Configure Linux process monitoring with top, htop, and btop for system performance analysis

#!/usr/bin/env bash

set -euo pipefail

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

# Global variables
PKG_MGR=""
PKG_INSTALL=""
UPDATE_CMD=""

# Logging functions
log_info() { echo -e "${BLUE}[INFO]${NC} $1"; }
log_success() { echo -e "${GREEN}[SUCCESS]${NC} $1"; }
log_warning() { echo -e "${YELLOW}[WARNING]${NC} $1"; }
log_error() { echo -e "${RED}[ERROR]${NC} $1"; }

# Usage information
usage() {
    cat << EOF
Usage: $0 [OPTIONS]
Install and configure Linux process monitoring tools (top, htop, btop)

OPTIONS:
    -h, --help      Show this help message
    --minimal       Install only htop (skip btop)
    --user-only     Configure only for current user (no system updates)

Examples:
    $0                  # Full installation
    $0 --minimal        # Install htop only
    $0 --user-only      # User configuration only
EOF
}

# Cleanup on error
cleanup() {
    local exit_code=$?
    if [ $exit_code -ne 0 ]; then
        log_error "Installation failed. Rolling back changes..."
        # Remove any partially created config files
        [ -f ~/.config/htop/htoprc.backup ] && mv ~/.config/htop/htoprc.backup ~/.config/htop/htoprc 2>/dev/null || true
        [ -f ~/.toprc.backup ] && mv ~/.toprc.backup ~/.toprc 2>/dev/null || true
    fi
    exit $exit_code
}

trap cleanup ERR

# Detect distribution and package manager
detect_distro() {
    log_info "Detecting Linux distribution..."
    
    if [ -f /etc/os-release ]; then
        . /etc/os-release
        case "$ID" in
            ubuntu|debian)
                PKG_MGR="apt"
                PKG_INSTALL="apt install -y"
                UPDATE_CMD="apt update && apt upgrade -y"
                ;;
            almalinux|rocky|centos|rhel|ol)
                PKG_MGR="dnf"
                PKG_INSTALL="dnf install -y"
                UPDATE_CMD="dnf update -y"
                ;;
            fedora)
                PKG_MGR="dnf"
                PKG_INSTALL="dnf install -y"
                UPDATE_CMD="dnf update -y"
                ;;
            amzn)
                PKG_MGR="yum"
                PKG_INSTALL="yum install -y"
                UPDATE_CMD="yum update -y"
                ;;
            *)
                log_error "Unsupported distribution: $ID"
                exit 1
                ;;
        esac
        log_success "Detected $PRETTY_NAME using $PKG_MGR"
    else
        log_error "Cannot detect Linux distribution (/etc/os-release not found)"
        exit 1
    fi
}

# Check prerequisites
check_prerequisites() {
    log_info "Checking prerequisites..."
    
    # Check if user has sudo privileges (if not running user-only mode)
    if [ "${USER_ONLY:-false}" != "true" ]; then
        if ! sudo -n true 2>/dev/null; then
            log_error "This script requires sudo privileges"
            exit 1
        fi
    fi
    
    # Check if package manager is available
    if ! command -v "$PKG_MGR" >/dev/null 2>&1; then
        log_error "Package manager $PKG_MGR not found"
        exit 1
    fi
    
    log_success "Prerequisites check passed"
}

# Update system packages
update_system() {
    if [ "${USER_ONLY:-false}" = "true" ]; then
        log_info "Skipping system update (user-only mode)"
        return
    fi
    
    echo "[1/6] Updating system packages..."
    log_info "Running system update..."
    
    if sudo bash -c "$UPDATE_CMD"; then
        log_success "System packages updated successfully"
    else
        log_warning "System update encountered issues, continuing..."
    fi
}

# Install htop
install_htop() {
    if [ "${USER_ONLY:-false}" = "true" ]; then
        log_info "Skipping htop installation (user-only mode)"
        return
    fi
    
    echo "[2/6] Installing htop..."
    
    if command -v htop >/dev/null 2>&1; then
        log_info "htop is already installed"
        return
    fi
    
    log_info "Installing htop..."
    sudo bash -c "$PKG_INSTALL htop"
    log_success "htop installed successfully"
}

# Install btop
install_btop() {
    if [ "${USER_ONLY:-false}" = "true" ]; then
        log_info "Skipping btop installation (user-only mode)"
        return
    fi
    
    if [ "${MINIMAL:-false}" = "true" ]; then
        log_info "Skipping btop installation (minimal mode)"
        return
    fi
    
    echo "[3/6] Installing btop..."
    
    if command -v btop >/dev/null 2>&1; then
        log_info "btop is already installed"
        return
    fi
    
    log_info "Installing btop..."
    
