Support configurable header layout in compose widget

10 files changed, 239 insertions, 168 deletions

diff --git a/commands/account/compose.go b/commands/account/compose.go
index cafba787..f615c0b7 100644
--- a/commands/account/compose.go
+++ b/commands/account/compose.go
@@ -27,9 +27,9 @@ func (_ Compose) Execute(aerc *widgets.Aerc, args []string) error {
 	}
 	acct := aerc.SelectedAccount()
 	composer := widgets.NewComposer(
-		aerc.Config(), acct.AccountConfig(), acct.Worker())
+		aerc.Config(), acct.AccountConfig(), acct.Worker(), nil)
 	tab := aerc.NewTab(composer, "New email")
-	composer.OnSubjectChange(func(subject string) {
+	composer.OnHeaderChange("Subject", func(subject string) {
 		if subject == "" {
 			tab.Name = "New email"
 		} else {
diff --git a/commands/msg/reply.go b/commands/msg/reply.go
index 85c5d3ab..029cb42b 100644
--- a/commands/msg/reply.go
+++ b/commands/msg/reply.go
@@ -113,14 +113,15 @@ func (_ reply) Execute(aerc *widgets.Aerc, args []string) error {
 		}
 	}
 
+	defaults := map[string]string{
+		"To":          strings.Join(to, ", "),
+		"Cc":          strings.Join(cc, ", "),
+		"Subject":     subject,
+		"In-Reply-To": msg.Envelope.MessageId,
+	}
+
 	composer := widgets.NewComposer(
-		aerc.Config(), acct.AccountConfig(), acct.Worker()).
-		Defaults(map[string]string{
-			"To":          strings.Join(to, ", "),
-			"Cc":          strings.Join(cc, ", "),
-			"Subject":     subject,
-			"In-Reply-To": msg.Envelope.MessageId,
-		})
+		aerc.Config(), acct.AccountConfig(), acct.Worker(), defaults)
 
 	if args[0] == "reply" {
 		composer.FocusTerminal()
@@ -128,7 +129,7 @@ func (_ reply) Execute(aerc *widgets.Aerc, args []string) error {
 
 	addTab := func() {
 		tab := aerc.NewTab(composer, subject)
-		composer.OnSubjectChange(func(subject string) {
+		composer.OnHeaderChange("Subject", func(subject string) {
 			if subject == "" {
 				tab.Name = "New email"
 			} else {
diff --git a/commands/msg/unsubscribe.go b/commands/msg/unsubscribe.go
index 720ff43e..f18da075 100644
--- a/commands/msg/unsubscribe.go
+++ b/commands/msg/unsubscribe.go
@@ -83,15 +83,19 @@ func parseUnsubscribeMethods(header string) (methods []*url.URL) {
 func unsubscribeMailto(aerc *widgets.Aerc, u *url.URL) error {
 	widget := aerc.SelectedTab().(widgets.ProvidesMessage)
 	acct := widget.SelectedAccount()
-	composer := widgets.NewComposer(aerc.Config(), acct.AccountConfig(),
-		acct.Worker())
-	composer.Defaults(map[string]string{
+	defaults := map[string]string{
 		"To":      u.Opaque,
 		"Subject": u.Query().Get("subject"),
-	})
+	}
+	composer := widgets.NewComposer(
+		aerc.Config(),
+		acct.AccountConfig(),
+		acct.Worker(),
+		defaults,
+	)
 	composer.SetContents(strings.NewReader(u.Query().Get("body")))
 	tab := aerc.NewTab(composer, "unsubscribe")
-	composer.OnSubjectChange(func(subject string) {
+	composer.OnHeaderChange("Subject", func(subject string) {
 		if subject == "" {
 			tab.Name = "unsubscribe"
 		} else {
diff --git a/config/aerc.conf.in b/config/aerc.conf.in
index 5b080e98..55dfa130 100644
--- a/config/aerc.conf.in
+++ b/config/aerc.conf.in
@@ -81,6 +81,13 @@ always-show-mime=false
 # supports it. Defaults to $EDITOR, or vi.
 editor=
 
