#!/bin/bash

# Script to mount Borg backup vault and qcow2 disk image
# Created: 2025-10-07

set -e  # Exit on error

BORG_REPO="/data_storage/Backup/borg/srvfs01"
BORG_MOUNT="/mnt/restore"
QCOW2_MOUNT="/mnt/qcow2"
QCOW2_FILE="vm-105-disk-3.qcow2"

# Function to format date from backup folder name
format_date() {
    local folder=$1
    # Extract date from folder name (e.g., vm105-20250904-145444 or vm105-20251006-020001)
    if [[ $folder =~ vm[0-9]+-([0-9]{4})([0-9]{2})([0-9]{2})-([0-9]{6}) ]]; then
        local year=${BASH_REMATCH[1]}
        local month=${BASH_REMATCH[2]}
        local day=${BASH_REMATCH[3]}
        local time=${BASH_REMATCH[4]}
        local hour=${time:0:2}
        local minute=${time:2:2}
        
        # Convert month number to German month name
        case $month in
            01) month_name="Januar" ;;
            02) month_name="Februar" ;;
            03) month_name="März" ;;
            04) month_name="April" ;;
            05) month_name="Mai" ;;
            06) month_name="Juni" ;;
            07) month_name="Juli" ;;
            08) month_name="August" ;;
            09) month_name="September" ;;
            10) month_name="Oktober" ;;
            11) month_name="November" ;;
            12) month_name="Dezember" ;;
        esac
        
        echo "$day. $month_name $year - $hour:$minute Uhr"
    else
        echo "$folder"
    fi
}

echo "=== Mounting Borg Backup Vault ==="
# Mount the Borg vault
borg mount "$BORG_REPO" "$BORG_MOUNT"
echo "✓ Borg vault mounted to $BORG_MOUNT"
echo ""

# Scan for backup folders
echo "=== Scanning for available backups ==="
mapfile -t backups < <(ls -1 "$BORG_MOUNT" | sort -r)

if [ ${#backups[@]} -eq 0 ]; then
    echo "Error: No backups found in $BORG_MOUNT"
    borg umount "$BORG_MOUNT"
    exit 1
fi

echo "Available backups:"
echo ""
for i in "${!backups[@]}"; do
    backup_date=$(format_date "${backups[$i]}")
    printf "%2d) %s\n" $((i+1)) "$backup_date"
done

echo ""
read -p "Select backup number (1-${#backups[@]}) or [Enter] for latest: " selection

# Default to latest (first in sorted list)
if [ -z "$selection" ]; then
    selection=1
fi

# Validate selection
if ! [[ "$selection" =~ ^[0-9]+$ ]] || [ "$selection" -lt 1 ] || [ "$selection" -gt ${#backups[@]} ]; then
    echo "Error: Invalid selection"
    borg umount "$BORG_MOUNT"
    exit 1
fi

selected_backup="${backups[$((selection-1))]}"
selected_date=$(format_date "$selected_backup")

echo ""
echo "✓ Selected backup: $selected_date"
echo ""

# Find the qcow2 file in the selected backup
echo "=== Searching for QCOW2 file ==="
qcow2_path=$(find "$BORG_MOUNT/$selected_backup" -name "$QCOW2_FILE" 2>/dev/null | head -n 1)

if [ -z "$qcow2_path" ]; then
    echo "Error: Could not find $QCOW2_FILE in backup"
    borg umount "$BORG_MOUNT"
    exit 1
fi

echo "✓ Found: $qcow2_path"
echo ""

echo "=== Mounting QCOW2 Disk Image ==="
# Load NBD kernel module
modprobe nbd max_part=8
echo "✓ NBD module loaded"

# Connect qcow2 image to NBD device in read-only mode
qemu-nbd --connect=/dev/nbd0 --read-only "$qcow2_path"
echo "✓ QCOW2 connected to /dev/nbd0"

# Wait a moment for device to be ready
sleep 2

# Scan for LVM volumes
pvscan > /dev/null 2>&1
vgscan > /dev/null 2>&1
echo "✓ LVM volumes scanned"

# Create mount point if it doesn't exist
mkdir -p "$QCOW2_MOUNT"

# Mount the logical volume in read-only mode without journal recovery
mount -t ext4 -o ro,noload /dev/vgdata/lvshare "$QCOW2_MOUNT"
echo "✓ Filesystem mounted to $QCOW2_MOUNT"

echo ""
echo "=== Mount Summary ==="
echo "Borg vault:    $BORG_MOUNT"
echo "Selected:      $selected_date"
echo "QCOW2 disk:    $QCOW2_MOUNT"
echo ""
df -h "$BORG_MOUNT" "$QCOW2_MOUNT"

echo ""
echo "Done! To unmount, run: /data_storage/Backup/borg/umount_backup.sh"