package com.sun.tools.javac.file;

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.ArrayList;

import java.util.Collections;

import java.util.List;

import java.util.StringTokenizer;

import java.util.jar.Attributes;

import java.util.jar.JarFile;

import java.util.jar.Manifest;

import com.sun.tools.javac.util.Context;

/**

 * Get meta-info about files. Default direct (non-caching) implementation.

 * @see CacheFSInfo

 *

 * <p><b>This is NOT part of any supported API.

 * If you write code that depends on this, you do so at your own risk.

 * This code and its internal interfaces are subject to change or

 * deletion without notice.</b>

 */

public class FSInfo {

    /** Get the FSInfo instance for this context.

     *  @param context the context

     *  @return the Paths instance for this context

     */

    public static FSInfo instance(Context context) {

        FSInfo instance = context.get(FSInfo.class);

        if (instance == null)

            instance = new FSInfo();

        return instance;

    }

    protected FSInfo() {

    }

    protected FSInfo(Context context) {

        context.put(FSInfo.class, this);

    }

    public Path getCanonicalFile(Path file) {

        try {

            return file.toRealPath();

        } catch (IOException e) {

        }

    }

    public boolean exists(Path file) {

        return Files.exists(file);

    }

    public boolean isDirectory(Path file) {

        return Files.isDirectory(file);

    }

    public boolean isFile(Path file) {

        return Files.isRegularFile(file);

    }

    public List<Path> getJarClassPath(Path file) throws IOException {

        Path parent = file.getParent();

        try (JarFile jarFile = new JarFile(file.toFile())) {

            Manifest man = jarFile.getManifest();

            if (man == null)

                return Collections.emptyList();

            Attributes attr = man.getMainAttributes();

            if (attr == null)

                return Collections.emptyList();

            String path = attr.getValue(Attributes.Name.CLASS_PATH);

            if (path == null)

                return Collections.emptyList();

            List<Path> list = new ArrayList<>();

            for (StringTokenizer st = new StringTokenizer(path);

                 st.hasMoreTokens(); ) {

                String elt = st.nextToken();

                Path f = Paths.get(elt);

                if (!f.isAbsolute() && parent != null)

                    f = parent.resolve(f).toAbsolutePath();

                list.add(f);

            }

            return list;

        }

    }

}