package service

import (
	"context"
	"fmt"
	"os"
	"os/signal"
	"sync"
	"syscall"

	"bash_go_service/shared/pkg/logger"
)

const (
	lockFile = "/tmp/bash_service.lock"
)

// Task 接口定义后台任务
type Task interface {
	Execute(ctx context.Context)
	Name() string
}

// WorkerPool 工作池结构体
type WorkerPool struct {
	tasks  []Task
	ctx    context.Context
	cancel context.CancelFunc
	wg     sync.WaitGroup
}

// NewWorkerPool 创建工作池
func NewWorkerPool(tasks []Task) *WorkerPool {
	ctx, cancel := context.WithCancel(context.Background())
	return &WorkerPool{
		tasks:  tasks,
		ctx:    ctx,
		cancel: cancel,
	}
}

// Start 启动工作池中的所有任务
func (wp *WorkerPool) Start() {
	for _, task := range wp.tasks {
		wp.wg.Add(1)
		go func(t Task) {
			defer wp.wg.Done()
			logger.Info("Starting task: %s", t.Name())
			t.Execute(wp.ctx)
		}(task)
	}
}

// Stop 停止所有任务
func (wp *WorkerPool) Stop() {
	wp.cancel()
	wp.wg.Wait()
}

// Service 服务结构体
type Service struct {
	workerPool *WorkerPool
}

// NewService 创建服务实例
func NewService() *Service {
	tasks := []Task{
		NewConfigManagerTask(), // 添加配置管理器任务
		NewWelcomeTask(),
	}

	return &Service{
		workerPool: NewWorkerPool(tasks),
	}
}

func CheckExistingInstance() bool {
	if data, err := os.ReadFile(lockFile); err == nil {
		existingPid := string(data)
		logger.Debug("Found existing instance with PID: %s", existingPid)
		return true
	}

	pid := os.Getpid()
	os.WriteFile(lockFile, []byte(fmt.Sprintf("%d", pid)), 0644)
	logger.Debug("Created new lock file with PID: %d", pid)
	return false
}

func Run() {
	service := NewService()

	// 信号处理
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)

	// 启动所有任务
	service.workerPool.Start()

	// 等待信号
	sig := <-sigChan
	logger.Info("Received signal: %v", sig)

	// 停止所有任务
	service.workerPool.Stop()
	cleanup()
}

func cleanup() {
	os.Remove(lockFile)
}