package main

import "errors"

type LockedCredentialManager interface {
	Unlock(masterKey string) (UnlockedCredentialManager, error)
}

type UnlockedCredentialManager interface {
	Lock() (LockedCredentialManager, error)
	Set(key string, secret string) error
	Get(key string) (string, error)
}

type credentialManager struct {
	unlocked bool
	entries  map[string]string
}

func NewCredentialManager() LockedCredentialManager {
	return &credentialManager{
		entries: make(map[string]string),
	}
}

func (t *credentialManager) Unlock(masterKey string) (UnlockedCredentialManager, error) {
	if t.unlocked {
		return nil, errors.New("already unlocked")
	}
	t.unlocked = true
	return t, nil
}

func (t *credentialManager) Lock() (LockedCredentialManager, error) {
	if !t.unlocked {
		return nil, errors.New("already locked")
	}
	t.unlocked = false
	return t, nil
}

func (t *credentialManager) Set(key string, secret string) error {
	if !t.unlocked {
		return errors.New("locked")
	}
	panic("todo")
}

func (t *credentialManager) Get(key string) (string, error) {
	if !t.unlocked {
		return "", errors.New("locked")
	}
	panic("todo")
}

func main() {
	pwLocked := NewCredentialManager()
	pwUnlocked, _ := pwLocked.Unlock("pssst")
	pwUnlocked.Set("foo", "bar")
	_, _ = pwUnlocked.Get("foo")
	pwUnlocked.Lock()
}