improved completion

src/main/kotlin/dev/hgh/jai/completion/JaiCompletionContributor.kt

@@ -6,6 +6,7 @@ import com.intellij.codeInsight.completion.CompletionProvider
 import com.intellij.codeInsight.completion.CompletionResultSet
 import com.intellij.codeInsight.completion.CompletionType
 import com.intellij.codeInsight.lookup.LookupElementBuilder
+import com.intellij.openapi.diagnostic.Logger
 import com.intellij.openapi.project.DumbAware
 import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.patterns.PlatformPatterns
@@ -17,8 +18,11 @@ import dev.hgh.jai.lexer.JaiTokenTypes
 import dev.hgh.jai.module.JaiModuleResolver
 import dev.hgh.jai.module.JaiPathMode
 import dev.hgh.jai.psi.JaiDirectiveExpr
+import dev.hgh.jai.reference.JaiSymbolResolver
 
 /** Directives and their adjacent comma flags before an import/load string. */
+private const val COMPLETION_DEBUG_PROPERTY = "jai.completion.debug"
+private val LOG = Logger.getInstance("dev.hgh.jai.completion")
 private val DIRECTIVE_WITH_FLAGS =
     Regex("""#(import|load)((?:\s*,\s*[A-Za-z_][A-Za-z0-9_]*)*)\s*$""")
 
@@ -43,6 +47,12 @@ private class JaiCompletionProvider : CompletionProvider<CompletionParameters>()
     ) {
         val completionContext = JaiCompletionContext(parameters)
         val moduleDirective = completionContext.moduleDirective
+        debug(
+            "request file=${parameters.originalFile.virtualFile?.path ?: parameters.originalFile.name} " +
+                "offset=${parameters.offset} token=${completionContext.debugToken} " +
+                "prefix='${completionContext.prefix}' module=$moduleDirective " +
+                "member=${completionContext.memberContext}",
+        )
         when {
             moduleDirective != null -> {
                 addModuleNames(parameters, moduleDirective, completionContext.prefix, resultSet)
@@ -52,12 +62,18 @@ private class JaiCompletionProvider : CompletionProvider<CompletionParameters>()
                 return
             }
 
+            completionContext.memberContext != null -> {
+                val member = completionContext.memberContext!!
+                addMemberSymbols(parameters, member, resultSet)
+            }
+
             completionContext.isDirectivePrefix -> {
                 addDirectives(completionContext.prefix, resultSet)
             }
 
             else -> {
                 addKeywords(completionContext.prefix, resultSet)
+                addSymbols(parameters, completionContext.prefix, resultSet)
             }
         }
     }
@@ -100,6 +116,53 @@ private class JaiCompletionProvider : CompletionProvider<CompletionParameters>()
             }
     }
 
+    private fun addSymbols(
+        parameters: CompletionParameters,
+        prefix: String,
+        resultSet: CompletionResultSet,
+    ) {
+        val candidates = JaiSymbolResolver.completionCandidates(parameters.originalFile, parameters.position)
+        debug("unqualified candidates=${candidates.size} names=${candidates.take(40).joinToString { it.name }}")
+        candidates
+            .filter { it.name.startsWith(prefix) }
+            .forEach { candidate ->
+                resultSet.addElement(
+                    LookupElementBuilder
+                        .create(candidate.name)
+                        .withPsiElement(candidate.element)
+                        .withTypeText(candidate.kind),
+                )
+            }
+    }
+
+    private fun addMemberSymbols(
+        parameters: CompletionParameters,
+        member: JaiCompletionContext.MemberContext,
+        resultSet: CompletionResultSet,
+    ) {
+        val candidates =
+            JaiSymbolResolver.memberCompletionCandidates(
+                parameters.originalFile,
+                parameters.position,
+                member.qualifier,
+            )
+        debug("member qualifier=${member.qualifier} candidates=${candidates.size} names=${candidates.take(40).joinToString { it.name }}")
+        candidates
+            .filter { it.name.startsWith(member.prefix) }
+            .forEach { candidate ->
+                resultSet.addElement(
+                    LookupElementBuilder
+                        .create(candidate.name)
+                        .withPsiElement(candidate.element)
+                        .withTypeText(candidate.kind),
+                )
+            }
+    }
+
+    private fun debug(message: String) {
+        if (java.lang.Boolean.getBoolean(COMPLETION_DEBUG_PROPERTY)) LOG.info(message)
+    }
+
     private fun addModuleNames(
         parameters: CompletionParameters,
         directive: String,
@@ -149,6 +212,23 @@ private class JaiCompletionContext(
     val isDirectivePrefix: Boolean
         get() = token?.type === JaiTokenTypes.DIRECTIVE || token?.type === JaiTokenTypes.HASH
 
+    val debugToken: String
+        get() = token?.let { "${it.type}@${it.start}..${it.end}" } ?: "none"
+
+    data class MemberContext(
+        val qualifier: String,
+        val prefix: String,
+    )
+
+    val memberContext: MemberContext?
+        get() =
+            MEMBER_PREFIX.find(text.substring(0, offset))?.let { match ->
+                MemberContext(
+                    qualifier = match.groupValues[1],
+                    prefix = match.groupValues.getOrNull(2).orEmpty(),
+                )
+            }
+
     val prefix: String
         get() {
             val current = token ?: return ""
@@ -210,6 +290,11 @@ private class JaiCompletionContext(
         val end: Int,
     )
 
+    private companion object {
+        val MEMBER_PREFIX =
+            Regex("""(?:^|[^A-Za-z0-9_`])(`?[A-Za-z_][A-Za-z0-9_]*`?)\s*\.\s*(`?[A-Za-z_][A-Za-z0-9_]*`?)?$""")
+    }
+
     private fun tokenAtCaret(
         text: String,
         offset: Int,