/*******************************************************************************
 * Copyright (c) 2009, 2017 Red Hat Inc. and others.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     Alexander Kurtakov - initial API and implementation
 *     Mat Booth
 *******************************************************************************/
package org.eclipse.dltk.sh.internal.ui.text;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.dltk.sh.internal.ui.Activator;
import org.eclipse.dltk.sh.internal.ui.IShellColorConstants;
import org.eclipse.dltk.ui.text.AbstractScriptScanner;
import org.eclipse.dltk.ui.text.IColorManager;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.text.rules.IRule;
import org.eclipse.jface.text.rules.IToken;
import org.eclipse.jface.text.rules.IWordDetector;
import org.eclipse.jface.text.rules.Token;
import org.eclipse.jface.text.rules.WhitespaceRule;
import org.eclipse.jface.text.rules.WordRule;

public class ShellCodeScanner extends AbstractScriptScanner {
	public static class ShellWordDetector implements IWordDetector {
		@Override
		public boolean isWordPart(char character) {
			return (Character.isJavaIdentifierPart(character) && (character != '$')) || (character == '-')
					|| (character == '.');
		}

		@Override
		public boolean isWordStart(char character) {
			return Character.isJavaIdentifierStart(character) && (character != 36);
		}
	}

	public static final String[] KEYWORDS = { "do", "done", "if", "fi", "then", "else", "elif", "case", "esac", "while",
			"for", "in", "select", "time", "until", "function", "[", "[[", "]", "]]", "set", "unset", "declare",
			"export", "source", "pushd", "popd", "exit" };

	private static List<String> fgCommands = getCommands();

	private static String fgTokenProperties[] = new String[] { IShellColorConstants.SHELL_DEFAULT,
			IShellColorConstants.SHELL_KEYWORD, IShellColorConstants.SHELL_VARIABLE,
			IShellColorConstants.SHELL_COMMAND };

	public ShellCodeScanner(IColorManager manager, IPreferenceStore store) {
		super(manager, store);
		this.initialize();
	}

	public static List<String> getCommands() {
		String path = System.getenv("PATH");
		List<String> commands = new ArrayList<>();
		String[] pathEntries = path.split(System.getProperty("path.separator"));
		for (String pathEntry : pathEntries) {
			File dir = new File(pathEntry);
			if (dir.exists() && dir.isDirectory()) {

				File[] files = dir.listFiles();

				// GRO: Prevent NullPointerException
				if (files == null) {
					// @formatter:off
					Activator.getDefault().getLog().log(// +
							new Status(IStatus.ERROR, Activator.PLUGIN_ID, "listFiles() returned null: " + dir));
					// @formatter:on
					files = new File[] {};
				}

				for (File file : files) {
					if (file.canExecute()) {
						if (file.getName().endsWith(".exe")) {
							commands.add(file.getName().substring(0, file.getName().length() - 4));
						} else {
							commands.add(file.getName());
						}
					}
				}
			}
		}
		return commands;
	}

	@Override
	protected List<IRule> createRules() {
		List<IRule> rules = new ArrayList<>();
		IToken keyword = this.getToken(IShellColorConstants.SHELL_KEYWORD);
		IToken commandToken = this.getToken(IShellColorConstants.SHELL_COMMAND);
		IToken other = this.getToken(IShellColorConstants.SHELL_DEFAULT);
		IToken variable = this.getToken(IShellColorConstants.SHELL_VARIABLE);
		rules.add(new WhitespaceRule(new WhitespaceDetector()));
		rules.add(new AssignmentRule(new AssignmentDetector(), Token.UNDEFINED, variable));
		rules.add(new DollarRule(new DollarDetector(), Token.UNDEFINED, variable));
		WordRule wordRule = new WordRule(new ShellWordDetector(), other);
		for (String element : KEYWORDS) {
			wordRule.addWord(element, keyword);
		}
		for (String command : fgCommands) {
			wordRule.addWord(command, commandToken);
		}
		rules.add(wordRule);
		return rules;
	}

	@Override
	protected String[] getTokenProperties() {
		return fgTokenProperties;
	}

}