cwtch/model/message.go

package model

import (
	"sort"
	"sync"
	"time"
)

type Timeline struct {
	Messages []Message
	lock     sync.Mutex
}

// Message is a local representation of a given message sent over a group chat channel.
type Message struct {
	Timestamp          time.Time
	PeerID             string
	Message            string
	Signature          []byte
	Verified           bool
	PreviousMessageSig []byte
}

func compareSignatures(a []byte, b []byte) bool {
	if len(a) != len(b) {
		return false
	}
	for i := range a {
		if a[i] != b[i] {
			return false
		}
	}
	return true
}

func (t Timeline) Len() int {
	return len(t.Messages)
}
func (t Timeline) Swap(i, j int) {
	t.Messages[i], t.Messages[j] = t.Messages[j], t.Messages[i]
}
func (t Timeline) Less(i, j int) bool {

	if compareSignatures(t.Messages[i].PreviousMessageSig, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}) {
		return true
	}

	if t.Messages[i].Timestamp.Before(t.Messages[j].Timestamp) {
		return true
	}

	if compareSignatures(t.Messages[i].Signature, t.Messages[j].PreviousMessageSig) {
		return true
	}

	return false
}

func (t *Timeline) Insert(mi *Message) {
	t.lock.Lock()
	t.Messages = append(t.Messages, *mi)
	sort.Sort(t)
	t.lock.Unlock()
}