#! /bin/bash

total_cargo_build_space() {
    local -r dir="$1"
    local -r list="$2"

    local cargo_toml_path
    local target_path

    find "$dir" -type f -name Cargo.toml \
    | while read -r cargo_toml_path
    do
        target_path=$(dirname "$cargo_toml_path")/target;
        if test -d "$target_path"
        then
            if [[ "$list" -eq 1 ]]
            then
                du -sh "$target_path"
            else
                du -s "$target_path"
            fi
        fi
    done \
    | if [[ "$list" -eq 1 ]]
    then
        sort -h -k 1
    else
        awk '{tot += $1} END {print tot * 1024}' | numfmt --to=iec
    fi
}

main() {
    local dir="$HOME"
    local list=0
    local arg

    while :
    do
        arg="$1"
        case "$arg" in
            '')
                break
                ;;
            -l | --list)
                list=1
                shift
                ;;
            -*)
                printf 'Unknown flag: "%s"\n' "$arg" >&2
                exit 1
                ;;
            *)
                dir="$arg"
                shift
        esac
    done

    total_cargo_build_space "$dir" "$list"
}

main "$@"