#!/usr/bin/env nix-shell
#! nix-shell -i bash -p curl nix coreutils
set -euxo pipefail

# This script piggybacks on the automatic code generation done by the nix-community emacs overlay
# You can use this to avoid running lengthy code generation jobs locally

export NIXPKGS_ALLOW_BROKEN=1

download_change() {
    local FILE_LOCATION="$1"

    local BASEURL="https://raw.githubusercontent.com/nix-community/emacs-overlay/master/repos"

    curl -s -O "${BASEURL}/${FILE_LOCATION}"
}

commit_change() {
    local MESSAGE="$1"
    local FILENAME="$2"

    git diff --exit-code "${FILENAME}" > /dev/null || \
        git commit -m "${MESSAGE}: updated $(date --iso) (from overlay)" -- "${FILENAME}"
}

test_packageset(){
    local PKGSET="$1"

    nix-instantiate --show-trace ../../../../../ -A "emacs.pkgs.$PKGSET"
}

download_change "elpa/elpa-generated.nix"
download_change "elpa/elpa-devel-generated.nix"
download_change "melpa/recipes-archive-melpa.json"
download_change "nongnu/nongnu-generated.nix"

test_packageset "nongnuPackages"
test_packageset "elpaPackages"
test_packageset "elpaDevelPackages"
test_packageset "melpaStablePackages"
test_packageset "melpaPackages"

commit_change "elpa-packages" "elpa-generated.nix"
commit_change "elpa-devel-packages" "elpa-devel-generated.nix"
commit_change "melpa-packages" "recipes-archive-melpa.json"
commit_change "nongnu-packages" "nongnu-generated.nix"