// SPDX-FileCopyrightText: V <v@anomalous.eu>
// SPDX-FileCopyrightText: edef <edef@edef.eu>
// SPDX-License-Identifier: OSL-3.0

package main

import (
	"time"
)

type Session struct {
	store *Store
	id    SessionID
	q     chan Message
	done  chan struct{}
}

func OpenSession(store *Store, host string) *Session {
	session := &Session{
		store: store,
		id:    store.WriteOpen(now(), host),
		q:     make(chan Message, 1024),
		done:  make(chan struct{}),
	}

	go session.batcher()
	return session
}

func (s *Session) Write(from Side, data string) {
	s.q <- Message{now(), from, data}
}

func (s *Session) Close(by Side, reason string) {
	close(s.q)
	<-s.done
	s.store.WriteClose(s.id, now(), by, reason)
}

func now() Timestamp {
	return Timestamp(time.Now().UnixNano())
}

func (s *Session) batcher() {
	batch := make([]Message, cap(s.q))
	for msg := range s.q {
		batch = append(batch[:0], msg)
	out:
		for len(batch) < cap(batch) {
			select {
			case msg, ok := <-s.q:
				if !ok {
					break out
				}
				batch = append(batch, msg)
			default:
				break out
			}
		}

		s.store.WriteBatch(s.id, batch)

		for i := range batch {
			batch[i] = Message{}
		}
	}

	close(s.done)
}