#!/usr/bin/python3

import csv, os, sys, math, json

cpi_data = {}
def get_cpi_data(cpi_data, year, month=12):
    return cpi_data[str(year)][month-1]

def calculate_return(start, end, startYear, endYear, cpi_data, adjust_cpi):
    if adjust_cpi: 
        # inflation adjusted
        ratio = (end/get_cpi_data(cpi_data, endYear))/(start/get_cpi_data(cpi_data, startYear))
    else:
        # non inflation-adjusted
        ratio = end/start
    return 100*(math.pow(ratio, float(1)/(endYear - startYear)) - 1)

dollar_shares_per_year = []
dollar_shares_cpi_per_year = []
def populate_dollar_shares_per_year(full_data, startYear, endYear):
    for year in range(startYear, endYear):
        number_of_shares = 100.0 / full_data[str(year) + '-12']
        number_of_shares_cpi = 100.0 / (full_data[str(year) + '-12'] / get_cpi_data(cpi_data, year, 12))
        for month in range(1, 12):
            number_of_shares += 100.0 / full_data[str(year+1) + '-%02d' % month]
            number_of_shares_cpi += 100.0 / (full_data[str(year+1) + '-%02d' % month] / get_cpi_data(cpi_data, year+1, month))
        dollar_shares_per_year.append(number_of_shares)
        dollar_shares_cpi_per_year.append(number_of_shares_cpi)

def calculate_dollar_return(full_data, trueStartYear, startYear, endYear, cpi_data, adjust_cpi):
    number_of_shares = 0
    # Always start in December
    for year in range(startYear, endYear):
        if adjust_cpi:
            number_of_shares += dollar_shares_cpi_per_year[year-trueStartYear]
        else:
            number_of_shares += dollar_shares_per_year[year-trueStartYear]
    if adjust_cpi:
        number_of_shares /= get_cpi_data(cpi_data, endYear, 12)
    end_ratio = (number_of_shares*full_data[str(endYear) + '-12'])/(1200.0 * (endYear - startYear)) # spent 100.0/month
    # TODO - reaaaallly not sure about this
    return 100*(math.pow(end_ratio, float(1)/(endYear - startYear)) - 1)



def print_returns(in_filename):
    data = []
    full_data = {}
    reader = csv.reader(open(in_filename, 'r'), delimiter=',')
    for row in reader:
        data.append([row[0], float(row[1])])
        full_data[row[0]] = float(row[1])
    data = data[::-1]
    #print data
    realData = []
    for d in data:
        if d[0][-2:] == '12':
            realData.append(d)
    data = realData
    reader = csv.reader(open('cpidata.csv', 'r'), delimiter=',')
    for row in reader:
        cpi_data[row[0]] = [float(x) for x in row[1:]]
    cpiReturnsData = []
    noncpiReturnsData = []
    cpiDollarReturnsData = []
    noncpiDollarReturnsData = []
    returnsData = {}
    returnsData['startYear'] = int(data[0][0][:4])
    returnsData['endYear'] = int(data[-1][0][:4])
    returnsData['cpiData'] = cpi_data
    populate_dollar_shares_per_year(full_data, returnsData['startYear'], returnsData['endYear'])
    for i in range(len(data)):
        cpiTempData = []
        noncpiTempData = []
        cpiDollarTempData = []
        noncpiDollarTempData = []
        yearI = int(data[i][0][:4])
        for j in range(i+1, len(data)):
            yearJ = int(data[j][0][:4])
            cpiTempData.append(calculate_return(data[i][1], data[j][1], yearI, yearJ, cpi_data, True))
            noncpiTempData.append(calculate_return(data[i][1], data[j][1], yearI, yearJ, cpi_data, False))
            cpiDollarTempData.append(calculate_dollar_return(full_data, returnsData['startYear'], yearI, yearJ, cpi_data, True))
            noncpiDollarTempData.append(calculate_dollar_return(full_data, returnsData['startYear'], yearI, yearJ, cpi_data, False))
        cpiReturnsData.append(cpiTempData)
        noncpiReturnsData.append(noncpiTempData)
        cpiDollarReturnsData.append(cpiDollarTempData)
        noncpiDollarReturnsData.append(noncpiDollarTempData)
    returnsData['cpiReturns'] = cpiReturnsData
    returnsData['noncpiReturns'] = noncpiReturnsData
    returnsData['cpiDollarReturns'] = cpiDollarReturnsData
    returnsData['noncpiDollarReturns'] = noncpiDollarReturnsData
    print(json.dumps(returnsData))

def main():
    print_returns('sandpdata.csv')

if (__name__ == '__main__'):
    main()