package westworld

import "sync"

// minerGlobalState is the Go version of the (not yet pasted)
// singleton class MinerGlobalState from the book. Same pattern as
// enterMineAndDigForNugget: unexported type, one shared instance,
// reached only through the function below. This is the state whose
// Execute runs on every single tick, regardless of whatever else
// the miner is currently doing (see StateMachine.Update).
type minerGlobalState struct{}

var (
	minerGlobalStateInstance *minerGlobalState
	minerGlobalStateOnce     sync.Once
)

// MinerGlobalState is the Go stand-in for
// "MinerGlobalState::Instance()".
func MinerGlobalState() *minerGlobalState {
	minerGlobalStateOnce.Do(func() {
		minerGlobalStateInstance = &minerGlobalState{}
	})
	return minerGlobalStateInstance
}

var _ State[Miner] = (*minerGlobalState)(nil)

// Enter, Execute and Exit are placeholders - the book hasn't shown
// us this state's real methods yet. This stub exists only so
// NewMiner can set it as the miner's global state and compile.

func (s *minerGlobalState) Enter(m *Miner) {
	// TODO: fill in once the book shows this method's body.
}

func (s *minerGlobalState) Execute(m *Miner) {
	// TODO: fill in once the book shows this method's body.
}

func (s *minerGlobalState) Exit(m *Miner) {
	// TODO: fill in once the book shows this method's body.
}