#!/usr/bin/python
import sys
import datetime

# Calculates death probabilities based on Social Security
# actuarial tables for a given group of people.

# Run with a list of ages/genders and an optional timespan (or year in the future):

# python actuary.py 63m 80m 75f 73m 10

# or:

# python actuary.py 63m 80m 75f 73m 2022

# This will give statistics for that group, including
# various probabilities over 10 years. Years can be
# ommitted and it will still give some statistics.
# If "Years" exceeds the current calendar year, it will be interpreted as a date.



bothtables=[[0.00756, 0.00052, 0.00035, 0.00025, 0.00020, 0.00018, 0.00017, 0.00016, 0.00014, 0.00011, 0.00009, 0.00010, 0.00015, 0.00027, 0.00043, 0.00061, 0.00078, 0.00094, 0.00107, 0.00119, 0.00131, 0.00142, 0.00149, 0.00151, 0.00148, 0.00143, 0.00140, 0.00138, 0.00137, 0.00139, 0.00141, 0.00143, 0.00147, 0.00152, 0.00158, 0.00165, 0.00174, 0.00186, 0.00202, 0.00221, 0.00243, 0.00267, 0.00291, 0.00317, 0.00344, 0.00373, 0.00405, 0.00441, 0.00480, 0.00524, 0.00573, 0.00623, 0.00671, 0.00714, 0.00756, 0.00800, 0.00853, 0.00917, 0.00995, 0.01086, 0.01190, 0.01301, 0.01413, 0.01522, 0.01635, 0.01760, 0.01906, 0.02073, 0.02265, 0.02482, 0.02729, 0.03001, 0.03289, 0.03592, 0.03918, 0.04292, 0.04715, 0.05173, 0.05665, 0.06206, 0.06821, 0.07522, 0.08302, 0.09163, 0.10119, 0.11183, 0.12367, 0.13679, 0.15124, 0.16702, 0.18414, 0.20255, 0.22224, 0.24314, 0.26520, 0.28709, 0.30846, 0.32891, 0.34803, 0.36544, 0.38371, 0.40289, 0.42304, 0.44419, 0.46640, 0.48972, 0.51421, 0.53992, 0.56691, 0.59526, 0.62502, 0.65628, 0.68909, 0.72354, 0.75972, 0.79771, 0.83759, 0.87947, 0.92345, 0.96962], [0.00615, 0.00041, 0.00025, 0.00018, 0.00015, 0.00014, 0.00014, 0.00013, 0.00012, 0.00011, 0.00010, 0.00010, 0.00012, 0.00016, 0.00021, 0.00028, 0.00034, 0.00039, 0.00042, 0.00043, 0.00045, 0.00047, 0.00048, 0.00049, 0.00050, 0.00051, 0.00052, 0.00053, 0.00056, 0.00059, 0.00063, 0.00068, 0.00073, 0.00078, 0.00084, 0.00091, 0.00098, 0.00108, 0.00118, 0.00130, 0.00144, 0.00158, 0.00173, 0.00189, 0.00206, 0.00225, 0.00244, 0.00264, 0.00285, 0.00306, 0.00329, 0.00355, 0.00382, 0.00409, 0.00437, 0.00468, 0.00505, 0.00549, 0.00603, 0.00665, 0.00736, 0.00813, 0.00890, 0.00967, 0.01047, 0.01136, 0.01239, 0.01357, 0.01491, 0.01641, 0.01816, 0.02008, 0.02210, 0.02418, 0.02641, 0.02902, 0.03206, 0.03538, 0.03899, 0.04301, 0.04766, 0.05307, 0.05922, 0.06618, 0.07403, 0.08285, 0.09270, 0.10365, 0.11574, 0.12899, 0.14343, 0.15907, 0.17591, 0.19393, 0.21312, 0.23254, 0.25193, 0.27097, 0.28933, 0.30670, 0.32510, 0.34460, 0.36528, 0.38720, 0.41043, 0.43505, 0.46116, 0.48883, 0.51816, 0.54925, 0.58220, 0.61714, 0.65416, 0.69341, 0.73502, 0.77912, 0.82587, 0.87542, 0.92345, 0.96962]]

