From f8086500a0737c49267cb460686a4ff8ab938da5 Mon Sep 17 00:00:00 2001
From: ShikiSuen <shikisuen@outlook.com>
Date: Sat, 9 Jul 2022 10:24:15 +0800
Subject: [PATCH] KeyHandler // Implement Alt+Fwd/Bwd support.

---
 .../ControllerModules/KeyHandler_Core.swift   | 24 +++++++++++++++----
 .../ControllerModules/KeyHandler_States.swift | 21 ++++++++++++++++
 2 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/Source/Modules/ControllerModules/KeyHandler_Core.swift b/Source/Modules/ControllerModules/KeyHandler_Core.swift
index 751e4005..0cdf9c6a 100644
--- a/Source/Modules/ControllerModules/KeyHandler_Core.swift
+++ b/Source/Modules/ControllerModules/KeyHandler_Core.swift
@@ -166,10 +166,10 @@ class KeyHandler {
   ///   - value: 給定之候選字字串。
   ///   - respectCursorPushing: 若該選項為 true，則會在選字之後始終將游標推送至選字厚的節錨的前方。
   func fixNode(value: String, respectCursorPushing: Bool = true) {
-    let cursorIndex = min(actualCandidateCursorIndex + (mgrPrefs.useRearCursorMode ? 1 : 0), compositorLength)
+    let adjustedIndex = max(0, min(actualCandidateCursorIndex + (mgrPrefs.useRearCursorMode ? 1 : 0), compositorLength))
     // 開始讓半衰模組觀察目前的狀況。
     let selectedNode: Megrez.NodeAnchor = compositor.grid.fixNodeSelectedCandidate(
-      location: cursorIndex, value: value
+      location: adjustedIndex, value: value
     )
     // 不要針對逐字選字模式啟用臨時半衰記憶模型。
     if !mgrPrefs.useSCPCTypingMode {
@@ -193,7 +193,7 @@ class KeyHandler {
         // 令半衰記憶模組觀測給定的三元圖。
         // 這個過程會讓半衰引擎根據當前上下文生成三元圖索引鍵。
         currentUOM.observe(
-          walkedAnchors: walkedAnchors, cursorIndex: cursorIndex, candidate: value,
+          walkedAnchors: walkedAnchors, cursorIndex: adjustedIndex, candidate: value,
           timestamp: NSDate().timeIntervalSince1970
         )
       }
@@ -206,7 +206,7 @@ class KeyHandler {
     if mgrPrefs.moveCursorAfterSelectingCandidate, respectCursorPushing {
       var nextPosition = 0
       for theAnchor in walkedAnchors {
-        if nextPosition >= cursorIndex { break }
+        if nextPosition >= adjustedIndex { break }
         nextPosition += theAnchor.spanningLength
       }
       if nextPosition <= compositorLength {
@@ -452,4 +452,20 @@ class KeyHandler {
   func deleteCompositorReadingToTheFrontOfCursor() {
     compositor.deleteReadingToTheFrontOfCursor()
   }
+
+  /// 獲取指定游標位置的鍵值長度。
+  /// - Returns: 指定游標位置的鍵值長度。
+  var keyLengthAtCurrentIndex: Int {
+    guard let node = walkedAnchors[compositorCursorIndex].node else { return 0 }
+    return node.key.split(separator: "-").count
+  }
+
+  var nextPhrasePosition: Int {
+    var nextPosition = 0
+    for theAnchor in walkedAnchors {
+      if nextPosition > actualCandidateCursorIndex { break }
+      nextPosition += theAnchor.spanningLength
+    }
+    return min(nextPosition, compositorLength)
+  }
 }
diff --git a/Source/Modules/ControllerModules/KeyHandler_States.swift b/Source/Modules/ControllerModules/KeyHandler_States.swift
index b84fad5a..c8334146 100644
--- a/Source/Modules/ControllerModules/KeyHandler_States.swift
+++ b/Source/Modules/ControllerModules/KeyHandler_States.swift
@@ -651,6 +651,15 @@ extension KeyHandler {
         errorCallback()
         stateCallback(state)
       }
+    } else if input.isOptionHold {
+      if compositorCursorIndex < compositorLength {
+        compositorCursorIndex = nextPhrasePosition
+        stateCallback(buildInputtingState)
+      } else {
+        IME.prtDebugIntel("33C3B580")
+        errorCallback()
+        stateCallback(state)
+      }
     } else {
       if compositorCursorIndex < compositorLength {
         compositorCursorIndex += 1
@@ -707,6 +716,18 @@ extension KeyHandler {
         errorCallback()
         stateCallback(state)
       }
+    } else if input.isOptionHold {
+      if compositorCursorIndex > 1 {
+        compositorCursorIndex -= 2
+        stateCallback(buildInputtingState)
+      } else if compositorCursorIndex == 1 {
+        compositorCursorIndex = 0
+        stateCallback(buildInputtingState)
+      } else {
+        IME.prtDebugIntel("8D50DD9E")
+        errorCallback()
+        stateCallback(state)
+      }
     } else {
       if compositorCursorIndex > 0 {
         compositorCursorIndex -= 1