package prox5

import (
	"context"
	"errors"
	"sync/atomic"
)

// engineState represents the current state of our ProxyEngine.
type engineState uint32

const (
	// StateRunning means the proxy pool is currently taking in proxys and validating them, and is available to dispense proxies.
	StateRunning engineState = iota
	// StatePaused means the proxy pool has been with ProxyEngine.Pause() and may be resumed with ProxyEngine.Resume()
	StatePaused
	// StateNew means the proxy pool has never been started.
	StateNew
)

// Start starts our proxy pool operations. Trying to start a running ProxyEngine will return an error.
func (p5 *ProxyEngine) Start() error {
	if atomic.LoadUint32(&p5.Status) != uint32(StateNew) {
		return p5.Resume()
	}
	p5.startDaemons()
	return nil
}

/*
Pause will cease the creation of any new proxy validation operations.
  - You will be able to start the proxy pool again with ProxyEngine.Resume(), it will have the same Statistics, options, and ratelimits.
  - During pause you are still able to dispense proxies.
  - Options may be changed and proxy lists may be loaded when paused.
  - Pausing an already paused ProxyEngine is a nonop.
*/
func (p5 *ProxyEngine) Pause() error {
	if !p5.IsRunning() {
		return errors.New("not running")
	}

	p5.dbgPrint(simpleString("pausing proxy pool"))

	p5.quit()

	atomic.StoreUint32(&p5.Status, uint32(StatePaused))
	return nil
}

func (p5 *ProxyEngine) startDaemons() {
	go p5.jobSpawner()
	atomic.StoreUint32(&p5.Status, uint32(StateRunning))
}

// Resume will resume pause proxy pool operations, attempting to resume a running ProxyEngine is returns an error.
func (p5 *ProxyEngine) Resume() error {
	if p5.IsRunning() {
		return errors.New("already running")
	}
	p5.ctx, p5.quit = context.WithCancel(context.Background())
	p5.startDaemons()
	return nil
}