/*
 * Copyright (C) 2018 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 android.tradefed.contentprovider;

import android.content.ContentProvider;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.MatrixCursor;
import android.net.Uri;
import android.os.Environment;
import android.os.ParcelFileDescriptor;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import android.util.Log;
import android.webkit.MimeTypeMap;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Content Provider implementation to hide sd card details away from host/device interactions, and
 * that allows to abstract the host/device interactions more by allowing device and host to
 * communicate files through the provider.
 *
 * <p>This implementation aims to be standard and work in all situations.
 */
public class ManagedFileContentProvider extends ContentProvider {

    public static final String COLUMN_ABSOLUTE_PATH = "absolute_path";
    public static final String COLUMN_URI = "uri";
    public static final String COLUMN_MIME_TYPE = "mime_type";
    public static final String COLUMN_METADATA = "metadata";
    // TODO: Complete the list of columns
    public static final String[] COLUMNS =
            new String[] {COLUMN_ABSOLUTE_PATH, COLUMN_URI, COLUMN_MIME_TYPE, COLUMN_METADATA};

    private static String TAG = "ManagedFileContentProvider";
    private static MimeTypeMap sMimeMap = MimeTypeMap.getSingleton();

    private Map<Uri, ContentValues> mFileTracker = new HashMap<>();

    @Override
    public boolean onCreate() {
        mFileTracker = new HashMap<>();
        return true;
    }

    @Nullable
    @Override
    public Cursor query(
            @NonNull Uri uri,
            @Nullable String[] projection,
            @Nullable String selection,
            @Nullable String[] selectionArgs,
            @Nullable String sortOrder) {
        File file = getFileForUri(uri);
        if ("/".equals(file.getAbsolutePath())) {
            // Querying the root will list all the known file (inserted)
            final MatrixCursor cursor = new MatrixCursor(COLUMNS, mFileTracker.size());
            for (Map.Entry<Uri, ContentValues> path : mFileTracker.entrySet()) {
                String metadata = path.getValue().getAsString(COLUMN_METADATA);
                cursor.addRow(
                        new String[] {
                            getFileForUri(path.getKey()).getAbsolutePath(),
                            uri.toString(),
                            getType(path.getKey()),
                            metadata
                        });
            }
            return cursor;
        }

        if (!file.exists()) {
            Log.e(TAG, String.format("Query - File from uri: '%s' does not exists.", uri));
            return null;
        }

        // If a particular file is requested, find it and return it.
        List<String> filePaths = new ArrayList<>();
        if (file.isDirectory()) {
            readDirectory(filePaths, file);
        } else {
            // If not a directory, return a single row - the name of the file.
            filePaths.add(file.getAbsolutePath());
        }

        // Add all the paths to the cursor.
        final MatrixCursor cursor = new MatrixCursor(COLUMNS, filePaths.size());
        for (String path : filePaths) {
            // TODO: Return a properly formed uri for each filepath
            cursor.addRow(
                    new String[] {
                        path,
                        uri.toString(),
                        getType(uri),
                        /* metadata */
                        null
                    });
        }

        return cursor;
    }

    @Nullable
    @Override
    public String getType(@NonNull Uri uri) {
        final File file = getFileForUri(uri);

        final int lastDot = file.getName().lastIndexOf('.');
        if (lastDot >= 0) {
            final String extension = file.getName().substring(lastDot + 1);
            final String mime = sMimeMap.getMimeTypeFromExtension(extension);
            if (mime != null) {
                return mime;
            }
        }

        return "application/octet-stream";
    }

    @Nullable
    @Override
    public Uri insert(@NonNull Uri uri, @Nullable ContentValues contentValues) {
        String extra = "";
        File file = getFileForUri(uri);
        if (!file.exists()) {
            Log.e(TAG, String.format("Insert - File from uri: '%s' does not exists.", uri));
            return null;
        }
        if (mFileTracker.get(uri) != null) {
            Log.e(
                    TAG,
                    String.format("Insert - File from uri: '%s' already exists, ignoring.", uri));
            return null;
        }
        mFileTracker.put(uri, contentValues);
        return uri;
    }

