Build response string more efficiently

This is definitely a dumb premature optimization, but this does some basic string builder stuff so that we're not duplicating strings all willy nilly.

cmd/kagi/main.go

@@ -1,11 +1,14 @@
 package main
 
 import (
+	"bufio"
+	"bytes"
 	"errors"
 	"flag"
 	"fmt"
 	"log"
 	"os"
+	"strconv"
 	"strings"
 
 	"github.com/bcspragu/kagi/api"
@@ -47,28 +50,68 @@ func run(args []string) error {
 		return fmt.Errorf("error performing query: %w", err)
 	}
 
-	response := respond(resp, query)
+	response, err := respond(resp, query)
+	if err != nil {
+		return fmt.Errorf("failed to build response: %w", err)
+	}
 	fmt.Print(response)
 
 	return nil
 }
 
-func respond(resp *api.FastGPTResponse, query string) (response string) {
-	// remove all repeated newlines or empty lines from the output
-  answer := strings.ReplaceAll(resp.Data.Output, "\n\n", "\n")
-
-  response = "# " + query + "\n" + answer + "\n"
+func respond(resp *api.FastGPTResponse, query string) (string, error) {
+	var buf bytes.Buffer
+	buf.WriteString("# ")
+	buf.WriteString(query)
+	buf.WriteRune('\n')
+	if err := streamAndRemoveDoubleNewlines(resp.Data.Output, &buf); err != nil {
+		return "", fmt.Errorf("failed to remove double newlines: %w", err)
+	}
+	buf.WriteRune('\n')
 
 	// If there are no references, return early
 	if len(resp.Data.References) == 0 {
-		return
+		return buf.String(), nil
 	}
 
-  response += "\n# References\n"
+	buf.WriteString("\n# References\n")
 
 	for i, ref := range resp.Data.References {
-    response += fmt.Sprintf("%d. %s - %s  - %s\n", i+1, ref.Title, ref.Link, ref.Snippet)
+		// fmt.Sprintf("%d. %s - %s  - %s\n", i+1, ref.Title, ref.Link, ref.Snippet)
+		buf.WriteString(strconv.Itoa(i + 1))
+		buf.WriteString(". ")
+		buf.WriteString(ref.Title)
+		buf.WriteString(" - ")
+		buf.WriteString(ref.Link)
+		buf.WriteString(" - ")
+		buf.WriteString(ref.Snippet)
+		buf.WriteRune('\n')
 	}
 
-	return
+	return buf.String(), nil
+}
+
+// Remove all repeated newlines or empty lines from the given string
+func streamAndRemoveDoubleNewlines(inp string, buf *bytes.Buffer) error {
+	r := strings.NewReader(inp)
+
+	sc := bufio.NewScanner(r)
+
+	first := true
+	for sc.Scan() {
+		if sc.Text() == "" {
+			continue
+		}
+		if !first {
+			buf.WriteRune('\n')
+		}
+		first = false
+		buf.WriteString(sc.Text())
+	}
+
+	if err := sc.Err(); err != nil {
+		return fmt.Errorf("error reading input: %w", err)
+	}
+
+	return nil
 }

cmd/kagi/main_test.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestStreamAndRemoveDoubleNewlines(t *testing.T) {
+	inp := `Hello
+
+I am a string with
+
+some double newlines
+
+
+And a triple newline!`
+
+	var buf bytes.Buffer
+	if err := streamAndRemoveDoubleNewlines(inp, &buf); err != nil {
+		t.Fatalf("streamAndRemoveDoubleNewlines: %v", err)
+	}
+
+	want := `Hello
+I am a string with
+some double newlines
+And a triple newline!`
+
+	got := buf.String()
+
+	if got != want {
+		t.Errorf("unexpected output = %q, want %q", got, want)
+	}
+}