#!/usr/bin/env bash
set -Eeuo pipefail
umask 027

# ---------------- Logging ----------------
LOG_DIR="/var/log/app-backup"
mkdir -p "$LOG_DIR"
ts="$(date '+%Y-%m-%d_%H-%M-%S')"
LOG_FILE="${LOG_DIR}/app-restore_${ts}.log"
exec > >(tee -a "$LOG_FILE" | systemd-cat -t app-restore -p info) 2>&1

# ---------------- Config ----------------
CONFIG_FILE="/etc/app-backup/app-backup.conf"
if [[ -r "$CONFIG_FILE" ]]; then
  # shellcheck disable=SC1090
  source "$CONFIG_FILE"
else
  echo "ERROR: Config not found/readable: $CONFIG_FILE"
  exit 2
fi

: "${WORKDIR:=/var/backups/app-backup}"
: "${STAGING_ROOT:=${WORKDIR}/restore-staging}"
: "${RCLONE_REMOTE:=onedrive:Sicherung}"
: "${RCLONE_BIN:=rclone}"
: "${NC_OCC_USER:=apache}"

ARCHIVE_PATH=""
REMOTE_NAME=""
DRY_RUN=false
FORCE=false

DO_WORDPRESS=true
DO_NEXTCLOUD=true
DO_NEXTCLOUD_DATA=true
DO_MAIL=true
DO_DB=true

usage() {
  cat <<EOF
Usage:
  app-restore.sh --archive /path/to/appbackup_....tar.(zst|gz)
  app-restore.sh --remote-file appbackup_....tar.(zst|gz)
Options:
  --archive <path>        Local archive path.
  --remote-file <name>    Download that file name from rclone remote (${RCLONE_REMOTE}) into ${WORKDIR}/restore-downloads/.
  --dry-run               No writes (rsync --dry-run; DB import skipped; services not restarted).
  --force                 Skip some safety checks.
  --only <list>           Comma-separated: wordpress,nextcloud,nextcloud-data,mail,db
  --skip <list>           Comma-separated: wordpress,nextcloud,nextcloud-data,mail,db
  -h|--help               Help.
EOF
}

set_all_false() { DO_WORDPRESS=false; DO_NEXTCLOUD=false; DO_NEXTCLOUD_DATA=false; DO_MAIL=false; DO_DB=false; }
parse_list_flags() {
  local mode="$1" list="$2"
  IFS=',' read -r -a items <<< "$list"
  for it in "${items[@]}"; do
    it="$(echo "$it" | tr '[:upper:]' '[:lower:]' | xargs)"
    case "$it" in
      wordpress)       [[ "$mode" == "only" ]] && DO_WORDPRESS=true || DO_WORDPRESS=false ;;
      nextcloud)       [[ "$mode" == "only" ]] && DO_NEXTCLOUD=true || DO_NEXTCLOUD=false ;;
      nextcloud-data)  [[ "$mode" == "only" ]] && DO_NEXTCLOUD_DATA=true || DO_NEXTCLOUD_DATA=false ;;
      mail)            [[ "$mode" == "only" ]] && DO_MAIL=true || DO_MAIL=false ;;
      db)              [[ "$mode" == "only" ]] && DO_DB=true || DO_DB=false ;;
      "" ) : ;;
      *) echo "WARN: unknown component: $it" ;;
    esac
  done
}

while [[ $# -gt 0 ]]; do
  case "$1" in
    --archive) ARCHIVE_PATH="${2:-}"; shift 2 ;;
    --remote-file) REMOTE_NAME="${2:-}"; shift 2 ;;
    --dry-run) DRY_RUN=true; shift ;;
    --force) FORCE=true; shift ;;
    --only) set_all_false; parse_list_flags "only" "${2:-}"; shift 2 ;;
    --skip) parse_list_flags "skip" "${2:-}"; shift 2 ;;
    -h|--help) usage; exit 0 ;;
    *) echo "ERROR: unknown arg: $1"; usage; exit 2 ;;
  esac
done

die(){ echo "ERROR: $*"; exit 1; }
have(){ command -v "$1" >/dev/null 2>&1; }
service_is_active(){ systemctl is-active --quiet "$1"; }

