templates: separate thread prefix from subject

Extract {{.ThreadPrefix}} from {{.Subject}} so that the prefix can be
styled in a different color.

Signed-off-by: Robin Jarry <robin@jarry.cc>
Acked-by: Tim Culverhouse <tim@timculverhouse.com>

8 files changed, 27 insertions, 16 deletions

diff --git a/config/aerc.conf b/config/aerc.conf
index 9d1f120e..cb6e8649 100644
--- a/config/aerc.conf
+++ b/config/aerc.conf
@@ -63,7 +63,7 @@
 #column-date={{.DateAutoFormat .Date.Local}}
 #column-name={{index (.From | names) 0}}
 #column-flags={{.Flags | join ""}}
-#column-subject={{.Subject}}
+#column-subject={{.ThreadPrefix}}{{.Subject}}
 
 #
 # String separator inserted between columns. When the column width specifier is
diff --git a/config/templates.go b/config/templates.go
index d3e7cfb0..96fbccb1 100644
--- a/config/templates.go
+++ b/config/templates.go
@@ -74,7 +74,8 @@ func (d *dummyData) ReplyTo() []*mail.Address        { return nil }
 func (d *dummyData) Date() time.Time                 { return time.Now() }
 func (d *dummyData) DateAutoFormat(time.Time) string { return "" }
 func (d *dummyData) Header(string) string            { return "" }
-func (d *dummyData) Subject() string                 { return "[PATCH] hey" }
+func (d *dummyData) ThreadPrefix() string            { return "└─>" }
+func (d *dummyData) Subject() string                 { return "Re: [PATCH] hey" }
 func (d *dummyData) Number() int                     { return 0 }
 func (d *dummyData) Labels() []string                { return nil }
 func (d *dummyData) Flags() []string                 { return nil }
diff --git a/config/ui.go b/config/ui.go
index f52cf7f8..4b2a303a 100644
--- a/config/ui.go
+++ b/config/ui.go
@@ -284,7 +284,7 @@ func (*UIConfig) ParseIndexColumns(section *ini.Section, key *ini.Key) ([]*Colum
 		_, _ = section.NewKey("column-flags", `{{.Flags | join ""}}`)
 	}
 	if !section.HasKey("column-subject") {
-		_, _ = section.NewKey("column-subject", `{{.Subject}}`)
+		_, _ = section.NewKey("column-subject", `{{.ThreadPrefix}}{{.Subject}}`)
 	}
 	return ParseColumnDefs(key, section)
 }
@@ -382,7 +382,7 @@ func indexVerbToTemplate(verb rune) (f, name string) {
 		f = `{{.Cc | persons | join ", "}}`
 		name = "cc"
 	case 's':
-		f = "{{.Subject}}"
+		f = "{{.ThreadPrefix}}{{.Subject}}"
 		name = "subject"
 	case 't':
 		f = "{{(index .To 0).Address}}"
diff --git a/config/ui_test.go b/config/ui_test.go
index 80373da2..188fae01 100644
--- a/config/ui_test.go
+++ b/config/ui_test.go
@@ -43,7 +43,7 @@ func TestConvertIndexFormat(t *testing.T) {
 	assert.Equal(t, "subject", columns[3].Name)
 	assert.Equal(t, 0.0, columns[3].Width)
 	assert.Equal(t, ALIGN_LEFT|WIDTH_AUTO, columns[3].Flags)
-	assert.Equal(t, `{{.Subject}}`, templateText(columns[3].Template))
+	assert.Equal(t, `{{.ThreadPrefix}}{{.Subject}}`, templateText(columns[3].Template))
 }
 
 func TestConvertDirlistFormat(t *testing.T) {
diff --git a/doc/aerc-templates.7.scd b/doc/aerc-templates.7.scd
index f3f2a568..63d9df6a 100644
--- a/doc/aerc-templates.7.scd
+++ b/doc/aerc-templates.7.scd
@@ -76,10 +76,11 @@ available always.
 	Refer to the *TEMPLATE FUNCTIONS* section for details.
 
 *Subject*
-	The subject of the email.
+	The subject of the email (_ThreadPrefix_ will be empty unless threading
+	is enabled).
 
 	```
-	{{.Subject}}
+	{{.ThreadPrefix}}{{.Subject}}
 	```
 
 *Flags*
diff --git a/lib/state/templates.go b/lib/state/templates.go
index d5631b11..2e351a7a 100644
--- a/lib/state/templates.go
+++ b/lib/state/templates.go
@@ -23,8 +23,8 @@ type TemplateData struct {
 	msgNum int
 
 	// message list threading
-	ThreadSameSubject bool
-	ThreadPrefix      string
+	threadSameSubject bool
+	threadPrefix      string
 
 	// selected account
 	account     *config.AccountConfig
@@ -50,6 +50,11 @@ func (d *TemplateData) SetInfo(info *models.MessageInfo, num int, marked bool) {
 	d.marked = marked
 }
 
+func (d *TemplateData) SetThreading(prefix string, same bool) {
+	d.threadPrefix = prefix
+	d.threadSameSubject = same
+}
+
 func (d *TemplateData) SetAccount(acct *config.AccountConfig) {
 	d.account = acct
 	d.myAddresses = make(map[string]bool)
@@ -220,6 +225,10 @@ func (d *TemplateData) Header(name string) string {
 	return text
 }
 
+func (d *TemplateData) ThreadPrefix() string {
+	return d.threadPrefix
+}
+
 func (d *TemplateData) Subject() string {
 	var subject string
 	switch {
@@ -228,10 +237,10 @@ func (d *TemplateData) Subject() string {
 	case d.headers != nil:
 		subject = d.Header("subject")
 	}
-	if d.ThreadSameSubject {
+	if d.threadSameSubject {
 		subject = ""
 	}
-	return d.ThreadPrefix + subject
+	return subject
 }
 
 func (d *TemplateData) SubjectBase() string {
diff --git a/models/templates.go b/models/templates.go
index 916b3974..5ee516ac 100644
--- a/models/templates.go
+++ b/models/templates.go
@@ -19,6 +19,7 @@ type TemplateData interface {
 	Date() time.Time
 	DateAutoFormat(date time.Time) string
 	Header(name string) string
+	ThreadPrefix() string
 	Subject() string
 	Number() int
 	Labels() []string
diff --git a/widgets/msglist.go b/widgets/msglist.go
index 24f3d3bf..4bf20b09 100644
--- a/widgets/msglist.go
+++ b/widgets/msglist.go
@@ -160,11 +160,10 @@ func (ml *MessageList) Draw(ctx *ui.Context) {
 				}
 
 				baseSubject := threadSubject(store, thread)
-				data.ThreadSameSubject = baseSubject == lastSubject &&
-					sameParent(thread, prevThread) &&
-					!isParent(thread)
-				data.ThreadPrefix = threadPrefix(thread,
-					store.ReverseThreadOrder())
+				data.SetThreading(
+					threadPrefix(thread, store.ReverseThreadOrder()),
+					baseSubject == lastSubject && sameParent(thread, prevThread) && !isParent(thread),
+				)
 				lastSubject = baseSubject
 				prevThread = thread