#!/usr/bin/env bash

# =============================================================================
# PulseGrid Metric Agent Uninstall Script
# =============================================================================
# 
# This script completely removes the PulseGrid Metric Agent from the system.
# It will stop and remove the service, delete all files and directories,
# and remove the system user and group.
#
# WARNING: This will permanently delete all agent data and configuration!
#
# =============================================================================

set -o errexit
set -o nounset

# =============================================================================
# CONFIGURATION SECTION
# =============================================================================

# Installation paths
DESTDIR="/usr/local/bin"
CONFIG_DIR="/etc/pulsegrid-metric-agent"
DATA_DIR="/var/lib/pulsegrid-metric-agent"

# Service configuration
SERVICE_NAME="pulsegrid-metric-agent"
SERVICE_USER="pulsegrid-metric-agent"
SERVICE_GROUP="pulsegrid-metric-agent"
SERVICE_FILE="/etc/systemd/system/${SERVICE_NAME}.service"

# =============================================================================
# COLOR OUTPUT CONFIGURATION
# =============================================================================

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

# =============================================================================
# SCRIPT EXECUTION
# =============================================================================

echo -e "${BLUE}[HEADER]${NC} PulseGrid Metric Agent Uninstallation"
echo -e "${GREEN}[INFO]${NC} This script will completely remove the PulseGrid Metric Agent from your system."
echo -e "${YELLOW}[WARNING]${NC} WARNING: This action cannot be undone!"
echo

# =============================================================================
# STEP 1: CHECK ROOT PRIVILEGES
# =============================================================================

echo -e "${GREEN}[INFO]${NC} Checking root privileges..."

if [ "$EUID" -ne 0 ]; then
    echo -e "${RED}[ERROR]${NC} This script must be run as root (use sudo)"
    echo -e "${GREEN}[INFO]${NC} Usage: sudo $0"
    exit 1
fi

echo -e "${GREEN}[INFO]${NC} Root privileges confirmed"

# =============================================================================
# STEP 2: CHECK INSTALLATION
# =============================================================================

echo -e "${GREEN}[INFO]${NC} Checking for PulseGrid Metric Agent installation..."

found_components=()

# Check if binary exists
if [ -f "$DESTDIR/pulsegrid-metric-agent" ]; then
    found_components+=("Binary file: $DESTDIR/pulsegrid-metric-agent")
fi

# Check if config directory exists
if [ -d "$CONFIG_DIR" ]; then
    found_components+=("Configuration directory: $CONFIG_DIR")
fi

# Check if data directory exists
if [ -d "$DATA_DIR" ]; then
    found_components+=("Data directory: $DATA_DIR")
fi

# Check if service exists
if [ -f "$SERVICE_FILE" ]; then
    found_components+=("Systemd service: $SERVICE_FILE")
fi

# Check if service is running
if systemctl is-active --quiet "$SERVICE_NAME" 2>/dev/null; then
    found_components+=("Running service: $SERVICE_NAME")
fi

# Check if user exists
if getent passwd "$SERVICE_USER" >/dev/null 2>&1; then
    found_components+=("System user: $SERVICE_USER")
fi

# Check if group exists
if getent group "$SERVICE_GROUP" >/dev/null 2>&1; then
    found_components+=("System group: $SERVICE_GROUP")
fi

if [ ${#found_components[@]} -eq 0 ]; then
    echo -e "${YELLOW}[WARNING]${NC} No PulseGrid Metric Agent installation found"
    echo -e "${GREEN}[INFO]${NC} Nothing to uninstall"
    exit 0
else
    echo -e "${YELLOW}[WARNING]${NC} Found PulseGrid Metric Agent installation:"
    for component in "${found_components[@]}"; do
        echo "  - $component"
    done
    echo
    
    echo -e "${YELLOW}[WARNING]${NC} WARNING: This will permanently delete all agent data and configuration!"
    echo -e "${YELLOW}[WARNING]${NC} This action cannot be undone!"
    echo
fi

# =============================================================================
# STEP 3: STOP AND DISABLE SERVICE
# =============================================================================

echo -e "${BLUE}[STEP]${NC} Stopping and disabling the agent service..."

