msglist: allow configuring default split

Add a new setting to configure the default split layout for message list
tabs. The syntax is a bit different from the :split and :vsplit commands
since it needs to convey the direction in the value as well. I didn't
reuse split/vsplit since they are a bit confusing when used in
a configuration file.

The syntax is as follows:

	message-list-split = [<direction>] <size>

The direction is optional and defaults to horizontal. The size is the
number of terminal cells that will be used to display the message list.

All these examples are equivalent:

	message-list-split = horiz 12
	message-list-split = h 12
	message-list-split = 12

Same idea for vertical splits:

	message-list-split = vertical 120
	message-list-split = vert 120
	message-list-split = v 120

Both :split and :vsplit commands remain usable as before. The
configuration options only affect the initial layout at startup.

Add config.SPLIT_* constants and sanitize AccountView.{Split,Vsplit}
methods.

Changelog-added: Configure default message list `:split` or `:vsplit`
 on startup with `message-list-split` in `aerc.conf`.
Signed-off-by: Robin Jarry <robin@jarry.cc>
Tested-by: Tim Culverhouse <tim@timculverhouse.com>

5 files changed, 88 insertions, 17 deletions

diff --git a/app/account.go b/app/account.go
index 2bdf970a..08ab6498 100644
--- a/app/account.go
+++ b/app/account.go
@@ -40,7 +40,8 @@ type AccountView struct {
 	split         *MessageViewer
 	splitSize     int
 	splitDebounce *time.Timer
-	splitDir      string
+	splitDir      config.SplitDirection
+	splitLoaded   bool
 
 	// Check-mail ticker
 	ticker       *time.Ticker
@@ -544,7 +545,7 @@ func (acct *AccountView) closeSplit() {
 		acct.split.Close()
 	}
 	acct.splitSize = 0
-	acct.splitDir = ""
+	acct.splitDir = config.SPLIT_NONE
 	acct.split = nil
 	acct.grid = ui.NewGrid().Rows([]ui.GridSpec{
 		{Strategy: ui.SIZE_WEIGHT, Size: ui.Const(1)},
@@ -561,7 +562,16 @@ func (acct *AccountView) closeSplit() {
 }
 
 func (acct *AccountView) updateSplitView(msg *models.MessageInfo) {
-	if acct.splitSize == 0 {
+	if !acct.splitLoaded {
+		switch acct.uiConf.MessageListSplit.Direction {
+		case config.SPLIT_HORIZONTAL:
+			acct.Split(acct.uiConf.MessageListSplit.Size)
+		case config.SPLIT_VERTICAL:
+			acct.Vsplit(acct.uiConf.MessageListSplit.Size)
+		}
+		acct.splitLoaded = true
+	}
+	if acct.splitSize == 0 || !acct.splitLoaded {
 		return
 	}
 	if acct.splitDebounce != nil {
@@ -580,9 +590,9 @@ func (acct *AccountView) updateSplitView(msg *models.MessageInfo) {
 				}
 				acct.split = NewMessageViewer(acct, view)
 				switch acct.splitDir {
-				case "split", "hsplit":
+				case config.SPLIT_HORIZONTAL:
 					acct.grid.AddChild(acct.split).At(1, 1)
-				case "vsplit":
+				case config.SPLIT_VERTICAL:
 					acct.grid.AddChild(acct.split).At(0, 2)
 				}
 			})
@@ -605,12 +615,12 @@ func (acct *AccountView) SetSplitSize(n int) {
 
 // Split splits the message list view horizontally. The message list will be n
 // rows high. If n is 0, any existing split is removed
-func (acct *AccountView) Split(n int) error {
+func (acct *AccountView) Split(n int) {
 	acct.SetSplitSize(n)
-	if acct.splitDir == "split" || n == 0 {
-		return nil
+	if acct.splitDir == config.SPLIT_HORIZONTAL || n == 0 {
+		return
 	}
-	acct.splitDir = "split"
+	acct.splitDir = config.SPLIT_HORIZONTAL
 	acct.grid = ui.NewGrid().Rows([]ui.GridSpec{
 		// Add 1 so that the splitSize is the number of visible messages
 		{Strategy: ui.SIZE_EXACT, Size: func() int { return acct.SplitSize() + 1 }},
@@ -627,17 +637,16 @@ func (acct *AccountView) Split(n int) error {
 	acct.split = NewMessageViewer(acct, nil)
 	acct.grid.AddChild(acct.split).At(1, 1)
 	acct.updateSplitView(acct.msglist.Selected())
-	return nil
 }
 
 // Vsplit splits the message list view vertically. The message list will be n
 // rows wide. If n is 0, any existing split is removed
-func (acct *AccountView) Vsplit(n int) error {
+func (acct *AccountView) Vsplit(n int) {
 	acct.SetSplitSize(n)
-	if acct.splitDir == "vsplit" || n == 0 {
-		return nil
+	if acct.splitDir == config.SPLIT_VERTICAL || n == 0 {
+		return
 	}
-	acct.splitDir = "vsplit"
+	acct.splitDir = config.SPLIT_VERTICAL
 	acct.grid = ui.NewGrid().Rows([]ui.GridSpec{
 		{Strategy: ui.SIZE_WEIGHT, Size: ui.Const(1)},
 	}).Columns([]ui.GridSpec{
@@ -653,7 +662,6 @@ func (acct *AccountView) Vsplit(n int) error {
 	acct.split = NewMessageViewer(acct, nil)
 	acct.grid.AddChild(acct.split).At(0, 2)
 	acct.updateSplitView(acct.msglist.Selected())
-	return nil
 }
 
