#!/bin/sh

set -eu

if [ "$#" -lt 1 ] || [ "$#" -gt 2 ]; then
    printf 'Usage: %s INPUT.csv [OUTPUT.csv]\n' "$0" >&2
    exit 2
fi

input=$1
output=${2:--}

process_csv() {
    awk -F '\",\"' '
    function clean_account(value, quoted) {
        quoted = substr(value, 1, 1) == "\"" &&
                 substr(value, length(value), 1) == "\""

        if (quoted) {
            value = substr(value, 2, length(value) - 2)
        }

        # Remove trailing non-numeric characters.
        # Internal hyphens are preserved.
        while (length(value) > 0 &&
               substr(value, length(value), 1) !~ /[0-9]/) {
            value = substr(value, 1, length(value) - 1)
        }

        if (quoted) {
            return "\"" value "\""
        }

        return value
    }

    function key_value(value) {
        if (substr(value, 1, 1) == "\"" &&
            substr(value, length(value), 1) == "\"") {
            return substr(value, 2, length(value) - 2)
        }

        return value
    }

    BEGIN {
        OFS = FS
    }

    {
        sub(/\r$/, "", $0)
    }

    NR == 1 {
        printf "%s,\"deleted\"\n", $0
        next
    }

    {
        cleaned = clean_account($5)
        key = key_value(cleaned)

        if (key == "") {
            cleaned = "000"
            key = "000"
        }

        $5 = cleaned

        # Deleted:
        # "000"  -> true
        # "000/" -> cleaned to "000" -> true
        # ""     -> changed to "000" -> true
        #
        # Everything else -> false
        if (key == "000" || key == "") {
            deleted = "\"true\""
        } else {
            deleted = "\"false\""
        }

        # Check duplicates only for non-deleted accounts
        if (key != "000" && key != "") {
            key_count[key]++

            if (!(key in key_order)) {
                key_order[key] = ++key_total
            }
        }

        printf "%s,%s\n", $0, deleted
    }

    END {
        for (key in key_order) {
            if (key_count[key] > 1) {
                printf "Non-unique column 5 key: %s (%d rows)\n",
                       key, key_count[key] > "/dev/stderr"
            }
        }
    }
' "$input"
}

if [ "$output" = "-" ]; then
    process_csv
else
    process_csv > "$output"
fi