+#
+# Default header fields to display when composing a message. To display
+# multiple headers in the same row, separate them with a pipe, e.g. "To|From". 
+#
+# Default: To|From,Subject
+header-layout=To|From,Subject
+
 [filters]
 #
 # Filters allow you to pipe an email body through a shell command to render
diff --git a/config/config.go b/config/config.go
index f8637292..356d5627 100644
--- a/config/config.go
+++ b/config/config.go
@@ -65,7 +65,8 @@ type BindingConfig struct {
 }
 
 type ComposeConfig struct {
-	Editor string `ini:"editor"`
+	Editor       string     `ini:"editor"`
+	HeaderLayout [][]string `ini:"-"`
 }
 
 type FilterConfig struct {
@@ -278,6 +279,12 @@ func (config *AercConfig) LoadConfig(file *ini.File) error {
 		if err := compose.MapTo(&config.Compose); err != nil {
 			return err
 		}
+		for key, val := range compose.KeysHash() {
+			switch key {
+			case "header-layout":
+				config.Compose.HeaderLayout = parseLayout(val)
+			}
+		}
 	}
 	if ui, err := file.GetSection("ui"); err == nil {
 		if err := ui.MapTo(&config.Ui); err != nil {
@@ -350,6 +357,13 @@ func LoadConfigFromFile(root *string, sharedir string) (*AercConfig, error) {
 				{"Subject"},
 			},
 		},
+
+		Compose: ComposeConfig{
+			HeaderLayout: [][]string{
+				{"To", "From"},
+				{"Subject"},
+			},
+		},
 	}
 	// These bindings are not configurable
 	config.Bindings.AccountWizard.ExKey = KeyStroke{
diff --git a/doc/aerc-config.5.scd b/doc/aerc-config.5.scd
index 08f65af1..592b7afd 100644
--- a/doc/aerc-config.5.scd
+++ b/doc/aerc-config.5.scd
@@ -151,6 +151,12 @@ These options are configured in the *[compose]* section of aerc.conf.
 	embedded terminal, though it may also launch a graphical window if the
 	environment supports it. Defaults to *$EDITOR*, or *vi*(1).
 
+*header-layout*
+	Defines the default headers to display when composing a message. To display
+	multiple headers in the same row, separate them with a pipe, e.g. "To|From".
+
+	Default: To|From,Subject
+
 ## FILTERS
 
 Filters allow you to pipe an email body through a shell command to render
diff --git a/widgets/aerc.go b/widgets/aerc.go
index 3cf1f647..050ba77b 100644
--- a/widgets/aerc.go
+++ b/widgets/aerc.go
@@ -353,7 +353,7 @@ func (aerc *Aerc) Mailto(addr *url.URL) error {
 		}
 	}
 	composer := NewComposer(aerc.Config(),
-		acct.AccountConfig(), acct.Worker()).Defaults(defaults)
+		acct.AccountConfig(), acct.Worker(), defaults)
 	composer.FocusSubject()
 	title := "New email"
 	if subj, ok := defaults["Subject"]; ok {
@@ -361,7 +361,7 @@ func (aerc *Aerc) Mailto(addr *url.URL) error {
 		composer.FocusTerminal()
 	}
 	tab := aerc.NewTab(composer, title)
-	composer.OnSubjectChange(func(subject string) {
+	composer.OnHeaderChange("Subject", func(subject string) {
 		if subject == "" {
 			tab.Name = "New email"
 		} else {
diff --git a/widgets/compose.go b/widgets/compose.go
index 82778114..b45892f4 100644
--- a/widgets/compose.go
+++ b/widgets/compose.go
@@ -24,11 +24,7 @@ import (
 )
 
 type Composer struct {
-	headers struct {
-		from    *headerEditor
-		subject *headerEditor
-		to      *headerEditor
-	}
+	editors map[string]*headerEditor
 
 	acct   *config.AccountConfig
 	config *config.AercConfig
@@ -45,77 +41,93 @@ type Composer struct {
 	focused   int
 }
 
