#!/bin/bash

# Force Purge System Data (351GB)
# The 351GB is likely "purgeable" space that macOS won't release until forced

set -e

echo "=== Force Purge System Data (351GB) ==="
echo ""
echo "The 351GB in System Data is likely PURGEABLE space."
echo "macOS shows it as 'used' but it's actually available."
echo "We'll force macOS to release it by creating a large file."
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 ""

echo "🔧 Method: Create a large file to force purge..."
echo ""
echo "   This will:"
echo "   1. Create a 50GB file (forces macOS to purge space)"
echo "   2. Delete it immediately"
echo "   3. This should release the purgeable space"
echo ""

read -p "Proceed? This is safe - file will be deleted immediately. (y/n) " -n 1 -r
echo ""
if [[ ! $REPLY =~ ^[Yy]$ ]]; then
    echo "Cancelled."
    exit 0
fi

echo ""
echo "Creating 50GB test file to force purge..."
echo "   (This may take a few minutes)"
echo ""

# Create large file to force purge
TEST_FILE="$HOME/test_force_purge_$(date +%s).tmp"
if dd if=/dev/zero of="$TEST_FILE" bs=1g count=50 2>/dev/null; then
    echo "   ✅ Created 50GB file"
    echo ""
    echo "   Checking space after creation..."
    sleep 2
    FREE_DURING=$(df / | tail -1 | awk '{print $4}')
    FREE_DURING_GB=$(echo "scale=2; $FREE_DURING / 1024 / 1024" | bc)
    echo "   Free space during: ${FREE_DURING_GB}GB"
    echo ""
    
    echo "   Deleting test file..."
    rm -f "$TEST_FILE"
    echo "   ✅ Deleted"
else
    echo "   ⚠️  Could not create file (not enough space or permission issue)"
    echo "   This means the purgeable space may not be available"
fi

echo ""
echo "⏳ Waiting for system to update..."
sleep 10

# Check final 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)

echo ""
echo "=== Results ==="
echo "   Before: ${FREE_SPACE_GB_BEFORE}GB free"
echo "   After:  ${FREE_SPACE_GB_AFTER}GB free"
if (( $(echo "$FREED_GB > 100" | bc -l) )); then
    echo "   ✅ Successfully freed: ${FREED_GB}GB!"
    echo "   The purgeable space was released!"
elif (( $(echo "$FREED_GB > 0" | bc -l) )); then
    echo "   ✅ Freed: ${FREED_GB}GB"
else
    echo "   ⚠️  No space freed"
fi
echo ""

echo "=== Understanding System Data (351GB) ==="
echo ""
echo "If System Data still shows 351GB but you have free space,"
echo "this is NORMAL macOS behavior:"
echo ""
echo "  - System Data includes PURGEABLE space"
echo "  - Purgeable space is AVAILABLE but shown as 'used'"
echo "  - macOS will release it automatically when needed"
echo "  - The space is actually available for use"
echo ""
echo "To verify space is available:"
echo "  1. Try creating a large file (you just did)"
echo "  2. Check Activity Monitor → Disk → Purgeable"
echo "  3. The space will be released when you actually need it"
echo ""
echo "The 351GB in System Data is misleading - much of it"
echo "is purgeable and available when needed."
echo ""