complete: allow disabling automatic completion

Allow setting complete-min-chars = manual to disable automatic
completion.

Changelog-added: Setting `complete-min-chars=manual` in `aerc.conf` now
 disables automatic completion, leaving only manually triggered
 completion.
Signed-off-by: Robin Jarry <robin@jarry.cc>
Reviewed-by: Tim Culverhouse <tim@timculverhouse.com>

config/aerc.conf

@@ -241,6 +241,10 @@
 # The minimum required characters to allow auto-completion to be triggered after
 # completion-delay.
 #
+# Setting this to "manual" disables automatic completion, leaving only the
+# manually triggered completion with the $complete key (see aerc-binds(5) for
+# more details).
+#
 # Default: 1
 #completion-min-chars=1
 

config/ui.go

@@ -3,6 +3,7 @@ package config
 import (
 	"bytes"
 	"fmt"
+	"math"
 	"path"
 	"regexp"
 	"strconv"
@@ -66,7 +67,7 @@ type UIConfig struct {
 	Sort                          []string      `ini:"sort" delim:" "`
 	NextMessageOnDelete           bool          `ini:"next-message-on-delete" default:"true"`
 	CompletionDelay               time.Duration `ini:"completion-delay" default:"250ms"`
-	CompletionMinChars            int           `ini:"completion-min-chars" default:"1"`
+	CompletionMinChars            int           `ini:"completion-min-chars" default:"1" parse:"ParseCompletionMinChars"`
 	CompletionPopovers            bool          `ini:"completion-popovers" default:"true"`
 	StyleSetDirs                  []string      `ini:"stylesets-dirs" delim:":"`
 	StyleSetName                  string        `ini:"styleset-name" default:"default"`
@@ -317,6 +318,15 @@ func (*UIConfig) ParseIndexColumns(section *ini.Section, key *ini.Key) ([]*Colum
 	return ParseColumnDefs(key, section)
 }
 
+const MANUAL_COMPLETE = math.MaxInt
+
+func (*UIConfig) ParseCompletionMinChars(section *ini.Section, key *ini.Key) (int, error) {
+	if key.String() == "manual" {
+		return MANUAL_COMPLETE, nil
+	}
+	return key.Int()
+}
+
 var indexFmtRegexp = regexp.MustCompile(`%(-?\d+)?(\.\d+)?([ACDFRTZadfgilnrstuv])`)
 
 func convertIndexFormat(indexFormat string) ([]*ColumnDef, error) {

doc/aerc-config.5.scd

@@ -283,6 +283,10 @@ These options are configured in the *[ui]* section of _aerc.conf_.
 	The minimum required characters to allow auto-completion to be triggered
 	after *completion-delay*.
 
+	Setting this to _manual_ disables automatic completion, leaving only the
+	manually triggered completion with the *$complete* key (see
+	*aerc-binds*(5) for more details).
+
 	Default: _1_
 
 *border-char-vertical* = _"<char>"_++

lib/ui/textinput.go

@@ -308,6 +308,10 @@ func (ti *TextInput) updateCompletions() {
 		// no completer
 		return
 	}
+	if ti.completeMinChars == config.MANUAL_COMPLETE {
+		// only manually triggered completion
+		return
+	}
 	if ti.completeDebouncer == nil {
 		ti.completeDebouncer = time.AfterFunc(ti.completeDelay, func() {
 			defer log.PanicHandler()