compose: allow removing headers

Allow removing headers from the compose window when edit-headers=false
(the default) with :header -d <name>.

Signed-off-by: Robin Jarry <robin@jarry.cc>
Acked-by: Koni Marti <koni.marti@gmail.com>

4 files changed, 47 insertions, 20 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2d5f4ed9..0af1cb45 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Edit email headers directly in the text editor with `[compose].edit-headers`
   in `aerc.conf` or with the `-e` flag for all compose related commands (e.g.
   `:compose`, `:forward`, `:recall`, etc.).
+- Remove headers from the compose window with `:header -d <name>`.
 
 ### Fixed
 
diff --git a/commands/compose/header.go b/commands/compose/header.go
index c512e341..59d01952 100644
--- a/commands/compose/header.go
+++ b/commands/compose/header.go
@@ -1,7 +1,6 @@
 package compose
 
 import (
-	"errors"
 	"fmt"
 	"strings"
 
@@ -30,47 +29,56 @@ func (Header) Aliases() []string {
 	return []string{"header"}
 }
 
+func (Header) Options() string {
+	return "fd"
+}
+
 func (Header) Complete(aerc *widgets.Aerc, args []string) []string {
 	return commands.CompletionFromList(aerc, headers, args)
 }
 
-func (Header) Execute(aerc *widgets.Aerc, args []string) error {
-	if len(args) < 2 {
-		return fmt.Errorf("Usage: %s [-f] field [value]", args[0])
+func (h Header) Execute(aerc *widgets.Aerc, args []string) error {
+	opts, optind, err := getopt.Getopts(args, h.Options())
+	args = args[optind:]
+	if err == nil && len(args) < 1 {
+		err = fmt.Errorf("not enough arguments")
 	}
-
-	opts, optind, err := getopt.Getopts(args, "f")
 	if err != nil {
-		return err
-	}
-
-	if len(args) < optind+1 {
-		return errors.New("command parsing failed")
+		return fmt.Errorf("%w. usage: header [-fd] <name> [<value>]", err)
 	}
 
 	var force bool = false
+	var remove bool = false
 	for _, opt := range opts {
-		if opt.Option == 'f' {
+		switch opt.Option {
+		case 'f':
 			force = true
+		case 'd':
+			remove = true
 		}
 	}
 
 	composer, _ := aerc.SelectedTabContent().(*widgets.Composer)
 
-	args[optind] = strings.TrimRight(args[optind], ":")
+	name := strings.TrimRight(args[0], ":")
+
+	if remove {
+		return composer.DelEditor(name)
+	}
 
-	value := strings.Join(args[optind+1:], " ")
+	value := strings.Join(args[1:], " ")
 
 	if !force {
 		headers, err := composer.PrepareHeader()
 		if err != nil {
 			return err
 		}
-
-		if headers.Has(args[optind]) && value != "" {
-			return fmt.Errorf("Header %s already exists", args[optind])
+		if headers.Get(name) != "" && value != "" {
+			return fmt.Errorf(
+				"Header %s is already set to %q (use -f to overwrite)",
+				name, headers.Get(name))
 		}
 	}
 
-	return composer.AddEditor(args[optind], value, false)
+	return composer.AddEditor(name, value, false)
 }
diff --git a/doc/aerc.1.scd b/doc/aerc.1.scd
index ab1333f8..5b1d36f3 100644
--- a/doc/aerc.1.scd
+++ b/doc/aerc.1.scd
@@ -640,8 +640,13 @@ message list, the message in the message viewer, etc).
 	*-n*: switch to next account
 
 *:header* [*-f*] _<name>_ [_<value>_]
-	Add a new email header. If the header already exists, *-f* must be
-	specified to replace the given value.
+*:header* [*-d*] _<name>_
+	Add a new email header to the compose window. If the header is already
+	set and is not empty, *-f* must be used to overwrite its value.
+
+	*-f*: Overwrite any existing header.
+
+	*-d*: Remove the header instead of adding it.
 
 *:encrypt*
 	Encrypt the message to all recipients. If a key for a recipient cannot
diff --git a/widgets/compose.go b/widgets/compose.go
index d1bbc547..c0f4af4f 100644
--- a/widgets/compose.go
+++ b/widgets/compose.go
@@ -1345,8 +1345,21 @@ func (c *Composer) addEditor(header string, value string, appendHeader bool) str
 	return value
 }
 
+// DelEditor removes a header editor from the compose window.
+func (c *Composer) DelEditor(header string) error {
+	c.Lock()
+	defer c.Unlock()
+	if c.editHeaders && c.editor != nil {
+		return errors.New("header should be removed directly in the text editor")
+	}
+	c.delEditor(header)
+	c.updateGrid()
+	return nil
+}
+
 func (c *Composer) delEditor(header string) {
 	header = strings.ToLower(header)
+	c.header.Del(header)
 	editor, ok := c.editors[header]
 	if !ok {
 		return