package main

type LockedCredentialManager struct {
	entries map[string]string
}

type UnlockedCredentialManager struct {
	entries map[string]string
}

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

func (m LockedCredentialManager) Unlock(masterSecret string) UnlockedCredentialManager {
	return UnlockedCredentialManager{
		entries: m.entries,
	}
}

func (m UnlockedCredentialManager) Set(key string, secret string) {
	panic("todo")
}

func (m UnlockedCredentialManager) Get(key string) (string, bool) {
	panic("todo")
}

func (m UnlockedCredentialManager) Lock() LockedCredentialManager {
	return LockedCredentialManager{
		entries: m.entries,
	}
}

func main() {
	pw := NewCredentialManager()

	unlocked := pw.Unlock("pssst")
	unlocked.Set("foo", "bar")
	_, _ = unlocked.Get("foo")

	unlocked.Lock()
}