STOPPED_SERVICES=()
stop_service_if_active() {
  local s="$1"
  if service_is_active "$s"; then
    echo "-- Stopping service: $s"
    [[ "$DRY_RUN" == "true" ]] || systemctl stop "$s"
    STOPPED_SERVICES+=("$s")
  fi
}

start_stopped_services() {
  if [[ "$DRY_RUN" == "true" ]]; then
    echo "-- DRY RUN: not starting services"
    return 0
  fi
  for s in "${STOPPED_SERVICES[@]}"; do
    echo "-- Starting service: $s"
    systemctl start "$s" || echo "WARN: failed to start $s"
  done
}

integrity_check() {
  local f="$1"
  if [[ "$f" == *.zst ]]; then
    have zstd || die "zstd missing but archive is .zst"
    zstd -t "$f"
  elif [[ "$f" == *.gz ]]; then
    have gzip || die "gzip missing but archive is .gz"
    gzip -t "$f"
  else
    die "Unsupported archive extension: $f"
  fi
}

extract_archive() {
  local f="$1" dest="$2"
  mkdir -p "$dest"
  if [[ "$f" == *.zst ]]; then
    tar --use-compress-program=unzstd -xf "$f" -C "$dest"
  else
    tar -xzf "$f" -C "$dest"
  fi
}

rsync_restore_dir() {
  local src="$1" dst="$2"
  [[ -d "$src" ]] || die "Staging source missing: $src"
  mkdir -p "$dst"
  local args=(-aHAX --numeric-ids --delete)
  [[ "$DRY_RUN" == "true" ]] && args+=(--dry-run)
  echo "-- Restoring: $src => $dst"
  rsync "${args[@]}" "$src"/ "$dst"/
}

mysql_import() {
  local cnf="$1" db="$2" sql="$3"
  [[ -r "$cnf" ]] || die "DB cnf not readable: $cnf"
  [[ -r "$sql" ]] || die "SQL dump not readable: $sql"
  have mysql || die "mysql client missing"
  if [[ "$DRY_RUN" == "true" ]]; then
    echo "-- DRY RUN: skipping DB import for $db"
    return 0
  fi
  mysql --defaults-extra-file="$cnf" -e "CREATE DATABASE IF NOT EXISTS \`${db}\`;"
  mysql --defaults-extra-file="$cnf" "$db" < "$sql"
}

NC_MAINTENANCE_ON=false
nc_maintenance_on() {
  if [[ "$DRY_RUN" == "true" ]]; then
    echo "-- DRY RUN: not toggling Nextcloud maintenance mode"
    return 0
  fi
  if [[ -f "${NC_DIR}/occ" ]]; then
    sudo -u "${NC_OCC_USER}" php "${NC_DIR}/occ" maintenance:mode --on
    NC_MAINTENANCE_ON=true
  fi
}
nc_maintenance_off() {
  if [[ "${NC_MAINTENANCE_ON}" == "true" ]]; then
    sudo -u "${NC_OCC_USER}" php "${NC_DIR}/occ" maintenance:mode --off || true
    NC_MAINTENANCE_ON=false
  fi
}

echo "== app-restore start: ${ts} =="
echo "-- Log: ${LOG_FILE}"
[[ $EUID -eq 0 ]] || die "Must run as root."

LOCKFILE="/run/app-restore.lock"
exec 9>"$LOCKFILE"
flock -n 9 || die "Another restore is already running (lock: $LOCKFILE)"

DOWNLOAD_DIR="${WORKDIR}/restore-downloads"
mkdir -p "$DOWNLOAD_DIR"

if [[ -n "$REMOTE_NAME" ]]; then
  have "$RCLONE_BIN" || die "rclone required for --remote-file"
  ARCHIVE_PATH="${DOWNLOAD_DIR}/${REMOTE_NAME}"
  if [[ "$DRY_RUN" == "true" ]]; then
    echo "-- DRY RUN: would download ${RCLONE_REMOTE}/${REMOTE_NAME} to ${ARCHIVE_PATH}"
  else
    "$RCLONE_BIN" copy "${RCLONE_REMOTE}/${REMOTE_NAME}" "$DOWNLOAD_DIR" --log-level INFO
  fi
fi

