package restarter

import (
	"os"
	"strconv"
	"strings"

	"github.com/sirupsen/logrus"
	"golang.org/x/sys/execabs"
)

const (
	BridgeCrashCount = "BRIDGE_CRASH_COUNT"
	BridgeLauncher   = "BRIDGE_LAUNCHER"
)

type Restarter struct {
	restart bool
	crash   bool
	exe     string
}

func New() *Restarter {
	var exe string

	if osExe, err := os.Executable(); err == nil {
		exe = osExe
	} else {
		logrus.WithError(err).Error("Failed to get executable path, the app will not be able to restart")
	}

	return &Restarter{exe: exe}
}

func (restarter *Restarter) Set(restart, crash bool) {
	restarter.restart = restart
	restarter.crash = crash
}

func (restarter *Restarter) Restart() {
	if !restarter.restart {
		return
	}

	if restarter.exe == "" {
		return
	}

	env := getEnvMap()

	if restarter.crash {
		env[BridgeCrashCount] = increment(env[BridgeLauncher])
	} else {
		delete(env, BridgeCrashCount)
	}

	cmd := execabs.Command(restarter.exe, os.Args[1:]...)

	cmd.Stdin = os.Stdin
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	cmd.Env = getEnvList(env)

	if err := run(cmd); err != nil {
		logrus.WithError(err).Error("Failed to restart")
	}
}

func getEnvMap() map[string]string {
	env := make(map[string]string)

	for _, entry := range os.Environ() {
		if split := strings.SplitN(entry, "=", 2); len(split) == 2 {
			env[split[0]] = split[1]
		}
	}

	return env
}

func getEnvList(envMap map[string]string) []string {
	env := make([]string, 0, len(envMap))

	for key, value := range envMap {
		env = append(env, key+"="+value)
	}

	return env
}

func increment(value string) string {
	var valueInt int

	if parsed, err := strconv.Atoi(value); err == nil {
		valueInt = parsed
	}

	return strconv.Itoa(valueInt + 1)
}