Fix tweet content generation (#43)

- Fix strings without spaces wouldn't get included in the tweet, made
  the splitting mechanism more naive - it now ignores spaces but should
  be less error prone.
- Fix link detection not accepting slashes as part of the links.

service/domain/content/lexer.go

@@ -8,6 +8,15 @@ import (
 	"github.com/boreq/errors"
 )
 
+const (
+	httpColonSlashSlash  = "http://"
+	httpsColonSlashSlash = "https://"
+	nostrColon           = "nostr:"
+	nevent               = "nevent"
+	npub                 = "npub"
+	note                 = "note"
+)
+
 type Token struct {
 	Type TokenType
 	Text string
@@ -168,15 +177,6 @@ func (l *Lexer) mergeConsecutiveTexts(tokens []Token) []Token {
 
 type stateFn func(l *Lexer) (stateFn, error)
 
-const (
-	httpColonSlashSlash  = "http://"
-	httpsColonSlashSlash = "https://"
-	nostrColon           = "nostr:"
-	nevent               = "nevent"
-	npub                 = "npub"
-	note                 = "note"
-)
-
 func stateText(l *Lexer) (stateFn, error) {
 	for {
 		if l.comesNext(httpColonSlashSlash) || l.comesNext(httpsColonSlashSlash) {
@@ -295,7 +295,7 @@ func stateNostrLinkData(l *Lexer) (stateFn, error) {
 }
 
 func isValidLinkCharacterExcludingDot(r rune) bool {
-	return unicode.IsLetter(r) || unicode.IsNumber(r) || r == '%'
+	return unicode.IsLetter(r) || unicode.IsNumber(r) || r == '%' || r == '/'
 }
 
 func isBech32(r rune) bool {

service/domain/content/lexer_test.go

@@ -133,6 +133,16 @@ func TestLexer(t *testing.T) {
 				},
 			},
 		},
+		{
+			Name: "only_link_with_path",
+			In:   `https://example.com/path`,
+			Out: []content.Token{
+				{
+					Type: content.TokenTypeLink,
+					Text: "https://example.com/path",
+				},
+			},
+		},
 	}
 
 	for _, testCase := range testCases {

service/domain/tweet_generator.go

@@ -3,6 +3,7 @@ package domain
 import (
 	"fmt"
 	"strings"
+	"unicode/utf8"
 
 	"github.com/boreq/errors"
 	"github.com/planetary-social/nos-crossposting-service/service/domain/content"
@@ -70,17 +71,16 @@ func (g *TweetGenerator) createContent(builder *strings.Builder, elements []cont
 
 			builder.WriteString(element.Text)
 		case content.ElementTypeText:
-			for i, part := range strings.Split(element.Text, " ") {
-				futureTotalLength := builder.Len() + len(part)
-				if futureTotalLength > noteContentMaxLengthInRunes {
-					builder.WriteString(ellipsis)
+			remainingLen := noteContentMaxLengthInRunes - utf8.RuneCountInString(builder.String())
+			numberOfWrittenRunes := 0
+			for _, r := range element.Text {
+				builder.WriteRune(r)
+				numberOfWrittenRunes++
+
+				if numberOfWrittenRunes >= remainingLen {
+					builder.WriteString("...")
 					return nil
 				}
-
-				if i > 0 {
-					builder.WriteString(" ")
-				}
-				builder.WriteString(part)
 			}
 		default:
 			return errors.New("unknown element")

service/domain/tweet_generator_test.go

@@ -29,6 +29,17 @@ func TestTweetGenerator(t *testing.T) {
 			},
 			ExpectedContent: "Some text.",
 		},
+		{
+			Name: "not_a_reply_long_without_spaces",
+			Event: nostr.Event{
+				Kind: domain.EventKindNote.Int(),
+				Tags: []nostr.Tag{
+					[]string{"p", fixtures.SomePublicKey().Hex()},
+				},
+				Content: strings.Repeat("a", 300),
+			},
+			ExpectedContent: strings.Repeat("a", 200) + "...",
+		},
 		{
 			Name: "not_a_reply_long",
 			Event: nostr.Event{
@@ -38,7 +49,18 @@ func TestTweetGenerator(t *testing.T) {
 				},
 				Content: strings.Repeat("Some text. ", 100),
 			},
-			ExpectedContent: "Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text....",
+			ExpectedContent: "Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. So...",
+		},
+		{
+			Name: "not_a_reply_huge_link",
+			Event: nostr.Event{
+				Kind: domain.EventKindNote.Int(),
+				Tags: []nostr.Tag{
+					[]string{"p", fixtures.SomePublicKey().Hex()},
+				},
+				Content: "https://example.com/" + strings.Repeat("a", 300),
+			},
+			ExpectedContent: "...",
 		},
 		{
 			Name: "reply",