#!/usr/bin/env bash
# Run on the Bazzite box BEFORE wiping it. Archives your home folder to server-marvin as
# tar.zst files, then reads every archive back to prove it's intact.
#
#   scripts/backup.sh                    # -> /var/mnt/server-marvin-personal/desktop-backup-<date>
#   scripts/backup.sh /some/other/dir    # any directory NOT on the disk you're about to wipe
#
# Re-running skips archives that already finished (FORCE=1 redoes them).
# Close Steam, Firefox, Discord and Claude first — files that change mid-read get a warning.
set -euo pipefail

SHARE=/var/mnt/server-marvin-personal
DEST="${1:-$SHARE/desktop-backup-$(date +%F)}"

step() { printf '\n\033[1;34m== %s ==\033[0m\n' "$*"; }
warn() { printf '\033[1;33mwarning:\033[0m %s\n' "$*" >&2; }
die()  { printf '\033[1;31merror:\033[0m %s\n' "$*" >&2; exit 1; }

# -- Make sure the backup lands somewhere that survives the reinstall ------------------
if [[ $DEST == "$SHARE"/* ]]; then
  ls "$SHARE" >/dev/null 2>&1 || true            # poke the automount
  mountpoint -q "$SHARE" || die "$SHARE isn't mounted — is server-marvin up?"
fi
mkdir -p "$DEST"
disk_of() { findmnt -n -o SOURCE -T "$1" | sed 's/\[.*//'; }
[[ $(disk_of "$DEST") != "$(disk_of "$HOME")" ]] \
  || die "$DEST is on the same disk as your home — that's the disk Ubuntu will wipe"
echo "Backing up $HOME -> $DEST"
df -h "$DEST" | tail -1

# -- Archive helper ---------------------------------------------------------------------
archive() {  # archive <name> <tar args + members...>
  local name=$1 out="$DEST/$1.tar.zst"; shift
  step "$name"
  if [[ -s $out && -z ${FORCE:-} ]]; then echo "already done, skipping"; return; fi
  local rc=0
  tar --create --file="$out.partial" --use-compress-program='zstd -T0 -3' \
      --directory="$HOME" \
      --checkpoint=100000 --checkpoint-action='ttyout=  %{%H:%M:%S}t  %T%*\r' \
      "$@" || rc=$?
  echo
  # GNU tar exits 1 when a file changed while it was being read (an app was still open).
  # Everything else still made it in, so keep the archive; anything above 1 is fatal.
  (( rc <= 1 )) || die "tar failed on $name (exit $rc)"
  (( rc == 0 )) || warn "$name: some files changed while being read — close apps and FORCE=1 to redo if it matters"
  mv "$out.partial" "$out"
  ls -lh "$out" | awk '{print "  " $5}'
}

# Big, self-contained folders get their own archive so they can be restored (or skipped)
# separately. Everything else goes in home.tar.zst.
archive home \
  --anchored \
  --exclude=./.cache \
  --exclude=./.local/share/Trash \
  --exclude=./.local/share/Steam \
  --exclude=./.steam \
  --exclude=./.local/share/containers \
  --exclude=./.local/share/flatpak \
  --exclude=./.local/share/baloo \
  --exclude='./.var/app/*/cache' \
  --exclude='./.claude.json.tmp.*' \
  --exclude=./.xlcore \
  --exclude=./ComfyUI \
  --no-anchored \
  --exclude=node_modules \
  --exclude=__pycache__ \
  .

# FFXIV game install (~124 GB) — Square's patch servers make a redownload take hours.
[[ -d $HOME/.xlcore ]] && archive xlcore ./.xlcore

# ComfyUI minus its venv (rebuilt on Ubuntu); this is ~110 GB of models.
[[ -d $HOME/ComfyUI ]] && archive comfyui \
  --anchored --exclude=./ComfyUI/venv --exclude=./ComfyUI/.venv \
  --no-anchored --exclude=__pycache__ \
  ./ComfyUI

# Steam: only saves and settings. Games get redownloaded; the ones on the Data drive stay put.
archive steam-saves \
  ./.local/share/Steam/userdata \
  ./.local/share/Steam/steamapps/compatdata

# -- Reference info for the rebuild -------------------------------------------------------
step "manifest"
m="$DEST/manifest"; mkdir -p "$m"
flatpak list --app --columns=application,origin,installation > "$m/flatpaks.txt" 2>/dev/null || true
code --list-extensions > "$m/vscode-extensions.txt" 2>/dev/null || true
brew leaves > "$m/brew-leaves.txt" 2>/dev/null || true
rpm-ostree status > "$m/rpm-ostree-status.txt" 2>/dev/null || true
cp /etc/fstab "$m/fstab"
cp -r "$HOME/.local/share/flatpak/overrides" "$m/flatpak-overrides-user" 2>/dev/null || true
cp -r /var/lib/flatpak/overrides "$m/flatpak-overrides-system" 2>/dev/null || true
lsblk -f > "$m/disks.txt"
ls "$HOME/.local/share/Steam/steamapps/common" > "$m/steam-games-home.txt" 2>/dev/null || true
ls /run/media/"$USER"/Data/SteamLibrary/steamapps/common > "$m/steam-games-data-drive.txt" 2>/dev/null || true
ls "$m"

# -- Prove every archive reads back cleanly ----------------------------------------------
if [[ -z ${SKIP_VERIFY:-} ]]; then
  for f in "$DEST"/*.tar.zst; do
    step "verify $(basename "$f")"
    tar --use-compress-program=zstd --list --file="$f" > /dev/null || die "$f is corrupt — rerun with FORCE=1"
    echo "ok"
  done
fi

step "done"
du -sh "$DEST"/*.tar.zst
echo "Backup is in: $DEST"
echo "Safe to wipe the 990 PRO once you've eyeballed that list."