-// TODO: Let caller configure headers, initial body (for replies), etc
 func NewComposer(conf *config.AercConfig,
-	acct *config.AccountConfig, worker *types.Worker) *Composer {
+	acct *config.AccountConfig, worker *types.Worker, defaults map[string]string) *Composer {
+
+	if defaults == nil {
+		defaults = make(map[string]string)
+	}
+	if from := defaults["From"]; from == "" {
+		defaults["From"] = acct.From
+	}
+
+	layout, editors, focusable := buildComposeHeader(conf.Compose.HeaderLayout, defaults)
+
+	header, headerHeight := layout.grid(
+		func(header string) ui.Drawable { return editors[header] },
+	)
 
 	grid := ui.NewGrid().Rows([]ui.GridSpec{
-		{ui.SIZE_EXACT, 3},
-		{ui.SIZE_WEIGHT, 1},
-	}).Columns([]ui.GridSpec{
+		{ui.SIZE_EXACT, headerHeight},
 		{ui.SIZE_WEIGHT, 1},
-	})
-
-	// TODO: let user specify extra headers to edit by default
-	headers := ui.NewGrid().Rows([]ui.GridSpec{
-		{ui.SIZE_EXACT, 1}, // To/From
-		{ui.SIZE_EXACT, 1}, // Subject
-		{ui.SIZE_EXACT, 1}, // [spacer]
 	}).Columns([]ui.GridSpec{
 		{ui.SIZE_WEIGHT, 1},
-		{ui.SIZE_WEIGHT, 1},
 	})
 
-	to := newHeaderEditor("To", "")
-	from := newHeaderEditor("From", acct.From)
-	subject := newHeaderEditor("Subject", "")
-	headers.AddChild(to).At(0, 0)
-	headers.AddChild(from).At(0, 1)
-	headers.AddChild(subject).At(1, 0).Span(1, 2)
-	headers.AddChild(ui.NewFill(' ')).At(2, 0).Span(1, 2)
-
 	email, err := ioutil.TempFile("", "aerc-compose-*.eml")
 	if err != nil {
 		// TODO: handle this better
 		return nil
 	}
 
-	grid.AddChild(headers).At(0, 0)
+	grid.AddChild(header).At(0, 0)
 
 	c := &Composer{
-		acct:   acct,
-		config: conf,
-		email:  email,
-		grid:   grid,
-		worker: worker,
+		editors:  editors,
+		acct:     acct,
+		config:   conf,
+		defaults: defaults,
+		email:    email,
+		grid:     grid,
+		worker:   worker,
 		// You have to backtab to get to "From", since you usually don't edit it
 		focused:   1,
-		focusable: []ui.DrawableInteractive{from, to, subject},
+		focusable: focusable,
 	}
-	c.headers.to = to
-	c.headers.from = from
-	c.headers.subject = subject
+
 	c.ShowTerminal()
 
 	return c
 }
 
-// Sets additional headers to be added to the outgoing email (e.g. In-Reply-To)
-func (c *Composer) Defaults(defaults map[string]string) *Composer {
-	c.defaults = defaults
-	if to, ok := defaults["To"]; ok {
-		c.headers.to.input.Set(to)
-		delete(defaults, "To")
+func buildComposeHeader(layout HeaderLayout, defaults map[string]string) (newLayout HeaderLayout, editors map[string]*headerEditor, focusable []ui.DrawableInteractive) {
+	editors = make(map[string]*headerEditor)
+	focusable = make([]ui.DrawableInteractive, 0)
+
+	for _, row := range layout {
+		for _, h := range row {
+			e := newHeaderEditor(h, "")
+			editors[h] = e
+			switch h {
+			case "From":
+				// Prepend From to support backtab
+				focusable = append([]ui.DrawableInteractive{e}, focusable...)
+			default:
+				focusable = append(focusable, e)
+			}
+		}
 	}
-	if from, ok := defaults["From"]; ok {
-		c.headers.from.input.Set(from)
-		delete(defaults, "From")
+
+	// Add Cc/Bcc editors to layout if in defaults and not already visible
+	for _, h := range []string{"Cc", "Bcc"} {
+		if val, ok := defaults[h]; ok && val != "" {
+			if _, ok := editors[h]; !ok {
+				e := newHeaderEditor(h, "")
+				editors[h] = e
+				focusable = append(focusable, e)
+				layout = append(layout, []string{h})
+			}
+		}
 	}
-	if subject, ok := defaults["Subject"]; ok {
-		c.headers.subject.input.Set(subject)
-		delete(defaults, "Subject")
+
+	// Set default values for all editors
+	for key := range editors {
+		if val, ok := defaults[key]; ok {
+			editors[key].input.Set(val)
+			delete(defaults, key)
+		}
 	}
-	return c
+	return layout, editors, focusable
 }
 
