#!/usr/bin/env bash
BOOTSTRAP_DIR=~/.dotfiles/bootstrap
OUTPUT=${BOOTSTRAP_DIR}/packages.tsv

pkg_all=$(pacman -Qqett | grep -v "$(pacman -Qqg base-devel)")

pkg_repo=$(pacman -Qqn)
pkg_aur=$(pacman -Qqm)

while getopts "nvh" opt; do
    case "$opt" in
    n) DRYRUN=true ;;
    v) VERBOSE=true ;;
    h | *)
        {
            printf "\nUpdate the list of installed packages.\n\nWill compare packages committed to the dotfile repository\nand those currently installed (on an Arch system, using pacman).\nUpdates the list of committed packages in repository\nand prints out the differences as a diff.\n\nOptions:\n\n\t-h\tDisplay this help.\n\t-v\tShow verbose information.\n\t-n\tPrint out changes without changing anything (dry-run).\n"
            exit 1
        }
        ;;
    esac
done

print_msg() {
    # shellcheck disable=2059
    [ -n "$VERBOSE" ] && printf "$@"
}

# tsv file:
# packagename, description, source, target
# toot  a toot manager  A   D

if [ -f "${OUTPUT}_TEMP" ]; then
    rm "${OUTPUT}_TEMP"
fi
touch "${OUTPUT}_TEMP"

# create new package list
for pkg in $pkg_all; do

    source=""
    if echo "$pkg_repo" | grep -F -q -x "$pkg"; then
        source="R"
    elif echo "$pkg_aur" | grep -F -q -x "$pkg"; then
        source="A"
    else
        echo "ERROR: The package $pkg could not be found in repositories or AUR."
        exit 1
    fi

    desc=$(pacman -Qs "$pkg" | grep -A1 --color "local/$pkg\s" | tail -n1)
    #remove leading whitespace
    desc="${desc#"${desc%%[![:space:]]*}"}"

    target=""
    if [ -f "$OUTPUT" ]; then
        found_line=$(grep -e "^$pkg" "$OUTPUT")
    fi
    if [ -n "$found_line" ]; then
        target=$(echo "$found_line" | cut -f4)
        print_msg "Updating pkg: %s:%s from: %s, for: %s\n" "$pkg" "$desc" "$source" "$target"
    else
        print_msg "Adding pkg: %s:%s from: %s, for: %s\n" "$pkg" "$desc" "$source" "$target"
    fi

    printf "%s\t%s\t%s\t%s\n" "$pkg" "$desc" "$source" "$target" >>"${OUTPUT}_TEMP"
done

# notify on any removed packages
if [ -f "$OUTPUT" ]; then
    while read -r line; do
        if ! echo "$line" | cut -f1 | xargs -I _ grep -F -q -x _ <(echo "$pkg_all"); then
            printf "REMOVED: %s\n" "$line"
        fi
    done <<<"$(tail +2 $OUTPUT)"
fi

# show file changes
if [ -f "$OUTPUT" ] && [ -f "$OUTPUT"_TEMP ]; then
    changes=$(diff --color=always -y --suppress-common-lines "$OUTPUT" "$OUTPUT"_TEMP | tail -n+2)
    printf "FILE CHANGES:\n=============\n%s" "$changes"
fi

# actually write to file
if [ -z "$DRYRUN" ]; then
    cat <(printf "Name\tDescription\tSource\tTarget\n") "${OUTPUT}_TEMP" >"$OUTPUT"
fi
rm "${OUTPUT}_TEMP"