Cthulhu is no longer a fork. Now it is a screen reader written in Golang.

internal/input/intent.go

@@ -0,0 +1,135 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package input
+
+import (
+	"strings"
+	"sync"
+	"time"
+)
+
+// Intent records only the kind of input, never the text the user typed.
+type Intent uint8
+
+const (
+	NoIntent Intent = iota
+	TypingIntent
+	LineIntent
+	WordIntent
+	CharacterIntent
+	DeleteIntent
+	OtherIntent
+)
+
+type Activity struct {
+	Selecting bool
+	Intent    Intent
+	Sequence  uint64
+	Clipboard ClipboardAction
+}
+
+type ClipboardAction uint8
+
+const (
+	NoClipboardAction ClipboardAction = iota
+	CopyAction
+	CutAction
+	PasteAction
+)
+
+type IntentTracker struct {
+	sequence  uint64
+	mutex     sync.Mutex
+	held      map[string]bool
+	intent    Intent
+	clipboard ClipboardAction
+	selecting bool
+	at        time.Time
+}
+
+func (tracker *IntentTracker) Observe(event Event) {
+	tracker.mutex.Lock()
+	defer tracker.mutex.Unlock()
+	if event.Pressed {
+		tracker.sequence++
+	}
+	if tracker.held == nil {
+		tracker.held = make(map[string]bool)
+	}
+	if event.Kind == KeyModifier {
+		tracker.held[event.Name] = event.Pressed
+		if event.Pressed {
+			tracker.intent, tracker.at = OtherIntent, time.Now()
+			tracker.clipboard = NoClipboardAction
+			tracker.selecting = false
+		}
+		return
+	}
+	if !event.Pressed {
+		return
+	}
+	ctrl := tracker.held["Control_L"] || tracker.held["Control_R"]
+	shift := tracker.held["Shift_L"] || tracker.held["Shift_R"]
+	alt := tracker.held["Alt_L"] || tracker.held["Alt_R"] || tracker.held["Meta_L"] || tracker.held["Meta_R"]
+	intent := OtherIntent
+	tracker.clipboard = NoClipboardAction
+	name := strings.TrimPrefix(event.Name, "KP_")
+	if !alt {
+		if ctrl && !shift {
+			switch strings.ToLower(name) {
+			case "c":
+				tracker.clipboard = CopyAction
+			case "x":
+				tracker.clipboard = CutAction
+			case "v":
+				tracker.clipboard = PasteAction
+			}
+		}
+		switch name {
+		case "Up", "Down", "Page_Up", "Page_Down", "Prior", "Next":
+			intent = LineIntent
+		case "Left", "Right":
+			intent = CharacterIntent
+			if ctrl {
+				intent = WordIntent
+			}
+		case "Home", "End":
+			intent = CharacterIntent
+			if ctrl {
+				intent = LineIntent
+			}
+		case "Insert", "Caps_Lock", "Num_Lock", "Scroll_Lock", "Super_L", "Super_R":
+			intent = OtherIntent
+		case "BackSpace", "Delete":
+			intent = DeleteIntent
+		default:
+			if !ctrl && (event.Name != "" && event.Kind == KeyUnknown) {
+				intent = TypingIntent
+			}
+		}
+	}
+	tracker.selecting = shift && (intent == CharacterIntent || intent == WordIntent || intent == LineIntent)
+	tracker.intent, tracker.at = intent, time.Now()
+}
+
+func (tracker *IntentTracker) RecentIntent() Intent { return tracker.RecentInput().Intent }
+
+// Reset retires held modifiers and presentation intent across secure input.
+func (tracker *IntentTracker) Reset() {
+	tracker.mutex.Lock()
+	defer tracker.mutex.Unlock()
+	clear(tracker.held)
+	tracker.intent, tracker.at = OtherIntent, time.Time{}
+	tracker.clipboard, tracker.selecting = NoClipboardAction, false
+}
+
+func (tracker *IntentTracker) RecentInput() Activity {
+	tracker.mutex.Lock()
+	defer tracker.mutex.Unlock()
+	if time.Since(tracker.at) > time.Second {
+		return Activity{}
+	}
+	return Activity{Intent: tracker.intent, Sequence: tracker.sequence, Clipboard: tracker.clipboard, Selecting: tracker.selecting}
+}