WTF-758 Open HN comments if there's no external link (#802)

If an HN story has no external link associated with it,
open the HN comments page for the story.

Closes #758

Signed-off-by: Chris Cummer <chriscummer@me.com>

modules/hackernews/story.go

@@ -1,5 +1,12 @@
 package hackernews
 
+import "fmt"
+
+const (
+	hnStoryPath = "https://news.ycombinator.com/item?id="
+)
+
+// Story represents a story submission on HackerNews
 type Story struct {
 	By          string `json:"by"`
 	Descendants int    `json:"descendants"`
@@ -11,3 +18,19 @@ type Story struct {
 	Type        string `json:"type"`
 	URL         string `json:"url"`
 }
+
+// CommentLink return the link to the HackerNews story comments page
+func (story *Story) CommentLink() string {
+	return fmt.Sprintf("%s%d", hnStoryPath, story.ID)
+}
+
+// Link returns the link to a story. If the story has an external link, that is returned
+// If the story has no external link, the HackerNews comments link is returned instead
+func (story *Story) Link() string {
+	if story.URL != "" {
+		return story.URL
+	}
+
+	// Fall back to the HackerNews comment link
+	return story.CommentLink()
+}

modules/hackernews/story_test.go

@@ -0,0 +1,50 @@
+package hackernews
+
+import (
+	"testing"
+
+	"gotest.tools/assert"
+)
+
+func Test_CommentLink(t *testing.T) {
+	story := Story{
+		ID: 3,
+	}
+
+	assert.Equal(t, "https://news.ycombinator.com/item?id=3", story.CommentLink())
+}
+
+func Test_Link(t *testing.T) {
+	tests := []struct {
+		name     string
+		id       int
+		url      string
+		expected string
+	}{
+		{
+			name:     "no external link",
+			id:       1,
+			url:      "",
+			expected: "https://news.ycombinator.com/item?id=1",
+		},
+		{
+			name:     "with external link",
+			id:       1,
+			url:      "https://www.link.ca",
+			expected: "https://www.link.ca",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			story := Story{
+				ID:  tt.id,
+				URL: tt.url,
+			}
+
+			actual := story.Link()
+
+			assert.Equal(t, tt.expected, actual)
+		})
+	}
+}

modules/hackernews/widget.go

@@ -99,18 +99,27 @@ func (widget *Widget) content() (string, string, bool) {
 	return title, str, false
 }
 
-func (widget *Widget) openStory() {
-	sel := widget.GetSelected()
-	if sel >= 0 && widget.stories != nil && sel < len(widget.stories) {
-		story := &widget.stories[sel]
-		utils.OpenFile(story.URL)
+func (widget *Widget) openComments() {
+	story := widget.selectedStory()
+	if story != nil {
+		utils.OpenFile(story.CommentLink())
 	}
 }
 
-func (widget *Widget) openComments() {
-	sel := widget.GetSelected()
-	if sel >= 0 && widget.stories != nil && sel < len(widget.stories) {
-		story := &widget.stories[sel]
-		utils.OpenFile(fmt.Sprintf("https://news.ycombinator.com/item?id=%d", story.ID))
+func (widget *Widget) openStory() {
+	story := widget.selectedStory()
+	if story != nil {
+		utils.OpenFile(story.Link())
 	}
 }
+
+func (widget *Widget) selectedStory() *Story {
+	var story *Story
+
+	sel := widget.GetSelected()
+	if sel >= 0 && widget.stories != nil && sel < len(widget.stories) {
+		story = &widget.stories[sel]
+	}
+
+	return story
+}