/*
 * Copyright 2016 The Bazel Authors. All rights reserved.
 *
 * 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.google.idea.blaze.android.sync;

import com.android.SdkConstants;
import com.android.sdklib.AndroidTargetHash;
import com.android.sdklib.AndroidVersion;
import com.android.sdklib.AndroidVersionHelper;
import com.android.tools.idea.sdk.IdeSdks;
import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.diagnostic.Logger;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

import javax.annotation.Nullable;

/**
 * Utility methods for handling the android sdk.
 */
public final class BlazeAndroidSdk {
  private static final Logger LOG = Logger.getInstance(BlazeAndroidSdk.class);

  private BlazeAndroidSdk() {
  }

  /**
   * Reads the android sdk level from your local SDK directory.
   */
  public static String getAndroidSdkLevelFromLocalChannel(String localSdkLocation,
      String androidSdkPlatform) {
    File androidSdkPlatformsDir = new File(new File(new File(localSdkLocation), "platforms"), androidSdkPlatform);
    File sourcePropertiesFile = new File(androidSdkPlatformsDir, SdkConstants.FN_SOURCE_PROP);
    return getAndroidSdkLevelFromSourceProperties(sourcePropertiesFile);
  }

  /**
   * The user's blazerc is read to discover the --android_sdk configuration. The resulting
   * label can be an indirection (eg. "latest" or "prerelease"), so blaze query is used to
   * query for "android_blaze.jar", which marks the actual android sdk directory.
   * <p/>
   * <p>This directory should have a source.properties file. This is read to discover the
   * platform API level (eg. "21"). This is hashed according to ADT standards to return
   * a unique SDK key, eg "android-21".
   */
  @Nullable
  public static String getAndroidSdkLevelFromBlazeRc(
    File androidPlatformDir) {
    File sourcePropertiesFile = new File(androidPlatformDir, SdkConstants.FN_SOURCE_PROP);
    return getAndroidSdkLevelFromSourceProperties(sourcePropertiesFile);
  }

  @Nullable
  public static String getAndroidSdkLevelFromSourceProperties(File sourcePropertiesFile) {
    if (!sourcePropertiesFile.exists()) {
      return null;
    }

    AndroidVersion androidVersion =
      readAndroidVersionFromSourcePropertiesFile(sourcePropertiesFile);
    if (androidVersion == null) {
      LOG.warn("Could not read source.properties from: " + sourcePropertiesFile);
      return null;
    }
    return AndroidTargetHash.getPlatformHashString(androidVersion);
  }

  @Nullable
  private static AndroidVersion readAndroidVersionFromSourcePropertiesFile(File sourcePropertiesFile) {
    Properties props = parseProperties(sourcePropertiesFile);
    if (props == null) {
      return null;
    }
    try {
      return AndroidVersionHelper.create(props);
    } catch (AndroidVersion.AndroidVersionException e) {
      return null;
    }
  }

  /**
   * Parses the given file as properties file if it exists.
   * Returns null if the file does not exist, cannot be parsed or has no properties.
   */
  @Nullable
  private static Properties parseProperties(File propsFile) {
    if (!propsFile.exists()) {
      return null;
    }
    try (InputStream fis = new FileInputStream(propsFile)) {
      Properties props = new Properties();
      props.load(fis);

      // To be valid, there must be at least one property in it.
      if (props.size() > 0) {
        return props;
      }
    } catch (IOException e) {
      // Ignore
    }
    return null;
  }

}