#!/bin/bash

# Script to resize LVM partition after expanding disk in Proxmox
# Must be run as root

# Exit on any error
set -e

# Function to check if running as root
check_root() {
    if [ "$(id -u)" != "0" ]; then
        echo "Error: This script must be run as root" >&2
        exit 1
    fi
}

# Function to check if required tools are installed
check_requirements() {
    local required_tools=("parted" "pvresize" "lvresize" "resize2fs")
    
    for tool in "${required_tools[@]}"; do
        if ! command -v "$tool" >/dev/null 2>&1; then
            echo "Error: Required tool '$tool' is not installed" >&2
            exit 1
        fi
    done
}

# Function to verify LVM setup
verify_lvm() {
    if ! vgs ubuntu-vg >/dev/null 2>&1; then
        echo "Error: Volume group 'ubuntu-vg' not found" >&2
        exit 1
    fi

    if ! lvs ubuntu-vg/ubuntu-lv >/dev/null 2>&1; then
        echo "Error: Logical volume 'ubuntu-lv' not found" >&2
        exit 1
    fi
}

# Function to backup partition table
backup_partition_table() {
    local backup_file="/root/partition_backup_$(date +%Y%m%d_%H%M%S).bak"
    echo "Creating partition table backup at $backup_file"
    sfdisk -d /dev/sda > "$backup_file"
}

# Main resize function
perform_resize() {
    echo "Starting disk resize process..."
    
    # Resize partition using parted
    echo "Resizing partition..."
    parted -s /dev/sda resizepart 3 100%
    
    # Give system time to register new partition size
    sleep 2
    
    echo "Resizing physical volume..."
    pvresize /dev/sda3
    
    echo "Resizing logical volume..."
    lvresize -l +100%FREE /dev/mapper/ubuntu--vg-ubuntu--lv
    
    echo "Resizing filesystem..."
    resize2fs /dev/mapper/ubuntu--vg-ubuntu--lv
}

# Function to verify successful resize
verify_resize() {
    echo "Verifying resize operation..."
    
    # Check if filesystem is clean
    if ! e2fsck -n /dev/mapper/ubuntu--vg-ubuntu--lv >/dev/null 2>&1; then
        echo "Warning: Filesystem check recommended after resize" >&2
    fi
    
    # Display new size information
    echo -e "\nNew disk space information:"
    df -h /
    lvs ubuntu-vg/ubuntu-lv
}

# Main execution
main() {
    echo "Starting LVM disk resize script..."
    
    # Run checks
    check_root
    check_requirements
    verify_lvm
    
    # Create backup
    backup_partition_table
    
    # Perform resize
    perform_resize
    
    # Verify results
    verify_resize
    
    echo -e "\nDisk resize completed successfully!"
}

# Execute main function with error handling
if main; then
    exit 0
else
    echo "Error: Resize process failed" >&2
    exit 1
fi