package app

import (
	"flag"
	"fmt"
	"log/slog"
	"os"
	"runtime/debug"
)

const shortIDLen = 12

var Version string

func Usage() {
	_, _ = fmt.Fprint(flag.CommandLine.Output(), "Usage: ds [flags]\n\nA terminal UI for Docker containers.\n\nFlags:\n")

	flag.PrintDefaults()
}

func ConfigureLogging(debug bool) {
	var handler slog.Handler
	if debug {
		handler = slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelDebug})
	} else {
		handler = slog.DiscardHandler
	}

	slog.SetDefault(slog.New(handler))
}

func ResolveVersion() string {
	if Version != "" {
		return Version
	}

	if info, ok := debug.ReadBuildInfo(); ok {
		if s := versionFromBuildInfo(info); s != "" {
			return s
		}
	}

	return "unknown"
}

func versionFromBuildInfo(info *debug.BuildInfo) string {
	var rev, modified string

	for _, s := range info.Settings {
		switch s.Key {
		case "vcs.revision":
			rev = s.Value
		case "vcs.modified":
			modified = s.Value
		}
	}

	if rev != "" {
		short := rev
		if len(short) > shortIDLen {
			short = short[:shortIDLen]
		}

		if modified == "true" {
			return short + "-dirty"
		}

		return short
	}

	if info.Main.Version != "" && info.Main.Version != "(devel)" {
		return info.Main.Version
	}

	return ""
}