Add pinned tabs

This adds the commands pin-tab and unpin-tab. Once pinned a tab lives on
the left of the tabstrip and has a configurable marker, defaulting to `
before its name.

6 files changed, 119 insertions, 6 deletions

diff --git a/commands/pin-tab.go b/commands/pin-tab.go
new file mode 100644
index 0000000..164a68b
--- /dev/null
+++ b/commands/pin-tab.go
@@ -0,0 +1,36 @@
+package commands
+
+import (
+	"fmt"
+
+	"git.sr.ht/~sircmpwn/aerc/widgets"
+)
+
+type PinTab struct{}
+
+func init() {
+	register(PinTab{})
+}
+
+func (PinTab) Aliases() []string {
+	return []string{"pin-tab", "unpin-tab"}
+}
+
+func (PinTab) Complete(aerc *widgets.Aerc, args []string) []string {
+	return nil
+}
+
+func (PinTab) Execute(aerc *widgets.Aerc, args []string) error {
+	if len(args) != 1 {
+		return fmt.Errorf("Usage: %s", args[0])
+	}
+
+	switch args[0] {
+	case "pin-tab":
+		aerc.PinTab()
+	case "unpin-tab":
+		aerc.UnpinTab()
+	}
+
+	return nil
+}
diff --git a/config/aerc.conf.in b/config/aerc.conf.in
index 39548cd..2f9f264 100644
--- a/config/aerc.conf.in
+++ b/config/aerc.conf.in
@@ -43,6 +43,11 @@ mouse-enabled=false
 # Default: yes
 new-message-bell=true
 
+# Marker to show before a pinned tab's name.
+#
+# Default: `
+pinned-tab-marker=`
+
 # Describes the format string to use for the directory list
 #
 # Default: %n %>r
diff --git a/config/config.go b/config/config.go
index 0393e46..5794388 100644
--- a/config/config.go
+++ b/config/config.go
@@ -31,6 +31,7 @@ type UIConfig struct {
 	TimestampFormat     string        `ini:"timestamp-format"`
 	ShowHeaders         []string      `delim:","`
 	RenderAccountTabs   string        `ini:"render-account-tabs"`
+	PinnedTabMarker     string        `ini:"pinned-tab-marker"`
 	SidebarWidth        int           `ini:"sidebar-width"`
 	PreviewHeight       int           `ini:"preview-height"`
 	EmptyMessage        string        `ini:"empty-message"`
@@ -446,6 +447,7 @@ func LoadConfigFromFile(root *string, sharedir string) (*AercConfig, error) {
 				"From", "To", "Cc", "Bcc", "Subject", "Date",
 			},
 			RenderAccountTabs:   "auto",
+			PinnedTabMarker:     "`",
 			SidebarWidth:        20,
 			PreviewHeight:       12,
 			EmptyMessage:        "(no messages)",
diff --git a/doc/aerc-config.5.scd b/doc/aerc-config.5.scd
index 687ea3a..36ac9c6 100644
--- a/doc/aerc-config.5.scd
+++ b/doc/aerc-config.5.scd
@@ -113,6 +113,11 @@ These options are configured in the *[ui]* section of aerc.conf.
 
 	Default: true
 
+*pinned-tab-marker*
+	Marker to show before a pinned tab's name.
+
+	Default: `
+
 *spinner*
 	Animation shown while loading, split by spinner-delimiter (below)
 
diff --git a/lib/ui/tab.go b/lib/ui/tab.go
index e1c53ea..7d1ce63 100644
--- a/lib/ui/tab.go
+++ b/lib/ui/tab.go
@@ -3,6 +3,8 @@ package ui
 import (
 	"github.com/gdamore/tcell"
 	"github.com/mattn/go-runewidth"
+
+	"git.sr.ht/~sircmpwn/aerc/config"
 )
 
 type Tabs struct {
@@ -12,6 +14,8 @@ type Tabs struct {
 	Selected   int
 	history    []int
 
+	uiConfig *config.UIConfig
+
 	onInvalidateStrip   func(d Drawable)
 	onInvalidateContent func(d Drawable)
 
