/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.idegen;

import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.collect.Collections2;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Sets;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FilenameFilter;
import java.io.IOException;
import java.net.URISyntaxException;
import java.util.Collection;
import java.util.HashSet;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Find directories utility.
 */
public class DirectorySearch {

    private static final Logger logger = Logger.getLogger(DirectorySearch.class.getName());

    public static final HashSet<String> SOURCE_DIRS = Sets.newHashSet();

    static {
        SOURCE_DIRS.add("src");
        SOURCE_DIRS.add("java");
    }

    private static final Pattern EXCLUDE_PATTERN = Pattern.compile("values-..(-.*)*");

    private static File repoRoot = null;
    public static final String REL_TEMPLATE_DIR = "templates";
    public static final String REL_TEMPLATE_PATH_FROM_ROOT = "development/tools/idegen/"
            + REL_TEMPLATE_DIR;

    /**
     * Returns the previously initialized repo root.
     */
    public static File getRepoRoot() {
        Preconditions.checkNotNull(repoRoot, "repoRoot has not been initialized yet.  Call "
                + "findAndInitRepoRoot() first.");
        return repoRoot;
    }

    /**
     * Find the repo root.  This is the root branch directory of a full repo checkout.
     *
     * @param file any file inside the root.
     * @return the root directory.
     */
    public static void findAndInitRepoRoot(File file) {
        Preconditions.checkNotNull(file);
        if (repoRoot != null) {
            return;
        }

        if (file.isDirectory()) {
            File[] files = file.listFiles(new FilenameFilter() {
                @Override
                public boolean accept(File dir, String name) {
                    return ".repo".equals(name);
                }
            });
            if (files.length > 0) {
                repoRoot = file;
            }
        }
        File parent = file.getParentFile();
        if (parent == null) {
            throw new IllegalStateException("Repo root not found from starting point " +
                    file.getPath());
        }
        findAndInitRepoRoot(parent);
    }

    /**
     * Searches up the parent chain to find the closes module root directory. A module root is one
     * with an Android.mk file in it. <p> For example, the module root for directory
     * <code>package/apps/Contacts/src</code> is <code>packages/apps/Contacts</code>
     *
     * @return the module root.
     * @throws IOException when module root is not found.
     */
    public static File findModuleRoot(File path) throws IOException {
        Preconditions.checkNotNull(path);
        File dir;
        if (path.isFile()) {
            dir = path.getParentFile();
        } else {
            dir = path;
        }
        while (dir != null) {
            File makeFile = new File(dir, "Android.mk");
            if (makeFile.exists()) {
                return dir;
            } else {
                dir = dir.getParentFile();
            }
        }
        // At this point, there are no parents and we have not found a module. Error.
        throw new IOException("Module root not found for path " + path.getCanonicalPath());
    }

    /**
     * Find all source directories from a given root file.
     *
     * If the root file is a file, the directory of that file will be used as the starting
     * location.
     *
     * @param file The starting location. Can be a file or directory.
     * @return List of
     */
    public static ImmutableList<File> findSourceDirs(File file) {
        Preconditions.checkNotNull(file);
        if (!file.exists()) {
            return ImmutableList.of();
        }
        if (!file.isDirectory()) {
            file = file.getParentFile();
        }
        ImmutableList.Builder<File> builder = ImmutableList.builder();
        File[] children = file.listFiles();
        for (File child : children) {
            if (child.isDirectory()) {
                // Recurse further down the tree first to cover case of:
                //
                // src/java
                //   or
                // java/src
                //   or
                // src/main/java/java
                //
                // In first two cases, we don't want the parent.
                // In third case we want the parent of the last "java", the last "java" is actually
                // part of namespace.
                ImmutableList<File> dirs = findSourceDirs(child);
                // filter out the third case.
                Collection<File> filteredDirs = Collections2.filter(dirs, new Predicate<File>() {
                    @Override
                    public boolean apply(File input) {
                        return !input.getAbsolutePath().endsWith("java/java");
                    }
                });
                if (filteredDirs.isEmpty()) {
                    if (SOURCE_DIRS.contains(child.getName())) {
                        builder.add(child);
                    }
                } else {
                    builder.addAll(filteredDirs);
                }
            }
        }

        return builder.build();
    }

    public static ImmutableList<File> findExcludeDirs(File file) {
        Preconditions.checkNotNull(file);
        if (!file.exists()) {
            return ImmutableList.of();
        }
        if (!file.isDirectory()) {
            file = file.getParentFile();
        }
        ImmutableList.Builder<File> builder = ImmutableList.builder();
        // Go into the res folder
        File resFile = new File(file, "res");
        if (resFile.exists()) {

            File[] children = resFile.listFiles();
            for (File child : children) {
                if (child.isDirectory()) {
                    Matcher matcher = EXCLUDE_PATTERN.matcher(child.getName());
                    if (matcher.matches()) {
                        // Exclude internationalization language folders.
                        // ex: values-zh
                        // But don't exclude values-land.  Assume all language folders are two
                        // letters.
                        builder.add(child);
                    }
                }
            }
        }

        return builder.build();
    }

    private static File templateDirCurrent = null;
    private static File templateDirRoot = null;

    public static File findTemplateDir() throws IOException {
        // Cache optimization.
        if (templateDirCurrent != null && templateDirCurrent.exists()) {
            return templateDirCurrent;
        }
        if (templateDirRoot != null && templateDirRoot.exists()) {
            return templateDirRoot;
        }

        File currentDir = null;
        try {
            currentDir = new File(
                    IntellijProject.class.getProtectionDomain().getCodeSource().getLocation()
                            .toURI().getPath()).getParentFile();
        } catch (URISyntaxException e) {
            logger.log(Level.SEVERE, "Could not get jar location.", e);
            return null;
        }
        // Support for program execution in intellij.
        if (currentDir.getPath().endsWith("out/production")) {
            return new File(currentDir.getParentFile().getParentFile(), REL_TEMPLATE_DIR);
        }
        // First check relative to current run directory.
        templateDirCurrent = new File(currentDir, REL_TEMPLATE_DIR);
        if (templateDirCurrent.exists()) {
            return templateDirCurrent;
        } else {
            // Then check relative to root directory.
            templateDirRoot = new File(repoRoot, REL_TEMPLATE_PATH_FROM_ROOT);
            if (templateDirRoot.exists()) {
                return templateDirRoot;
            }
        }
        throw new FileNotFoundException(
                "Unable to find template dir. Tried the following locations:\n" +
                        templateDirCurrent.getCanonicalPath() + "\n" +
                        templateDirRoot.getCanonicalPath());
    }
}