From dd6590a0fda614fa2fb0ca9e4ad11b086393372e Mon Sep 17 00:00:00 2001
From: Akshay Nair <phenax5@gmail.com>
Date: Sun, 16 Mar 2025 20:53:33 +0530
Subject: Add simple key sequence parser

---
 include/keymap/KeySeqParser.hpp | 20 +++++++++++
 spec/KeySeqParserSpec.cpp       | 52 +++++++++++++++++++++++++++
 src/keymap/KeySeqParser.cpp     | 79 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 151 insertions(+)
 create mode 100644 include/keymap/KeySeqParser.hpp
 create mode 100644 spec/KeySeqParserSpec.cpp
 create mode 100644 src/keymap/KeySeqParser.cpp

diff --git a/include/keymap/KeySeqParser.hpp b/include/keymap/KeySeqParser.hpp
new file mode 100644
index 0000000..aefcb62
--- /dev/null
+++ b/include/keymap/KeySeqParser.hpp
@@ -0,0 +1,20 @@
+#pragma once
+
+#include <QtCore/qnamespace.h>
+#include <QtCore>
+
+struct KeyChord {
+  Qt::KeyboardModifiers mod;
+  Qt::Key key;
+};
+bool operator==(const KeyChord a, const KeyChord b);
+
+class KeySeqParser {
+public:
+  KeySeqParser();
+
+  QList<KeyChord> parse(QString keySequence);
+
+private:
+  Qt::Key parseKey(QString keyName);
+};
diff --git a/spec/KeySeqParserSpec.cpp b/spec/KeySeqParserSpec.cpp
new file mode 100644
index 0000000..a29c97e
--- /dev/null
+++ b/spec/KeySeqParserSpec.cpp
@@ -0,0 +1,52 @@
+#include "testUtils.h"
+#include <QtCore/qnamespace.h>
+#include <QtCore>
+
+#include "keymap/KeySeqParser.hpp"
+
+class KeySeqParserSpec : public QObject {
+  Q_OBJECT
+
+private slots:
+  void testThings() {
+    context("when mix of upper/lower cases");
+    it("parses keys ignoring the casing") {
+      KeySeqParser parser;
+
+      QList<KeyChord> keys = parser.parse("<C-tab><c-tAb><c-Tab>");
+
+      QList<KeyChord> expectedKeys = {
+          {.mod = Qt::ControlModifier, .key = Qt::Key_Tab},
+          {.mod = Qt::ControlModifier, .key = Qt::Key_Tab},
+          {.mod = Qt::ControlModifier, .key = Qt::Key_Tab},
+      };
+      QCOMPARE(keys, expectedKeys);
+    }
+
+    context("when input contains individual keys");
+    it("parses the characters") {
+      KeySeqParser parser;
+
+      QList<KeyChord> keys = parser.parse("ab<c><s><sPace><tab><esC>z");
+
+      for (auto &k : keys) {
+        qDebug() << k.key << k.mod;
+      }
+
+      QList<KeyChord> expectedKeys = {
+          {.mod = Qt::NoModifier, .key = Qt::Key_A},
+          {.mod = Qt::NoModifier, .key = Qt::Key_B},
+          {.mod = Qt::NoModifier, .key = Qt::Key_C},
+          {.mod = Qt::NoModifier, .key = Qt::Key_S},
+          {.mod = Qt::NoModifier, .key = Qt::Key_Space},
+          {.mod = Qt::NoModifier, .key = Qt::Key_Tab},
+          {.mod = Qt::NoModifier, .key = Qt::Key_Escape},
+          {.mod = Qt::NoModifier, .key = Qt::Key_Z},
+      };
+      QCOMPARE(keys, expectedKeys);
+    }
+  }
+};
+
+QTEST_REGISTER(KeySeqParserSpec)
+#include "KeySeqParserSpec.moc"
diff --git a/src/keymap/KeySeqParser.cpp b/src/keymap/KeySeqParser.cpp
new file mode 100644
index 0000000..c5534eb
--- /dev/null
+++ b/src/keymap/KeySeqParser.cpp
@@ -0,0 +1,79 @@
+#include <QWidget>
+#include <QtCore>
+#include <algorithm>
+
+#include "keymap/KeySeqParser.hpp"
+
+bool operator==(const KeyChord a, const KeyChord b) {
+  return a.mod == b.mod && a.key == b.key;
+}
+
+KeySeqParser::KeySeqParser() {}
+
+QList<KeyChord> KeySeqParser::parse(QString keySequence) {
+  QList<KeyChord> keyChords;
+  KeyChord lastKey;
+
+  // TODO: Refactor
+  // TODO: Support <C-S-t>
+  keySequence = keySequence.toLower();
+  while (!keySequence.isEmpty()) {
+    int skipCount = 1;
+    if (keySequence.startsWith("<c-")) {
+      int nextClosing = keySequence.indexOf('>');
+      auto keyName = keySequence.sliced(3, nextClosing - 3);
+      lastKey.mod = lastKey.mod | Qt::KeyboardModifier::ControlModifier;
+      lastKey.key = parseKey(keyName);
+      skipCount = nextClosing + 1;
+    } else if (keySequence.startsWith("<s-")) {
+      int nextClosing = keySequence.indexOf('>');
+      auto keyName = keySequence.sliced(3, nextClosing - 3);
+      lastKey.mod = lastKey.mod | Qt::KeyboardModifier::ShiftModifier;
+      lastKey.key = parseKey(keyName);
+      skipCount = nextClosing + 1;
+    } else if (keySequence.startsWith("<")) {
+      int nextClosing = keySequence.indexOf('>');
+      auto keyName = keySequence.sliced(1, nextClosing - 1);
+      lastKey.mod = Qt::KeyboardModifier::NoModifier;
+      lastKey.key = parseKey(keyName);
+      skipCount = nextClosing + 1;
+    } else {
+      auto keyName = keySequence.first(1);
+      lastKey.mod = Qt::KeyboardModifier::NoModifier;
+      lastKey.key = parseKey(keyName);
+    }
+
+    keySequence.slice(std::max(1, skipCount));
+    keyChords.push_back(lastKey);
+    lastKey = KeyChord();
+  }
+
+  return keyChords;
+}
+
+Qt::Key KeySeqParser::parseKey(QString keyName) {
+  if (keyName.length() == 0)
+    return Qt::Key_T; // TODO: tmp
+
+  if (keyName.length() == 1) {
+    char c = keyName.toStdString().at(0);
+    return Qt::Key(Qt::Key_A + (c - 'a'));
+  }
+
+  if (keyName == "space")
+    return Qt::Key_Space;
+
+  if (keyName == "cr")
+    return Qt::Key_Return;
+
+  if (keyName == "esc")
+    return Qt::Key_Escape;
+
+  if (keyName == "bs")
+    return Qt::Key_Backspace;
+
+  if (keyName == "tab")
+    return Qt::Key_Tab;
+
+  return Qt::Key_T;
+}
-- 
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