fix(tui): mouse wheel ansi codes leaking into editor

1 files changed, 196 insertions, 0 deletions

diff --git a/packages/tui/input/driver.go b/packages/tui/input/driver.go
new file mode 100644
index 000000000..ded96e756
--- /dev/null
+++ b/packages/tui/input/driver.go
@@ -0,0 +1,196 @@
+//nolint:unused,revive,nolintlint
+package input
+
+import (
+	"bytes"
+	"io"
+	"unicode/utf8"
+
+	"github.com/muesli/cancelreader"
+)
+
+// Logger is a simple logger interface.
+type Logger interface {
+	Printf(format string, v ...any)
+}
+
+// win32InputState is a state machine for parsing key events from the Windows
+// Console API into escape sequences and utf8 runes, and keeps track of the last
+// control key state to determine modifier key changes. It also keeps track of
+// the last mouse button state and window size changes to determine which mouse
+// buttons were released and to prevent multiple size events from firing.
+type win32InputState struct {
+	ansiBuf                    [256]byte
+	ansiIdx                    int
+	utf16Buf                   [2]rune
+	utf16Half                  bool
+	lastCks                    uint32 // the last control key state for the previous event
+	lastMouseBtns              uint32 // the last mouse button state for the previous event
+	lastWinsizeX, lastWinsizeY int16  // the last window size for the previous event to prevent multiple size events from firing
+}
+
+// Reader represents an input event reader. It reads input events and parses
+// escape sequences from the terminal input buffer and translates them into
+// human-readable events.
+type Reader struct {
+	rd    cancelreader.CancelReader
+	table map[string]Key // table is a lookup table for key sequences.
+
+	term string // term is the terminal name $TERM.
+
+	// paste is the bracketed paste mode buffer.
+	// When nil, bracketed paste mode is disabled.
+	paste []byte
+
+	buf [256]byte // do we need a larger buffer?
+
+	// partialSeq holds incomplete escape sequences that need more data
+	partialSeq []byte
+
+	// keyState keeps track of the current Windows Console API key events state.
+	// It is used to decode ANSI escape sequences and utf16 sequences.
+	keyState win32InputState
+
+	parser Parser
+	logger Logger
+}
+
+// NewReader returns a new input event reader. The reader reads input events
+// from the terminal and parses escape sequences into human-readable events. It
+// supports reading Terminfo databases. See [Parser] for more information.
+//
+// Example:
+//
+//	r, _ := input.NewReader(os.Stdin, os.Getenv("TERM"), 0)
+//	defer r.Close()
+//	events, _ := r.ReadEvents()
+//	for _, ev := range events {
+//	  log.Printf("%v", ev)
+//	}
+func NewReader(r io.Reader, termType string, flags int) (*Reader, error) {
+	d := new(Reader)
+	cr, err := newCancelreader(r, flags)
+	if err != nil {
+		return nil, err
+	}
+
+	d.rd = cr
+	d.table = buildKeysTable(flags, termType)
+	d.term = termType
+	d.parser.flags = flags
+	return d, nil
+}
+
+// SetLogger sets a logger for the reader.
+func (d *Reader) SetLogger(l Logger) {
+	d.logger = l
+}
+
+// Read implements [io.Reader].
+func (d *Reader) Read(p []byte) (int, error) {
+	return d.rd.Read(p) //nolint:wrapcheck
+}
+
+// Cancel cancels the underlying reader.
+func (d *Reader) Cancel() bool {
+	return d.rd.Cancel()
+}
+
+// Close closes the underlying reader.
+func (d *Reader) Close() error {
+	return d.rd.Close() //nolint:wrapcheck
+}
+
+func (d *Reader) readEvents() ([]Event, error) {
+	nb, err := d.rd.Read(d.buf[:])
+	if err != nil {
+		return nil, err //nolint:wrapcheck
+	}
+
+	var events []Event
+
+	// Combine any partial sequence from previous read with new data
+	var buf []byte
+	if len(d.partialSeq) > 0 {
+		buf = make([]byte, len(d.partialSeq)+nb)
+		copy(buf, d.partialSeq)
+		copy(buf[len(d.partialSeq):], d.buf[:nb])
+		d.partialSeq = nil // clear the partial sequence
+	} else {
+		buf = d.buf[:nb]
+	}
+
+	// Lookup table first
+	if bytes.HasPrefix(buf, []byte{'\x1b'}) {
+		if k, ok := d.table[string(buf)]; ok {
+			if d.logger != nil {
+				d.logger.Printf("input: %q", buf)
+			}
+			events = append(events, KeyPressEvent(k))
+			return events, nil
+		}
+	}
+
+	var i int
+	for i < len(buf) {
+		nb, ev := d.parser.parseSequence(buf[i:])
+		if d.logger != nil && nb > 0 {
+			d.logger.Printf("input: %q", buf[i:i+nb])
+		}
+
+		// Handle incomplete sequences - when parseSequence returns (0, nil)
+		// it means we need more data to complete the sequence
+		if nb == 0 && ev == nil {
+			// Store the remaining data for the next read
+			remaining := len(buf) - i
+			if remaining > 0 {
+				d.partialSeq = make([]byte, remaining)
+				copy(d.partialSeq, buf[i:])
+			}
+			break
+		}
+
+		// Handle bracketed-paste
+		if d.paste != nil {
+			if _, ok := ev.(PasteEndEvent); !ok {
+				d.paste = append(d.paste, buf[i])
+				i++
+				continue
+			}
+		}
+
+		switch ev.(type) {
+		case UnknownEvent:
+			// If the sequence is not recognized by the parser, try looking it up.
+			if k, ok := d.table[string(buf[i:i+nb])]; ok {
+				ev = KeyPressEvent(k)
+			}
+		case PasteStartEvent:
+			d.paste = []byte{}
+		case PasteEndEvent:
+			// Decode the captured data into runes.
+			var paste []rune
+			for len(d.paste) > 0 {
+				r, w := utf8.DecodeRune(d.paste)
+				if r != utf8.RuneError {
+					paste = append(paste, r)
+				}
+				d.paste = d.paste[w:]
+			}
+			d.paste = nil // reset the buffer
+			events = append(events, PasteEvent(paste))
+		case nil:
+			i++
+			continue
+		}
+
+		if mevs, ok := ev.(MultiEvent); ok {
+			events = append(events, []Event(mevs)...)
+		} else {
+			events = append(events, ev)
+		}
+		i += nb
+	}
+
+	return events, nil
+}