#!/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

# ---------- Defaults ----------
: "${WORKDIR:=/var/backups/app-backup}"
: "${RESTORE_ROOT:=${WORKDIR}/restore}"
: "${RCLONE_REMOTE:=onedrive:Sicherung}"
: "${RCLONE_BIN:=rclone}"

: "${DRY_RUN:=false}"       # true = show what would happen
: "${RESTORE_DB:=true}"     # true/false
: "${RESTORE_FILES:=true}"  # true/false
: "${RESTORE_STRICT_DELETE:=false}"  # true = rsync --delete on restore

: "${ENABLE_NEXTCLOUD_MAINTENANCE:=true}"
: "${NC_OCC_USER:=apache}"
: "${NC_FILES_SCAN_AFTER_RESTORE:=false}"

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

run_cmd() {
  if [[ "${DRY_RUN}" == "true" ]]; then
    echo "[DRY_RUN] $*"
  else
    "$@"
  fi
}

# Nextcloud maintenance-mode safety trap
NC_MAINTENANCE_ON=false
nc_maintenance_off() {
  if [[ "${NC_MAINTENANCE_ON}" == "true" ]]; then
    echo "-- Nextcloud maintenance mode OFF (trap)..."
    run_cmd sudo -u "${NC_OCC_USER}" php "${NC_DIR}/occ" maintenance:mode --off || true
    NC_MAINTENANCE_ON=false
  fi
}

on_exit() {
  local exit_code=$?
  nc_maintenance_off
  exit "${exit_code}"
}
trap on_exit EXIT

# ---------- Preconditions ----------
[[ $EUID -eq 0 ]] || die "Must run as root."

for t in tar rsync flock df find stat; do
  have "$t" || die "Missing required tool: $t"
done

mkdir -p "$WORKDIR" "$RESTORE_ROOT" "$LOG_DIR"

# ---------- Locking ----------
LOCKFILE="/run/app-backup.lock"
exec 9>"$LOCKFILE"
if ! flock -n 9; then
  die "Another backup/restore already running (lock: $LOCKFILE)"
fi

# ---------- Input ----------
# Usage:
#   app-restore.sh /path/to/appbackup_YYYY-mm-dd_HH-MM-SS.tar.zst
# or
#   app-restore.sh /path/to/appbackup_YYYY-mm-dd_HH-MM-SS.tar.gz
# or
#   app-restore.sh --remote appbackup_YYYY-mm-dd_HH-MM-SS.tar.zst
# (copies from RCLONE_REMOTE to RESTORE_ROOT first)
ARCHIVE_PATH=""
REMOTE_NAME=""

if [[ "${1:-}" == "--remote" ]]; then
  REMOTE_NAME="${2:-}"
  [[ -n "$REMOTE_NAME" ]] || die "Usage: $0 --remote <archive_filename>"
  have "$RCLONE_BIN" || die "rclone missing but --remote used"
else
  ARCHIVE_PATH="${1:-}"
  [[ -n "$ARCHIVE_PATH" ]] || die "Usage: $0 <archive_file.tar.zst|tar.gz>  OR  $0 --remote <archive_filename>"
fi

echo "== app-restore start: ${ts} =="
echo "-- Config: ${CONFIG_FILE}"
echo "-- Log: ${LOG_FILE}"
echo "-- DRY_RUN: ${DRY_RUN}"
echo "-- RESTORE_FILES: ${RESTORE_FILES}"
echo "-- RESTORE_DB: ${RESTORE_DB}"
echo "-- STRICT_DELETE: ${RESTORE_STRICT_DELETE}"

# ---------- Fetch from remote if requested ----------
if [[ -n "$REMOTE_NAME" ]]; then
  ARCHIVE_PATH="${RESTORE_ROOT}/${REMOTE_NAME}"
  echo "-- Fetching from remote: ${RCLONE_REMOTE}/${REMOTE_NAME} -> ${ARCHIVE_PATH}"
  run_cmd "$RCLONE_BIN" copy "${RCLONE_REMOTE}/${REMOTE_NAME}" "${RESTORE_ROOT}" --checksum --log-level INFO
fi

[[ -f "$ARCHIVE_PATH" ]] || die "Archive not found: $ARCHIVE_PATH"

# ---------- Detect compression ----------
ARCHIVE_BASENAME="$(basename "$ARCHIVE_PATH")"
IS_ZSTD=false
IS_GZIP=false

case "$ARCHIVE_BASENAME" in
  *.tar.zst) IS_ZSTD=true ;;
  *.tar.gz)  IS_GZIP=true ;;
  *)
    # fallback: try file(1)
    if have file; then
      ftype="$(file -b "$ARCHIVE_PATH" || true)"
      if echo "$ftype" | grep -qi zstd; then
        IS_ZSTD=true
      elif echo "$ftype" | grep -qi gzip; then
        IS_GZIP=true
      else
        die "Cannot detect archive compression for: $ARCHIVE_PATH"
      fi
    else
      die "Unknown archive extension and file(1) not available: $ARCHIVE_PATH"
    fi
    ;;
esac

if [[ "$IS_ZSTD" == "true" ]]; then
  have zstd || die "zstd archive but zstd missing"
elif [[ "$IS_GZIP" == "true" ]]; then
  have gzip || die "gzip archive but gzip missing"
fi

# ---------- Extract ----------
RUN_DIR="${RESTORE_ROOT}/run_${ts}"
STAGING_DIR="${RUN_DIR}/staging"
mkdir -p "$STAGING_DIR"

echo "-- Extracting archive to: ${STAGING_DIR}"
if [[ "$IS_ZSTD" == "true" ]]; then
  run_cmd tar --zstd -xf "$ARCHIVE_PATH" -C "$STAGING_DIR"
elif [[ "$IS_GZIP" == "true" ]]; then
  run_cmd tar -xzf "$ARCHIVE_PATH" -C "$STAGING_DIR"
fi

