#!/usr/bin/env bash

set -eu
set -o pipefail

readonly PLIST_DEST=/Library/LaunchDaemons/org.nixos.nix-daemon.plist

dsclattr() {
    /usr/bin/dscl . -read "$1" \
        | awk "/$2/ { print \$2 }"
}

poly_validate_assumptions() {
    if [ "$(uname -s)" != "Darwin" ]; then
        failure "This script is for use with macOS!"
    fi
}

poly_service_installed_check() {
    [ -e "$PLIST_DEST" ]
}

poly_service_uninstall_directions() {
        cat <<EOF
$1. Delete $PLIST_DEST

  sudo launchctl unload $PLIST_DEST
  sudo rm $PLIST_DEST

EOF
}

poly_service_setup_note() {
    cat <<EOF
 - load and start a LaunchDaemon (at $PLIST_DEST) for nix-daemon

EOF
}

poly_configure_nix_daemon_service() {
    _sudo "to set up the nix-daemon as a LaunchDaemon" \
          ln -sfn "/nix/var/nix/profiles/default$PLIST_DEST" "$PLIST_DEST"

    _sudo "to load the LaunchDaemon plist for nix-daemon" \
          launchctl load /Library/LaunchDaemons/org.nixos.nix-daemon.plist

    _sudo "to start the nix-daemon" \
          launchctl start org.nixos.nix-daemon

}

poly_group_exists() {
    /usr/bin/dscl . -read "/Groups/$1" > /dev/null 2>&1
}

poly_group_id_get() {
    dsclattr "/Groups/$1" "PrimaryGroupID"
}

poly_create_build_group() {
    _sudo "Create the Nix build group, $NIX_BUILD_GROUP_NAME" \
          /usr/sbin/dseditgroup -o create \
          -r "Nix build group for nix-daemon" \
          -i "$NIX_BUILD_GROUP_ID" \
          "$NIX_BUILD_GROUP_NAME" >&2
}

poly_user_exists() {
    /usr/bin/dscl . -read "/Users/$1" > /dev/null 2>&1
}

poly_user_id_get() {
    dsclattr "/Users/$1" "UniqueID"
}

poly_user_hidden_get() {
    dsclattr "/Users/$1" "IsHidden"
}

poly_user_hidden_set() {
    _sudo "in order to make $1 a hidden user" \
          /usr/bin/dscl . -create "/Users/$1" "IsHidden" "1"
}

poly_user_home_get() {
    dsclattr "/Users/$1" "NFSHomeDirectory"
}

poly_user_home_set() {
    _sudo "in order to give $1 a safe home directory" \
          /usr/bin/dscl . -create "/Users/$1" "NFSHomeDirectory" "$2"
}

poly_user_note_get() {
    dsclattr "/Users/$1" "RealName"
}

poly_user_note_set() {
    _sudo "in order to give $username a useful note" \
          /usr/bin/dscl . -create "/Users/$1" "RealName" "$2"
}

poly_user_shell_get() {
    dsclattr "/Users/$1" "UserShell"
}

poly_user_shell_set() {
    _sudo "in order to give $1 a safe home directory" \
          /usr/bin/dscl . -create "/Users/$1" "UserShell" "$2"
}

poly_user_in_group_check() {
    username=$1
    group=$2
    dseditgroup -o checkmember -m "$username" "$group" > /dev/null 2>&1
}

poly_user_in_group_set() {
    username=$1
    group=$2

    _sudo "Add $username to the $group group"\
          /usr/sbin/dseditgroup -o edit -t user \
          -a "$username" "$group"
}

poly_user_primary_group_get() {
    dsclattr "/Users/$1" "PrimaryGroupID"
}

poly_user_primary_group_set() {
    _sudo "to let the nix daemon use this user for builds (this might seem redundant, but there are two concepts of group membership)" \
          /usr/bin/dscl . -create "/Users/$1" "PrimaryGroupID" "$2"
}

poly_create_build_user() {
    username=$1
    uid=$2
    builder_num=$3

    _sudo "Creating the Nix build user (#$builder_num), $username" \
          /usr/bin/dscl . create "/Users/$username" \
          UniqueID "${uid}"
}
