#!/bin/bash

# Find Real 351GB Usage in System Data
# Since purgeable space test failed, the space is actually being used

set -e

echo "=== Find Real 351GB Usage in System Data ==="
echo ""
echo "The 50GB file creation FAILED, which means:"
echo "  - The 351GB is NOT purgeable"
echo "  - It's actually being used"
echo "  - We need to find what's using it"
echo ""

echo "📊 Container Analysis:"
CONTAINER_TOTAL=$(diskutil info / | grep 'Container Total' | awk '{print $4, $5}')
CONTAINER_FREE=$(diskutil info / | grep 'Container Free' | awk '{print $4, $5}')
CONTAINER_USED=$(diskutil apfs list 2>/dev/null | grep "Capacity In Use" | awk '{print $6, $7}')

echo "   Container Total: $CONTAINER_TOTAL"
echo "   Container Free:  $CONTAINER_FREE"
echo "   Container Used:  $CONTAINER_USED"
echo ""

echo "📦 APFS Volume Breakdown:"
diskutil apfs list 2>/dev/null | grep -E "Volume|Capacity Consumed" | while read line; do
    if echo "$line" | grep -q "Volume"; then
        VOL_NAME=$(echo "$line" | sed 's/.*Name: *\([^(]*\).*/\1/')
        echo "   Volume: $VOL_NAME"
    elif echo "$line" | grep -q "Capacity Consumed"; then
        SIZE=$(echo "$line" | awk '{print $3, $4}')
        echo "     Size: $SIZE"
    fi
done
echo ""

echo "📸 APFS Snapshots:"
APFS_SNAPS=$(diskutil apfs listSnapshots / 2>/dev/null)
if [ -n "$APFS_SNAPS" ]; then
    echo "$APFS_SNAPS" | head -20 | sed 's/^/   /'
    echo ""
    echo "   ⚠️  The OS update snapshot may be holding space"
    echo "   This snapshot is NOT purgeable and can't be deleted"
else
    echo "   No snapshots found"
fi
echo ""

echo "🔍 Large System Directories:"
echo "   /System:"
sudo du -h -d 2 /System/Volumes/Data/System 2>/dev/null | sort -hr | head -5 | awk '{printf "     %8s  %s\n", $1, $2}'
echo ""
echo "   /Library:"
sudo du -h -d 2 /System/Volumes/Data/Library 2>/dev/null | sort -hr | head -5 | awk '{printf "     %8s  %s\n", $1, $2}'
echo ""

echo "🔍 Searching for large files (>10GB)..."
echo "   (This may take a moment)"
LARGE_FILES=$(sudo find /System/Volumes/Data -type f -size +10G 2>/dev/null | head -5)
if [ -n "$LARGE_FILES" ]; then
    echo "$LARGE_FILES" | while read file; do
        SIZE=$(sudo du -h "$file" 2>/dev/null | awk '{print $1}')
        echo "     $SIZE  $file"
    done
else
    echo "     No files >10GB found"
fi
echo ""

echo "=== Analysis ==="
echo ""
echo "The 351GB in System Data is likely:"
echo ""
echo "1. **APFS Snapshot Overhead** (Most Likely)"
echo "   - The OS update snapshot (12.2GB visible)"
echo "   - May be holding 300+ GB of deleted file space"
echo "   - APFS snapshots preserve deleted files"
echo "   - This space is NOT purgeable until snapshot is deleted"
echo ""
echo "2. **Time Machine Local Snapshots**"
echo "   - The stuck snapshot entry"
echo "   - May be holding space even though it's a 'ghost'"
echo ""
echo "3. **System Reserved Space**"
echo "   - macOS reserves space for operations"
echo "   - Shown in System Data but not easily identifiable"
echo ""

echo "=== Solution ==="
echo ""
echo "The OS update snapshot CANNOT be deleted (it's required)."
echo "However, you can try:"
echo ""
echo "1. **Update macOS** (if available):"
echo "   System Settings → General → Software Update"
echo "   Installing updates may clear old snapshots"
echo ""
echo "2. **Check for macOS Install Data** (11GB found):"
echo "   sudo rm -rf /System/Volumes/Data/macOS\ Install\ Data"
echo "   (Safe to delete after installation completes)"
echo ""
echo "3. **The space may be in APFS snapshot overhead**:"
echo "   This is space held by the OS update snapshot"
echo "   It will be released when you update macOS"
echo ""
echo "4. **Check Storage Management for details**:"
echo "   Apple Menu → About This Mac → Storage"
echo "   Hover over 'System Data' for more details"
echo ""