#!/bin/bash

# Force Free Space - Remove APFS and Time Machine Snapshots
# This script removes snapshots that are holding onto deleted file space

set -e

echo "=== Force Free Space - Remove Snapshots ==="
echo ""
echo "This script will remove APFS and Time Machine snapshots that may be"
echo "holding onto space from deleted files."
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 ""

# List current snapshots
echo "📸 Current Snapshots:"
echo ""

echo "1. Time Machine Local Snapshots:"
TM_SNAPSHOTS=$(tmutil listlocalsnapshots / 2>/dev/null | grep -v "Snapshots for disk" | grep -v "^$")
if [ -n "$TM_SNAPSHOTS" ]; then
    echo "$TM_SNAPSHOTS" | while read snapshot; do
        if [ -n "$snapshot" ]; then
            echo "   - $snapshot"
        fi
    done
else
    echo "   None found"
fi
echo ""

echo "2. APFS System Snapshots:"
APFS_SNAPSHOTS=$(diskutil apfs listSnapshots / 2>/dev/null | grep -E "Snapshot Name|Snapshot UUID" | head -10)
if [ -n "$APFS_SNAPSHOTS" ]; then
    echo "$APFS_SNAPSHOTS"
else
    echo "   None found (or cannot list)"
fi
echo ""

# Ask for confirmation
read -p "Do you want to delete Time Machine local snapshots? (y/n) " -n 1 -r
echo ""
if [[ $REPLY =~ ^[Yy]$ ]]; then
    echo ""
    echo "🗑️  Deleting Time Machine local snapshots..."
    
    # Delete each snapshot
    echo "$TM_SNAPSHOTS" | while read snapshot; do
        if [ -n "$snapshot" ]; then
            echo "   Deleting: $snapshot"
            sudo tmutil deletelocalsnapshots "$snapshot" 2>/dev/null && \
                echo "   ✓ Deleted $snapshot" || \
                echo "   ⚠️  Could not delete $snapshot (may be in use)"
        fi
    done
    
    # Also try to delete all at once
    sudo tmutil deletelocalsnapshots / 2>/dev/null || true
    
    echo "   ✓ Time Machine snapshots cleanup attempted"
fi

echo ""

# Force purge of purgeable space
echo "3. Purging Purgeable Space..."
echo "   This forces macOS to actually free up space from deleted files."
echo ""

read -p "Do you want to purge purgeable space? (y/n) " -n 1 -r
echo ""
if [[ $REPLY =~ ^[Yy]$ ]]; then
    echo ""
    echo "   Running purge command..."
    
    # Method 1: Use purge command (if available)
    if command -v purge &> /dev/null; then
        sudo purge
        echo "   ✓ Purge command executed"
    fi
    
    # Method 2: Disable and re-enable local snapshots to force cleanup
    echo "   Disabling local snapshots..."
    sudo tmutil disablelocal 2>/dev/null || true
    sleep 2
    echo "   Re-enabling local snapshots..."
    sudo tmutil enablelocal 2>/dev/null || true
    
    # Method 3: Force Time Machine to clean up
    echo "   Triggering Time Machine cleanup..."
    sudo tmutil thinlocalsnapshots / 1000000000 4 2>/dev/null || true
    
    echo "   ✓ Purge operations completed"
fi

echo ""

# Check new free space
sleep 2
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 (may need to wait or try other methods)"
fi
echo ""

if (( $(echo "$FREED_GB < 15" | bc -l) )) && (( $(echo "$FREE_SPACE_GB_AFTER < 5" | bc -l) )); then
    echo "⚠️  Still low on space. Additional steps:"
    echo ""
    echo "1. Wait a few minutes - macOS may still be processing"
    echo ""
    echo "2. Restart your Mac - this often frees up snapshot space"
    echo ""
    echo "3. Check for large files in other locations:"
    echo "   ./free_disk_space.sh"
    echo ""
    echo "4. Manually delete the Time Machine snapshot:"
    SNAP=$(tmutil listlocalsnapshots / 2>/dev/null | grep -v "Snapshots for disk" | grep -v "^$" | head -1)
    if [ -n "$SNAP" ]; then
        echo "   sudo tmutil deletelocalsnapshots $SNAP"
    fi
    echo ""
    echo "5. 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 ""