# Stop service if running
if systemctl is-active --quiet "$SERVICE_NAME" 2>/dev/null; then
    echo -e "${GREEN}[INFO]${NC} Stopping running service..."
    systemctl stop "$SERVICE_NAME" || true
    echo -e "${GREEN}[INFO]${NC} ✓ Service stopped"
else
    echo -e "${GREEN}[INFO]${NC} ✓ Service is not running"
fi

# Disable service if enabled
if systemctl is-enabled --quiet "$SERVICE_NAME" 2>/dev/null; then
    echo -e "${GREEN}[INFO]${NC} Disabling service..."
    systemctl disable "$SERVICE_NAME" || true
    echo -e "${GREEN}[INFO]${NC} ✓ Service disabled"
else
    echo -e "${GREEN}[INFO]${NC} ✓ Service is not enabled"
fi

echo -e "${GREEN}[SUCCESS]${NC} Service stopped and disabled"

# =============================================================================
# STEP 4: REMOVE SYSTEMD SERVICE FILE
# =============================================================================

echo -e "${BLUE}[STEP]${NC} Removing systemd service file..."

if [ -f "$SERVICE_FILE" ]; then
    echo -e "${GREEN}[INFO]${NC} Removing service file: $SERVICE_FILE"
    rm -f "$SERVICE_FILE"
    echo -e "${GREEN}[INFO]${NC} ✓ Service file removed"
    
    # Reload systemd daemon
    systemctl daemon-reload
    echo -e "${GREEN}[INFO]${NC} ✓ Systemd daemon reloaded"
else
    echo -e "${GREEN}[INFO]${NC} ✓ Service file not found"
fi

echo -e "${GREEN}[SUCCESS]${NC} Systemd service file removed"

# =============================================================================
# STEP 5: REMOVE BINARY FILE
# =============================================================================

echo -e "${BLUE}[STEP]${NC} Removing agent binary..."

if [ -f "$DESTDIR/pulsegrid-metric-agent" ]; then
    echo -e "${GREEN}[INFO]${NC} Removing binary file: $DESTDIR/pulsegrid-metric-agent"
    rm -f "$DESTDIR/pulsegrid-metric-agent"
    echo -e "${GREEN}[INFO]${NC} ✓ Binary file removed"
else
    echo -e "${GREEN}[INFO]${NC} ✓ Binary file not found"
fi

echo -e "${GREEN}[SUCCESS]${NC} Agent binary removed"

# =============================================================================
# STEP 6: REMOVE CONFIGURATION AND DATA DIRECTORIES
# =============================================================================

echo -e "${BLUE}[STEP]${NC} Removing configuration and data directories..."

# Remove configuration directory
if [ -d "$CONFIG_DIR" ]; then
    echo -e "${GREEN}[INFO]${NC} Removing configuration directory: $CONFIG_DIR"
    rm -rf "$CONFIG_DIR"
    echo -e "${GREEN}[INFO]${NC} ✓ Configuration directory removed"
else
    echo -e "${GREEN}[INFO]${NC} ✓ Configuration directory not found"
fi

# Remove data directory
if [ -d "$DATA_DIR" ]; then
    echo -e "${GREEN}[INFO]${NC} Removing data directory: $DATA_DIR"
    rm -rf "$DATA_DIR"
    echo -e "${GREEN}[INFO]${NC} ✓ Data directory removed"
else
    echo -e "${GREEN}[INFO]${NC} ✓ Data directory not found"
fi

echo -e "${GREEN}[SUCCESS]${NC} Configuration and data directories removed"

# =============================================================================
# STEP 7: REMOVE SYSTEM USER AND GROUP
# =============================================================================

echo -e "${BLUE}[STEP]${NC} Removing system user and group..."