@@ -20,16 +24,19 @@ type Tabs struct {
 }
 
 type Tab struct {
-	Content Drawable
-	Name    string
-	invalid bool
+	Content        Drawable
+	Name           string
+	invalid        bool
+	pinned         bool
+	indexBeforePin int
 }
 
 type TabStrip Tabs
 type TabContent Tabs
 
-func NewTabs() *Tabs {
+func NewTabs(uiConf *config.UIConfig) *Tabs {
 	tabs := &Tabs{}
+	tabs.uiConfig = uiConf
 	tabs.TabStrip = (*TabStrip)(tabs)
 	tabs.TabStrip.parent = tabs
 	tabs.TabContent = (*TabContent)(tabs)
@@ -173,6 +180,52 @@ func (tabs *Tabs) MoveTab(to int) {
 	tabs.TabStrip.Invalidate()
 }
 
+func (tabs *Tabs) PinTab() {
+	if tabs.Tabs[tabs.Selected].pinned {
+		return
+	}
+
+	pinEnd := len(tabs.Tabs)
+	for i, t := range tabs.Tabs {
+		if !t.pinned {
+			pinEnd = i
+			break
+		}
+	}
+
+	for _, t := range tabs.Tabs {
+		if t.pinned && t.indexBeforePin > tabs.Selected-pinEnd {
+			t.indexBeforePin -= 1
+		}
+	}
+
+	tabs.Tabs[tabs.Selected].pinned = true
+	tabs.Tabs[tabs.Selected].indexBeforePin = tabs.Selected - pinEnd
+
+	tabs.MoveTab(pinEnd)
+}
+
+func (tabs *Tabs) UnpinTab() {
+	if !tabs.Tabs[tabs.Selected].pinned {
+		return
+	}
+
+	pinEnd := len(tabs.Tabs)
+	for i, t := range tabs.Tabs {
+		if i != tabs.Selected && t.pinned && t.indexBeforePin > tabs.Tabs[tabs.Selected].indexBeforePin {
+			t.indexBeforePin += 1
+		}
+		if !t.pinned {
+			pinEnd = i
+			break
+		}
+	}
+
+	tabs.Tabs[tabs.Selected].pinned = false
+
+	tabs.MoveTab(tabs.Tabs[tabs.Selected].indexBeforePin + pinEnd - 1)
+}
+
 func (tabs *Tabs) NextTab() {
 	next := tabs.Selected + 1
 	if next >= len(tabs.Tabs) {
@@ -233,7 +286,11 @@ func (strip *TabStrip) Draw(ctx *Context) {
 		if ctx.Width()-x < tabWidth {
 			tabWidth = ctx.Width() - x - 2
 		}
-		trunc := runewidth.Truncate(tab.Name, tabWidth, "…")
+		name := tab.Name
+		if tab.pinned {
+			name = strip.uiConfig.PinnedTabMarker + name
+		}
+		trunc := runewidth.Truncate(name, tabWidth, "…")
 		x += ctx.Printf(x, 0, style, " %s ", trunc)
 		if x >= ctx.Width() {
 			break
diff --git a/widgets/aerc.go b/widgets/aerc.go
index b7071e1..4c8d09d 100644
--- a/widgets/aerc.go
+++ b/widgets/aerc.go
@@ -43,7 +43,7 @@ func NewAerc(conf *config.AercConfig, logger *log.Logger,
 	cmd func(cmd []string) error, complete func(cmd string) []string,
 	cmdHistory lib.History) *Aerc {
 
-	tabs := ui.NewTabs()
+	tabs := ui.NewTabs(&conf.Ui)
 
 	statusbar := ui.NewStack()
 	statusline := NewStatusLine()
@@ -321,6 +321,14 @@ func (aerc *Aerc) MoveTab(i int) {
 	aerc.tabs.MoveTab(i)
 }
 
+func (aerc *Aerc) PinTab() {
+	aerc.tabs.PinTab()
+}
+
+func (aerc *Aerc) UnpinTab() {
+	aerc.tabs.UnpinTab()
+}
+
 func (aerc *Aerc) NextTab() {
 	aerc.tabs.NextTab()
 }