package api

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"net"
	"net/http"
	"os/exec"
	"runtime"
	"strconv"
	"strings"
	"time"

	"github.com/labstack/echo/v4"
	"golang.org/x/text/encoding/simplifiedchinese"
	"golang.org/x/text/transform"
)

type ToolsApi struct{}

func (api ToolsApi) TcpingEndpoint(c echo.Context) error {
	host := c.QueryParam("host")
	port := c.QueryParam("port")
	attemptsStr := c.QueryParam("attempts")

	attempts := 4
	if attemptsStr != "" {
		attempts, _ = strconv.Atoi(attemptsStr)
	}

	c.Response().Header().Set("Content-Type", "text/event-stream")
	c.Response().Header().Set("Cache-Control", "no-cache")
	c.Response().Header().Set("Connection", "keep-alive")

	flusher, ok := c.Response().Writer.(http.Flusher)
	if !ok {
		return echo.NewHTTPError(500, "Streaming unsupported")
	}

	for i := 0; i < attempts; i++ {
		start := time.Now()
		conn, err := net.DialTimeout("tcp", host+":"+port, 5*time.Second)
		elapsed := time.Since(start)

		var result string
		if err != nil {
			result = fmt.Sprintf("TCP ping %s:%s - Failed: %v", host, port, err)
		} else {
			conn.Close()
			result = fmt.Sprintf("TCP ping %s:%s - Connected, time=%v", host, port, elapsed.Round(time.Millisecond))
		}

		fmt.Fprintf(c.Response(), "data: %s\n\n", result)
		flusher.Flush()

		if i < attempts-1 {
			time.Sleep(1 * time.Second)
		}
	}

	fmt.Fprintf(c.Response(), "event: done\ndata: completed\n\n")
	flusher.Flush()

	return nil
}

func (api ToolsApi) PingEndpoint(c echo.Context) error {
	host := c.QueryParam("host")
	attemptsStr := c.QueryParam("attempts")

	attempts := 4
	if attemptsStr != "" {
		attempts, _ = strconv.Atoi(attemptsStr)
	}

	c.Response().Header().Set("Content-Type", "text/event-stream")
	c.Response().Header().Set("Cache-Control", "no-cache")
	c.Response().Header().Set("Connection", "keep-alive")

	flusher, ok := c.Response().Writer.(http.Flusher)
	if !ok {
		return echo.NewHTTPError(500, "Streaming unsupported")
	}

	var cmd *exec.Cmd
	if runtime.GOOS == "windows" {
		cmd = exec.Command("ping", "-n", strconv.Itoa(attempts), host)
	} else {
		cmd = exec.Command("ping", "-c", strconv.Itoa(attempts), host)
	}

	stdout, err := cmd.StdoutPipe()
	if err != nil {
		fmt.Fprintf(c.Response(), "data: Error: %v\n\n", err)
		flusher.Flush()
		return nil
	}

	if err := cmd.Start(); err != nil {
		fmt.Fprintf(c.Response(), "data: Error: %v\n\n", err)
		flusher.Flush()
		return nil
	}

	var reader io.Reader = stdout
	if runtime.GOOS == "windows" {
		reader = transform.NewReader(stdout, simplifiedchinese.GBK.NewDecoder())
	}

	scanner := bufio.NewScanner(reader)
	for scanner.Scan() {
		line := scanner.Text()
		if strings.TrimSpace(line) != "" {
			fmt.Fprintf(c.Response(), "data: %s\n\n", line)
			flusher.Flush()
		}
	}

	_ = cmd.Wait()

	fmt.Fprintf(c.Response(), "event: done\ndata: completed\n\n")
	flusher.Flush()

	return nil
}

func (api ToolsApi) TelnetEndpoint(c echo.Context) error {
	host := c.QueryParam("host")
	port := c.QueryParam("port")

	c.Response().Header().Set("Content-Type", "text/event-stream")
	c.Response().Header().Set("Cache-Control", "no-cache")
	c.Response().Header().Set("Connection", "keep-alive")

	flusher, ok := c.Response().Writer.(http.Flusher)
	if !ok {
		return echo.NewHTTPError(500, "Streaming unsupported")
	}

	start := time.Now()
	conn, err := net.DialTimeout("tcp", host+":"+port, 10*time.Second)
	elapsed := time.Since(start)

	var result bytes.Buffer
	if err != nil {
		result.WriteString(fmt.Sprintf("Telnet %s:%s - Connection failed: %v", host, port, err))
	} else {
		conn.Close()
		result.WriteString(fmt.Sprintf("Telnet %s:%s - Connected successfully in %v", host, port, elapsed.Round(time.Millisecond)))
	}

	fmt.Fprintf(c.Response(), "data: %s\n\n", result.String())
	flusher.Flush()

	fmt.Fprintf(c.Response(), "event: done\ndata: completed\n\n")
	flusher.Flush()

	return nil
}