package main

import (
    "fmt"
    "net"
    "os"
    "os/exec"
    "strings"
)

func main() {
    hostnames := os.Getenv("HOSTNAMES")
    if hostnames == "" {
        fmt.Println("Error: Environment variable HOSTNAMES not set or empty.")
        return
    }
    hosts := strings.Split(hostnames, ",") 

    // Environment Variables
    failOnError := os.Getenv("FAIL_ON_ERROR") == "true"
    commandStr := os.Getenv("COMMAND")  
    errorCommandStr := os.Getenv("ERROR_COMMAND")  

    for _, host := range hosts {
        host = strings.TrimSpace(host)

        fmt.Println("\n---", host, "---")

        // DNS Resolution (Remove if you don't need this)
        ip, err := net.LookupIP(host) 
        if err != nil {
            fmt.Println("DNS Resolution Failed:", err)
        } else {
            fmt.Println("Resolved IPs:", ip)
        }

        // Ping
        pingCmd := exec.Command("ping", "-c", "3", host) 
        pingOutput, err := pingCmd.Output()
        if err != nil {
            fmt.Println("Ping Failed:", err)
            if failOnError {
                os.Exit(1) 
            }

            // Execute error command if specified
            if errorCommandStr != "" {
                cmdParts := strings.Fields(errorCommandStr) 
                cmd := exec.Command(cmdParts[0], cmdParts[1:]...)
                cmdOutput, cmdErr := cmd.Output()
                if cmdErr != nil {
                    fmt.Println("Error Command Execution Failed:", errorCommandStr, cmdErr)
                } else {
                    fmt.Println("Error Command Output:\n", string(cmdOutput))
                }
            }
        } else {
            fmt.Println("Ping Output:\n", string(pingOutput))
        }

        // Execute additional command if specified
        if commandStr != "" {
            cmdParts := strings.Fields(commandStr)
            cmd := exec.Command(cmdParts[0], cmdParts[1:]...)
            cmdOutput, err := cmd.Output()
            if err != nil {
                fmt.Println("Command Execution Failed:", commandStr, err)
            } else {
                fmt.Println("Command Output:\n", string(cmdOutput))
            }
        }
    }
}