    @Override
    public int delete(
            @NonNull Uri uri,
            @Nullable String selection,
            @Nullable String[] selectionArgs) {
        // TODO: Support deleting a file created via content write
        ContentValues values = mFileTracker.remove(uri);
        if (values == null) {
            return 0;
        }
        File file = getFileForUri(uri);
        int num = recursiveDelete(file);
        return 1;
    }

    @Override
    public int update(
            @NonNull Uri uri,
            @Nullable ContentValues values,
            @Nullable String selection,
            @Nullable String[] selectionArgs) {
        File file = getFileForUri(uri);
        if (!file.exists()) {
            Log.e(TAG, String.format("Update - File from uri: '%s' does not exists.", uri));
            return 0;
        }
        if (mFileTracker.get(uri) == null) {
            Log.e(
                    TAG,
                    String.format(
                            "Update - File from uri: '%s' is not tracked yet, use insert.", uri));
            return 0;
        }
        mFileTracker.put(uri, values);
        return 1;
    }

    @Override
    public ParcelFileDescriptor openFile(
            @NonNull Uri uri, @NonNull String mode) throws FileNotFoundException {
        // TODO: Track the file created via this callback (content write)
        final File file = getFileForUri(uri);
        final int fileMode = modeToMode(mode);

        if ((fileMode & ParcelFileDescriptor.MODE_CREATE) == ParcelFileDescriptor.MODE_CREATE) {
            // If the file is being created, create all its parent directories that don't already
            // exist.
            file.getParentFile().mkdirs();
        }
        return ParcelFileDescriptor.open(file, fileMode);
    }

    private File getFileForUri(@NonNull Uri uri) {
        // TODO: apply the /sdcard resolution to query() too.
        String uriPath = uri.getPath();
        if (uriPath.startsWith("/sdcard/")) {
            uriPath =
                    uriPath.replaceAll(
                            "/sdcard", Environment.getExternalStorageDirectory().getAbsolutePath());
        }
        return new File(uriPath);
    }

    private void readDirectory(List<String> files, File dir) {
        for (File f : dir.listFiles()) {
            if (f.isDirectory()) {
                readDirectory(files, f);
            } else {
                files.add(f.getAbsolutePath());
            }
        }
    }

    /** Copied from FileProvider.java. */
    private static int modeToMode(String mode) {
        int modeBits;
        if ("r".equals(mode)) {
            modeBits = ParcelFileDescriptor.MODE_READ_ONLY;
        } else if ("w".equals(mode) || "wt".equals(mode)) {
            modeBits =
                    ParcelFileDescriptor.MODE_WRITE_ONLY
                            | ParcelFileDescriptor.MODE_CREATE
                            | ParcelFileDescriptor.MODE_TRUNCATE;
        } else if ("wa".equals(mode)) {
            modeBits =
                    ParcelFileDescriptor.MODE_WRITE_ONLY
                            | ParcelFileDescriptor.MODE_CREATE
                            | ParcelFileDescriptor.MODE_APPEND;
        } else if ("rw".equals(mode)) {
            modeBits = ParcelFileDescriptor.MODE_READ_WRITE | ParcelFileDescriptor.MODE_CREATE;
        } else if ("rwt".equals(mode)) {
            modeBits =
                    ParcelFileDescriptor.MODE_READ_WRITE
                            | ParcelFileDescriptor.MODE_CREATE
                            | ParcelFileDescriptor.MODE_TRUNCATE;
        } else {
            throw new IllegalArgumentException("Invalid mode: " + mode);
        }
        return modeBits;
    }

    /**
     * Recursively delete given file or directory and all its contents.
     *
     * @param rootDir the directory or file to be deleted; can be null
     * @return The number of deleted files.
     */
    private int recursiveDelete(File rootDir) {
        int count = 0;
        if (rootDir != null) {
            if (rootDir.isDirectory()) {
                File[] childFiles = rootDir.listFiles();
                if (childFiles != null) {
                    for (File child : childFiles) {
                        count += recursiveDelete(child);
                    }
                }
            }
            rootDir.delete();
            count++;
        }
        return count;
    }
}