#!/bin/bash

# Emergency Package Installer for LVM Migration
# Handles different Debian/Ubuntu distributions and package availability

set -e

# Colors
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

log() { echo -e "${BLUE}[$(date '+%H:%M:%S')]${NC} $1"; }
error() { echo -e "${RED}[ERROR]${NC} $1" >&2; }
success() { echo -e "${GREEN}[SUCCESS]${NC} $1"; }
warning() { echo -e "${YELLOW}[WARNING]${NC} $1"; }

echo -e "${GREEN}=== Emergency Package Installer ===${NC}"
echo "Installing all packages required for LVM migration..."

# Check if running as root
if [ "$EUID" -ne 0 ]; then
    error "This script must be run as root. Use: sudo $0"
    exit 1
fi

# Detect distribution
if [ -f /etc/os-release ]; then
    . /etc/os-release
    DISTRO="$ID"
    VERSION="$VERSION_ID"
    log "Detected distribution: $PRETTY_NAME"
else
    DISTRO="unknown"
    warning "Could not detect distribution"
fi

# Update package lists
log "Updating package lists..."
apt update || warning "Failed to update package lists"

# Function to try installing a package with alternatives
try_install_package() {
    local primary="$1"
    shift
    local alternatives=("$@")
    
    log "Installing $primary..."
    if apt install -y "$primary" >/dev/null 2>&1; then
        success "Installed $primary"
        return 0
    fi
    
    # Try alternatives
    for alt in "${alternatives[@]}"; do
        log "Trying alternative: $alt"
        if apt install -y "$alt" >/dev/null 2>&1; then
            success "Installed $alt (alternative for $primary)"
            return 0
        fi
    done
    
    warning "Failed to install $primary or any alternatives"
    return 1
}

# Install packages with error handling and alternatives
log "Installing core utilities..."
try_install_package "util-linux"
try_install_package "coreutils" 
try_install_package "bc"
try_install_package "bsdmainutils" "bsdutils"

log "Installing LVM and device mapper tools..."
try_install_package "lvm2"
try_install_package "dmsetup" "device-mapper"

log "Installing encryption tools..."
try_install_package "cryptsetup" "cryptsetup-bin"

log "Installing filesystem tools..."
try_install_package "e2fsprogs"
try_install_package "dosfstools" "mtools"
try_install_package "parted"

log "Installing backup and monitoring tools..."
try_install_package "rsync"
try_install_package "pv" "pipe-viewer"

log "Installing GRUB bootloader components..."
# Different distributions may have different GRUB package names
case "$DISTRO" in
    debian)
        try_install_package "grub-efi-amd64" "grub-efi" "grub-efi-amd64-bin"
        try_install_package "grub-pc-bin" "grub-pc"
        try_install_package "grub-common"
        ;;
    ubuntu)
        try_install_package "grub-efi-amd64" "grub-efi"
        try_install_package "grub-pc-bin" "grub-pc"  
        try_install_package "grub-common"
        try_install_package "grub2-common"
        ;;
    *)
        # Generic attempt for unknown distributions
        warning "Unknown distribution, trying generic GRUB packages..."
        try_install_package "grub-efi-amd64" "grub-efi" "grub"
        try_install_package "grub-pc-bin" "grub-pc" "grub"
        try_install_package "grub-common" "grub2-common"
        ;;
esac

log "Installing kernel and initramfs tools..."
try_install_package "initramfs-tools" "dracut"
# Don't install kernel on live system as it's not needed and may cause issues
# try_install_package "linux-image-generic" "linux-image-amd64"

log "Installing additional required tools..."
try_install_package "udev" "systemd-udev"
try_install_package "kmod" "module-init-tools"

# Load kernel modules
log "Loading required kernel modules..."
modprobe dm_mod 2>/dev/null || warning "Failed to load dm_mod"
modprobe dm_crypt 2>/dev/null || warning "Failed to load dm_crypt"  
modprobe dm_snapshot 2>/dev/null || warning "Failed to load dm_snapshot"

# Check if LVM service is available and start it
if systemctl list-unit-files | grep -q lvm2; then
    log "Starting LVM services..."
    systemctl start lvm2-monitor 2>/dev/null || warning "Could not start lvm2-monitor"
    systemctl start lvm2-lvmpolld 2>/dev/null || warning "Could not start lvm2-lvmpolld"
fi

# Verify critical tools are available
log "Verifying tool installation..."
missing_critical=()

# Check for tool availability with alternatives
check_tool() {
    local primary="$1"
    shift
    local alternatives=("$@")
    
    if command -v "$primary" >/dev/null 2>&1; then
        return 0
    fi
    
    for alt in "${alternatives[@]}"; do
        if command -v "$alt" >/dev/null 2>&1; then
            return 0
        fi
    done
    
    missing_critical+=("$primary")
    return 1
}

check_tool "lvm" "lvm2"
check_tool "vgdisplay" "lvm"
check_tool "pvcreate" "lvm"  
check_tool "lvcreate" "lvm"
check_tool "cryptsetup"
check_tool "rsync"
check_tool "parted"
check_tool "pv"
check_tool "mkfs.ext4" "mke2fs"
check_tool "mkfs.fat" "mkfs.vfat"
check_tool "grub-install" "grub2-install"
check_tool "update-grub" "grub-mkconfig"
check_tool "update-initramfs" "dracut"

if [ ${#missing_critical[@]} -eq 0 ]; then
    success "All critical tools are now available!"
    echo
    echo "Available tools:"
    for cmd in lvm vgdisplay cryptsetup rsync parted pv mkfs.ext4 grub-install; do
        if command -v "$cmd" >/dev/null 2>&1; then
            echo "  ✓ $cmd: $(which $cmd)"
        fi
    done
    echo
    echo "You can now run: ./migrate_to_lvm.sh"
else
    error "Still missing critical tools: ${missing_critical[*]}"
    echo
    echo "You may need to:"
    echo "1. Check internet connection for package downloads"
    echo "2. Try different package repositories"  
    echo "3. Install packages manually with different names"
    echo "4. Use a different live system distribution"
    exit 1
fi

echo
echo -e "${GREEN}Installation completed successfully!${NC}"
echo "The system is now ready for LVM migration."
echo
echo "Next steps:"
echo "1. Run: ./migrate_to_lvm.sh"
echo "2. Follow the interactive prompts"
echo "3. Validate with: ./validate_lvm_migration.sh"