Make inspection lenses clickable and show popup with intentions

src/main/kotlin/com/chylex/intellij/inspectionlens/editor/EditorLensInlay.kt

@@ -32,7 +32,9 @@ internal value class EditorLensInlay(private val inlay: Inlay<LensRenderer>) {
 			val renderer = LensRenderer(info)
 			val properties = InlayProperties().relatesToPrecedingText(true).disableSoftWrapping(true).priority(priority)
 			
-			return editor.inlayModel.addAfterLineEndElement(offset, properties, renderer)?.let(::EditorLensInlay)
+			return editor.inlayModel.addAfterLineEndElement(offset, properties, renderer)
+				?.also(renderer::setInlay)
+				?.let(::EditorLensInlay)
 		}
 		
 		/**

src/main/kotlin/com/chylex/intellij/inspectionlens/editor/IntentionPopup.kt

@@ -0,0 +1,67 @@
+package com.chylex.intellij.inspectionlens.editor
+
+import com.intellij.codeInsight.daemon.impl.HighlightInfo
+import com.intellij.codeInsight.daemon.impl.HighlightInfo.IntentionActionDescriptor
+import com.intellij.codeInsight.daemon.impl.ShowIntentionsPass.IntentionsInfo
+import com.intellij.codeInsight.intention.impl.CachedIntentions
+import com.intellij.codeInsight.intention.impl.IntentionHintComponent
+import com.intellij.codeInsight.intention.impl.ShowIntentionActionsHandler
+import com.intellij.lang.annotation.HighlightSeverity
+import com.intellij.openapi.application.ModalityState
+import com.intellij.openapi.application.ReadAction
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.editor.Inlay
+import com.intellij.openapi.project.DumbService
+import com.intellij.openapi.project.Project
+import com.intellij.openapi.vfs.findPsiFile
+import com.intellij.psi.PsiFile
+import com.intellij.ui.awt.RelativePoint
+import com.intellij.util.concurrency.AppExecutorUtil
+import java.lang.invoke.MethodHandles
+
+internal object IntentionPopup {
+	fun show(info: HighlightInfo, inlay: Inlay<*>, point: RelativePoint) {
+		val editor = inlay.editor
+		val project = editor.project ?: return
+		val psiFile = editor.virtualFile.findPsiFile(project) ?: return
+		
+		ReadAction
+			.nonBlocking<IntentionsInfo> { collectIntentions(editor, project, psiFile, info, inlay.offset) }
+			.finishOnUiThread(ModalityState.current()) { showPopup(project, psiFile, editor, it, point) }
+			.submit(AppExecutorUtil.getAppExecutorService())
+	}
+	
+	private fun collectIntentions(editor: Editor, project: Project, psiFile: PsiFile, info: HighlightInfo, offset: Int): IntentionsInfo {
+		val intentions = mutableListOf<IntentionActionDescriptor>()
+		
+		info.findRegisteredQuickFix { descriptor, _ ->
+			if (DumbService.getInstance(project).isUsableInCurrentContext(descriptor.action) && ShowIntentionActionsHandler.availableFor(psiFile, editor, offset, descriptor.action)) {
+				intentions.add(descriptor)
+			}
+			null
+		}
+		
+		return IntentionsInfo().also {
+			it.offset = offset
+			
+			if (info.severity === HighlightSeverity.ERROR) {
+				it.errorFixesToShow.addAll(intentions)
+			}
+			else {
+				it.inspectionFixesToShow.addAll(intentions)
+			}
+		}
+	}
+	
+	private val showPopupMethod by lazy {
+		IntentionHintComponent::class.java.getDeclaredMethod("showPopup", RelativePoint::class.java)
+			.also { it.isAccessible = true }
+			.let(MethodHandles.lookup()::unreflect)
+	}
+	
+	private fun showPopup(project: Project, psiFile: PsiFile, editor: Editor, intentions: IntentionsInfo, point: RelativePoint) {
+		val cachedIntentions = CachedIntentions.create(project, psiFile, editor, intentions)
+		val component = IntentionHintComponent.showIntentionHint(project, psiFile, editor, false, cachedIntentions)
+		showPopupMethod.invoke(component, point)
+	}
+}