 // Note: this does not reload the editor. You must call this before the first
@@ -133,7 +145,7 @@ func (c *Composer) FocusTerminal() *Composer {
 		return c
 	}
 	c.focusable[c.focused].Focus(false)
-	c.focused = 3
+	c.focused = len(c.editors)
 	c.focusable[c.focused].Focus(true)
 	return c
 }
@@ -145,10 +157,13 @@ func (c *Composer) FocusSubject() *Composer {
 	return c
 }
 
-func (c *Composer) OnSubjectChange(fn func(subject string)) {
-	c.headers.subject.OnChange(func() {
-		fn(c.headers.subject.input.String())
-	})
+// OnHeaderChange registers an OnChange callback for the specified header.
+func (c *Composer) OnHeaderChange(header string, fn func(subject string)) {
+	if editor, ok := c.editors[header]; ok {
+		editor.OnChange(func() {
+			fn(editor.input.String())
+		})
+	}
 }
 
 func (c *Composer) Draw(ctx *ui.Context) {
@@ -209,7 +224,9 @@ func (c *Composer) Worker() *types.Worker {
 
 func (c *Composer) PrepareHeader() (*mail.Header, []string, error) {
 	// Extract headers from the email, if present
-	c.email.Seek(0, os.SEEK_SET)
+	if err := c.reloadEmail(); err != nil {
+		return nil, nil, err
+	}
 	var (
 		rcpts  []string
 		header mail.Header
@@ -224,23 +241,62 @@ func (c *Composer) PrepareHeader() (*mail.Header, []string, error) {
 	// Update headers
 	mhdr := (*message.Header)(&header.Header)
 	mhdr.SetText("Message-Id", mail.GenerateMessageID())
-	if subject, _ := header.Subject(); subject == "" {
-		header.SetSubject(c.headers.subject.input.String())
+
+	headerKeys := make([]string, 0, len(c.editors))
+	for key := range c.editors {
+		headerKeys = append(headerKeys, key)
 	}
-	if date, err := header.Date(); err != nil || date == (time.Time{}) {
-		header.SetDate(time.Now())
+	// Ensure headers which require special processing are included.
+	for _, key := range []string{"To", "From", "Cc", "Bcc", "Subject", "Date"} {
+		if _, ok := c.editors[key]; !ok {
+			headerKeys = append(headerKeys, key)
+		}
 	}
-	from := c.headers.from.input.String()
-	from_addrs, err := gomail.ParseAddressList(from)
-	if err != nil {
-		return nil, nil, errors.Wrapf(err, "ParseAddressList(%s)", from)
-	} else {
-		var simon_from []*mail.Address
-		for _, addr := range from_addrs {
-			simon_from = append(simon_from, (*mail.Address)(addr))
+
+	for _, h := range headerKeys {
+		val := ""
+		editor, ok := c.editors[h]
+		if ok {
+			val = editor.input.String()
+		} else {
+			val, _ = mhdr.Text(h)
+		}
+		switch h {
+		case "Subject":
+			if subject, _ := header.Subject(); subject == "" {
+				header.SetSubject(val)
+			}
+		case "Date":
+			if date, err := header.Date(); err != nil || date == (time.Time{}) {
+				header.SetDate(time.Now())
+			}
+		case "From", "To", "Cc", "Bcc": // Address headers
