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

BACKUP_DIR="${1:-/mnt2/backed-up-drive/backupstore/volumes/2c/df/pvc-5c1f48e3-346f-4c35-8e6a-8fc0c4c3a842}"
OUTPUT_IMG="${2:-./nextcloud-data-restored.img}"

BACKUP_CFG="$BACKUP_DIR/backups/backup_backup-eac0221d1cab4a9c.cfg"
BLOCKS_DIR="$BACKUP_DIR/blocks"

if [[ ! -f "$BACKUP_CFG" ]]; then
    echo "Error: Backup config not found at $BACKUP_CFG"
    exit 1
fi

echo "========================================"
echo "  Longhorn Backup Restore Tool"
echo "========================================"
echo ""
echo "Backup: $BACKUP_DIR"
echo "Output: $OUTPUT_IMG"
echo ""

SIZE=$(python3 -c "import json; print(json.load(open('$BACKUP_CFG'))['Size'])")
BLOCK_COUNT=$(python3 -c "import json; print(len(json.load(open('$BACKUP_CFG'))['Blocks']))")

echo "Volume size: $((SIZE / 1024 / 1024 / 1024)) GB ($SIZE bytes)"
echo "Block count: $BLOCK_COUNT"
echo ""

read -p "Continue? [y/N] " -n 1 -r
echo ""
if [[ ! $REPLY =~ ^[Yy]$ ]]; then
    echo "Aborted."
    exit 1
fi

echo ""
echo "Creating sparse image..."
truncate -s "$SIZE" "$OUTPUT_IMG"

echo "Restoring blocks..."
python3 << 'PYEOF'
import json
import os
import sys

backup_cfg = os.environ['BACKUP_CFG']
blocks_dir = os.environ['BLOCKS_DIR']
output_img = os.environ['OUTPUT_IMG']

with open(backup_cfg) as f:
    data = json.load(f)

blocks = data['Blocks']
total = len(blocks)

with open(output_img, 'r+b') as img:
    for i, block in enumerate(blocks):
        offset = block['Offset']
        checksum = block['BlockChecksum']
        
        block_path = f"{blocks_dir}/{checksum[:2]}/{checksum[2:4]}/{checksum}.blk"
        
        if not os.path.exists(block_path):
            print(f"Warning: Block not found: {checksum}")
            continue
        
        with open(block_path, 'rb') as bf:
            img.seek(offset)
            img.write(bf.read())
        
        if (i + 1) % 1000 == 0 or i + 1 == total:
            percent = (i + 1) * 100 // total
            bar = '=' * (percent // 2) + ' ' * (50 - percent // 2)
            sys.stdout.write(f"\r[{bar}] {percent}% ({i + 1}/{total})")
            sys.stdout.flush()

print()
PYEOF

echo ""
echo "========================================"
echo "  Restore Complete!"
echo "========================================"
echo ""
echo "Image: $OUTPUT_IMG"
echo "Size: $(du -sh "$OUTPUT_IMG" | cut -f1)"
echo ""
echo "To mount:"
echo "  sudo losetup -fP $OUTPUT_IMG"
echo "  sudo mount /dev/loopX /mnt/point"
echo ""
echo "Or directly:"
echo "  sudo mount -o loop $OUTPUT_IMG /mnt/point"