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

usage() {
  cat <<'USAGE'
Usage: fedora-backup-home DESTINATION [options]

Rsync your home folder to an external drive or mounted network share.
Dry-run is the default. Add --run when the preview looks right.

Examples:
  fedora-backup-home /run/media/$USER/BackupDrive
  fedora-backup-home /run/media/$USER/BackupDrive --run
  fedora-backup-home /mnt/nas/backups --run --delete

Options:
  --run       Actually copy files. Without this, rsync runs in dry-run mode.
  --delete    Delete files in the backup that no longer exist in your home folder.
  -h, --help  Show this help.
USAGE
}

log() { printf '\n\033[1m==> %s\033[0m\n' "$*"; }
die() { printf '\033[31mERROR:\033[0m %s\n' "$*" >&2; exit 1; }

[[ $# -gt 0 ]] || { usage; exit 1; }

DEST_ROOT=""
RUN=false
DELETE=false

while [[ $# -gt 0 ]]; do
  case "$1" in
    --run) RUN=true ;;
    --delete) DELETE=true ;;
    -h|--help) usage; exit 0 ;;
    -*) die "Unknown option: $1" ;;
    *)
      if [[ -z "$DEST_ROOT" ]]; then DEST_ROOT="$1"; else die "Unexpected extra argument: $1"; fi
      ;;
  esac
  shift
done

[[ -n "$DEST_ROOT" ]] || die "Missing DESTINATION."
command -v rsync >/dev/null 2>&1 || die "rsync is not installed. Run: sudo dnf5 install rsync"
[[ -d "$DEST_ROOT" ]] || die "Destination does not exist: $DEST_ROOT"

HOST="$(hostname -s 2>/dev/null || hostname)"
DEST="$DEST_ROOT/${HOST}-${USER}-home"
mkdir -p "$DEST"

# Prevent accidental recursive backup if destination is inside $HOME.
case "$(realpath -m "$DEST")" in
  "$(realpath -m "$HOME")"/*) die "Destination is inside your home folder; choose an external path." ;;
esac

RSYNC_OPTS=(-aAXH --human-readable --info=progress2)
[[ "$RUN" == "false" ]] && RSYNC_OPTS+=(--dry-run --itemize-changes)
[[ "$DELETE" == "true" ]] && RSYNC_OPTS+=(--delete)

EXCLUDES=(
  --exclude='/.cache/'
  --exclude='/.local/share/Trash/'
  --exclude='/.var/app/*/cache/'
  --exclude='/Downloads/*.iso'
  --exclude='/Downloads/*.img'
  --exclude='/Downloads/*.qcow2'
  --exclude='/.npm/_cacache/'
  --exclude='/.cargo/registry/'
  --exclude='/.cargo/git/'
  --exclude='/.gradle/caches/'
  --exclude='/**/node_modules/'
  --exclude='/**/.venv/'
)

log "Backing up $HOME to $DEST"
if [[ "$RUN" == "false" ]]; then
  printf 'Mode: DRY RUN. Add --run to actually copy files.\n'
else
  printf 'Mode: REAL RUN.\n'
fi
[[ "$DELETE" == "true" ]] && printf 'Delete mode: enabled.\n'

rsync "${RSYNC_OPTS[@]}" "${EXCLUDES[@]}" "$HOME/" "$DEST/"

log "Done"
if [[ "$RUN" == "false" ]]; then
  printf 'Review the dry-run above, then rerun with --run when ready.\n'
fi