#!/bin/bash

# Clean External LVM Boot Configuration Script
# Fixes: 1) Encrypted home partition passphrase prompt during boot
#        2) Internal drive entries appearing in GRUB menu

set -e

LOG_FILE="/tmp/clean_external_boot_$(date +%Y%m%d_%H%M%S).log"

echo "🧹 Cleaning External LVM Boot Configuration - $(date)" | tee "$LOG_FILE"
echo "====================================================" | tee -a "$LOG_FILE"

# Function to cleanup mounts on exit
cleanup() {
    echo "🧹 Cleaning up mounts..." | tee -a "$LOG_FILE"
    sudo umount /tmp/external-root/proc 2>/dev/null || true
    sudo umount /tmp/external-root/sys 2>/dev/null || true
    sudo umount /tmp/external-root/dev 2>/dev/null || true
    sudo umount /tmp/external-root/boot/efi 2>/dev/null || true
    sudo umount /tmp/external-root/boot 2>/dev/null || true
    sudo umount /tmp/external-root 2>/dev/null || true
    sudo rmdir /tmp/external-root 2>/dev/null || true
}
trap cleanup EXIT

# Check if LVM is active
echo "📋 Checking LVM status..." | tee -a "$LOG_FILE"
if ! sudo lvs system-vg/root &>/dev/null; then
    echo "❌ LVM system-vg/root not found. Please ensure the external M.2 is connected." | tee -a "$LOG_FILE"
    exit 1
fi

# Mount external LVM system
echo "💾 Mounting external LVM system..." | tee -a "$LOG_FILE"
sudo mkdir -p /tmp/external-root
sudo mount /dev/system-vg/root /tmp/external-root
sudo mount /dev/system-vg/boot /tmp/external-root/boot
sudo mount /dev/sda1 /tmp/external-root/boot/efi

# Bind mount system directories for chroot
echo "🔗 Setting up chroot environment..." | tee -a "$LOG_FILE"
sudo mount --bind /proc /tmp/external-root/proc
sudo mount --bind /sys /tmp/external-root/sys  
sudo mount --bind /dev /tmp/external-root/dev

echo "🔧 Fixing encrypted home partition issue..." | tee -a "$LOG_FILE"

# Backup current files
sudo cp /tmp/external-root/etc/crypttab /tmp/external-root/etc/crypttab.backup.$(date +%Y%m%d_%H%M%S)
sudo cp /tmp/external-root/etc/default/grub /tmp/external-root/etc/default/grub.backup.$(date +%Y%m%d_%H%M%S)

# Remove internal drive encryption from crypttab
echo "   • Cleaning /etc/crypttab..." | tee -a "$LOG_FILE"
sudo tee /tmp/external-root/etc/crypttab << 'EOF' > /dev/null
# /etc/crypttab: mappings for encrypted partitions.
#
# External LVM system - no encrypted partitions needed
# Internal drive encryption removed to prevent boot prompts
#
# <name>               <device>                         <password> <options>
EOF

echo "🎛️  Disabling GRUB os-prober..." | tee -a "$LOG_FILE"

# Disable os-prober in GRUB to prevent internal drive detection
sudo sed -i 's/#GRUB_DISABLE_OS_PROBER=false/GRUB_DISABLE_OS_PROBER=true/' /tmp/external-root/etc/default/grub

# Add the line if it doesn't exist
if ! grep -q "GRUB_DISABLE_OS_PROBER" /tmp/external-root/etc/default/grub; then
    echo "GRUB_DISABLE_OS_PROBER=true" | sudo tee -a /tmp/external-root/etc/default/grub > /dev/null
fi

echo "🔄 Updating system configuration..." | tee -a "$LOG_FILE"

# Update initramfs to reflect crypttab changes
echo "   • Updating initramfs..." | tee -a "$LOG_FILE"
sudo chroot /tmp/external-root update-initramfs -u -k all

# Regenerate GRUB configuration without os-prober
echo "   • Regenerating GRUB configuration..." | tee -a "$LOG_FILE"
sudo chroot /tmp/external-root update-grub

echo "✅ Verification..." | tee -a "$LOG_FILE"

# Verify no internal drive references
INTERNAL_REFS=$(sudo grep -c "nvme0n1p1\|b6d5bc23-1077-4ab3-8b55-918fb121847e" /tmp/external-root/boot/grub/grub.cfg 2>/dev/null || echo "0")
GRUB_ENTRIES=$(sudo grep -c "menuentry.*Kubuntu" /tmp/external-root/boot/grub/grub.cfg 2>/dev/null || echo "0")

echo "   • Internal drive references in GRUB: $INTERNAL_REFS" | tee -a "$LOG_FILE"
echo "   • Kubuntu menu entries: $GRUB_ENTRIES" | tee -a "$LOG_FILE"

if [ "$INTERNAL_REFS" -eq 0 ] && [ "$GRUB_ENTRIES" -gt 0 ]; then
    echo "✅ SUCCESS: External LVM boot configuration cleaned!" | tee -a "$LOG_FILE"
    echo "" | tee -a "$LOG_FILE"
    echo "🚀 Results:" | tee -a "$LOG_FILE"
    echo "   • No more encrypted home partition prompts during boot" | tee -a "$LOG_FILE"
    echo "   • Clean GRUB menu with only external LVM entries" | tee -a "$LOG_FILE"
    echo "   • Internal drive completely excluded from boot process" | tee -a "$LOG_FILE"
    echo "" | tee -a "$LOG_FILE"
    echo "🎯 Next steps:" | tee -a "$LOG_FILE"
    echo "   1. Reboot system" | tee -a "$LOG_FILE"
    echo "   2. Should boot directly without any prompts" | tee -a "$LOG_FILE"
    echo "   3. GRUB menu should only show Kubuntu entries" | tee -a "$LOG_FILE"
else
    echo "⚠️  Warning: Configuration may need manual review" | tee -a "$LOG_FILE"
    echo "   Internal refs: $INTERNAL_REFS, Kubuntu entries: $GRUB_ENTRIES" | tee -a "$LOG_FILE"
fi

echo "" | tee -a "$LOG_FILE"
echo "📋 Log saved to: $LOG_FILE" | tee -a "$LOG_FILE"
echo "🧹 External LVM boot configuration cleaning completed at $(date)" | tee -a "$LOG_FILE"