update-defaulter

#!/bin/bash
set -x

location=$(dirname "$HOME")



{ [[ -n "$1" ]] && ! [[ "$1" == '--help' ]]; } && limit=$(date +%s -d "$1") || {
    echo "Usage: updateDefaulter yymmdd"
    echo "defaulter -> anyone who has not paid before given date."
    exit 1;
}

tempfile=$(mktemp)

# Get a list of all fees.txt files
readarray -t feefiles < <(find "$location" -name 'fees.txt' -type f)

# List each file with its most recent payment timestamp in the temp file
# If timestamp is not before given date, do not add to list; instead, add
# student's rollno. to feeDefaulters.txt
for path in "${feefiles[@]}"; do

    # Get a UNIX timestamp of the most recent transaction recorded in the file
    timestamp=$(tac "$path" | grep 'Fee payment on' | cut -f4 -d' ' | xargs date +%s -d)

    # Get the student's userDetails.txt
    userfile=$(dirname $(dirname "$path"))/userDetails.txt

    # Get name of student
    name=$(sed -nE 's/Name: (.*)/\1/p' "$userfile")

    # Get rollno of student
    rollno=$(grep -o -E '[0-9]{9}' "$userfile")

    if [[ -z $timestamp ]] || [[ $timestamp -gt $limit ]]; then # student is defaulter

        printf '%s %s\n' "$name" "$rollno" >> "$location"/feeDefaulters.txt

    else # add to the list

        printf '%s %s %s\n' "$timestamp" "$name" "$rollno" >> "$tempfile"

    fi

done

# Sort the list
sort -k1,1 -n -o "$tempfile"{,}

# Add top 5 students to announcements.txt
readarray -n 5 lines < <(cat "$tempfile" | cut -f2,3 -d' ')
echo 'The following are the first 5 students to pay fees:' > "$location"/announcements.txt
printf '%s\n' "${lines[@]}" >> "$location"/announcements.txt

rm -f "$tempfile"