#!/bin/bash

# Delete Local Snapshot to Free Space
# Since files are on NAS, it's safe to remove the snapshot

set -e

echo "=== Delete Local Snapshot to Free Space ==="
echo ""
echo "Since your files are safely backed up on NAS, we can delete"
echo "the local snapshot to free up space."
echo ""

FREE_SPACE_BEFORE=$(df / | tail -1 | awk '{print $4}')
FREE_SPACE_GB_BEFORE=$(echo "scale=2; $FREE_SPACE_BEFORE / 1024 / 1024" | bc)
echo "Current free space: ${FREE_SPACE_GB_BEFORE}GB"
echo ""

# Check snapshot
SNAPSHOT=$(tmutil listlocalsnapshots / 2>/dev/null | grep -v "Snapshots for disk" | grep -v "^$" | head -1)
if [ -z "$SNAPSHOT" ]; then
    echo "✅ No snapshot found - you're all set!"
    exit 0
fi

echo "Found snapshot: $SNAPSHOT"
echo ""

# Extract date
SNAP_DATE=$(echo "$SNAPSHOT" | sed 's/.*\.\([0-9]\{4\}-[0-9]\{2\}-[0-9]\{2\}-[0-9]\{6\}\)\.backup/\1/')

if [ -z "$SNAP_DATE" ]; then
    echo "⚠️  Could not parse snapshot date"
    exit 1
fi

echo "Attempting to delete snapshot: $SNAP_DATE"
echo ""

# Try to delete
if sudo tmutil deletelocalsnapshots "$SNAP_DATE" 2>/dev/null; then
    echo "✅ Successfully deleted snapshot!"
    echo ""
    echo "⏳ Waiting for space to be released..."
    sleep 5
    
    FREE_SPACE_AFTER=$(df / | tail -1 | awk '{print $4}')
    FREE_SPACE_GB_AFTER=$(echo "scale=2; $FREE_SPACE_AFTER / 1024 / 1024" | bc)
    FREED_GB=$(echo "scale=2; $FREE_SPACE_GB_AFTER - $FREE_SPACE_GB_BEFORE" | bc)
    
    echo ""
    echo "=== Results ==="
    echo "   Before: ${FREE_SPACE_GB_BEFORE}GB free"
    echo "   After:  ${FREE_SPACE_GB_AFTER}GB free"
    if (( $(echo "$FREED_GB > 0" | bc -l) )); then
        echo "   ✅ Freed: ${FREED_GB}GB"
    fi
else
    echo "⚠️  Could not delete snapshot (Stale NFS file handle error)"
    echo ""
    echo "This is a known issue. The snapshot is stuck because:"
    echo "  - Time Machine had a stale connection to NAS"
    echo "  - The snapshot reference is corrupted"
    echo ""
    echo "=== Solutions ==="
    echo ""
    echo "Option 1: Restart your Mac (Recommended)"
    echo "  This will release the stuck snapshot and free the space."
    echo "  After restart, the snapshot should be gone."
    echo ""
    echo "Option 2: Wait for macOS to auto-clean"
    echo "  macOS will eventually clean up stuck snapshots, but this"
    echo "  can take hours or days."
    echo ""
    echo "The good news: The snapshot is a GHOST ENTRY (not in APFS)."
    echo "This means the space may already be available - the entry"
    echo "is just a stale database record that will clear on restart."
    echo ""
fi

echo ""