#!/usr/bin/env bash
# vim: set ft=bash
# adapted from https://github.com/cachix/install-nix-action/blob/master/lib/install-nix.sh

set -euo pipefail

install_nix() {

    echo "Installing Nix"

    # Set jobs to number of cores
    sudo sh -c 'echo max-jobs = auto >> /tmp/nix.conf'
    # Allow binary caches for runner user
    sudo sh -c 'echo trusted-users = root runner >> /tmp/nix.conf'

    sh <(curl -L ${INPUT_INSTALL_URL:-https://nixos.org/nix/install}) \
      --daemon --daemon-user-count 4 --nix-extra-conf-file /tmp/nix.conf --darwin-use-unencrypted-nix-store-volume --no-channel-add

    if [[ $OSTYPE =~ darwin ]]; then
      # Disable spotlight indexing of /nix to speed up performance
      sudo mdutil -i off /nix

      # macOS needs certificates hints
      cert_file=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt
      echo "::set-env name=NIX_SSL_CERT_FILE::$cert_file"
      export NIX_SSL_CERT_FILE=$cert_file
      sudo launchctl setenv NIX_SSL_CERT_FILE "$cert_file"
    fi

    # Set paths
    echo "::add-path::/nix/var/nix/profiles/per-user/runner/profile/bin"
    echo "::add-path::/nix/var/nix/profiles/default/bin"
    . '/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh'
}

install_cachix() {
    echo "Installing cachix"

    nix-env -iA cachix -f https://cachix.org/api/v1/install

    echo "Setting up cachix"

    cachix_cache="${GITHUB_REPOSITORY##*/}"

    echo "Using cache '$cachix_cache' for '$GITHUB_REPOSITORY'"

    cachix use "$cachix_cache"

    script_path="$HOME/.local/bin/save-cache"
    mkdir -p "$(dirname $script_path)"
}

save_cache() {

    cachix_cache="${GITHUB_REPOSITORY##*/}"

    echo "Using cache '$cachix_cache' for '$GITHUB_REPOSITORY'"

    set +x
    if [ -z "${CACHIX_SIGNING_KEY:-}" ] && [ -n "${INPUT_CACHIX_SIGNING_KEY:-}" ]; then
        echo "CACHIX_SIGNING_KEY not set, but INPUT_CACHIX_SIGNING_KEY is present"
        echo "setting CACHIX_SIGNING_KEY"
        export CACHIX_SIGNING_KEY="$INPUT_CACHIX_SIGNING_KEY"
    fi

    if [ -n "${CACHIX_SIGNING_KEY:-}" ];
    then
        echo "CACHIX_SIGNING_KEY is set, uploading cache"
        nix path-info --all | cachix push $cachix_cache
    else
        echo "CACHIX_SIGNING_KEY not set, not uploading cache"
    fi
    set -x
}

set -x

if [ "${INSTALL_NIX_WAS_RUN:-}" == "1" ]; then
    save_cache
else
    install_nix
    install_cachix
    echo "::set-env name=INSTALL_NIX_WAS_RUN::1"
fi