    # Enable EPEL for RHEL-based systems if needed
    if [ "$PKG_MGR" = "dnf" ] && [ "$ID" != "fedora" ]; then
        if ! dnf repolist | grep -q epel; then
            log_info "Enabling EPEL repository for btop..."
            sudo dnf install -y epel-release || log_warning "Could not enable EPEL, btop may not be available"
        fi
    fi
    
    if sudo bash -c "$PKG_INSTALL btop"; then
        log_success "btop installed successfully"
    else
        log_warning "btop installation failed, continuing without btop"
    fi
}

# Configure htop
configure_htop() {
    echo "[4/6] Configuring htop..."
    
    local htop_dir="$HOME/.config/htop"
    local htop_config="$htop_dir/htoprc"
    
    # Create htop config directory
    mkdir -p "$htop_dir"
    
    # Backup existing config
    if [ -f "$htop_config" ]; then
        cp "$htop_config" "$htop_config.backup"
        log_info "Backed up existing htop configuration"
    fi
    
    # Create optimized htop configuration
    cat > "$htop_config" << 'EOF'
fields=0 48 17 18 38 39 40 2 46 47 49 1
sort_key=46
sort_direction=1
tree_sort_key=0
tree_sort_direction=1
hide_kernel_threads=1
hide_userland_threads=0
shadow_other_users=0
show_thread_names=0
show_program_path=1
highlight_base_name=0
highlight_megabytes=1
highlight_threads=1
highlight_changes=0
highlight_changes_delay_secs=5
find_comm_in_cmdline=1
strip_exe_from_cmdline=1
show_merged_command=0
tree_view=1
tree_view_always_by_pid=0
all_branches_collapsed=0
header_margin=1
detailed_cpu_time=0
cpu_count_from_one=0
show_cpu_usage=1
show_cpu_frequency=0
show_cpu_temperature=0
degree_fahrenheit=0
update_process_names=0
account_guest_in_cpu_meter=0
color_scheme=0
enable_mouse=1
delay=15
left_meters=LeftCPUs Memory Swap
left_meter_modes=1 1 1
right_meters=RightCPUs Tasks LoadAverage Uptime
right_meter_modes=1 2 2 2
EOF

    chmod 644 "$htop_config"
    log_success "htop configuration created"
}

# Configure top
configure_top() {
    echo "[5/6] Creating top configuration guide..."
    
    # Create a simple script to help users configure top
    cat > "$HOME/.toprc_setup.sh" << 'EOF'
#!/bin/bash
echo "To configure top with recommended settings:"
echo "1. Run 'top'"
echo "2. Press '1' to show individual CPU cores"
echo "3. Press 'f' to select fields, then 'q' to return"
echo "4. Press 'W' to save configuration"
echo "5. Press 'q' to quit"
echo ""
echo "Useful top commands:"
echo "- Press 'M' to sort by memory usage"
echo "- Press 'P' to sort by CPU usage"
echo "- Press 'k' to kill a process"
echo "- Press 'r' to renice a process"
EOF

    chmod 755 "$HOME/.toprc_setup.sh"
    log_success "Top configuration guide created at ~/.toprc_setup.sh"
}

# Verify installation
verify_installation() {
    echo "[6/6] Verifying installation..."
    
    local tools_installed=0
    local tools_total=1  # top is always available
    
    # Check top (always available)
    if command -v top >/dev/null 2>&1; then
        log_success "top is available"
        tools_installed=$((tools_installed + 1))
    fi
    
    # Check htop if not in user-only mode
    if [ "${USER_ONLY:-false}" != "true" ]; then
        tools_total=$((tools_total + 1))
        if command -v htop >/dev/null 2>&1; then
            log_success "htop is available"
            tools_installed=$((tools_installed + 1))
        else
            log_warning "htop is not available"
        fi
    fi
    
    # Check btop if not in minimal or user-only mode
    if [ "${MINIMAL:-false}" != "true" ] && [ "${USER_ONLY:-false}" != "true" ]; then
        tools_total=$((tools_total + 1))
        if command -v btop >/dev/null 2>&1; then
            log_success "btop is available"
            tools_installed=$((tools_installed + 1))
        else
            log_warning "btop is not available"
        fi
    fi
    
    # Check htop configuration
    if [ -f "$HOME/.config/htop/htoprc" ]; then
        log_success "htop configuration is in place"
    else
        log_warning "htop configuration not found"
    fi
    
    log_success "Installation complete! ($tools_installed/$tools_total tools available)"
    echo ""
    echo "Quick start:"
    echo "- Run 'top' for basic process monitoring"
    [ "${USER_ONLY:-false}" != "true" ] && echo "- Run 'htop' for enhanced interactive monitoring"
    [ "${MINIMAL:-false}" != "true" ] && [ "${USER_ONLY:-false}" != "true" ] && echo "- Run 'btop' for modern visualization"
    echo "- Run '~/.toprc_setup.sh' for top configuration help"
}

# Main function
main() {
    local MINIMAL=false
    local USER_ONLY=false
    
    # Parse arguments
    while [[ $# -gt 0 ]]; do
        case $1 in
            -h|--help)
                usage
                exit 0
                ;;
            --minimal)
                MINIMAL=true
                shift
                ;;
            --user-only)
                USER_ONLY=true
                shift
                ;;
            *)
                log_error "Unknown option: $1"
                usage
                exit 1
                ;;
        esac
    done
    
    log_info "Starting Linux process monitoring tools installation..."
    
    detect_distro
    check_prerequisites
    update_system
    install_htop
    install_btop
    configure_htop
    configure_top
    verify_installation
    
    log_success "Process monitoring tools setup completed successfully!"
}

# Only run main if script is executed directly
if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
    main "$@"
fi