#!/usr/bin/env bash
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
# shellcheck disable=SC1091
source "${SCRIPT_DIR}/common.sh"

STEP="time-sync"
CHRONY_SOURCES_DIR="/etc/chrony/sources.d"
CHRONY_SOURCE_FILE="${CHRONY_SOURCES_DIR}/blitz-robot.sources"
CHRONY_MAIN_CONF="/etc/chrony/chrony.conf"
CHRONY_MAIN_CONF_BAK="/etc/chrony/chrony.conf.blitz-bak"
CHRONY_BURST_SAMPLES="${CHRONY_BURST_SAMPLES:-1/2}"

chrony_unit_name() {
  if systemctl list-unit-files chrony.service --no-legend 2>/dev/null | grep -q '^chrony\.service'; then
    printf '%s\n' "chrony.service"
    return 0
  fi
  if systemctl list-unit-files chronyd.service --no-legend 2>/dev/null | grep -q '^chronyd\.service'; then
    printf '%s\n' "chronyd.service"
    return 0
  fi
  printf '%s\n' "chrony.service"
}

ensure_chrony_main_conf() {
  local temp_file

  blitz_require_file "${CHRONY_MAIN_CONF}" "${STEP}"
  mkdir -p "${CHRONY_SOURCES_DIR}"

  if [[ ! -f "${CHRONY_MAIN_CONF_BAK}" ]]; then
    cp -a "${CHRONY_MAIN_CONF}" "${CHRONY_MAIN_CONF_BAK}"
    blitz_log "${STEP}" "backup-config" "success" "backup=${CHRONY_MAIN_CONF_BAK}" 0
  fi

  temp_file="$(mktemp)"
  awk '
    /^[[:space:]]*#/ { print; next }
    /^[[:space:]]*(pool|server)[[:space:]]+/ {
      print "# blitz-managed-disabled " $0
      next
    }
    { print }
  ' "${CHRONY_MAIN_CONF}" > "${temp_file}"

  if ! grep -Eq '^[[:space:]]*sourcedir[[:space:]]+/etc/chrony/sources\.d([[:space:]]|$)' "${temp_file}"; then
    printf '\n# blitz-managed\nsourcedir /etc/chrony/sources.d\n' >> "${temp_file}"
  fi

  if ! cmp -s "${temp_file}" "${CHRONY_MAIN_CONF}"; then
    cp "${temp_file}" "${CHRONY_MAIN_CONF}"
    blitz_log "${STEP}" "rewrite-main-config" "success" "commented non-Blitz pool/server entries in ${CHRONY_MAIN_CONF}" 0
  else
    blitz_log "${STEP}" "rewrite-main-config" "success" "main config already matches Blitz expectations" 0
  fi

  rm -f "${temp_file}"
}

write_chrony_source_file() {
  local temp_file

  temp_file="$(mktemp)"
  cat <<EOF > "${temp_file}"
# blitz-managed
server ${BLITZ_TIME_SERVER_IP} port ${BLITZ_TIME_SERVER_PORT} iburst
EOF

  if [[ ! -f "${CHRONY_SOURCE_FILE}" ]] || ! cmp -s "${temp_file}" "${CHRONY_SOURCE_FILE}"; then
    cp "${temp_file}" "${CHRONY_SOURCE_FILE}"
    blitz_log "${STEP}" "write-source" "success" "source_file=${CHRONY_SOURCE_FILE} server=${BLITZ_TIME_SERVER_IP} port=${BLITZ_TIME_SERVER_PORT}" 0
  else
    blitz_log "${STEP}" "write-source" "success" "source_file already matches ${BLITZ_TIME_SERVER_IP}:${BLITZ_TIME_SERVER_PORT}" 0
  fi

  rm -f "${temp_file}"
}

blitz_load_boot_env
blitz_require_root "${STEP}"
blitz_require_command systemctl "${STEP}"
blitz_require_command chronyc "${STEP}"

if [[ -z "${BLITZ_TIME_SERVER_IP}" ]]; then
  blitz_log "${STEP}" "precheck" "failure" "BLITZ_TIME_SERVER_IP is empty and no fallback could be derived" 1
  exit 1
fi
if ! [[ "${BLITZ_TIME_SERVER_PORT}" =~ ^[0-9]+$ ]] || (( BLITZ_TIME_SERVER_PORT < 1 || BLITZ_TIME_SERVER_PORT > 65535 )); then
  blitz_log "${STEP}" "precheck" "failure" "BLITZ_TIME_SERVER_PORT must be an integer between 1 and 65535" 1
  exit 1
fi

ensure_chrony_main_conf
write_chrony_source_file

CHRONY_UNIT="$(chrony_unit_name)"
blitz_run "${STEP}" "restart-chrony" systemctl restart "${CHRONY_UNIT}"
blitz_run "${STEP}" "burst" chronyc burst "${CHRONY_BURST_SAMPLES}"

blitz_log "${STEP}" "waitsync" "start" "server=${BLITZ_TIME_SERVER_IP} port=${BLITZ_TIME_SERVER_PORT} wait_sec=${BLITZ_TIME_SYNC_WAIT_SEC} max_offset_sec=${BLITZ_TIME_SYNC_MAX_OFFSET_SEC} interval_sec=${BLITZ_TIME_SYNC_INTERVAL_SEC}" 0
if chronyc waitsync "${BLITZ_TIME_SYNC_WAIT_SEC}" "${BLITZ_TIME_SYNC_MAX_OFFSET_SEC}" 1000 "${BLITZ_TIME_SYNC_INTERVAL_SEC}"; then
  blitz_log "${STEP}" "waitsync" "success" "chrony synchronized to ${BLITZ_TIME_SERVER_IP}:${BLITZ_TIME_SERVER_PORT}" 0
else
  rc=$?
  blitz_log "${STEP}" "waitsync" "soft_fail" "chrony did not synchronize to ${BLITZ_TIME_SERVER_IP}:${BLITZ_TIME_SERVER_PORT} within the configured timeout" "${rc}"
fi

blitz_log "${STEP}" "tracking" "start" "chronyc tracking" 0
chronyc tracking || true
blitz_log "${STEP}" "sources" "start" "chronyc sources -v" 0
chronyc sources -v || true
blitz_log "${STEP}" "complete" "success" "time-sync step finished" 0