+			if val != "" {
+				hdrRcpts, err := gomail.ParseAddressList(val)
+				if err != nil {
+					return nil, nil, errors.Wrapf(err, "ParseAddressList(%s)", val)
+				}
+				edRcpts := make([]*mail.Address, len(hdrRcpts))
+				for i, addr := range hdrRcpts {
+					edRcpts[i] = (*mail.Address)(addr)
+				}
+				header.SetAddressList(h, edRcpts)
+				if h != "From" {
+					for _, addr := range edRcpts {
+						rcpts = append(rcpts, addr.Address)
+					}
+				}
+			}
+		default:
+			// Handle user configured header editors.
+			if ok && !mhdr.Header.Has(h) {
+				if val := editor.input.String(); val != "" {
+					mhdr.SetText(h, val)
+				}
+			}
 		}
-		header.SetAddressList("From", simon_from)
 	}
+
 	// Merge in additional headers
 	txthdr := mhdr.Header
 	for key, value := range c.defaults {
@@ -248,56 +304,14 @@ func (c *Composer) PrepareHeader() (*mail.Header, []string, error) {
 			mhdr.SetText(key, value)
 		}
 	}
-	if to := c.headers.to.input.String(); to != "" {
-		// Dammit Simon, this branch is 3x as long as it ought to be because
-		// your types aren't compatible enough with each other
-		to_rcpts, err := gomail.ParseAddressList(to)
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "ParseAddressList(%s)", to)
-		}
-		ed_rcpts, err := header.AddressList("To")
-		if err != nil {
-			return nil, nil, errors.Wrap(err, "AddressList(To)")
-		}
-		for _, addr := range to_rcpts {
-			ed_rcpts = append(ed_rcpts, (*mail.Address)(addr))
-		}
-		header.SetAddressList("To", ed_rcpts)
-		for _, addr := range ed_rcpts {
-			rcpts = append(rcpts, addr.Address)
-		}
-	}
-	if cc, _ := mhdr.Text("Cc"); cc != "" {
-		cc_rcpts, err := gomail.ParseAddressList(cc)
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "ParseAddressList(%s)", cc)
-		}
-		// TODO: Update when the user inputs Cc's through the UI
-		for _, addr := range cc_rcpts {
-			rcpts = append(rcpts, addr.Address)
-		}
-	}
-	if bcc, _ := mhdr.Text("Bcc"); bcc != "" {
-		bcc_rcpts, err := gomail.ParseAddressList(bcc)
-		if err != nil {
-			return nil, nil, errors.Wrapf(err, "ParseAddressList(%s)", bcc)
-		}
-		// TODO: Update when the user inputs Bcc's through the UI
-		for _, addr := range bcc_rcpts {
-			rcpts = append(rcpts, addr.Address)
-		}
-	}
+
 	return &header, rcpts, nil
 }
 
 func (c *Composer) WriteMessage(header *mail.Header, writer io.Writer) error {
-	name := c.email.Name()
-	c.email.Close()
-	file, err := os.Open(name)
-	if err != nil {
-		return errors.Wrap(err, "FileOpen")
+	if err := c.reloadEmail(); err != nil {
+		return err
 	}
-	c.email = file
 	var body io.Reader
 	reader, err := mail.CreateReader(c.email)
 	if err == nil {
@@ -472,6 +486,17 @@ func (c *Composer) NextField() {
 	c.focusable[c.focused].Focus(true)
 }
 
