/*******************************************************************************
 * Copyright (c) 2008, 2016 xored software, Inc. and others.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     xored software, Inc. - initial API and Implementation (Alex Panchenko)
 *******************************************************************************/
package org.eclipse.dltk.ruby.formatter;

import java.io.IOException;
import java.io.LineNumberReader;
import java.io.Reader;
import java.io.StringReader;
import java.util.Map;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.dltk.formatter.AbstractScriptFormatter;
import org.eclipse.dltk.formatter.FormatterDocument;
import org.eclipse.dltk.formatter.FormatterIndentDetector;
import org.eclipse.dltk.formatter.FormatterWriter;
import org.eclipse.dltk.formatter.IFormatterContainerNode;
import org.eclipse.dltk.formatter.IFormatterContext;
import org.eclipse.dltk.ruby.formatter.internal.DumpContentException;
import org.eclipse.dltk.ruby.formatter.internal.Messages;
import org.eclipse.dltk.ruby.formatter.internal.RubyFormatterContext;
import org.eclipse.dltk.ruby.formatter.internal.RubyFormatterNodeBuilder;
import org.eclipse.dltk.ruby.formatter.internal.RubyFormatterNodeRewriter;
import org.eclipse.dltk.ruby.formatter.internal.RubyFormatterPlugin;
import org.eclipse.dltk.ruby.formatter.internal.RubyParser;
import org.eclipse.dltk.ui.formatter.FormatterException;
import org.eclipse.dltk.ui.formatter.FormatterSyntaxProblemException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.text.edits.MultiTextEdit;
import org.eclipse.text.edits.ReplaceEdit;
import org.eclipse.text.edits.TextEdit;
import org.jruby.parser.RubyParserResult;

public class RubyFormatter extends AbstractScriptFormatter {

	protected static final String[] INDENTING = {
			RubyFormatterConstants.INDENT_CLASS,
			RubyFormatterConstants.INDENT_MODULE,
			RubyFormatterConstants.INDENT_METHOD,
			RubyFormatterConstants.INDENT_BLOCKS,
			RubyFormatterConstants.INDENT_IF,
			RubyFormatterConstants.INDENT_CASE,
			RubyFormatterConstants.INDENT_WHEN };

	protected static final String[] BLANK_LINES = {
			RubyFormatterConstants.LINES_FILE_AFTER_REQUIRE,
			RubyFormatterConstants.LINES_FILE_BETWEEN_MODULE,
			RubyFormatterConstants.LINES_FILE_BETWEEN_CLASS,
			RubyFormatterConstants.LINES_FILE_BETWEEN_METHOD,
			RubyFormatterConstants.LINES_BEFORE_FIRST,
			RubyFormatterConstants.LINES_BEFORE_MODULE,
			RubyFormatterConstants.LINES_BEFORE_CLASS,
			RubyFormatterConstants.LINES_BEFORE_METHOD };

	private final String lineDelimiter;

	public RubyFormatter(String lineDelimiter, Map<String, ? extends Object> preferences) {
		super(preferences);
		this.lineDelimiter = lineDelimiter;
	}

	@Override
	public int detectIndentationLevel(IDocument document, int offset) {
		final String input = document.get();
		final RubyParserResult result;
		try {
			result = RubyParser.parse(input);
			final RubyFormatterNodeBuilder builder = new RubyFormatterNodeBuilder();
			final FormatterDocument fDocument = createDocument(input);
			IFormatterContainerNode root = builder.build(result, fDocument);
			new RubyFormatterNodeRewriter(result).rewrite(root);
			final IFormatterContext context = new RubyFormatterContext(0);
			FormatterIndentDetector detector = new FormatterIndentDetector(
					offset);
			try {
				root.accept(context, detector);
				return detector.getLevel();
			} catch (Exception e) {
				// ignore
			}
		} catch (FormatterSyntaxProblemException e) {
			// ignore
		}
		// TODO keep current indent
		return 0;
	}