 // setTitle executes the title template and sets the tab title
diff --git a/commands/account/split.go b/commands/account/split.go
index 4b01da2d..5f09f21b 100644
--- a/commands/account/split.go
+++ b/commands/account/split.go
@@ -70,9 +70,9 @@ func (s Split) Execute(args []string) error {
 	}
 	switch args[0] {
 	case "split", "hsplit":
-		return acct.Split(s.Size)
+		acct.Split(s.Size)
 	case "vsplit":
-		return acct.Vsplit(s.Size)
+		acct.Vsplit(s.Size)
 	}
 	return nil
 }
diff --git a/config/aerc.conf b/config/aerc.conf
index 51c73a8f..17b9d216 100644
--- a/config/aerc.conf
+++ b/config/aerc.conf
@@ -163,6 +163,19 @@
 #sidebar-width=22
 
 #
+# Default split layout for message list tabs. The syntax is:
+#
+#       [<direction>] <size>
+#
+# <direction> is optional and defaults to horizontal. It can take one
+# of the following values: h, horiz, horizontal, v, vert, vertical.
+#
+# <size> is a positive integer representing the size (in terminal cells)
+# of the message list window.
+#
+#message-list-split=
+
+#
 # Message to display when viewing an empty folder.
 #
 # Default: (no messages)
diff --git a/config/ui.go b/config/ui.go
index 8b10c8a8..a6034d46 100644
--- a/config/ui.go
+++ b/config/ui.go
@@ -5,6 +5,7 @@ import (
 	"math"
 	"path"
 	"regexp"
+	"strconv"
 	"text/template"
 	"time"
 
@@ -32,6 +33,7 @@ type UIConfig struct {
 	MessageViewThisYearTimeFormat string        `ini:"message-view-this-year-time-format"`
 	PinnedTabMarker               string        "ini:\"pinned-tab-marker\" default:\"`\""
 	SidebarWidth                  int           `ini:"sidebar-width" default:"22"`
+	MessageListSplit              SplitParams   `ini:"message-list-split" parse:"ParseSplit"`
 	EmptyMessage                  string        `ini:"empty-message" default:"(no messages)"`
 	EmptyDirlist                  string        `ini:"empty-dirlist" default:"(no folders)"`
 	EmptySubject                  string        `ini:"empty-subject" default:"(no subject)"`
@@ -233,6 +235,42 @@ func (*UIConfig) ParseIndexColumns(section *ini.Section, key *ini.Key) ([]*Colum
 	return ParseColumnDefs(key, section)
 }
 
+type SplitDirection int
+
+const (
+	SPLIT_NONE SplitDirection = iota
+	SPLIT_HORIZONTAL
+	SPLIT_VERTICAL
+)
+
+type SplitParams struct {
+	Direction SplitDirection
+	Size      int
+}
+
+func (*UIConfig) ParseSplit(section *ini.Section, key *ini.Key) (p SplitParams, err error) {
+	re := regexp.MustCompile(`^\s*(v(?:ert(?:ical)?)?|h(?:oriz(?:ontal)?)?)?\s+(\d+)\s*$`)
+	match := re.FindStringSubmatch(key.String())
+	if len(match) != 3 {
+		err = fmt.Errorf("bad option value")
+		return
+	}
+	p.Direction = SPLIT_HORIZONTAL
+	switch match[1] {
+	case "v", "vert", "vertical":
+		p.Direction = SPLIT_VERTICAL
+	case "h", "horiz", "horizontal":
+		p.Direction = SPLIT_HORIZONTAL
+	}
+	size, e := strconv.ParseUint(match[2], 10, 32)
+	if e != nil {
+		err = e
+		return
+	}
+	p.Size = int(size)
+	return
+}
+
 const MANUAL_COMPLETE = math.MaxInt
 
 func (*UIConfig) ParseCompletionMinChars(section *ini.Section, key *ini.Key) (int, error) {
diff --git a/doc/aerc-config.5.scd b/doc/aerc-config.5.scd
index b13d6e89..ea931675 100644
--- a/doc/aerc-config.5.scd
+++ b/doc/aerc-config.5.scd
@@ -179,6 +179,18 @@ These options are configured in the *[ui]* section of _aerc.conf_.
 
 	Default: _22_
 
+*message-list-split* = _[<direction>] <size>_
+	The default split layout for message list tabs.
+
+	_<direction>_ is optional and defaults to _horizontal_. It can take one
+	of the following values: _h_, _horiz_, _horizontal_, _v_, _vert_,
+	_vertical_.
+
+	_<size>_ is a positive integer representing the size (in terminal cells)
+	of the message list window.
+
+	See *:split* in *aerc*(1) for more details.
+
 *empty-message* = _<string>_
 	Message to display when viewing an empty folder.