main.go

package main

import (
	"bufio"
	"context"
	"fmt"
	"io"
	"os"
	"os/exec"
	"strings"
	"time"
)

func spinner() *time.Ticker {
	ticker := time.NewTicker(400 * time.Millisecond)
	fmt.Fprintf(os.Stderr, "thinking")
	go func() {
		frames := []string{"thinking   ", "thinking.  ", "thinking.. ", "thinking..."}
		i := 1
		for range ticker.C {
			fmt.Fprintf(os.Stderr, "\r%s", frames[i%len(frames)])
			i++
		}
	}()
	return ticker
}

func clearSpinner() {
	fmt.Fprint(os.Stderr, "\r           \r")
}

const systemPrompt = `You are a terse CLI assistant. Output plain text only, no markdown formatting. Be concise and direct. Give the shortest useful answer.

Question: `

func main() {
	if len(os.Args) < 2 {
		fmt.Fprintln(os.Stderr, "Usage: how <question>")
		os.Exit(1)
	}

	claudePath, err := exec.LookPath("claude")
	if err != nil {
		fmt.Fprintln(os.Stderr, "Error: claude-code not installed. Install from: https://docs.anthropic.com/claude-code")
		os.Exit(1)
	}

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	checkCmd := exec.CommandContext(ctx, claudePath, "--version")
	if err := checkCmd.Run(); err != nil {
		fmt.Fprintln(os.Stderr, "Error: run 'claude' first to authenticate")
		os.Exit(1)
	}

	query := systemPrompt + "how " + strings.Join(os.Args[1:], " ")

	cmd := exec.Command(claudePath, "--print", query)
	stdout, err := cmd.StdoutPipe()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
		os.Exit(1)
	}
	cmd.Stderr = os.Stderr

	t := spinner()

	if err := cmd.Start(); err != nil {
		t.Stop()
		clearSpinner()
		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
		os.Exit(1)
	}

	reader := bufio.NewReader(stdout)
	firstByte := true
	buf := make([]byte, 1024)
	for {
		n, err := reader.Read(buf)
		if n > 0 {
			if firstByte {
				t.Stop()
				clearSpinner()
				firstByte = false
			}
			os.Stdout.Write(buf[:n])
		}
		if err == io.EOF {
			break
		}
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error reading output: %v\n", err)
			break
		}
	}

	if err := cmd.Wait(); err != nil {
		if exitErr, ok := err.(*exec.ExitError); ok {
			os.Exit(exitErr.ExitCode())
		}
		os.Exit(1)
	}
}