipcode has only zero or one rate plans
            csv_rows.append('{},{}'.format(zipcode, ''))
    print('\n'.join(csv_rows))


def get_silver_plans(plans):
    silver_plans = []
    for plan in plans:
        if plan['metal_level'] == 'Silver':
            silver_plans.append(plan)
    return silver_plans


if __name__ == '__main__':
    if len(sys.argv) == 4:
        slcsp_csv = sys.argv[1]
        zips_csv = sys.argv[2]
        plans_csv = sys.argv[3]
    else:
        slcsp_csv = DEFAULT_SLCSP_CSV_FILEPATH
        zips_csv = DEFAULT_ZIPS_CSV_FILEPATH
        plans_csv = DEFAULT_PLANS_CSV_FILEPATH

    calculate_slcsp(slcsp_csv, zips_csv, plans_csv)