docmlet/org.eclipse.statet.docmlet.tex.ui/src/org/eclipse/statet/internal/docmlet/tex/ui/sourceediting/LtxAssistInvocationContext.java

/*=============================================================================#
 # Copyright (c) 2009, 2019 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.internal.docmlet.tex.ui.sourceediting;

import static org.eclipse.statet.jcommons.lang.ObjectUtils.nonNullAssert;

import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;

import org.eclipse.statet.jcommons.lang.NonNullByDefault;
import org.eclipse.statet.jcommons.lang.Nullable;

import org.eclipse.statet.docmlet.tex.core.TexCore;
import org.eclipse.statet.docmlet.tex.core.TexCoreAccess;
import org.eclipse.statet.docmlet.tex.core.ast.ControlNode;
import org.eclipse.statet.docmlet.tex.core.ast.Group;
import org.eclipse.statet.docmlet.tex.core.ast.Label;
import org.eclipse.statet.docmlet.tex.core.ast.TexAst;
import org.eclipse.statet.docmlet.tex.core.ast.TexAstNode;
import org.eclipse.statet.docmlet.tex.core.ast.Text;
import org.eclipse.statet.docmlet.tex.core.commands.TexCommand;
import org.eclipse.statet.docmlet.tex.core.model.TexSourceUnit;
import org.eclipse.statet.docmlet.tex.core.source.LtxHeuristicTokenScanner;
import org.eclipse.statet.ltk.model.core.IModelManager;
import org.eclipse.statet.ltk.model.core.elements.ISourceUnit;
import org.eclipse.statet.ltk.ui.sourceediting.ISourceEditor;
import org.eclipse.statet.ltk.ui.sourceediting.assist.AssistInvocationContext;


@NonNullByDefault
public class LtxAssistInvocationContext extends AssistInvocationContext {
	
	
	public class CommandCall {
		
		
		private final ControlNode controlNode;
		private final @Nullable TexAstNode[] argNodes;
		
		private final int invocationArgIdx;
		
		
		private CommandCall(final ControlNode controlNode) {
			nonNullAssert(controlNode.getCommand());
			this.controlNode= controlNode;
			this.argNodes= TexAst.resolveArguments(controlNode);
			this.invocationArgIdx= TexAst.getIndexAt(this.argNodes, getInvocationOffset());
		}
		
		
		/**
		 * Returns the node of the command call.
		 * @return the ast node
		 */
		public final ControlNode getControlNode() {
			return this.controlNode;
		}
		
		@SuppressWarnings("null")
		public final TexCommand getCommand() {
			return this.controlNode.getCommand();
		}
		
		/**
		 * Returns the node of the argument.
		 * @param argIdx the index of the argument
		 * @return the list with ast nodes
		 */
		public final @Nullable TexAstNode getArgNode(final int argIdx) {
			return this.argNodes[argIdx];
		}
		
		/**
		 * Returns the index of the argument at the {@link LtxAssistInvocationContext#getInvocationOffset() invocation offset}.
		 * @return the index of the argument
		 */
		public final int getInvocationArgIdx() {
			return this.invocationArgIdx;
		}
		
	}
	
	
	private @Nullable LtxHeuristicTokenScanner scanner;
	
	private int invocationChecked;
	private @Nullable CommandCall invocationDirect;
	private @Nullable CommandCall invocationAny;
	
	
	public LtxAssistInvocationContext(final ISourceEditor editor,
			final int offset, final String contentType,
			final boolean isProposal, final IProgressMonitor monitor) {
		super(editor, offset, contentType,
				(isProposal) ? IModelManager.MODEL_FILE : IModelManager.NONE, monitor );
	}
	
	
	public TexCoreAccess getTexCoreAccess() {
		final ISourceUnit sourceUnit= getSourceUnit();
		if (sourceUnit instanceof TexSourceUnit) {
			return ((TexSourceUnit) sourceUnit).getTexCoreAccess();
		}
		return TexCore.getWorkbenchAccess();
	}
	
	
	public final LtxHeuristicTokenScanner getLtxHeuristicTokenScanner() {
		LtxHeuristicTokenScanner scanner= this.scanner;
		if (scanner == null) {
			scanner= LtxHeuristicTokenScanner.create(getEditor().getDocumentContentInfo());
			this.scanner= scanner;
		}
		return scanner;
	}
	
	
	@Override
	protected String computeIdentifierPrefix(int offset) {
		final IDocument document= getDocument();
		
		try {
			int start= offset;
			SEARCH_START: while (offset > 0) {
				final char c= document.getChar(offset - 1);
				switch (c) {
				case 'a':
				case 'b':
				case 'c':
				case 'd':
				case 'e':
				case 'f':
				case 'g':
				case 'h':
				case 'i':
				case 'j':
				case 'k':
				case 'l':
				case 'm':
				case 'n':
				case 'o':
				case 'p':
				case 'q':
				case 'r':
				case 's':
				case 't':
				case 'u':
				case 'v':
				case 'w':
				case 'x':
				case 'y':
				case 'z':
				case 'A':
				case 'B':
				case 'C':
				case 'D':
				case 'E':
				case 'F':
				case 'G':
				case 'H':
				case 'I':
				case 'J':
				case 'K':
				case 'L':
				case 'M':
				case 'N':
				case 'O':
				case 'P':
				case 'Q':
				case 'R':
				case 'S':
				case 'T':
				case 'U':
				case 'V':
				case 'W':
				case 'X':
				case 'Y':
				case 'Z':
					start= --offset;
					continue SEARCH_START;
				case '\\':
					start= offset;
					while (true) {
						if (--offset <= 0 || document.getChar(offset - 1) != '\\') {
							start--;
							break SEARCH_START;
						}
						if (--offset <= 0 || document.getChar(offset -1) != '\\') {
							break SEARCH_START;
						}
					}
				default:
					break SEARCH_START;
				}
			}
			return document.get(start, getInvocationOffset() - start);
		}
		catch (final BadLocationException e) {
			return ""; //$NON-NLS-1$
		}
	}
	
	
	private @Nullable CommandCall searchCommandCall(final boolean direct) {
		if (getAstSelection().getCovering() instanceof TexAstNode) {
			TexAstNode texNode= (TexAstNode)getAstSelection().getCovering();
			if (direct) {
				if (texNode instanceof Label || texNode instanceof Text) {
					texNode= texNode.getTexParent();
				}
			}
			else {
				while (texNode != null && !(texNode instanceof Group)) {
					texNode= texNode.getTexParent();
				}
			}
			ControlNode controlNode;
			if (texNode instanceof Group && texNode.getParent() instanceof ControlNode
					&& (controlNode= (ControlNode)texNode.getParent()).getCommand() != null) {
				return new CommandCall(controlNode);
			}
			if (texNode instanceof ControlNode
					&& (controlNode= (ControlNode)texNode).getCommand() != null
					&& controlNode.getArgsStartOffset() <= getStartOffset()
					&& controlNode.getEndOffset() >= getEndOffset() ) {
				return new CommandCall(controlNode);
			}
		}
		return null;
	}
	
	public @Nullable CommandCall getCommandCall(final boolean direct) {
		if (this.invocationChecked == 0) {
			this.invocationChecked= 1;
			this.invocationDirect= searchCommandCall(true);
		}
		if (direct) {
			return this.invocationDirect;
		}
		if (this.invocationChecked == 1) {
			this.invocationChecked= 2;
			this.invocationAny= (this.invocationDirect != null) ? this.invocationDirect :
					searchCommandCall(false);
		}
		return this.invocationAny;
	}
	
}