package fsmcore

import (
	"gitea.neur0tx.site/Neur0toxine/vegapokerbot/internal/handler/fsm/fsmcontract"
)

type (
	MachineErrorHandler func(fsmcontract.Machine, fsmcontract.Context, error)
	NewContextFunc      func() fsmcontract.Context
)

type Machine struct {
	ctx            *AtomicValue[fsmcontract.Context]
	entryState     fsmcontract.State
	state          *AtomicValue[fsmcontract.State]
	newContextFunc NewContextFunc
	errHandler     MachineErrorHandler
}

func NewMachine(ctx fsmcontract.Context, entryState fsmcontract.State,
	newContextFunc NewContextFunc, errHandler MachineErrorHandler) *Machine {
	return &Machine{
		ctx:            NewAtomicValue[fsmcontract.Context](ctx),
		entryState:     entryState,
		state:          NewAtomicValue[fsmcontract.State](entryState),
		newContextFunc: newContextFunc,
		errHandler:     errHandler,
	}
}

func (m *Machine) Handle() {
	ctx := m.ctx.Load()
	state := m.state.Load()
	next, newCtx, err := state.Handle(ctx)
	if err != nil {
		m.HandleError(err)
	}
	if next != state {
		m.state.Store(next)
	}
	m.ctx.Store(newCtx)
}

func (m *Machine) Reset() {
	var ctx fsmcontract.Context
	if m.newContextFunc != nil {
		ctx = m.newContextFunc()
	}
	m.ctx.Store(ctx)
	m.state.Store(m.entryState)
}

func (m *Machine) HandleError(err error) {
	if m.errHandler != nil {
		m.errHandler(m, m.ctx.Load(), err)
	}
}