wip

internal/app/keymatch.go

@@ -40,6 +40,36 @@ type csiuKey struct {
 	event int
 }
 
+// parseSGRMouseWheel decodes the parameter run from an SGR-encoded
+// mouse press (`CSI < button ; col ; row M`) and returns a row delta
+// when the event is a scroll wheel. Wheel-up returns -wheelStep,
+// wheel-down returns +wheelStep. Modifier bits in the button code
+// (shift=4, alt=8, ctrl=16) are stripped before matching, so e.g.
+// shift+wheel still scrolls. Non-wheel buttons return false.
+func parseSGRMouseWheel(params []byte) (int, bool) {
+	const wheelStep = 3
+	// Button code runs up to the first ';'.
+	end := 0
+	for end < len(params) && params[end] != ';' {
+		end++
+	}
+	if end == 0 {
+		return 0, false
+	}
+	btn, err := strconv.Atoi(string(params[:end]))
+	if err != nil {
+		return 0, false
+	}
+	if btn&64 == 0 {
+		return 0, false
+	}
+	// Bit 0 selects up (0) vs down (1) for wheel events.
+	if btn&1 == 0 {
+		return -wheelStep, true
+	}
+	return wheelStep, true
+}
+
 // decodeCSIu parses the parameter string of a `CSI ... u` sequence.
 // The kitty shape is:
 //