#!/bin/bash

# Fix: Free Space After Deleting Files
# When you delete files but don't see space back, this script fixes it

set -e

echo "=== Fix: Free Space After Deleting Files ==="
echo ""
echo "This script handles the common issue where deleted files don't free up space"
echo "because APFS snapshots are holding onto them."
echo ""

# Check current free space
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 for Time Machine local snapshots
echo "📸 Checking for Time Machine local snapshots..."
TM_SNAPSHOTS=$(tmutil listlocalsnapshots / 2>/dev/null | grep -v "Snapshots for disk" | grep -v "^$")
if [ -n "$TM_SNAPSHOTS" ]; then
    echo "   Found snapshot(s) that may be holding space:"
    echo "$TM_SNAPSHOTS" | sed 's/^/   - /'
    echo ""
    
    read -p "Delete these snapshots to free space? (y/n) " -n 1 -r
    echo ""
    if [[ $REPLY =~ ^[Yy]$ ]]; then
        echo ""
        echo "🗑️  Deleting snapshots..."
        
        # Disable local snapshots first (helps with stuck snapshots)
        echo "   1. Disabling local snapshots..."
        sudo tmutil disablelocal 2>/dev/null || true
        sleep 2
        
        # Delete each snapshot
        echo "   2. Deleting snapshots..."
        echo "$TM_SNAPSHOTS" | while read snapshot; do
            if [ -n "$snapshot" ]; then
                # Extract date part from snapshot name
                SNAP_DATE=$(echo "$snapshot" | sed 's/.*\.\([0-9]\{4\}-[0-9]\{2\}-[0-9]\{2\}-[0-9]\{6\}\)\.backup/\1/')
                if [ -n "$SNAP_DATE" ]; then
                    echo "      Deleting: $snapshot"
                    sudo tmutil deletelocalsnapshots "$SNAP_DATE" 2>/dev/null && \
                        echo "      ✓ Deleted" || \
                        echo "      ⚠️  Could not delete (may need restart)"
                fi
            fi
        done
        
        # Try to thin all snapshots
        echo "   3. Thinning all local snapshots..."
        sudo tmutil thinlocalsnapshots / 1000000000 4 2>/dev/null || true
        
        # Re-enable local snapshots
        echo "   4. Re-enabling local snapshots..."
        sleep 2
        sudo tmutil enablelocal 2>/dev/null || true
        
        echo "   ✓ Snapshot cleanup completed"
    fi
else
    echo "   ✓ No Time Machine snapshots found"
fi

echo ""

# Force purge of memory and disk caches
echo "🧹 Purging system caches..."
if command -v purge &> /dev/null; then
    sudo purge
    echo "   ✓ Purge completed"
else
    echo "   ⚠️  Purge command not available"
fi

echo ""

# Wait a moment for system to update
echo "⏳ Waiting for system to update disk space..."
sleep 5

# Check new free space
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"
else
    echo "   ⚠️  No space freed yet"
fi
echo ""

if (( $(echo "$FREED_GB < 15" | bc -l) )) && (( $(echo "$FREE_SPACE_GB_AFTER < 5" | bc -l) )); then
    echo "⚠️  If space still not freed, try these steps:"
    echo ""
    echo "1. **Restart your Mac** - This is often the most effective solution."
    echo "   Snapshots are sometimes only released after a restart."
    echo ""
    echo "2. Check if Time Machine is trying to connect:"
    echo "   - Open System Settings → Time Machine"
    echo "   - If it says 'Connecting...', wait for it to finish or disconnect"
    echo "   - Then try deleting snapshots again"
    echo ""
    echo "3. Manually delete the snapshot after disabling Time Machine:"
    echo "   sudo tmutil disablelocal"
    echo "   sudo tmutil deletelocalsnapshots <date>"
    echo "   sudo tmutil enablelocal"
    echo ""
    echo "4. Use macOS Storage Management:"
    echo "   Apple Menu → About This Mac → Storage → Manage"
    echo "   This tool can identify and remove large system files"
    echo ""
fi

echo ""