package rep

import (
	"crypto/subtle"
	"git.crumpington.com/public/jldb/lib/httpconn"
	"log"
	"net/http"
	"time"
)

const (
	cmdGetInfo   = 10
	cmdSendState = 20
	cmdStreamWAL = 30
)

// ---------------------------------------------------------------------------

func (rep *Replicator) Handle(w http.ResponseWriter, r *http.Request) {
	logf := func(pattern string, args ...any) {
		log.Printf("[HTTP-HANDLER] "+pattern, args...)
	}

	conn, err := httpconn.Accept(w, r)
	if err != nil {
		logf("Failed to accept connection: %s", err)
		return
	}
	defer conn.Close()

	psk := make([]byte, 256)

	conn.SetReadDeadline(time.Now().Add(rep.conf.NetTimeout))
	if _, err := conn.Read(psk); err != nil {
		logf("Failed to read PSK: %v", err)
		return
	}

	expected := rep.pskBytes
	if subtle.ConstantTimeCompare(expected, psk) != 1 {
		logf("PSK mismatch.")
		return
	}

	cmd := make([]byte, 1)

	for {
		conn.SetReadDeadline(time.Now().Add(rep.conf.NetTimeout))
		if _, err := conn.Read(cmd); err != nil {
			logf("Read failed: %v", err)
			return
		}

		switch cmd[0] {

		case cmdGetInfo:
			if err := sendJSON(rep.Info(), conn, rep.conf.NetTimeout); err != nil {
				logf("Failed to send info: %s", err)
				return
			}

		case cmdSendState:

			if err := rep.sendState(conn); err != nil {
				if !rep.stopped() {
					logf("Failed to send state: %s", err)
				}
				return
			}

		case cmdStreamWAL:
			err := rep.wal.Send(conn, rep.conf.NetTimeout)
			if !rep.stopped() {
				logf("Failed when sending WAL: %s", err)
			}
			return
		}
	}
}