def deathprob(age, years):
    #negative ages = female
    act=[]
    if age<0:
        act=bothtables[1]
        age=-1*age
    else:
        act=bothtables[0]
    while(len(act)<int(age+years+2)): # slower/bloaiter but keeps things clean
        act.append(act[-1]**0.5)
    liveprob=1
    i=0
    iage=int(age)
    fage=age%1
    while i<=years-1:
        thisyear=(1-fage)*act[iage+i]+fage*act[iage+i+1]
        liveprob*=1-thisyear
        i+=1
    if years%1: # Amortizes risk of dying over a partial year, which is
                # 1-P(living last full year)^(year fraction)
        lastyear=(1-fage)*act[iage+i]+fage*act[iage+i+1]
        lastyearlive=1-lastyear
        lastyearlive=lastyearlive**((years%1))
        liveprob*=lastyearlive
    return 1-liveprob

def proballdie(ages, years):
    probsliving=[]
    for i in ages:
        probsliving.append(1-deathprob(i, years))
    prod=1
    for i in probsliving:
        prod*=(1-i)
    return prod

def probanydie(ages, years):
    probsliving=[]
    for i in ages:
        probsliving.append(1-deathprob(i, years))
    prod=1
    for i in probsliving:
        prod*=i
    return 1-prod

def calcexp(ages, prob, flag):
    i=0
    for interval in (10, 1, 0.1, 0.01):
        probs=0
        while(probs<prob):
            i+=interval
            if flag==0:
                probs=proballdie(ages, i)
            else:
                probs=probanydie(ages, i)
        i-=interval
    return i

ages=[]
# print sys.argv[1:]
for arg in sys.argv[1:]:
    gender=1
    years=1.0
    if arg[-1]=='m' or arg[-1]=='M':
        try:
            ages.append(1*float(arg[:-1]))
        except:
            print "Error parsing argument", arg
    elif arg[-1]=='f' or arg[-1]=='F':
        try:
            ages.append(-1*float(arg[:-1]))
        except:
            print "Error parsing argument", arg
    else:
        try:
            years=float(arg)
            break
        except:
            print "Error parsing argument", arg

if not sys.argv[1:]:
    print "The format is 'actuary.py 15m 80f 23', with a list of ages and a number of years to run the projections."
    raise SystemExit
if not ages:
    print "No ages specified.  Format is 12m, 17f, etc."
    raise SystemExit

# print "Ages:", ages
# print "Years:", years

(datetime.date.today()+datetime.timedelta(days=365.242191*1)).year
someone_years=[calcexp(ages, 0.05, 1),
               calcexp(ages, 0.5, 1),
               calcexp(ages, 0.95, 1)]
someone_dates=[(datetime.date.today()+datetime.timedelta(days=365.242191*someone_years[0])).year,
               (datetime.date.today()+datetime.timedelta(days=365.242191*someone_years[1])).year,
               (datetime.date.today()+datetime.timedelta(days=365.242191*someone_years[2])).year]
print "There is a 5%  chance of someone dying within", someone_years[0], "years (by", str(someone_dates[0])+")."
print "There is a 50% chance of someone dying within", someone_years[1], "years (by", str(someone_dates[1])+")."
print "There is a 95% chance of someone dying within", someone_years[2], "years (by", str(someone_dates[2])+")."
print ""

if len(ages)>1:
    everyone_years=[calcexp(ages, 0.05, 0),
                   calcexp(ages, 0.5, 0),
                   calcexp(ages, 0.95, 0)]
    everyone_dates=[(datetime.date.today()+datetime.timedelta(days=365.242191*everyone_years[0])).year,
                   (datetime.date.today()+datetime.timedelta(days=365.242191*everyone_years[1])).year,
                   (datetime.date.today()+datetime.timedelta(days=365.242191*everyone_years[2])).year]
    print "There is a 5%  chance of everyone dying within", everyone_years[0], "years (by", str(everyone_dates[0])+")."
    print "There is a 50% chance of everyone dying within", everyone_years[1], "years (by", str(everyone_dates[1])+")."
    print "There is a 95% chance of everyone dying within", everyone_years[2], "years (by", str(everyone_dates[2])+")."


if years:
    yearword="years"
    if years==1:
        yearword="year"

    print ""
    if years>datetime.date.today().year:
        years=years-datetime.date.today().year
    if len(ages)>1:
        p=100*proballdie(ages, years)
        printable=""
        if p<0.001:
            printable="<0.001"
        elif p>99.99:
            printable=">99.99"
        else:
            printable=str(p)[:5]
        print "Probability of all dying in", years, yearword+":  ", printable+"%"
    p=100*probanydie(ages, years)
    printable=""
    if p<0.001:
        printable="<0.001"
    elif p>99.99:
        printable=">99.99"
        print p
    else:
        printable=str(p)[:5]
    print "Probability of a death within", years, yearword+":", printable+"%"
raise SystemExit