src/main/kotlin/com/chylex/intellij/inspectionlens/editor/LensRenderer.kt

@@ -1,25 +1,46 @@
 package com.chylex.intellij.inspectionlens.editor
 
+import com.intellij.codeInsight.codeVision.ui.popup.layouter.bottom
 import com.intellij.codeInsight.daemon.impl.HighlightInfo
 import com.intellij.codeInsight.daemon.impl.HintRenderer
+import com.intellij.codeInsight.hints.presentation.InputHandler
 import com.intellij.openapi.editor.Editor
 import com.intellij.openapi.editor.Inlay
+import com.intellij.openapi.editor.colors.EditorFontType
+import com.intellij.openapi.editor.impl.EditorImpl
 import com.intellij.openapi.editor.markup.TextAttributes
 import com.intellij.openapi.util.text.StringUtil
+import com.intellij.ui.awt.RelativePoint
+import com.intellij.ui.paint.EffectPainter
+import com.intellij.util.ui.UIUtil
+import java.awt.Cursor
 import java.awt.Graphics
+import java.awt.Graphics2D
+import java.awt.Point
 import java.awt.Rectangle
+import java.awt.event.MouseEvent
+import javax.swing.SwingUtilities
 
 /**
  * Renders the text of an inspection lens.
  */
-class LensRenderer(info: HighlightInfo) : HintRenderer(null) {
+class LensRenderer(private var info: HighlightInfo) : HintRenderer(null), InputHandler {
 	private lateinit var severity: LensSeverity
+	private lateinit var inlay: Inlay<*>
+	private var hovered = false
 	
 	init {
 		setPropertiesFrom(info)
 	}
 	
+	fun setInlay(inlay: Inlay<*>) {
+		check(!this::inlay.isInitialized) { "Inlay already set" }
+		this.inlay = inlay
+	}
+	
 	fun setPropertiesFrom(info: HighlightInfo) {
+		this.info = info
+		
 		text = getValidDescriptionText(info.description)
 		severity = LensSeverity.from(info.severity)
 	}
@@ -27,6 +48,14 @@ class LensRenderer(info: HighlightInfo) : HintRenderer(null) {
 	override fun paint(inlay: Inlay<*>, g: Graphics, r: Rectangle, textAttributes: TextAttributes) {
 		fixBaselineForTextRendering(r)
 		super.paint(inlay, g, r, textAttributes)
+		
+		if (hovered) {
+			val editor = inlay.editor as EditorImpl
+			val font = editor.colorsScheme.getFont(EditorFontType.PLAIN)
+			
+			g.color = severity.textAttributes.foregroundColor
+			EffectPainter.LINE_UNDERSCORE.paint(g as Graphics2D, r.x + TEXT_PADDING_SIDE, r.y + editor.ascent + 1, r.width - UNDERLINE_SHRINKAGE, editor.descent, font)
+		}
 	}
 	
 	override fun getTextAttributes(editor: Editor): TextAttributes {
@@ -37,7 +66,47 @@ class LensRenderer(info: HighlightInfo) : HintRenderer(null) {
 		return true
 	}
 	
+	override fun mouseMoved(event: MouseEvent, translated: Point) {
+		setHovered(true)
+	}
+	
+	override fun mouseExited() {
+		setHovered(false)
+	}
+	
+	private fun setHovered(hovered: Boolean) {
+		if (this.hovered == hovered) {
+			return
+		}
+		
+		this.hovered = hovered
+		inlay.repaint()
+		
+		val cursor = Cursor.getPredefinedCursor(if (hovered) Cursor.HAND_CURSOR else Cursor.DEFAULT_CURSOR)
+		val contentComponent = inlay.editor.contentComponent
+		if (contentComponent.cursor != cursor) {
+			UIUtil.setCursor(contentComponent, cursor)
+		}
+	}
+	
+	override fun mousePressed(event: MouseEvent, translated: Point) {
+		if (!SwingUtilities.isLeftMouseButton(event)) {
+			return
+		}
+		
+		val bounds = inlay.bounds ?: return
+		
+		event.consume()
+		IntentionPopup.show(info, inlay, RelativePoint(event.component, Point(bounds.x + TEXT_PADDING_SIDE + 1, bounds.bottom + 3)))
+	}
+	
 	private companion object {
+		/**
+		 * [HintRenderer.paintHint] renders padding around text, but not around effects.
+		 */
+		private const val TEXT_PADDING_SIDE = 8
+		private const val UNDERLINE_SHRINKAGE = (TEXT_PADDING_SIDE * 2) + 1
+		
 		private fun getValidDescriptionText(text: String?): String {
 			return if (text.isNullOrBlank()) " " else addMissingPeriod(unescapeHtmlEntities(text))
 		}