move ExternalPointer to nip73 and write nip27.Parse() that gets all the parts of the text including URLs, Nostr URIs and just raw text.

nip27/blocks.go

@@ -0,0 +1,152 @@
+package nip27
+
+import (
+	"iter"
+	"net/url"
+	"regexp"
+	"strings"
+
+	"github.com/nbd-wtf/go-nostr"
+	"github.com/nbd-wtf/go-nostr/nip19"
+	"github.com/nbd-wtf/go-nostr/nip73"
+)
+
+type Block struct {
+	Text    string
+	Start   int
+	Pointer nostr.Pointer
+}
+
+var (
+	noCharacter    = regexp.MustCompile(`(?m)\W`)
+	noURLCharacter = regexp.MustCompile(`(?m)\W |\W$|$|,| `)
+)
+
+func Parse(content string) iter.Seq[Block] {
+	return func(yield func(Block) bool) {
+		max := len(content)
+		index := 0
+		prevIndex := 0
+
+		for index < max {
+			pu := strings.IndexRune(content[index:], ':')
+			if pu == -1 {
+				// reached end
+				break
+			}
+			u := pu + index
+
+			switch {
+			case u >= 5 && content[u-5:u] == "nostr" && u+60 < max:
+				m := noCharacter.FindStringIndex(content[u+60:])
+				end := max
+				if m != nil {
+					end = u + 60 + m[0]
+				}
+
+				prefix, data, err := nip19.Decode(content[u+1 : end])
+				if err != nil {
+					// ignore this, not a valid nostr uri
+					index = u + 1
+					continue
+				}
+
+				var pointer nostr.Pointer
+				switch prefix {
+				case "npub":
+					pointer = nostr.ProfilePointer{PublicKey: data.(string)}
+				case "nprofile", "nevent", "naddr":
+					pointer = data.(nostr.Pointer)
+				case "note", "nsec":
+					fallthrough // I'm so cool
+				default:
+					// ignore this, treat it as not a valid uri
+					index = end + 1
+					continue
+				}
+
+				if prevIndex != u-5 {
+					if !yield(Block{Text: content[prevIndex : u-5], Start: prevIndex}) {
+						return
+					}
+				}
+
+				if !yield(Block{Pointer: pointer, Text: content[u-5 : end], Start: u - 5}) {
+					return
+				}
+
+				index = end
+				prevIndex = index
+				continue
+			case (u >= 5 && content[u-5:u] == "https") || (u >= 4 && content[u-4:u] == "http"):
+				m := noURLCharacter.FindStringIndex(content[u+4:])
+				end := max
+				if m != nil {
+					end = u + 4 + m[0]
+				}
+				prefixLen := 4
+				if content[u-1] == 's' {
+					prefixLen = 5
+				}
+				parsed, err := url.Parse(content[u-prefixLen : end])
+				if err != nil || !strings.Contains(parsed.Host, ".") {
+					// ignore this, not a valid url
+					index = end + 1
+					continue
+				}
+
+				if prevIndex != u-prefixLen {
+					if !yield(Block{Text: content[prevIndex : u-prefixLen], Start: prevIndex}) {
+						return
+					}
+				}
+
+				if !yield(Block{Pointer: nip73.ExternalPointer{Thing: content[u-prefixLen : end]}, Text: content[u-prefixLen : end], Start: u - prefixLen}) {
+					return
+				}
+
+				index = end
+				prevIndex = index
+				continue
+			case (u >= 3 && content[u-3:u] == "wss") || (u >= 2 && content[u-2:u] == "ws"):
+				m := noURLCharacter.FindStringIndex(content[u+4:])
+				end := max
+				if m != nil {
+					end = u + 4 + m[0]
+				}
+				prefixLen := 2
+				if content[u-1] == 's' {
+					prefixLen = 3
+				}
+				parsed, err := url.Parse(content[u-prefixLen : end])
+				if err != nil || !strings.Contains(parsed.Host, ".") {
+					// ignore this, not a valid url
+					index = end + 1
+					continue
+				}
+
+				if prevIndex != u-prefixLen {
+					if !yield(Block{Text: content[prevIndex : u-prefixLen], Start: prevIndex}) {
+						return
+					}
+				}
+
+				if !yield(Block{Pointer: nip73.ExternalPointer{Thing: content[u-prefixLen : end]}, Text: content[u-prefixLen : end], Start: u - prefixLen}) {
+					return
+				}
+
+				index = end
+				prevIndex = index
+				continue
+			default:
+				// ignore this, it is nothing
+				index = u + 1
+				continue
+			}
+		}
+
+		if prevIndex != max {
+			yield(Block{Text: content[prevIndex:], Start: prevIndex})
+		}
+	}
+}