#!/bin/bash

# Use External Drive to Free Space for Update

set -e

echo "=== Use External Drive for Update ==="
echo ""
echo "External drive detected! This is your solution."
echo ""

# Find external drive
EXTERNAL_VOLUMES=$(ls -d /Volumes/* 2>/dev/null | grep -v -E "Macintosh|Preboot|Recovery|VM|Download" || echo "")

if [ -z "$EXTERNAL_VOLUMES" ]; then
    echo "⚠️  No external volumes found mounted"
    echo ""
    echo "Please:"
    echo "  1. Connect your external USB drive"
    echo "  2. Wait for it to mount"
    echo "  3. Run this script again"
    exit 1
fi

echo "Found external volume(s):"
echo "$EXTERNAL_VOLUMES" | while read vol; do
    SIZE=$(df -h "$vol" 2>/dev/null | tail -1 | awk '{print $2}')
    FREE=$(df -h "$vol" 2>/dev/null | tail -1 | awk '{print $4}')
    echo "  - $vol ($SIZE total, $FREE free)"
done
echo ""

# Use first external volume
EXTERNAL_VOL=$(echo "$EXTERNAL_VOLUMES" | head -1)
echo "Using: $EXTERNAL_VOL"
echo ""

FREE_SPACE=$(df / | tail -1 | awk '{print $4}')
FREE_SPACE_GB=$(echo "scale=2; $FREE_SPACE / 1024 / 1024" | bc)
echo "Current Mac free space: ${FREE_SPACE_GB}GB"
echo "Need: 17.64GB"
echo ""

echo "📦 Large files you can move to external drive:"
echo ""
echo "  Downloads: 8.7GB"
echo "  .ollama: 17GB"
echo "  .local: 18GB"
echo "  Total: ~44GB"
echo ""

echo "🔧 Steps:"
echo ""
echo "1. Move large files to external drive:"
echo "   mv ~/Downloads \"$EXTERNAL_VOL/Downloads_backup\""
echo "   mv ~/.ollama \"$EXTERNAL_VOL/ollama_backup\""
echo "   mv ~/.local \"$EXTERNAL_VOL/local_backup\""
echo ""
echo "2. This should free ~44GB on Mac"
echo ""
echo "3. Install macOS update"
echo ""
echo "4. After update clears snapshot, move files back"
echo ""

read -p "Move Downloads, .ollama, and .local to external drive? (y/n) " -n 1 -r
echo ""
if [[ $REPLY =~ ^[Yy]$ ]]; then
    echo ""
    echo "Moving files..."
    
    # Move Downloads
    if [ -d ~/Downloads ]; then
        echo "Moving Downloads (8.7GB)..."
        mv ~/Downloads "$EXTERNAL_VOL/Downloads_backup" && \
            echo "  ✅ Moved Downloads" || \
            echo "  ⚠️  Error moving Downloads"
        mkdir ~/Downloads
    fi
    
    # Move .ollama
    if [ -d ~/.ollama ]; then
        echo "Moving .ollama (17GB)..."
        mv ~/.ollama "$EXTERNAL_VOL/ollama_backup" && \
            echo "  ✅ Moved .ollama" || \
            echo "  ⚠️  Error moving .ollama"
    fi
    
    # Move .local
    if [ -d ~/.local ]; then
        echo "Moving .local (18GB)..."
        mv ~/.local "$EXTERNAL_VOL/local_backup" && \
            echo "  ✅ Moved .local" || \
            echo "  ⚠️  Error moving .local"
    fi
    
    echo ""
    echo "⏳ Waiting for space to update..."
    sleep 5
    
    NEW_FREE=$(df / | tail -1 | awk '{print $4}')
    NEW_FREE_GB=$(echo "scale=2; $NEW_FREE / 1024 / 1024" | bc)
    
    echo ""
    echo "New free space: ${NEW_FREE_GB}GB"
    echo ""
    
    if (( $(echo "$NEW_FREE_GB > 17" | bc -l) )); then
        echo "✅ Enough space! Now install update:"
        echo "   System Settings → General → Software Update"
        echo "   OR"
        echo "   sudo softwareupdate --download --all"
    else
        echo "⚠️  Still not enough. May need to move more files."
    fi
else
    echo "Cancelled."
fi

echo ""