package netProgram

import (
	"log"
	"net"
	"sync"
	"time"
)

// 网络轮询器

// 网络IO(使用系统调用syscall的IO)的阻塞
func BIONet() {
	addr := "127.0.0.1:5678"
	wg := sync.WaitGroup{}

	// 1模拟读，体会读的阻塞状态
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()

		conn, _ := net.Dial("tcp", addr)
		defer conn.Close()

		buf := make([]byte, 1024)
		// 注意：两次时间的间隔
		log.Println("start read.", time.Now().Format("03:04:05.000"))
		n, _ := conn.Read(buf)
		log.Println("content:", string(buf[:n]), time.Now().Format("03:04:05.000"))
	}(&wg)

	// 2模拟写
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()

		l, _ := net.Listen("tcp", addr)
		defer l.Close()

		for {
			conn, _ := l.Accept()
			go func(conn net.Conn) {
				defer conn.Close()
				log.Println("connected.")

				// 阻塞时长
				time.Sleep(3 * time.Second)
				conn.Write([]byte("Blocking I/O"))
			}(conn)
		}
	}(&wg)

	wg.Wait()
}

// Channel(Go的自管理的IO）的阻塞
func BIOChannel() {
	// 0初始化数据
	wg := sync.WaitGroup{}
	// IO channel
	ch := make(chan struct{})

	// 1模拟读，体会读的阻塞状态
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()
		log.Println("start read.", time.Now().Format("03:04:05.000"))

		content := <-ch // IO Read, Receive

		log.Println("content:", content, time.Now().Format("03:04:05.000"))
	}(&wg)

	// 2模拟写
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()

		// 阻塞时长
		time.Sleep(3 * time.Second)
		ch <- struct{}{} // Write, Send
	}(&wg)

	wg.Wait()
}

// 网络IO(使用系统调用syscall的IO)的非阻塞
func NIONet() {
	addr := "127.0.0.1:5678"
	wg := sync.WaitGroup{}

	// 1模拟读，体会读的阻塞状态
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()

		conn, _ := net.Dial("tcp", addr)
		defer conn.Close()

		buf := make([]byte, 1024)
		// 注意：两次时间的间隔
		log.Println("start read.", time.Now().Format("03:04:05.000"))
		// 设置截止时间
		conn.SetReadDeadline(time.Now().Add(400 * time.Millisecond))
		n, _ := conn.Read(buf)
		log.Println("content:", string(buf[:n]), time.Now().Format("03:04:05.000"))
	}(&wg)

	// 2模拟写
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()

		l, _ := net.Listen("tcp", addr)
		defer l.Close()

		for {
			conn, _ := l.Accept()
			go func(conn net.Conn) {
				defer conn.Close()
				log.Println("connected.")

				// 阻塞时长
				time.Sleep(3 * time.Second)
				conn.Write([]byte("Blocking I/O"))
			}(conn)
		}
	}(&wg)

	wg.Wait()
}

// Channel(Go的自管理的IO）的非阻塞
func NIOChannel() {
	// 0初始化数据
	wg := sync.WaitGroup{}
	// IO channel
	ch := make(chan struct{ id uint })

	// 1模拟读，体会读的阻塞状态
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()
		log.Println("start read.", time.Now().Format("03:04:05.000"))

		content := struct{ id uint }{}
		select {
		case content = <-ch: // IO Read, Receive
		default:
		}

		log.Println("content:", content, time.Now().Format("03:04:05.000"))
	}(&wg)

	// 2模拟写
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()

		// 阻塞时长
		time.Sleep(3 * time.Second)
		ch <- struct{ id uint }{42} // Write, Send
	}(&wg)

	wg.Wait()
}

// 网络IO(使用系统调用syscall的IO)的非阻塞
func NIONetChannel() {
	addr := "127.0.0.1:5678"
	wg := sync.WaitGroup{}

	// 1模拟读，体会读的阻塞状态
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()

		conn, _ := net.Dial("tcp", addr)
		defer conn.Close()

		// 注意：两次时间的间隔
		log.Println("start read.", time.Now().Format("03:04:05.000"))

		// 独立的goroutine，完成Read操作，将结果Send到channel中
		wgwg := sync.WaitGroup{}
		chRead := make(chan []byte)
		wgwg.Add(1)
		go func() {
			defer wgwg.Done()
			buf := make([]byte, 1024)
			n, _ := conn.Read(buf)
			chRead <- buf[:n]
		}()

		//time.Sleep(100 * time.Millisecond)

		// 是select+default实现非阻塞操作
		var data []byte
		select {
		case data = <-chRead:
		default:
		}

		log.Println("content:", string(data), time.Now().Format("03:04:05.000"))
		wgwg.Wait()
	}(&wg)

	// 2模拟写
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()

		l, _ := net.Listen("tcp", addr)
		defer l.Close()

		for {
			conn, _ := l.Accept()
			go func(conn net.Conn) {
				defer conn.Close()
				log.Println("connected.")

				// 阻塞时长
				time.Sleep(3 * time.Second)
				conn.Write([]byte("Blocking I/O"))
			}(conn)
		}
	}(&wg)

	wg.Wait()
}