#!/bin/bash

# Force Delete Stuck Snapshot - Last Resort Methods
# When normal deletion methods fail

set -e

echo "=== Force Delete Stuck Snapshot ==="
echo ""
echo "This script tries aggressive methods to free stuck snapshot 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 ""

SNAPSHOTS=$(tmutil listlocalsnapshots / 2>/dev/null | grep -v "Snapshots for disk" | grep -v "^$")
if [ -z "$SNAPSHOTS" ]; then
    echo "✅ No snapshots found!"
    exit 0
fi

echo "Found stuck snapshot(s):"
echo "$SNAPSHOTS" | sed 's/^/  - /'
echo ""

read -p "Try aggressive cleanup methods? (y/n) " -n 1 -r
echo ""
if [[ ! $REPLY =~ ^[Yy]$ ]]; then
    exit 0
fi

echo ""
echo "Method 1: Aggressive snapshot thinning..."
sudo tmutil thinlocalsnapshots / 1000000000 1 2>&1 || true
echo "   ✓ Completed"
echo ""

echo "Method 2: System purge..."
if command -v purge &> /dev/null; then
    sudo purge
    echo "   ✓ Purged"
else
    echo "   ⚠️  Purge command not available"
fi
echo ""

echo "Method 3: Checking APFS snapshots..."
APFS_SNAPS=$(diskutil apfs listSnapshots / 2>/dev/null)
if echo "$APFS_SNAPS" | grep -qi "timemachine"; then
    echo "   Found Time Machine snapshot in APFS"
    # Try to get UUID and delete
    SNAP_UUID=$(echo "$APFS_SNAPS" | grep -A 2 -i "timemachine" | grep "UUID" | awk '{print $NF}' | head -1)
    if [ -n "$SNAP_UUID" ]; then
        echo "   Attempting to delete APFS snapshot: $SNAP_UUID"
        sudo diskutil apfs deleteSnapshot / -uuid "$SNAP_UUID" 2>&1 || echo "   ⚠️  Could not delete (may be protected)"
    fi
else
    echo "   ℹ️  Snapshot not in APFS list (ghost entry)"
fi
echo ""

echo "Method 4: Force filesystem sync..."
sync
echo "   ✓ Filesystem synced"
echo ""

echo "Method 5: Check for Time Machine temp files..."
TM_TEMP=$(sudo find /System/Volumes/Data/.timemachine -type f 2>/dev/null | wc -l | tr -d ' ')
if [ "$TM_TEMP" -gt 0 ]; then
    TEMP_SIZE=$(sudo du -sh /System/Volumes/Data/.timemachine 2>/dev/null | awk '{print $1}' || echo "0")
    echo "   Found Time Machine temp files: $TEMP_SIZE"
    read -p "   Delete Time Machine temp files? (y/n) " -n 1 -r
    echo ""
    if [[ $REPLY =~ ^[Yy]$ ]]; then
        sudo rm -rf /System/Volumes/Data/.timemachine/* 2>/dev/null || true
        echo "   ✓ Cleaned"
    fi
else
    echo "   ✓ No temp files found"
fi
echo ""

echo "⏳ Waiting for system to update..."
sleep 5

# Check results
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)

REMAINING_SNAPS=$(tmutil listlocalsnapshots / 2>/dev/null | grep -v "Snapshots for disk" | grep -v "^$" | wc -l | tr -d ' ')

echo ""
echo "=== Results ==="
echo "   Free space: ${FREE_SPACE_GB_BEFORE}GB → ${FREE_SPACE_GB_AFTER}GB"
if (( $(echo "$FREED_GB > 15" | bc -l) )); then
    echo "   ✅ Successfully freed: ${FREED_GB}GB"
elif (( $(echo "$FREED_GB > 0" | bc -l) )); then
    echo "   ✅ Freed: ${FREED_GB}GB"
else
    echo "   ⚠️  No space freed yet"
fi

if [ "$REMAINING_SNAPS" -gt 0 ]; then
    echo "   ⚠️  Snapshot still listed (ghost entry)"
    echo ""
    echo "   The snapshot entry may persist, but if space was freed,"
    echo "   it's likely just a database entry and not taking space."
else
    echo "   ✅ Snapshot removed!"
fi

echo ""

if (( $(echo "$FREED_GB < 15" | bc -l) )); then
    echo "⚠️  Space still not fully freed. Final options:"
    echo ""
    echo "1. **Restart your Mac** - This is the most reliable solution."
    echo "   The snapshot will be released after restart."
    echo ""
    echo "2. Wait 10-15 minutes - macOS may still be processing"
    echo ""
    echo "3. Check if space is actually available but not showing:"
    echo "   - Try creating a large file to test"
    echo "   - Check Activity Monitor → Disk tab"
    echo ""
fi

echo ""