package peer

import (
	"fmt"
	"log"
	"runtime/debug"
	"sync/atomic"
	"time"
)

type connHandler struct {
	// Communication.
	mediatorUpdates chan byte
	peerUpdates     chan peerUpdate
	pings           chan wrapper[Ping]
	pongs           chan wrapper[Pong]

	data *connData
}

func newConnHandler(
	server bool,
	peerIP byte,
	routes [MAX_IP]*atomic.Pointer[route],
	encPrivKey []byte,
	sender *safeConnSender,
) *connHandler {
	d := &connData{
		server:       server,
		pingTimer:    time.NewTimer(pingInterval),
		timeoutTimer: time.NewTimer(timeoutInterval),
		routes:       routes,
		route:        routes[peerIP],
		peerIP:       peerIP,
		encPrivKey:   encPrivKey,
		buf:          make([]byte, BUFFER_SIZE),
		sender:       sender,
	}

	h := &connHandler{
		mediatorUpdates: make(chan byte, 1),
		peerUpdates:     make(chan peerUpdate, 1),
		pings:           make(chan wrapper[Ping], 1),
		pongs:           make(chan wrapper[Pong], 1),
		data:            d,
	}

	go h.mainLoop()
	return h
}

func (h *connHandler) mainLoop() {
	defer func() {
		if r := recover(); r != nil {
			fmt.Println("stacktrace from panic: \n" + string(debug.Stack()))
		}
	}()

	var (
		data  = h.data
		state = newConnNull(data)
		name  = state.Name()
	)

	for {
		select {

		case update := <-h.peerUpdates:
			state = data.HandlePeerUpdate(state, update)

		case w := <-h.pings:
			state = state.HandlePing(w)

		case w := <-h.pongs:
			state = state.HandlePong(w)

		case <-data.pingTimer.C:
			data.HandleSendPing()

		case <-data.timeoutTimer.C:
			log.Printf("[%s] Connection timeout.", state.Name())
			state = state.HandleTimeout()
		}

		if state.Name() != name {
			log.Printf("[%03d] STATE: %s", data.peerIP, state.Name())
			name = state.Name()
		}
	}
}

func (c *connHandler) HandlePing(w wrapper[Ping]) {
	select {
	case c.pings <- w:
	default:
	}
}

func (c *connHandler) HandlePong(w wrapper[Pong]) {
	select {
	case c.pongs <- w:
	default:
	}
}

func (c *connHandler) UpdatePeer(update peerUpdate) {
	select {
	case c.peerUpdates <- update:
	default:
	}
}