[[ -n "$ARCHIVE_PATH" ]] || { usage; die "Provide --archive or --remote-file"; }
[[ -f "$ARCHIVE_PATH" ]] || die "Archive not found: $ARCHIVE_PATH"

echo "-- Selected archive: $ARCHIVE_PATH"
integrity_check "$ARCHIVE_PATH"

STAGING_DIR="${STAGING_ROOT}/run_${ts}"
trap 'nc_maintenance_off; start_stopped_services; rm -rf "${STAGING_DIR:?}"' EXIT
extract_archive "$ARCHIVE_PATH" "$STAGING_DIR"

[[ -d "$STAGING_DIR/files" ]] || die "Invalid archive: missing 'files' dir"

# stop services to prevent writes
if systemctl list-unit-files | grep -q '^httpd\.service'; then stop_service_if_active httpd; fi
if [[ "$DO_MAIL" == "true" ]]; then
  if systemctl list-unit-files | grep -q '^postfix\.service'; then stop_service_if_active postfix; fi
  if systemctl list-unit-files | grep -q '^dovecot\.service'; then stop_service_if_active dovecot; fi
fi

# nextcloud maintenance for restore
if [[ "$DO_NEXTCLOUD" == "true" || "$DO_NEXTCLOUD_DATA" == "true" || "$DO_DB" == "true" ]]; then
  nc_maintenance_on
fi

# restore files
[[ "$DO_WORDPRESS" == "true" && -d "$STAGING_DIR/files/wordpress" ]] && rsync_restore_dir "$STAGING_DIR/files/wordpress" "$WP_DIR" || true
[[ "$DO_NEXTCLOUD" == "true" && -d "$STAGING_DIR/files/nextcloud" ]] && rsync_restore_dir "$STAGING_DIR/files/nextcloud" "$NC_DIR" || true
[[ "$DO_NEXTCLOUD_DATA" == "true" && -d "$STAGING_DIR/files/nextcloud-data" ]] && rsync_restore_dir "$STAGING_DIR/files/nextcloud-data" "$NC_DATA_DIR" || true

if [[ "$DO_MAIL" == "true" ]]; then
  [[ -d "$STAGING_DIR/files/mail" && -n "${MAIL_DIR:-}" ]] && rsync_restore_dir "$STAGING_DIR/files/mail" "$MAIL_DIR" || true
  [[ -d "$STAGING_DIR/files/postfix" && -n "${POSTFIX_DIR:-}" ]] && rsync_restore_dir "$STAGING_DIR/files/postfix" "$POSTFIX_DIR" || true
  [[ -d "$STAGING_DIR/files/dovecot" && -n "${DOVECOT_DIR:-}" ]] && rsync_restore_dir "$STAGING_DIR/files/dovecot" "$DOVECOT_DIR" || true
fi

# restore DBs
if [[ "$DO_DB" == "true" && "${ENABLE_DB_DUMPS:-false}" == "true" ]]; then
  WP_SQL="$(ls -1 "$STAGING_DIR/db"/wordpress_*.sql 2>/dev/null | tail -n 1 || true)"
  NC_SQL="$(ls -1 "$STAGING_DIR/db"/nextcloud_*.sql 2>/dev/null | tail -n 1 || true)"
  [[ "$DO_WORDPRESS" == "true" && -n "${WP_DB_NAME:-}" && -n "$WP_SQL" ]] && mysql_import "$WP_DB_CNF" "$WP_DB_NAME" "$WP_SQL" || true
  [[ ( "$DO_NEXTCLOUD" == "true" || "$DO_NEXTCLOUD_DATA" == "true" ) && -n "${NC_DB_NAME:-}" && -n "$NC_SQL" ]] && mysql_import "$NC_DB_CNF" "$NC_DB_NAME" "$NC_SQL" || true
fi

nc_maintenance_off
start_stopped_services

echo "== app-restore done: ${ts} =="
echo "-- Log: ${LOG_FILE}"