package cmd

import (
	"errors"
	"fmt"
	"github.com/spf13/cobra"
	"io"

	"github.com/warkanum/unitdore/config"
	"github.com/warkanum/unitdore/initsys"
	"github.com/warkanum/unitdore/sysuser"
)

// runtimeLabel is the RUNTIME column value for list/status.
func runtimeLabel(u config.Unit) string {
	if u.IsStack() {
		return u.Runtime + " (stack)"
	}
	return u.Runtime
}

// lingerHint prints, once per user, how to make user units start at boot.
func lingerHint(w io.Writer, ini initsys.Init, seen map[string]bool, u config.Unit) {
	if !ini.SupportsLinger() || u.User == "" || seen[u.User] || sysuser.LingerEnabled(u.User) {
		return
	}
	seen[u.User] = true
	fmt.Fprintf(w, "  ! linger not enabled for %s — user units won't start at boot: sudo loginctl enable-linger %s\n", u.User, u.User)
}

// nameOrAll requires exactly one unit name, or none when --all is set.
func nameOrAll(all *bool) cobra.PositionalArgs {
	return func(cmd *cobra.Command, args []string) error {
		if *all {
			if len(args) != 0 {
				return errors.New("--all takes no unit name")
			}
			return nil
		}
		if len(args) != 1 {
			return errors.New("requires a unit name, or --all")
		}
		return nil
	}
}

// installedUnit finds a unit by name and checks that its service file exists.
func installedUnit(cfg *config.Config, ini initsys.Init, name string) (*config.Unit, error) {
	u := cfg.FindUnit(name)
	if u == nil {
		return nil, fmt.Errorf("unit %q not found", name)
	}
	if !ini.IsInstalled(*u, cfg.Prefix, cfg.Suffix) {
		return nil, fmt.Errorf("%s is not installed — run 'unitdore install %s' first", name, name)
	}
	return u, nil
}

// loadInit loads the config and selects the init backend.
func loadInit() (*config.Config, initsys.Init, error) {
	cfg, err := config.Load(configPath)
	if err != nil {
		return nil, nil, err
	}
	ini, err := initsys.New(cfg)
	if err != nil {
		return nil, nil, err
	}
	return cfg, ini, nil
}