#!/bin/sh
# This do script creates an indirect root to an input flake

exec >&2

pfx=${2%.rw}

redo-ifchange ../flake.nix ../flake.lock || true

resolve_flake() {
    STORE_PATH=$(nix flake info --json --inputs-from .. "$pfx" | jq -r .path)

    # Do this after 'info' to avoid unnecessary network activity. nix flake
    # archive may try to download a flake although the store path is available.
    if [ ! -d "$STORE_PATH" ]; then
        nix flake archive --inputs-from .. "$pfx"
    fi
}

case $2 in
    # Resolves cleanup targets by their softlinks
    clean)
        redo-always || true
        find . -type l -print -exec realpath -P --relative-base="$PWD" {} \+ |
            while read p; do
                if [ "$p" = "${p#/}" ]; then
                    rm -rf -- "$p"
                fi
            done
        ;;
    *.rw)
        resolve_flake "$@"
        rm -rf -- ".$2"
        cp --reflink=auto -r --no-preserve=mode "$STORE_PATH" ".$2"
        ln -sf ".$2" "$3"
        ;;
    *)
        resolve_flake "$@"
        nix-store -r "$STORE_PATH" --indirect --add-root "$2"
        [ "$2" = "$3" ] || mv "$2" "$3"
        ;;
esac