# function-specific parameters
library(sp500SlidingWindow)
window_width <- 30           # life expectancy
annual_fee   <- 0.0125       # brokerage fees
output_path  <- "images_rjournal/"

# analysis-specific parameters
current_age        <- 65      # starting age
annual_inflation   <- 0.025   # annual inflation
initial_investment <- 3000000 # our nest egg

# withdraw this much each year
withdrawal_percent <- 0.03171
initial_withdrawal <- initial_investment * withdrawal_percent       

investment_vector <- c(initial_investment,
                       rep(0,window_width-1))

fmt(investment_vector)
#>  [1] "3,000,000" "        0" "        0" "        0" "        0"
#>  [6] "        0" "        0" "        0" "        0" "        0"
#> [11] "        0" "        0" "        0" "        0" "        0"
#> [16] "        0" "        0" "        0" "        0" "        0"
#> [21] "        0" "        0" "        0" "        0" "        0"
#> [26] "        0" "        0" "        0" "        0" "        0"

withdrawal_vector <- sapply(0:(window_width-1), function(i) {
    return(initial_withdrawal * (1 + annual_inflation)**i)
})

# total amount we hope to withdraw over the whole period
total_hoped_for_wdr <- sum(withdrawal_vector)
fmt(total_hoped_for_wdr)
#> [1] "4,176,464"

# year-by-year hoped-for withdrawals
fmt(withdrawal_vector)
#>  [1] " 95,130" " 97,508" " 99,946" "102,445" "105,006" "107,631" "110,322"
#>  [8] "113,080" "115,907" "118,804" "121,774" "124,819" "127,939" "131,138"
#> [15] "134,416" "137,777" "141,221" "144,752" "148,370" "152,080" "155,882"
#> [22] "159,779" "163,773" "167,867" "172,064" "176,366" "180,775" "185,294"
#> [29] "189,927" "194,675"

remaining_amt    <- initial_investment
ages             <- current_age:(window_width+current_age-1)
remaining_amount <- sapply(1:window_width, function(i) {
    remaining_amt <<- remaining_amt - withdrawal_vector[i]
    return(remaining_amt)
})

# test if we go below zero
if (length(which(remaining_amount<=0))) {
    # goes below zero
    plot_points = TRUE
    busted_age <- current_age+which(remaining_amount<=0)[1]-1
    sub = paste0("Run out of money at age ", busted_age)
} else {
    # does not go below zero
    plot_points = FALSE
    sub="Starting amount covers withdrawals without investment"
}

ylim <- c(min(min(remaining_amount, 0)), initial_investment)
plot(ages, remaining_amount, pch=20,
     xlab="Age", ylab=NA, yaxt="n", ylim=ylim,
     main="What if I simply live off the cash?",
     sub=sub)
if (plot_points) {
    points(which(remaining_amount<=0)+current_age-1, 
           remaining_amount[which(remaining_amount<=0)], col="red", pch=20)
    abline(v=busted_age, col="red", lty=2)
    abline(h=0, col="red", lty=2)
}

axis(2, las=2, at=axTicks(2), labels=fmt(axTicks(2)), cex.axis=0.72)
grid()

dev.copy(png, paste0(output_path, "invested_in_cash.png"))
#> png 
#>   3
dev.off()
#> png 
#>   2

plot_ending_bal_distribution(window_df, NULL, window_width)

library(png)
worst_period <- which.min(window_df$wdr)

worst_year_path <- paste0(output_path, 
                          window_df$start_year[worst_period], "-",
                          window_df$end_year[worst_period], ".png")
pp <- readPNG(worst_year_path, native = TRUE, info = TRUE)
plot(0:1, 0:1, type="n", ann=FALSE, axes=FALSE)
rasterImage(pp, 0, 0, 1, 1)

best_period  <- which.max(window_df$ending_bal)

best_year_path <- paste0(output_path, 
                          window_df$start_year[best_period], "-",
                          window_df$end_year[best_period], ".png")
pp <- readPNG(best_year_path, native = TRUE, info = TRUE)
plot(0:1, 0:1, type="n", ann=FALSE, axes=FALSE)
rasterImage(pp, 0, 0, 1, 1)

bal_hist_obj    <- hist(window_df$ending_bal, plot=FALSE)
mod_end_bal     <- bal_hist_obj$mids[which.max(bal_hist_obj$counts)]
mod_window_idx  <- which.min(abs(window_df$ending_bal - mod_end_bal))
closest_mod_bal <- window_df$ending_bal[mod_window_idx]

mode_year_path <- paste0(output_path, 
                          window_df$start_year[mod_window_idx], "-",
                          window_df$end_year[mod_window_idx], ".png")
pp <- readPNG(mode_year_path, native = TRUE, info = TRUE)
plot(0:1, 0:1, type="n", ann=FALSE, axes=FALSE)
rasterImage(pp, 0, 0, 1, 1)