package westworldwithmessaging

import (
	"fmt"
	"math/rand"
	"sync"
)

// doHousework is Elsa's everyday default state - the singleton
// pattern is the same one used throughout this package.
type doHousework struct{}

var (
	doHouseworkInstance *doHousework
	doHouseworkOnce     sync.Once
)

// DoHousework is the Go stand-in for "DoHousework::Instance()".
func DoHousework() *doHousework {
	doHouseworkOnce.Do(func() {
		doHouseworkInstance = &doHousework{}
	})
	return doHouseworkInstance
}

var _ State[Elsa] = (*doHousework)(nil)

// chores is our own small stand-in for the book's actual chore list
// - its sample output shows three examples ("Moppin' the floor",
// "Makin' the bed", "Washin' the dishes"), so that's exactly what's
// reused here. One gets picked at random each tick.
var chores = []string{
	"Moppin' the floor",
	"Makin' the bed",
	"Washin' the dishes",
}

// Enter announces that Elsa is back to her ordinary routine. A
// sample run of the book's program shows this line printed right
// after she finishes cooking and switches back to this state - an
// earlier, more abridged sample output we saw didn't show this line
// after a bathroom-break revert, but that sample was explicitly
// described as just "a sample," not a complete transcript, so this
// message firing every time Enter runs (bathroom revert included)
// isn't a contradiction.
func (s *doHousework) Enter(e *Elsa) {
	fmt.Printf("\n%s: Time to do some more housework!", GetNameOfEntity(e.ID()))
}

// Execute announces one randomly chosen chore per tick.
func (s *doHousework) Execute(e *Elsa) {
	fmt.Printf("\n%s: %s", GetNameOfEntity(e.ID()), chores[rand.Intn(len(chores))])
}

// Exit does nothing - no sample output ever shows a message here.
func (s *doHousework) Exit(e *Elsa) {}

// OnMessage is required now that State[T] includes it, so that every
// state satisfies the interface. This state doesn't do anything
// special with messages yet - false means "I didn't handle it,"
// which lets StateMachine.HandleMessage fall through and try the
// global state instead.
func (s *doHousework) OnMessage(e *Elsa, msg Telegram) bool {
	return false
}