Add code completion popup shortcut to go back up a page

src/main/kotlin/com/chylex/intellij/keyboardmaster/configuration/PluginConfigurable.kt

@@ -10,6 +10,7 @@ class PluginConfigurable : Configurable {
 	
 	private val codeCompletionItemShortcuts = JBTextField(20)
 	private val codeCompletionNextPageShortcut = JBTextField(2)
+	private val codeCompletionPrevPageShortcut = JBTextField(2)
 	
 	override fun getDisplayName(): String {
 		return "Keyboard Master"
@@ -20,6 +21,7 @@ class PluginConfigurable : Configurable {
 			titledRow("Code Completion") {
 				row("Item shortcuts:") { component(codeCompletionItemShortcuts) }
 				row("Next page shortcut:") { component(codeCompletionNextPageShortcut) }
+				row("Prev page shortcut:") { component(codeCompletionPrevPageShortcut) }
 			}
 		}
 		
@@ -34,6 +36,7 @@ class PluginConfigurable : Configurable {
 		PluginConfiguration.modify {
 			it.codeCompletionItemShortcuts = codeCompletionItemShortcuts.text
 			it.codeCompletionNextPageShortcut = codeCompletionNextPageShortcut.text.firstOrNull()?.code ?: 0
+			it.codeCompletionPrevPageShortcut = codeCompletionPrevPageShortcut.text.firstOrNull()?.code ?: 0
 		}
 	}
 	
@@ -41,6 +44,7 @@ class PluginConfigurable : Configurable {
 		PluginConfiguration.read {
 			codeCompletionItemShortcuts.text = it.codeCompletionItemShortcuts
 			codeCompletionNextPageShortcut.text = it.codeCompletionNextPageShortcut.let { code -> if (code == 0) "" else code.toChar().toString() }
+			codeCompletionPrevPageShortcut.text = it.codeCompletionPrevPageShortcut.let { code -> if (code == 0) "" else code.toChar().toString() }
 		}
 	}
 }

src/main/kotlin/com/chylex/intellij/keyboardmaster/configuration/PluginConfiguration.kt

@@ -14,6 +14,7 @@ import com.intellij.util.xmlb.XmlSerializerUtil
 class PluginConfiguration : PersistentStateComponent<PluginConfiguration> {
 	var codeCompletionItemShortcuts = "123456789"
 	var codeCompletionNextPageShortcut: Int = '0'.code
+	var codeCompletionPrevPageShortcut: Int = 0
 	
 	companion object {
 		private val instance: PluginConfiguration
@@ -32,7 +33,7 @@ class PluginConfiguration : PersistentStateComponent<PluginConfiguration> {
 		}
 		
 		private fun update(instance: PluginConfiguration) = with(instance) {
-			CodeCompletionPopupConfiguration.updateShortcuts(codeCompletionItemShortcuts, codeCompletionNextPageShortcut)
+			CodeCompletionPopupConfiguration.updateShortcuts(codeCompletionItemShortcuts, codeCompletionNextPageShortcut, codeCompletionPrevPageShortcut)
 		}
 	}
 	

src/main/kotlin/com/chylex/intellij/keyboardmaster/feature/codeCompletion/CodeCompletionPopupConfiguration.kt

@@ -5,7 +5,8 @@ import com.intellij.util.containers.IntIntHashMap
 
 object CodeCompletionPopupConfiguration {
 	const val SHORTCUT_NONE = -1
-	const val SHORTCUT_NEXT_PAGE = 0
+	const val SHORTCUT_NEXT_PAGE = -2
+	const val SHORTCUT_PREV_PAGE = -3
 	
 	private val charToShortcutMap = IntIntHashMap(16, SHORTCUT_NONE)
 	private var hintTexts = mutableListOf<String>()
@@ -17,13 +18,19 @@ object CodeCompletionPopupConfiguration {
 		PluginConfiguration.load()
 	}
 	
-	fun updateShortcuts(itemShortcutChars: String, nextPageShortcutCode: Int) {
+	fun updateShortcuts(itemShortcutChars: String, nextPageShortcutCode: Int, previousPageShortcutCode: Int) {
 		charToShortcutMap.clear()
+		
 		if (nextPageShortcutCode != 0) {
 			charToShortcutMap[nextPageShortcutCode] = SHORTCUT_NEXT_PAGE
 		}
+		
+		if (previousPageShortcutCode != 0) {
+			charToShortcutMap[previousPageShortcutCode] = SHORTCUT_PREV_PAGE
+		}
+		
 		for ((index, char) in itemShortcutChars.withIndex()) {
-			charToShortcutMap[char.code] = index + 1
+			charToShortcutMap[char.code] = index
 		}
 		
 		hintTexts.clear()

src/main/kotlin/com/chylex/intellij/keyboardmaster/feature/codeCompletion/CodeCompletionPopupKeyHandler.kt