+func (c *Composer) reloadEmail() error {
+	name := c.email.Name()
+	c.email.Close()
+	file, err := os.Open(name)
+	if err != nil {
+		return errors.Wrap(err, "ReloadEmail")
+	}
+	c.email = file
+	return nil
+}
+
 type headerEditor struct {
 	name  string
 	input *ui.TextInput
diff --git a/widgets/headerlayout.go b/widgets/headerlayout.go
new file mode 100644
index 00000000..c6e61615
--- /dev/null
+++ b/widgets/headerlayout.go
@@ -0,0 +1,41 @@
+package widgets
+
+import (
+	"git.sr.ht/~sircmpwn/aerc/lib/ui"
+	"git.sr.ht/~sircmpwn/aerc/models"
+)
+
+type HeaderLayout [][]string
+
+// forMessage returns a filtered header layout, removing rows whose headers
+// do not appear in the provided message.
+func (layout HeaderLayout) forMessage(msg *models.MessageInfo) HeaderLayout {
+	headers := msg.RFC822Headers
+	result := make(HeaderLayout, 0, len(layout))
+	for _, row := range layout {
+		// To preserve layout alignment, only hide rows if all columns are empty
+		for _, col := range row {
+			if headers.Get(col) != "" {
+				result = append(result, row)
+				break
+			}
+		}
+	}
+	return result
+}
+
+// grid builds a ui grid, populating each cell by calling a callback function
+// with the current header string.
+func (layout HeaderLayout) grid(cb func(string) ui.Drawable) (grid *ui.Grid, height int) {
+	rowCount := len(layout) + 1 // extra row for spacer
+	grid = ui.MakeGrid(rowCount, 1, ui.SIZE_EXACT, ui.SIZE_WEIGHT)
+	for i, cols := range layout {
+		r := ui.MakeGrid(1, len(cols), ui.SIZE_EXACT, ui.SIZE_WEIGHT)
+		for j, col := range cols {
+			r.AddChild(cb(col)).At(0, j)
+		}
+		grid.AddChild(r).At(i, 0)
+	}
+	grid.AddChild(ui.NewFill(' ')).At(rowCount-1, 0)
+	return grid, rowCount
+}
diff --git a/widgets/msgviewer.go b/widgets/msgviewer.go
index 7d928616..5b97f6f1 100644
--- a/widgets/msgviewer.go
+++ b/widgets/msgviewer.go
@@ -46,7 +46,16 @@ type PartSwitcher struct {
 
 func NewMessageViewer(acct *AccountView, conf *config.AercConfig,
 	store *lib.MessageStore, msg *models.MessageInfo) *MessageViewer {
-	header, headerHeight := createHeader(msg, conf.Viewer.HeaderLayout)
+
+	layout := HeaderLayout(conf.Viewer.HeaderLayout).forMessage(msg)
+	header, headerHeight := layout.grid(
+		func(header string) ui.Drawable {
+			return &HeaderView{
+				Name:  header,
+				Value: fmtHeader(msg, header),
+			}
+		},
+	)
 
 	grid := ui.NewGrid().Rows([]ui.GridSpec{
 		{ui.SIZE_EXACT, headerHeight},
@@ -78,42 +87,6 @@ func NewMessageViewer(acct *AccountView, conf *config.AercConfig,
 	}
 }
 
-func createHeader(msg *models.MessageInfo, layout [][]string) (grid *ui.Grid, height int) {
-	presentHeaders := presentHeaders(msg, layout)
-	rowCount := len(presentHeaders) + 1 // extra row for spacer
-	grid = ui.MakeGrid(rowCount, 1, ui.SIZE_EXACT, ui.SIZE_WEIGHT)
-	for i, cols := range presentHeaders {
-		r := ui.MakeGrid(1, len(cols), ui.SIZE_EXACT, ui.SIZE_WEIGHT)
-		for j, col := range cols {
-			r.AddChild(
-				&HeaderView{
-					Name:  col,
-					Value: fmtHeader(msg, col),
-				}).At(0, j)
-		}
-		grid.AddChild(r).At(i, 0)
-	}
-	grid.AddChild(ui.NewFill(' ')).At(rowCount-1, 0)
-	return grid, rowCount
-}
-
-// presentHeaders returns a filtered header layout, removing rows whose headers
-// do not appear in the provided message.
-func presentHeaders(msg *models.MessageInfo, layout [][]string) [][]string {
-	headers := msg.RFC822Headers
-	result := make([][]string, 0, len(layout))
-	for _, row := range layout {
-		// To preserve layout alignment, only hide rows if all columns are empty
-		for _, col := range row {
-			if headers.Get(col) != "" {
-				result = append(result, row)
-				break
-			}
-		}
-	}
-	return result
-}
-
 func fmtHeader(msg *models.MessageInfo, header string) string {
 	switch header {
 	case "From":