#!/usr/bin/env bash
set -o errexit
set -o nounset
set -o pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
# shellcheck source=00-platform-guard.inc
source "$SCRIPT_DIR/00-platform-guard.inc"
JOURNAL_SOURCE="$SCRIPT_DIR/../files/systemd/journald-ailab-limits.conf"
JOURNAL_DEST="/etc/systemd/journald.conf.d/ailab-limits.conf"
SYSCTL_SOURCE="$SCRIPT_DIR/../files/sysctl/99-ailab.conf"
SYSCTL_DEST="/etc/sysctl.d/99-ailab.conf"

install_config() {
  local source_path="$1"
  local destination_path="$2"
  local mode="$3"
  local backup

  install -d -m 0755 "$(dirname "$destination_path")"
  if [[ -f "$destination_path" ]] && cmp -s "$source_path" "$destination_path"; then
    printf 'OK: %s is already current\n' "$destination_path"
    return 0
  fi
  if [[ -f "$destination_path" ]]; then
    backup="${destination_path}.$(date '+%Y%m%d-%H%M%S').bak"
    install -m "$mode" "$destination_path" "$backup"
    printf 'INFO: backed up %s to %s\n' "$destination_path" "$backup"
  fi
  install -m "$mode" "$source_path" "$destination_path"
  printf 'OK: installed %s\n' "$destination_path"
}

if ((EUID != 0)); then
  printf 'CRITICAL: tuning setup must run as root\n' >&2
  exit 2
fi
require_supported_ubuntu
for source_path in "$JOURNAL_SOURCE" "$SYSCTL_SOURCE"; do
  if [[ ! -r "$source_path" ]]; then
    printf 'CRITICAL: required configuration is missing: %s\n' "$source_path" >&2
    exit 2
  fi
done

if ! command -v sysctl >/dev/null 2>&1 || ! command -v systemctl >/dev/null 2>&1; then
  printf 'CRITICAL: sysctl and systemctl are required\n' >&2
  exit 2
fi

if ! command -v sensors-detect >/dev/null 2>&1 || \
  ! systemctl cat sysstat.service >/dev/null 2>&1; then
  apt-get update
  DEBIAN_FRONTEND=noninteractive apt-get install -y lm-sensors sysstat
fi

install_config "$JOURNAL_SOURCE" "$JOURNAL_DEST" 0644
install_config "$SYSCTL_SOURCE" "$SYSCTL_DEST" 0644

sysctl --system
systemctl restart systemd-journald
systemctl enable --now sysstat

if command -v sensors-detect >/dev/null 2>&1; then
  sensors-detect --auto || printf 'WARNING: sensors-detect did not complete successfully\n'
fi
printf 'OK: host tuning completed\n'