package org.javacs;

import com.sun.source.util.JavacTask;

import com.sun.source.util.TreePath;

import com.sun.source.util.Trees;

import java.util.Optional;

import java.util.stream.Stream;

import javax.lang.model.element.Element;

import org.eclipse.lsp4j.Location;

public class References {

public static Stream<Location> findReferences(FocusedResult compiled, FindSymbols find) {

return compiled.cursor

.map(cursor -> new References(compiled.task, find).doFindReferences(cursor))

.orElseGet(Stream::empty);

}

public static Optional<Location> gotoDefinition(FocusedResult compiled, FindSymbols find) {

return compiled.cursor.flatMap(

cursor -> new References(compiled.task, find).doGotoDefinition(cursor));

}

private final JavacTask task;

private final FindSymbols find;

private References(JavacTask task, FindSymbols find) {

this.task = task;

this.find = find;

}

private Stream<Location> doFindReferences(TreePath cursor) {

Trees trees = Trees.instance(task);

Element symbol = trees.getElement(cursor);

if (symbol == null) return Stream.empty();

else return find.references(symbol);

}

private Optional<Location> doGotoDefinition(TreePath cursor) {

CursorContext context = CursorContext.from(cursor);

if (context == CursorContext.NewClass) cursor = context.find(cursor);

Trees trees = Trees.instance(task);

Element symbol = trees.getElement(cursor);

return find.find(symbol);

}

}