#!/bin/bash
URL="https://thedataweb.rm.census.gov/pub/cps/march/asec2018_pubuse.dat.gz"
FILE="asec2018.dat"

# Download data file if not already present
if [[ ! -f "$FILE" ]]; then
    echo "Downloading $URL"
    curl -s "$URL" -o "${FILE}.gz"
    gunzip "${FILE}.gz"
fi

# Walk through the file line by line, filling the counters
IFS=$'\n'
lines=( $(cat $FILE) )
total_pop=0
poor_pop=0
for l in "${lines[@]}"; do

    # Ignore non-person records
    RECORD="${l:0:1}"
    if [ $RECORD -ne 3 ]; then
        continue
    fi

    # Ignore chilren below age 15 not living with family
    FAMREL="${l:35:1}"
    AGE="${l:18:2}"
    if [ $FAMREL -eq 0 ] && [ $AGE -lt 15 ]; then
        continue
    fi

    # Add up total and poor population
    WEIGHT="${l:154:8}"
    PERLIS="${l:605:1}"
    total_pop=$(bc <<<"$total_pop + $WEIGHT")
    if [ $PERLIS -eq 1 ]; then
        poor_pop=$(bc <<<"$poor_pop + $WEIGHT")
    fi
done

# Divide by 100 due to 2 implied decimal places
total_pop=$(bc -l <<<"scale=2; $total_pop / 100")
poor_pop=$(bc -l <<<"scale=2; $poor_pop / 100")
poverty_rate=$(bc -l <<<"scale=1; $poor_pop*100 / $total_pop")

echo "Total Population: $total_pop"
echo "Poor Population: $poor_pop"
echo "Poverty Rate: $poverty_rate"