#!/bin/bash

# LVM Boot Diagnostics Script
# Checks the current state of the LVM migration and identifies boot issues

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

log() { echo -e "${BLUE}[$(date '+%H:%M:%S')]${NC} $1"; }
error() { echo -e "${RED}[ERROR]${NC} $1"; }
success() { echo -e "${GREEN}[SUCCESS]${NC} $1"; }
warning() { echo -e "${YELLOW}[WARNING]${NC} $1"; }

echo -e "${GREEN}=== LVM Boot Diagnostics ===${NC}"
echo

# Check system state
log "Checking current system state..."
echo "Currently booted from: $(df / | tail -1 | awk '{print $1}')"
echo "Running kernel: $(uname -r)"
echo "System: $(hostname)"
echo

# Check available drives  
log "Available block devices:"
lsblk -f

echo

# Check LVM status
log "LVM Status:"
echo "Physical Volumes:"
sudo pvs 2>/dev/null || echo "No PVs found"

echo "Volume Groups:"
sudo vgs 2>/dev/null || echo "No VGs found"

echo "Logical Volumes:"
sudo lvs 2>/dev/null || echo "No LVs found"

echo

# Check for system-vg specifically
if sudo vgs system-vg >/dev/null 2>&1; then
    success "Found system-vg volume group"
    
    log "system-vg details:"
    sudo vgs system-vg
    sudo lvs system-vg
    
    # Try to mount and check contents
    log "Checking external system contents..."
    
    if [ ! -d /tmp/check-external ]; then
        mkdir -p /tmp/check-external
        
        if sudo mount /dev/system-vg/root /tmp/check-external >/dev/null 2>&1; then
            success "External root filesystem is mountable"
            
            # Check key system directories
            for dir in "/etc" "/boot" "/usr" "/var"; do
                if [ -d "/tmp/check-external$dir" ]; then
                    success "Found system directory: $dir"
                else
                    warning "Missing system directory: $dir"  
                fi
            done
            
            # Check for GRUB files
            if [ -d "/tmp/check-external/boot/grub" ]; then
                success "GRUB directory found"
                if [ -f "/tmp/check-external/boot/grub/grub.cfg" ]; then
                    success "GRUB configuration found"
                else
                    warning "GRUB configuration missing"
                fi
            else
                warning "GRUB directory missing"
            fi
            
            # Check fstab
            if [ -f "/tmp/check-external/etc/fstab" ]; then
                success "fstab found"
                log "fstab LVM entries:"
                grep -E "system-vg|UUID=" "/tmp/check-external/etc/fstab" || echo "No LVM entries found"
            else
                warning "fstab missing"
            fi
            
            sudo umount /tmp/check-external
        else
            error "Cannot mount external root filesystem"
        fi
    fi
    
else
    error "system-vg volume group not found"
    echo "This suggests the LVM migration did not complete successfully"
fi

echo

# Check EFI partition
log "Checking for EFI boot partition..."
if [ -b /dev/sda1 ]; then
    success "Found EFI partition /dev/sda1"
    
    if [ ! -d /tmp/check-efi ]; then
        mkdir -p /tmp/check-efi
        
        if sudo mount /dev/sda1 /tmp/check-efi >/dev/null 2>&1; then
            success "EFI partition is mountable"
            
            if [ -d "/tmp/check-efi/EFI" ]; then
                success "EFI directory found"
                log "EFI boot entries:"
                ls -la "/tmp/check-efi/EFI/" 2>/dev/null || echo "No EFI entries"
                
                if [ -f "/tmp/check-efi/EFI/debian/grubx64.efi" ]; then
                    success "Debian GRUB EFI bootloader found"
                else
                    warning "Debian GRUB EFI bootloader missing"
                fi
            else
                warning "EFI directory missing"
            fi
            
            sudo umount /tmp/check-efi
        else
            error "Cannot mount EFI partition"
        fi
    fi
else
    error "EFI partition /dev/sda1 not found"
fi

echo

# Provide diagnosis and recommendations
log "=== DIAGNOSIS ==="

if sudo vgs system-vg >/dev/null 2>&1; then
    success "LVM migration appears to have completed"
    
    if [ -b /dev/sda1 ] && sudo mount /dev/sda1 /tmp/check-efi >/dev/null 2>&1; then
        if [ -f "/tmp/check-efi/EFI/debian/grubx64.efi" ]; then
            success "GRUB bootloader appears to be installed"
            echo
            echo -e "${BLUE}Likely causes of boot reset issue:${NC}"
            echo "1. GRUB configuration points to wrong device"
            echo "2. initramfs missing LVM support" 
            echo "3. BIOS/UEFI boot order incorrect"
            echo "4. Secure Boot enabled (conflicts with GRUB)"
            echo
            echo -e "${GREEN}Recommended action:${NC}"
            echo "Run: sudo ./fix_grub_boot.sh"
        else
            warning "GRUB bootloader missing"
            echo -e "${GREEN}Recommended action:${NC}"
            echo "Run: sudo ./fix_grub_boot.sh"
        fi
        sudo umount /tmp/check-efi 2>/dev/null || true
    else
        error "EFI partition issues detected"
        echo -e "${GREEN}Recommended action:${NC}"  
        echo "Run: sudo ./fix_grub_boot.sh"
    fi
else
    error "LVM migration incomplete or failed"
    echo -e "${GREEN}Recommended action:${NC}"
    echo "Re-run migration: sudo ./migrate_to_lvm.sh"
fi

# Cleanup
rm -rf /tmp/check-external /tmp/check-efi 2>/dev/null || true