# Remove user if exists
if getent passwd "$SERVICE_USER" >/dev/null 2>&1; then
    echo -e "${GREEN}[INFO]${NC} Removing system user: $SERVICE_USER"
    userdel "$SERVICE_USER" || true
    echo -e "${GREEN}[INFO]${NC} ✓ System user removed"
else
    echo -e "${GREEN}[INFO]${NC} ✓ System user not found"
fi

# Remove group if exists
if getent group "$SERVICE_GROUP" >/dev/null 2>&1; then
    echo -e "${GREEN}[INFO]${NC} Removing system group: $SERVICE_GROUP"
    groupdel "$SERVICE_GROUP" || true
    echo -e "${GREEN}[INFO]${NC} ✓ System group removed"
else
    echo -e "${GREEN}[INFO]${NC} ✓ System group not found"
fi

echo -e "${GREEN}[SUCCESS]${NC} System user and group removed"

# =============================================================================
# STEP 8: CLEANUP REMAINING FILES
# =============================================================================

echo -e "${BLUE}[STEP]${NC} Cleaning up any remaining files..."

remaining_files=()

# Check for any remaining files in common locations
if [ -f "$DESTDIR/pulsegrid-metric-agent" ]; then
    remaining_files+=("$DESTDIR/pulsegrid-metric-agent")
fi

if [ -d "$CONFIG_DIR" ]; then
    remaining_files+=("$CONFIG_DIR")
fi

if [ -d "$DATA_DIR" ]; then
    remaining_files+=("$DATA_DIR")
fi

if [ -f "$SERVICE_FILE" ]; then
    remaining_files+=("$SERVICE_FILE")
fi

if [ ${#remaining_files[@]} -gt 0 ]; then
    echo -e "${YELLOW}[WARNING]${NC} Found remaining files that could not be removed:"
    for file in "${remaining_files[@]}"; do
        echo "  - $file"
    done
    echo -e "${GREEN}[INFO]${NC} You may need to remove these files manually"
else
    echo -e "${GREEN}[INFO]${NC} ✓ All files cleaned up successfully"
fi

echo -e "${GREEN}[SUCCESS]${NC} Cleanup completed"

# =============================================================================
# STEP 9: VERIFY UNINSTALLATION
# =============================================================================

echo -e "${BLUE}[STEP]${NC} Verifying uninstallation..."

remaining_components=()

# Check if binary still exists
if [ -f "$DESTDIR/pulsegrid-metric-agent" ]; then
    remaining_components+=("Binary file")
fi

# Check if config directory still exists
if [ -d "$CONFIG_DIR" ]; then
    remaining_components+=("Configuration directory")
fi

# Check if data directory still exists
if [ -d "$DATA_DIR" ]; then
    remaining_components+=("Data directory")
fi

# Check if service file still exists
if [ -f "$SERVICE_FILE" ]; then
    remaining_components+=("Systemd service file")
fi

# Check if service is still running
if systemctl is-active --quiet "$SERVICE_NAME" 2>/dev/null; then
    remaining_components+=("Running service")
fi

# Check if user still exists
if getent passwd "$SERVICE_USER" >/dev/null 2>&1; then
    remaining_components+=("System user")
fi

# Check if group still exists
if getent group "$SERVICE_GROUP" >/dev/null 2>&1; then
    remaining_components+=("System group")
fi

if [ ${#remaining_components[@]} -eq 0 ]; then
    echo -e "${GREEN}[SUCCESS]${NC} Uninstallation verification completed successfully!"
    echo -e "${GREEN}[INFO]${NC} All PulseGrid Metric Agent components have been removed"
else
    echo -e "${YELLOW}[WARNING]${NC} Some components could not be removed:"
    for component in "${remaining_components[@]}"; do
        echo "  - $component"
    done
    echo -e "${GREEN}[INFO]${NC} You may need to remove these components manually"
fi

# =============================================================================
# STEP 10: SHOW UNINSTALLATION SUMMARY
# =============================================================================

echo
echo -e "${BLUE}[HEADER]${NC} Uninstallation Summary"
echo
echo "PulseGrid Metric Agent has been successfully uninstalled!"
echo
echo "Removed Components:"
echo "  - Binary file: $DESTDIR/pulsegrid-metric-agent"
echo "  - Configuration directory: $CONFIG_DIR"
echo "  - Data directory: $DATA_DIR"
echo "  - Systemd service: $SERVICE_FILE"
echo "  - System user: $SERVICE_USER"
echo "  - System group: $SERVICE_GROUP"
echo
echo "Note: All agent data and configuration have been permanently deleted."
echo
echo -e "${GREEN}[SUCCESS]${NC} Uninstallation completed successfully!"