package ngs

import (
	"fmt"
	"git.noahlan.cn/northlan/ngs/cluster"
	"git.noahlan.cn/northlan/ngs/component"
	"git.noahlan.cn/northlan/ngs/internal/env"
	"git.noahlan.cn/northlan/ngs/internal/log"
	"git.noahlan.cn/northlan/ngs/internal/runtime"
	"git.noahlan.cn/northlan/ngs/scheduler"
	"os"
	"os/signal"
	"path/filepath"
	"strings"
	"sync/atomic"
	"syscall"
	"time"
)

var running int32

var (
	// app represents the current server process
	app = &struct {
		name    string    // current application name
		startAt time.Time // startup time
	}{}
)

// Listen listens on the TCP network address addr
// and then calls Serve with handler to handle requests
// on incoming connections.
func Listen(addr string, opts ...Option) {
	if atomic.AddInt32(&running, 1) != 1 {
		log.Println("Ngs has running")
		return
	}

	// application initialize
	app.name = strings.TrimLeft(filepath.Base(os.Args[0]), "/")
	app.startAt = time.Now()

	// environment initialize
	if wd, err := os.Getwd(); err != nil {
		panic(err)
	} else {
		env.Wd, _ = filepath.Abs(wd)
	}

	opt := cluster.Options{
		Components: &component.Components{},
	}
	for _, option := range opts {
		option(&opt)
	}

	// Use listen address as client address in non-cluster mode
	if !opt.IsMaster && opt.AdvertiseAddr == "" && opt.ClientAddr == "" {
		log.Println("The current server running in singleton mode")
		opt.ClientAddr = addr
	}

	// Set the retry interval to 3 secondes if doesn't set by user
	if opt.RetryInterval == 0 {
		opt.RetryInterval = time.Second * 3
	}

	node := &cluster.Node{
		Options:     opt,
		ServiceAddr: addr,
	}
	err := node.Startup()
	if err != nil {
		log.Fatalf("Node startup failed: %v", err)
	}
	runtime.CurrentNode = node

	if node.ClientAddr != "" {
		log.Println(fmt.Sprintf("Startup *Ngs gate server* %s, client address: %v, service address: %s",
			app.name, node.ClientAddr, node.ServiceAddr))
	} else {
		log.Println(fmt.Sprintf("Startup *Ngs backend server* %s, service address %s",
			app.name, node.ServiceAddr))
	}

	go scheduler.Schedule()
	sg := make(chan os.Signal)
	signal.Notify(sg, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGKILL, syscall.SIGTERM)

	select {
	case <-env.Die:
		log.Println("The app will shutdown in a few seconds")
	case s := <-sg:
		log.Println("Ngs server got signal", s)
	}

	log.Println("Ngs server is stopping...")

	node.Shutdown()
	runtime.CurrentNode = nil
	scheduler.Close()
	atomic.StoreInt32(&running, 0)
}

// Shutdown send a signal to let 'ngs' shutdown itself.
func Shutdown() {
	close(env.Die)
}