package monitor

import (
	"Watchdog_Linux-systemd/postLog"
	"Watchdog_Linux-systemd/socket"
	"fmt"
	"os/exec"
	"strings"
	"sync"
	"time"
)

type ServiceMonitor struct {
	ServiceName string
	StopChan    chan struct{}
	Running     bool
}

var (
	monitors      = make(map[string]*ServiceMonitor)
	monitorsMutex sync.RWMutex
)

func AddServiceMonitor(serviceName string) error {
	monitorsMutex.Lock()
	defer monitorsMutex.Unlock()

	if _, exists := monitors[serviceName]; exists {
		return fmt.Errorf("service monitor '%s' already exists", serviceName)
	}

	stopChan := make(chan struct{})
	monitor := &ServiceMonitor{
		ServiceName: serviceName,
		StopChan:    stopChan,
		Running:     true,
	}

	monitors[serviceName] = monitor

	go runMonitor(monitor)

	postLog.Info(fmt.Sprintf("[Monitor] Added service monitor for: %s", serviceName))
	return nil
}

func RemoveServiceMonitor(serviceName string) error {
	monitorsMutex.Lock()
	defer monitorsMutex.Unlock()

	monitor, exists := monitors[serviceName]
	if !exists {
		return fmt.Errorf("service monitor '%s' not found", serviceName)
	}

	close(monitor.StopChan)
	monitor.Running = false
	delete(monitors, serviceName)

	postLog.Info(fmt.Sprintf("[Monitor] Removed service monitor for: %s", serviceName))
	return nil
}

func runMonitor(m *ServiceMonitor) {
	postLog.Info(fmt.Sprintf("[Monitor] Started monitoring service: %s", m.ServiceName))

	ticker := time.NewTicker(5 * time.Second)
	defer ticker.Stop()

	for {
		select {
		case <-m.StopChan:
			postLog.Info(fmt.Sprintf("[Monitor] Stopped monitoring service: %s", m.ServiceName))
			return
		case <-ticker.C:
			serviceStatus, err := checkServiceStatus(m.ServiceName)
			if err != nil {
				throwException(m.ServiceName, fmt.Sprintf("Failed to check service status: %v", err))
				continue
			}

			logStatus, err := checkServiceLogs(m.ServiceName)
			if err != nil {
				throwException(m.ServiceName, fmt.Sprintf("Failed to check service logs: %v", err))
				continue
			}

			if !serviceStatus || !logStatus {
				throwException(m.ServiceName, fmt.Sprintf("Service check failed - Status: %v, Logs: %v", serviceStatus, logStatus))
			}
		}
	}
}

func checkServiceStatus(serviceName string) (bool, error) {
	cmd := exec.Command("systemctl", "is-active", serviceName)
	output, err := cmd.Output()
	if err != nil {
		return false, fmt.Errorf("failed to execute systemctl: %w", err)
	}

	status := strings.TrimSpace(string(output))
	return status == "active", nil
}

func checkServiceLogs(serviceName string) (bool, error) {
	cmd := exec.Command("journalctl", "-u", serviceName, "-n", "50", "--no-pager")
	output, err := cmd.Output()
	if err != nil {
		return false, fmt.Errorf("failed to execute journalctl: %w", err)
	}

	logContent := string(output)
	errorKeywords := []string{"error", "fatal", "failed", "critical", "exception"}

	for _, keyword := range errorKeywords {
		if strings.Contains(strings.ToLower(logContent), keyword) {
			return false, nil
		}
	}

	return true, nil
}

func throwException(serviceName, errorContent string) error {
	postLog.Error(fmt.Sprintf("[Monitor] Service: %s - Exception: %s", serviceName, errorContent))
	err := socket.SendMsg(fmt.Sprintf("service %s exception: %s", serviceName, errorContent))
	if err != nil {
		return fmt.Errorf("failed to send exception message: %v", err)
	}
	return nil
}

func GetActiveMonitors() []string {
	monitorsMutex.RLock()
	defer monitorsMutex.RUnlock()

	var activeServices []string
	for name := range monitors {
		activeServices = append(activeServices, name)
	}
	return activeServices
}