package main

import (
	"bufio"
	"context"
	"errors"
	"fmt"
	"io"
	"os"
	"os/signal"
	"strings"
	"sync/atomic"
	"syscall"
	"time"

	"github.com/google/uuid"
	"hnyfkj.com.cn/rtu/linux/baseapp"
)

const MODULE_NAME = "YFKJ_SSH_CLIENT"

var (
	coupler               *MQTTCoupler
	Version               = "1.0.0.1"
	ErrBrokerAddressEmpty = errors.New("mqtt server address is empty")
	ErrIMEINotAvailable   = errors.New("device imei is not available")
)

func main() {
	if baseapp.IsArgsParam("-h") {
		help()
		return
	}

	if baseapp.IsArgsParam("-v") {
		fmt.Println("程序版本:", Version, "\n构建时间:", baseapp.BuildTime)
		return
	}

	devIMEI := baseapp.GetArgsParamStr("-c", "")
	if devIMEI == "" {
		help()
		return
	}

	if err := loadAppConfig(); err != nil {
		fmt.Printf("[%s] 错误: %v!!\n", MODULE_NAME, err)
		return
	}
	if CfgServers.MQTTSrv.Address == "" {
		fmt.Printf("[%s] 错误: %v!!\n", MODULE_NAME, ErrBrokerAddressEmpty)
		return
	}

	ctx, cancel := context.WithCancel(context.Background())
	coupler = &MQTTCoupler{
		ctx:      ctx,
		cancel:   cancel,
		broker:   CfgServers.MQTTSrv.Address,
		username: CfgServers.MQTTSrv.Username,
		password: CfgServers.MQTTSrv.Password,
		clientID: uuid.New().String(),
		imei:     devIMEI,
		cwd:      "/",
	}

	if err := coupler.init2(); err != nil {
		fmt.Printf("[%s] 错误: %v\n!!", MODULE_NAME, err)
		return
	}

	term() // 启动终端模拟器卍
}

// SHELL终端模拟器
// 1, 连接远程设备, 是否成功
// 2, 等待用户输入, 封装请求
// 3, 没有用户输入, 封装心跳
// 4, 发送请求数据, 远程执行
// 5, 耗时用户请求, 允许中断, Ctrl+C
// 6, 等待返回结果, 打印输出
// 7, 循环等待下次, 直到退出
func term() {
	var pingState atomic.Bool
	var executing atomic.Bool

	// -在线-心跳检测
	heartbeatLoop(&pingState)

	// Ctrl+C中断处理
	interruptLoop(&executing)

	reader := bufio.NewReader(os.Stdin)
	for {
		if !pingState.Load() {
			fmt.Printf("[%s] 无法连接目标设备!!\n", MODULE_NAME)
			break
		}

		fmt.Print("\033[?25h") // 显示光标
		fmt.Printf("root@%s:%s# ", coupler.imei, coupler.cwd)

		input, err := reader.ReadString('\n')
		if err != nil {
			if err == io.EOF {
				os.Exit(0)
			}
			fmt.Println("读取用户输入失败:", err)
			continue
		}

		input = strings.TrimSpace(input)
		if input == "" {
			continue
		}

		switch input {
		case "quit":
			_, _ = coupler.quit()
			os.Exit(0)
		}

		fmt.Print("\033[?25l") // 隐藏光标
		executing.Store(true)
		result, err := coupler.exec(input)
		executing.Store(false)

		if err != nil {
			fmt.Printf("执行错误: %v\n", err)
			continue
		}

		if result.Stdout != "" {
			fmt.Println(result.Stdout)
		}
		if result.Stderr != "" {
			fmt.Fprintln(os.Stderr, result.Stderr)
		}

		if result.Cwd != "" {
			coupler.cwd = result.Cwd
		}
	}
}

func help() {
	h := `
-h 显示帮助提示
-v 当前程序版本
-c 连接目标设备(IMEI), 例如: -c 869523059113051
`

	fmt.Println(h)
}

func interruptLoop(executing *atomic.Bool) {
	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT)
	go func() {
		for range sigCh {
			if executing.Load() {
				_, _ = coupler.stop()
			}
			fmt.Print("\n^C\n")
		} // end for
	}()
}

func heartbeatLoop(pingState *atomic.Bool) {
	go func() {
		ticker := time.NewTicker(1 * time.Second)
		defer ticker.Stop()
		for range ticker.C {
			resp, err := coupler.ping()
			if err == nil && resp.Error == nil && resp.Result != nil && string(resp.Result) == "pong" {
				pingState.Store(true)
			} else {
				pingState.Store(false)
			} // end if
		} // end for
	}()
}