#!/bin/bash
# Docker Volume Backup Script
# Wird remote auf dem Server ausgeführt
# Sichert alle Docker Volumes automatisch

set -e

# Parameter
BACKUP_DATE="${BACKUP_DATE:-$(date +%Y%m%d_%H%M%S)}"
BACKUP_BASE_DIR="$HOME/backups"
BACKUP_DIR="$BACKUP_BASE_DIR/$BACKUP_DATE"
EXCLUDE_VOLUMES="${EXCLUDE_VOLUMES:-}"  # Komma-separierte Liste von Volumes die übersprungen werden sollen

echo "========================================"
echo "Docker Volume Backup"
echo "========================================"
echo "Backup directory: $BACKUP_DIR"
echo "Date: $(date)"
echo "Server: ${SERVER_NAME:-unknown}"
echo ""

# Backup-Verzeichnis erstellen
echo "Creating backup directory: $BACKUP_DIR"
mkdir -p "$BACKUP_DIR"

echo "Discovering Docker volumes..."
VOLUMES=$(docker volume ls --format '{{.Name}}')
VOLUME_COUNT=$(echo "$VOLUMES" | wc -l)

if [ -z "$VOLUMES" ]; then
  echo "⚠ No Docker volumes found!"
  exit 0
fi

echo "Found $VOLUME_COUNT volumes to backup"
if [ -n "$EXCLUDE_VOLUMES" ]; then
  echo "Excluding: $EXCLUDE_VOLUMES"
fi
echo ""

# Funktion zum Prüfen ob Volume ausgeschlossen werden soll
is_excluded() {
  local VOLUME_NAME=$1
  if [ -z "$EXCLUDE_VOLUMES" ]; then
    return 1  # Nicht ausgeschlossen
  fi

  IFS=',' read -ra EXCLUDED <<< "$EXCLUDE_VOLUMES"
  for excluded in "${EXCLUDED[@]}"; do
    if [[ "$VOLUME_NAME" == "$excluded" ]]; then
      return 0  # Ausgeschlossen
    fi
  done
  return 1  # Nicht ausgeschlossen
}

# Funktion zum Backup eines Volumes
backup_volume() {
  local VOLUME_NAME=$1
  local SAFE_NAME=$(echo "$VOLUME_NAME" | tr '/' '_' | tr ':' '_')

  # Prüfen ob ausgeschlossen
  if is_excluded "$VOLUME_NAME"; then
    echo "⊘ Skipping $VOLUME_NAME (excluded)"
    return 0
  fi

  echo "Backing up: $VOLUME_NAME..."

  if docker run --rm \
    -v "$VOLUME_NAME":/source:ro \
    -v "$BACKUP_DIR":/backup \
    alpine tar czf "/backup/${SAFE_NAME}.tar.gz" -C /source . 2>/dev/null; then

    SIZE=$(du -h "$BACKUP_DIR/${SAFE_NAME}.tar.gz" | cut -f1)
    echo "✓ $VOLUME_NAME backed up ($SIZE)"
  else
    echo "✗ Failed to backup $VOLUME_NAME"
    return 1
  fi
}

# Alle Volumes sichern
SUCCESS_COUNT=0
FAILED_COUNT=0

while IFS= read -r volume; do
  if backup_volume "$volume"; then
    ((SUCCESS_COUNT++)) || true
  else
    ((FAILED_COUNT++)) || true
  fi
  echo ""
done <<< "$VOLUMES"

# Create manifest
echo "========================================"
echo "Creating backup manifest..."
cd "$BACKUP_DIR"
cat > manifest.txt << EOF
Backup created: $(date)
Hostname: $(hostname)
Server: ${SERVER_NAME:-unknown}
Total volumes: $VOLUME_COUNT
Successful: $SUCCESS_COUNT
Failed: $FAILED_COUNT

Files:
$(ls -lh *.tar.gz 2>/dev/null || echo "No backup files created")

Checksums (SHA256):
$(sha256sum *.tar.gz 2>/dev/null || echo "No files to checksum")
EOF

echo "Backup manifest:"
cat manifest.txt

echo ""
echo "Total backup size: $(du -sh $BACKUP_DIR | cut -f1)"
echo "========================================"
echo "Summary:"
echo "  Total volumes: $VOLUME_COUNT"
echo "  Successful: $SUCCESS_COUNT"
echo "  Failed: $FAILED_COUNT"
echo "========================================"

if [ $FAILED_COUNT -gt 0 ]; then
  echo "⚠ Backup completed with errors!"
  exit 1
else
  echo "✓ Backup completed successfully!"
  exit 0
fi