@@ -8,6 +8,7 @@ import com.intellij.openapi.actionSystem.DataContext
 import com.intellij.openapi.editor.Editor
 import com.intellij.openapi.editor.actionSystem.TypedActionHandler
 import com.intellij.ui.ScrollingUtil
+import javax.swing.ListModel
 
 /**
  * Handles configured key bindings inside a code completion popup menu.
@@ -30,30 +31,44 @@ class CodeCompletionPopupKeyHandler(originalHandler: TypedActionHandler?) : Type
 			return false
 		}
 		
-		val offset = CodeCompletionPopupListener.getLookupOffset(lookup)
+		val offset = CodeCompletionPopupListener.getPageOffset(lookup)
 		
 		if (shortcutItem == CodeCompletionPopupConfiguration.SHORTCUT_NEXT_PAGE) {
-			val list = lookup.list
-			val itemCount = list.model.size
-			
-			val shortcutCount = CodeCompletionPopupConfiguration.itemShortcutCount
-			val topIndex = (offset + shortcutCount).let { if (it >= itemCount) 0 else it }
-			
-			CodeCompletionPopupListener.setLookupOffset(lookup, topIndex)
-			lookup.selectedIndex = topIndex
-			ScrollingUtil.ensureRangeIsVisible(list, topIndex, topIndex + shortcutCount - 1)
-			lookup.markSelectionTouched()
-			lookup.refreshUi(false, true)
+			setPageOffset(lookup) {
+				val newTopIndex = offset + CodeCompletionPopupConfiguration.itemShortcutCount
+				if (newTopIndex >= it.size) 0 else newTopIndex
+			}
+		}
+		else if (shortcutItem == CodeCompletionPopupConfiguration.SHORTCUT_PREV_PAGE) {
+			setPageOffset(lookup) {
+				val newTopIndex = offset - CodeCompletionPopupConfiguration.itemShortcutCount
+				if (newTopIndex < 0) 0 else newTopIndex
+			}
 		}
 		else {
-			if (!lookup.isFocused) {
-				lookup.lookupFocusDegree = LookupFocusDegree.FOCUSED
-				lookup.refreshUi(false, true)
-			}
-			
-			lookup.selectedIndex = offset + shortcutItem - 1
+			selectItem(lookup, offset + shortcutItem)
 		}
 		
 		return true
 	}
+	
+	private inline fun setPageOffset(lookup: LookupImpl, getNewTopIndex: (ListModel<*>) -> Int) {
+		val list = lookup.list
+		val newTopIndex = getNewTopIndex(list.model)
+		
+		CodeCompletionPopupListener.setPageOffset(lookup, newTopIndex)
+		lookup.selectedIndex = newTopIndex
+		ScrollingUtil.ensureRangeIsVisible(list, newTopIndex, newTopIndex + CodeCompletionPopupConfiguration.itemShortcutCount - 1)
+		lookup.markSelectionTouched()
+		lookup.refreshUi(false, true)
+	}
+	
+	private fun selectItem(lookup: LookupImpl, index: Int) {
+		if (!lookup.isFocused) {
+			lookup.lookupFocusDegree = LookupFocusDegree.FOCUSED
+			lookup.refreshUi(false, true)
+		}
+		
+		lookup.selectedIndex = index
+	}
 }

src/main/kotlin/com/chylex/intellij/keyboardmaster/feature/codeCompletion/CodeCompletionPopupListener.kt

@@ -14,7 +14,7 @@ class CodeCompletionPopupListener : LookupManagerListener {
 		private val OFFSET_KEY = Key.create<Int>("chylexKeyboardMasterOffset")
 		private val IS_MODIFIED_KEY = Key.create<Boolean>("chylexKeyboardMasterModified")
 		
-		fun getLookupOffset(lookup: LookupImpl): Int {
+		fun getPageOffset(lookup: LookupImpl): Int {
 			val offset = lookup.getUserData(OFFSET_KEY)
 			if (offset == null || offset >= lookup.list.model.size) {
 				return 0
@@ -24,7 +24,7 @@ class CodeCompletionPopupListener : LookupManagerListener {
 			}
 		}
 		
-		fun setLookupOffset(lookup: LookupImpl, newOffset: Int) {
+		fun setPageOffset(lookup: LookupImpl, newOffset: Int) {
 			lookup.putUserData(OFFSET_KEY, newOffset)
 		}
 	}
@@ -40,7 +40,7 @@ class CodeCompletionPopupListener : LookupManagerListener {
 		newLookup.addPresentationCustomizer { item, presentation ->
 			val itemList = newLookup.list.model
 			val itemCount = itemList.size
-			val offset = getLookupOffset(newLookup)
+			val offset = getPageOffset(newLookup)
 			
 			for (index in 0 until CodeCompletionPopupConfiguration.itemShortcutCount) {
 				val itemIndex = offset + index