From 9b2b3b90397be530edb76a4e502a970ec604e96e Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@gmail.com>
Date: Sat, 8 Jul 2023 07:50:54 -0300
Subject: [PATCH] inbox-outbox relay barebones helpers on sdk package.

---
 sdk/relays.go | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 sdk/relays.go

diff --git a/sdk/relays.go b/sdk/relays.go
new file mode 100644
index 0000000..e8eb97f
--- /dev/null
+++ b/sdk/relays.go
@@ -0,0 +1,107 @@
+package sdk
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/nbd-wtf/go-nostr"
+)
+
+type Relay struct {
+	URL    string
+	Inbox  bool
+	Outbox bool
+}
+
+func FetchRelaysForPubkey(ctx context.Context, pool *nostr.SimplePool, pubkey string, extraRelays ...string) []Relay {
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	relays := append(extraRelays,
+		"wss://nostr-pub.wellorder.net",
+		"wss://relay.damus.io",
+		"wss://nos.lol",
+		"wss://nostr.mom",
+		"wss://relay.nostr.bg",
+	)
+
+	ch := pool.SubManyEose(ctx, relays, nostr.Filters{
+		{
+			Kinds:   []int{10002, 3},
+			Authors: []string{pubkey},
+			Limit:   2,
+		},
+	})
+
+	result := make([]Relay, 0, 20)
+	i := 0
+	for event := range ch {
+		switch event.Kind {
+		case 10002:
+			result = append(result, ParseRelaysFromKind10002(event)...)
+		case 3:
+			result = append(result, ParseRelaysFromKind3(event)...)
+		}
+
+		i++
+		if i >= 2 {
+			break
+		}
+	}
+
+	return result
+}
+
+func ParseRelaysFromKind10002(evt *nostr.Event) []Relay {
+	result := make([]Relay, 0, len(evt.Tags))
+	for _, tag := range evt.Tags {
+		if u := tag.Value(); u != "" && tag[0] == "r" {
+			relay := Relay{
+				URL: u,
+			}
+
+			if len(tag) == 2 {
+				relay.Inbox = true
+				relay.Outbox = true
+			} else if tag[2] == "write" {
+				relay.Outbox = true
+			} else if tag[2] == "read" {
+				relay.Inbox = true
+			}
+
+			result = append(result, relay)
+		}
+	}
+
+	return result
+}
+
+func ParseRelaysFromKind3(evt *nostr.Event) []Relay {
+	type Item struct {
+		Read  bool `json:"read"`
+		Write bool `json:"write"`
+	}
+
+	items := make(map[string]Item, 20)
+	json.Unmarshal([]byte(evt.Content), &items)
+
+	results := make([]Relay, len(items))
+	i := 0
+	for u, item := range items {
+		relay := Relay{
+			URL: u,
+		}
+
+		if item.Read {
+			relay.Inbox = true
+		}
+		if item.Write {
+			relay.Outbox = true
+		}
+
+		results = append(results, relay)
+		i++
+	}
+
+	return results
+}