[[ -d "$STAGING_DIR/files" ]] || die "Invalid archive content: missing files/ in extracted staging"

# ---------- Maintenance mode (Nextcloud) ----------
if [[ "${ENABLE_NEXTCLOUD}" == "true" && "${ENABLE_NEXTCLOUD_MAINTENANCE}" == "true" ]]; then
  if [[ -d "${NC_DIR}" && -f "${NC_DIR}/occ" ]]; then
    echo "-- Nextcloud maintenance mode ON..."
    run_cmd sudo -u "${NC_OCC_USER}" php "${NC_DIR}/occ" maintenance:mode --on
    NC_MAINTENANCE_ON=true
  else
    echo "WARN: Nextcloud directory/occ not found at NC_DIR=${NC_DIR} - cannot toggle maintenance mode"
  fi
fi

# ---------- Restore files ----------
rsync_restore_dir() {
  local src="$1"
  local dst="$2"

  [[ -d "$src" ]] || die "Restore source missing: $src"
  mkdir -p "$dst"

  local delete_flag=()
  if [[ "${RESTORE_STRICT_DELETE}" == "true" ]]; then
    delete_flag=(--delete)
  fi

  run_cmd rsync -aHAX --numeric-ids --info=stats2 \
    "${delete_flag[@]}" \
    "$src"/ "$dst"/
}

if [[ "${RESTORE_FILES}" == "true" ]]; then
  echo "-- Restoring files..."

  if [[ "${ENABLE_WORDPRESS}" == "true" ]]; then
    echo "-- Restore WordPress (webroot) to: ${WP_DIR}"
    # Backup excluded nextcloud/ automatically, so this should not overwrite Nextcloud.
    rsync_restore_dir "$STAGING_DIR/files/wordpress" "${WP_DIR}"
  fi

  if [[ "${ENABLE_NEXTCLOUD}" == "true" ]]; then
    echo "-- Restore Nextcloud code to: ${NC_DIR}"
    rsync_restore_dir "$STAGING_DIR/files/nextcloud" "${NC_DIR}"

    if [[ "${ENABLE_NEXTCLOUD_DATA}" == "true" ]]; then
      echo "-- Restore Nextcloud data to: ${NC_DATA_DIR}"
      rsync_restore_dir "$STAGING_DIR/files/nextcloud-data" "${NC_DATA_DIR}"
    fi
  fi

  if [[ "${ENABLE_MAIL}" == "true" ]]; then
    echo "-- Restore mail files..."
    [[ -d "$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
else
  echo "-- RESTORE_FILES=false (skipping file restore)"
fi

# ---------- Restore databases ----------
mysql_restore_sql() {
  local cnf="$1"
  local db="$2"
  local sql_file="$3"
  [[ -r "$cnf" ]] || die "DB CNF not readable: $cnf"
  [[ -r "$sql_file" ]] || die "SQL file not readable: $sql_file"

  echo "-- Import DB: ${db} from ${sql_file}"
  run_cmd mysql --defaults-extra-file="$cnf" "$db" < "$sql_file"
}

if [[ "${RESTORE_DB}" == "true" ]]; then
  echo "-- Restoring databases..."

  if [[ -n "${WP_DB_NAME:-}" ]]; then
    wp_sql="$(ls -1 "$STAGING_DIR/db"/wordpress_*.sql 2>/dev/null | tail -n 1 || true)"
    if [[ -n "$wp_sql" ]]; then
      mysql_restore_sql "${WP_DB_CNF}" "${WP_DB_NAME}" "$wp_sql"
    else
      echo "WARN: No WordPress SQL dump found in archive."
    fi
  fi

  if [[ -n "${NC_DB_NAME:-}" ]]; then
    nc_sql="$(ls -1 "$STAGING_DIR/db"/nextcloud_*.sql 2>/dev/null | tail -n 1 || true)"
    if [[ -n "$nc_sql" ]]; then
      mysql_restore_sql "${NC_DB_CNF}" "${NC_DB_NAME}" "$nc_sql"
    else
      echo "WARN: No Nextcloud SQL dump found in archive."
    fi
  fi
else
  echo "-- RESTORE_DB=false (skipping DB restore)"
fi

# ---------- Post-restore Nextcloud steps ----------
if [[ "${ENABLE_NEXTCLOUD}" == "true" && -d "${NC_DIR}" && -f "${NC_DIR}/occ" ]]; then
  echo "-- Nextcloud post-restore: maintenance:repair"
  run_cmd sudo -u "${NC_OCC_USER}" php "${NC_DIR}/occ" maintenance:repair || true

  echo "-- Nextcloud post-restore: files:scan (optional, can be slow)"
  if [[ "${NC_FILES_SCAN_AFTER_RESTORE}" == "true" ]]; then
    run_cmd sudo -u "${NC_OCC_USER}" php "${NC_DIR}/occ" files:scan --all || true
  else
    echo "-- Skipping files:scan (set NC_FILES_SCAN_AFTER_RESTORE=true to enable)"
  fi

  if [[ "${ENABLE_NEXTCLOUD_MAINTENANCE}" == "true" ]]; then
    echo "-- Nextcloud maintenance mode OFF..."
    run_cmd sudo -u "${NC_OCC_USER}" php "${NC_DIR}/occ" maintenance:mode --off
    NC_MAINTENANCE_ON=false
  fi
fi

echo "== app-restore done: ${ts} =="
echo "-- Extracted staging kept at: ${STAGING_DIR}"
echo "-- Log: ${LOG_FILE}"