From 0b85740bc98047f0acebf263343ce3218a878b98 Mon Sep 17 00:00:00 2001
From: Joop Kiefte <ikojba@gmail.com>
Date: Sat, 11 Dec 2021 03:18:04 +0000
Subject: Add P2P receive capability

---
 message/message.go | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 67 insertions(+), 4 deletions(-)

(limited to 'message/message.go')

diff --git a/message/message.go b/message/message.go
index aa2a3e5..6d8ddcd 100644
--- a/message/message.go
+++ b/message/message.go
@@ -5,7 +5,9 @@ import (
 	"crypto/sha256"
 	"encoding/json"
 	"fmt"
+	"io"
 	"math/bits"
+	"sync"
 	"time"
 
 	ipfs "github.com/ipfs/go-ipfs-api"
@@ -90,21 +92,82 @@ func New(msg string, n int, timestamp int64) *Message {
 }
 
 // Map Messages maps the stamp of the message to the message itself
-type Messages map[string]*Message
+type Messages struct {
+	lock sync.RWMutex
+	msgs map[string]*Message
+}
+
+// MessagesFromIPFS takes a CID and returns a Messages map
+func MessagesFromIPFS(cid string) (*Messages, error) {
+	emptyMsgs := Messages{msgs: make(map[string]*Message)}
+	// Create an IPFS instance based on the IPFSGateway
+	myIPFS := ipfs.NewShell(IPFSGateway)
+	// Get the JSON from IPFS
+	jsonr, err := myIPFS.Cat(cid)
+	if err != nil {
+		return &emptyMsgs, err
+	}
+	jsonb, err := io.ReadAll(jsonr)
+	if err != nil {
+		return &emptyMsgs, err
+	}
+	// Unmarshal the JSON into a Messages map
+	var messages Messages
+	err = json.Unmarshal(jsonb, &(messages.msgs))
+	if err != nil {
+		return &emptyMsgs, err
+	}
+	return &messages, nil
+}
 
 // Add a message to the Messages map
 func (m *Messages) Add(msg *Message) {
-	(*m)[msg.Stamp()] = msg
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	if m.msgs == nil {
+		m.msgs = make(map[string]*Message)
+	}
+	m.msgs[msg.Stamp()] = msg
+}
+
+// AddMany adds another Messages map to the current Messages map
+func (m *Messages) AddMany(msgs *Messages) {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	msgs.lock.RLock()
+	defer msgs.lock.RUnlock()
+	if m.msgs == nil {
+		m.msgs = make(map[string]*Message)
+	}
+	for _, msg := range msgs.msgs {
+		m.msgs[msg.Stamp()] = msg
+	}
 }
 
 // Remove a message from the Messages map by stamp
 func (m *Messages) Remove(stamp string) {
-	delete(*m, stamp)
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	delete(m.msgs, stamp)
 }
 
 // Return a JSON representation of the Messages map
 func (m *Messages) JSON() ([]byte, error) {
-	return json.Marshal(m)
+	m.lock.RLock()
+	defer m.lock.RUnlock()
+	return json.Marshal(m.msgs)
+}
+
+// Do something with each message in the Messages map
+func (m *Messages) Each(f func(msg *Message)) {
+	m.lock.RLock()
+	defer m.lock.RUnlock()
+	if m.msgs == nil {
+		return
+	}
+	for _, msg := range m.msgs {
+		f(msg)
+	}
 }
 
 // Add the messages as a JSON object to IPFS
-- 
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