omissis/goarkitect

package cli

import (
    "errors"
    "fmt"
    "os"

    flag "github.com/spf13/pflag"
)

var (
    ErrEmptyAppName       = errors.New("app name cannot be empty")
    ErrEmptyCommands      = errors.New("app must have at least one command")
    ErrNoCommandSpecified = errors.New("app command was not specified")
    ErrCommandNotFound    = errors.New("app command not found")
)

func NewApp(
    name string,
    commands []Command,
    flagSet *flag.FlagSet,
) (*App, error) {
    if name == "" {
        return nil, ErrEmptyAppName
    }

    if len(commands) < 1 {
        return nil, ErrEmptyCommands
    }

    if flagSet == nil {
        flagSet = flag.NewFlagSet("global", flag.ContinueOnError)
    }

    return &App{
        name:     name,
        commands: commands,
        flagSet:  flagSet,
    }, nil
}

type App struct {
    name     string
    commands []Command
    flagSet  *flag.FlagSet
}

func (a *App) Run() error {
    if err := a.flagSet.Parse(GetArgs(os.Args, 1)); err != nil {
        return fmt.Errorf("error parsing flags: %w", err)
    }

    args := a.flagSet.Args()
    if len(args) < 1 {
        return ErrNoCommandSpecified
    }

    for _, cmd := range a.commands {
        if cmd.Name() == args[0] {
            if err := cmd.Run(args); err != nil {
                return fmt.Errorf("error running command '%s': %w", cmd.Name(), err)
            }

            return nil
        }
    }

    return fmt.Errorf("'%s': %w", args[0], ErrCommandNotFound)
}