From f2b201926879cebacb8c6df99b439acba58fa0e0 Mon Sep 17 00:00:00 2001
From: hirasawayuki <yuki.hirasawa1206@gmail.com>
Date: Sun, 20 Oct 2024 11:54:44 +0900
Subject: [PATCH] feat: add comment formatter and unit tests

---
 private/buf/buflsp/symbol.go      | 49 +++++++++++++++++-------
 private/buf/buflsp/symbol_test.go | 63 +++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+), 13 deletions(-)
 create mode 100644 private/buf/buflsp/symbol_test.go

diff --git a/private/buf/buflsp/symbol.go b/private/buf/buflsp/symbol.go
index 8ea0da97f1..53fd4421de 100644
--- a/private/buf/buflsp/symbol.go
+++ b/private/buf/buflsp/symbol.go
@@ -498,24 +498,12 @@ func (s *symbol) FormatDocs(ctx context.Context) string {
 	var printed bool
 	for _, comments := range allComments {
 		for i := 0; i < comments.Len(); i++ {
-			comment := comments.Index(i).RawText()
-
 			// The compiler does not currently provide comments without their
 			// delimited removed, so we have to do this ourselves.
-			if strings.HasPrefix(comment, "//") {
-				// NOTE: We do not trim the space here, because indentation is
-				// significant for Markdown code fences, and if every line
-				// starts with a space, Markdown will trim it for us, even off
-				// of code blocks.
-				comment = strings.TrimPrefix(comment, "//")
-			} else {
-				comment = strings.TrimSuffix(strings.TrimPrefix(comment, "/*"), "*/")
-			}
-
+			comment := formatComment(comments.Index(i).RawText())
 			if comment != "" {
 				printed = true
 			}
-
 			// No need to process Markdown in comment; this Just Works!
 			fmt.Fprintln(&tooltip, comment)
 		}
@@ -528,6 +516,41 @@ func (s *symbol) FormatDocs(ctx context.Context) string {
 	return tooltip.String()
 }
 
+// formatComment takes a raw comment string and formats it by removing comment
+// delimiters and unnecessary whitespace. It handles both single-line (//) and
+// multi-line (/* */) comments.
+func formatComment(comment string) string {
+	comment = strings.TrimSpace(comment)
+
+	if strings.HasPrefix(comment, "//") {
+		// NOTE: We do not trim the space here, because indentation is
+		// significant for Markdown code fences, and if every line
+		// starts with a space, Markdown will trim it for us, even off
+		// of code blocks.
+		return strings.TrimPrefix(comment, "//")
+	}
+
+	if strings.HasPrefix(comment, "/*") && strings.HasSuffix(comment, "*/") {
+		comment = strings.Trim(comment, "/*")
+		// single-line
+		if !strings.Contains(comment, "\n") {
+			return strings.TrimSpace(comment)
+		}
+
+		lines := strings.Split(strings.TrimSpace(comment), "\n")
+		for i, line := range lines {
+			line = strings.TrimSpace(line)
+			line = strings.TrimLeft(line, "*")
+			line = strings.TrimPrefix(line, " ")
+			lines[i] = line
+		}
+
+		return strings.Join(lines, "\n")
+	}
+
+	return comment
+}
+
 // symbolWalker is an AST walker that generates the symbol table for a file in IndexSymbols().
 type symbolWalker struct {
 	file    *file
diff --git a/private/buf/buflsp/symbol_test.go b/private/buf/buflsp/symbol_test.go
new file mode 100644
index 0000000000..dbfe2a74a7
--- /dev/null
+++ b/private/buf/buflsp/symbol_test.go
@@ -0,0 +1,63 @@
+package buflsp
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_formatComment(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "Single-line comment",
+			input:    "// This is a single-line comment",
+			expected: " This is a single-line comment",
+		},
+		{
+			name:     "Multi-line comment",
+			input:    "/*\n * This is a\n * multi-line comment\n */",
+			expected: "This is a\nmulti-line comment",
+		},
+		{
+			name:     "Multi-line comment with mixed indentation",
+			input:    "/*\n  * First line\n  * - Second line\n  *   - Third line\n */",
+			expected: "First line\n- Second line\n  - Third line",
+		},
+		{
+			name:     "Multi-line comment with multi-asterisks",
+			input:    "/*** This is a\n   *** multi-line comment\n   *** with multi-asterisks ***/",
+			expected: "This is a\nmulti-line comment\nwith multi-asterisks",
+		},
+		{
+			name:     "Multi-line comment without asterisks",
+			input:    "/* This is a\n   multi-line comment\n   without asterisks */",
+			expected: "This is a\nmulti-line comment\nwithout asterisks",
+		},
+		{
+			name:     "Single-line multi-line comment",
+			input:    "/* Single-line multi-line comment */",
+			expected: "Single-line multi-line comment",
+		},
+		{
+			name:     "Empty comment",
+			input:    "/**/",
+			expected: "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			result := formatComment(tt.input)
+			if result != tt.expected {
+				assert.Equal(t, tt.input, result)
+			}
+		})
+	}
+}