codecrafters-shell-go/app/main.go

package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
)

type Context struct {
	stdout io.Writer
	stderr io.Writer
	stdin  io.Reader
}

type GetCommandResult int

const (
	GetCommandResultOk GetCommandResult = iota
	GetCommandResultError
)

func getCommand(ctx *Context) (string, error) {
	fmt.Print("$ ")
	command_line, err := bufio.NewReader(ctx.stdin).ReadString('\n')
	if err != nil {
		return "", err
	}
	command, err := parseCommand(ctx, command_line)
	if err != nil {
		return "", err
	}
	return command, nil
}

func parseCommand(ctx *Context, command_line string) (string, error) {
	_ = ctx
	return command_line[:len(command_line)-1], nil
}

func handleCommand(ctx Context, command string) {
	fmt.Fprintln(ctx.stderr, command+": command not found")
}

func main() {
	ctx := Context{
		stdout: os.Stdout,
		stderr: os.Stderr,
		stdin:  os.Stdin,
	}
	for {
		command, err := getCommand(&ctx)
		if err != nil {
			fmt.Fprintln(os.Stderr, "Error reading input: ", err)
			os.Exit(1)
		}
		handleCommand(ctx, command)
	}
}