	@Override
	public TextEdit format(String source, int offset, int length, int indent)
			throws FormatterException {
		final String input = source.substring(offset, offset + length);
		final RubyParserResult result = RubyParser.parse(input);
		final String output = format(input, result, indent);
		if (output != null) {
			if (!input.equals(output)) {
				if (!isValidation()
						|| equalsIgnoreBlanks(new StringReader(input),
								new StringReader(output))) {
					return new ReplaceEdit(offset, length, output);
				} else {
					RubyFormatterPlugin.log(new Status(IStatus.ERROR,
							RubyFormatterPlugin.PLUGIN_ID, IStatus.OK,
							Messages.RubyFormatter_contentCorrupted,
							new DumpContentException(input)));
				}
			} else {
				return new MultiTextEdit(); // NOP
			}
		}
		return null;
	}

	protected boolean isValidation() {
		return !getBoolean(RubyFormatterConstants.WRAP_COMMENTS);
	}

	/**
	 * @param input
	 * @param result
	 * @return
	 */
	private String format(String input, RubyParserResult result, int indent) {
		final RubyFormatterNodeBuilder builder = new RubyFormatterNodeBuilder();
		final FormatterDocument document = createDocument(input);
		IFormatterContainerNode root = builder.build(result, document);
		new RubyFormatterNodeRewriter(result).rewrite(root);
		IFormatterContext context = new RubyFormatterContext(indent);
		FormatterWriter writer = new FormatterWriter(document, lineDelimiter,
				createIndentGenerator());
		writer
				.setWrapLength(getInt(RubyFormatterConstants.WRAP_COMMENTS_LENGTH));
		writer.setLinesPreserve(getInt(RubyFormatterConstants.LINES_PRESERVE));
		try {
			root.accept(context, writer);
			writer.flush(context);
			return writer.getOutput();
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}

	private FormatterDocument createDocument(String input) {
		FormatterDocument document = new FormatterDocument(input);
		for (int i = 0; i < INDENTING.length; ++i) {
			document.setBoolean(INDENTING[i], getBoolean(INDENTING[i]));
		}
		for (int i = 0; i < BLANK_LINES.length; ++i) {
			document.setInt(BLANK_LINES[i], getInt(BLANK_LINES[i]));
		}
		document.setInt(RubyFormatterConstants.FORMATTER_TAB_SIZE,
				getInt(RubyFormatterConstants.FORMATTER_TAB_SIZE));
		document.setBoolean(RubyFormatterConstants.WRAP_COMMENTS,
				getBoolean(RubyFormatterConstants.WRAP_COMMENTS));
		return document;
	}

	public static boolean isBooleanOption(String optionName) {
		for (int i = 0; i < INDENTING.length; ++i) {
			if (INDENTING[i].equals(optionName)) {
				return true;
			}
		}
		return false;
	}

	public static boolean isIntegerOption(String optionName) {
		for (int i = 0; i < BLANK_LINES.length; ++i) {
			if (BLANK_LINES[i].equals(optionName)) {
				return true;
			}
		}
		return false;
	}

	private boolean equalsIgnoreBlanks(Reader inputReader, Reader outputReader) {
		LineNumberReader input = new LineNumberReader(inputReader);
		LineNumberReader output = new LineNumberReader(outputReader);
		for (;;) {
			final String inputLine = readLine(input);
			final String outputLine = readLine(output);
			if (inputLine == null) {
				if (outputLine == null) {
					return true;
				} else {
					return false;
				}
			} else if (outputLine == null) {
				return false;
			} else if (!inputLine.equals(outputLine)) {
				return false;
			}
		}
	}

	private String readLine(LineNumberReader reader) {
		String line;
		do {
			try {
				line = reader.readLine();
			} catch (IOException e) {
				// should not happen
				return null;
			}
			if (line == null) {
				return line;
			}
			line = line.trim();
		} while (line.length() == 0);
		return line;
	}

}