/*
 * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
 *
 * 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 net.micode.notes.gtask.remote;

import android.accounts.Account;
import android.accounts.AccountManager;
import android.accounts.AccountManagerFuture;
import android.app.Activity;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Log;

import net.micode.notes.gtask.data.Node;
import net.micode.notes.gtask.data.Task;
import net.micode.notes.gtask.data.TaskList;
import net.micode.notes.gtask.exception.ActionFailureException;
import net.micode.notes.gtask.exception.NetworkFailureException;
import net.micode.notes.tool.GTaskStringUtils;
import net.micode.notes.ui.NotesPreferenceActivity;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.cookie.Cookie;
import org.apache.http.impl.client.BasicCookieStore;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.LinkedList;
import java.util.List;
import java.util.zip.GZIPInputStream;
import java.util.zip.Inflater;
import java.util.zip.InflaterInputStream;

// GTaskClient 类用于与 Google Tasks 进行交互，主要包含任务和任务列表的创建、删除、修改等操作
public class GTaskClient {
    private static final String TAG = GTaskClient.class.getSimpleName();

    // 定义 GTASK 的 URL 地址
    private static final String GTASK_URL = "https://mail.google.com/tasks/";
    private static final String GTASK_GET_URL = "https://mail.google.com/tasks/ig";
    private static final String GTASK_POST_URL = "https://mail.google.com/tasks/r/ig";

    private static GTaskClient mInstance = null; // 单例对象
    private DefaultHttpClient mHttpClient;  // HTTP 客户端
    private String mGetUrl;  // GET 请求 URL
    private String mPostUrl;  // POST 请求 URL
    private long mClientVersion;  // 客户端版本
    private boolean mLoggedin;  // 登录状态
    private long mLastLoginTime;  // 上次登录时间
    private int mActionId;  // 操作 ID，用于唯一标识每个操作
    private Account mAccount;  // 当前登录的 Google 帐号
    private JSONArray mUpdateArray;  // 更新操作数组

    // 私有化构造方法，避免外部实例化
    private GTaskClient() {
        mHttpClient = null;
        mGetUrl = GTASK_GET_URL;
        mPostUrl = GTASK_POST_URL;
        mClientVersion = -1;
        mLoggedin = false;
        mLastLoginTime = 0;
        mActionId = 1;
        mAccount = null;
        mUpdateArray = null;
    }

    // 单例模式获取 GTaskClient 实例
    public static synchronized GTaskClient getInstance() {
        if (mInstance == null) {
            mInstance = new GTaskClient();
        }
        return mInstance;
    }

    // 登录方法，返回是否成功
    public boolean login(Activity activity) {
        // 每 5 分钟重新登录一次
        final long interval = 1000 * 60 * 5;
        if (mLastLoginTime + interval < System.currentTimeMillis()) {
            mLoggedin = false;
        }

        // 如果切换了帐号，也需要重新登录
        if (mLoggedin && !TextUtils.equals(getSyncAccount().name, NotesPreferenceActivity.getSyncAccountName(activity))) {
            mLoggedin = false;
        }

        if (mLoggedin) {
            Log.d(TAG, "已经登录");
            return true;
        }

        mLastLoginTime = System.currentTimeMillis();
        String authToken = loginGoogleAccount(activity, false);
        if (authToken == null) {
            Log.e(TAG, "Google 帐号登录失败");
            return false;
        }

        // 如果是自定义域名帐号，需要构建对应的 URL
        if (!(mAccount.name.toLowerCase().endsWith("gmail.com") || mAccount.name.toLowerCase().endsWith("googlemail.com"))) {
            StringBuilder url = new StringBuilder(GTASK_URL).append("a/");
            int index = mAccount.name.indexOf('@') + 1;
            String suffix = mAccount.name.substring(index);
            url.append(suffix + "/");
            mGetUrl = url.toString() + "ig";
            mPostUrl = url.toString() + "r/ig";

            if (tryToLoginGtask(activity, authToken)) {
                mLoggedin = true;
            }
        }

        // 尝试使用 Google 官方 URL 登录
        if (!mLoggedin) {
            mGetUrl = GTASK_GET_URL;
            mPostUrl = GTASK_POST_URL;
            if (!tryToLoginGtask(activity, authToken)) {
                return false;
            }
        }

        mLoggedin = true;
        return true;
    }

    // 获取授权令牌
    private String loginGoogleAccount(Activity activity, boolean invalidateToken) {
        String authToken;
        AccountManager accountManager = AccountManager.get(activity);
        Account[] accounts = accountManager.getAccountsByType("com.google");

        if (accounts.length == 0) {
            Log.e(TAG, "没有可用的 Google 帐号");
            return null;
        }

        // 根据设置中的帐号名称来选择帐户
        String accountName = NotesPreferenceActivity.getSyncAccountName(activity);
        Account account = null;
        for (Account a : accounts) {
            if (a.name.equals(accountName)) {
                account = a;
                break;
            }
        }
        if (account != null) {
            mAccount = account;
        } else {
            Log.e(TAG, "无法找到相同名称的帐户");
            return null;
        }

        // 获取授权令牌
        AccountManagerFuture<Bundle> accountManagerFuture = accountManager.getAuthToken(account, "goanna_mobile", null, activity, null, null);
        try {
            Bundle authTokenBundle = accountManagerFuture.getResult();
            authToken = authTokenBundle.getString(AccountManager.KEY_AUTHTOKEN);
            if (invalidateToken) {
                accountManager.invalidateAuthToken("com.google", authToken);
                loginGoogleAccount(activity, false);
            }
        } catch (Exception e) {
            Log.e(TAG, "获取授权令牌失败");
            authToken = null;
        }

        return authToken;
    }

    // 尝试登录 Google 任务
    private boolean tryToLoginGtask(Activity activity, String authToken) {
        if (!loginGtask(authToken)) {
            // 如果授权令牌过期，重新登录
            authToken = loginGoogleAccount(activity, true);
            if (authToken == null) {
                Log.e(TAG, "Google 帐号登录失败");
                return false;
            }

            if (!loginGtask(authToken)) {
                Log.e(TAG, "登录 Google Tasks 失败");
                return false;
            }
        }
        return true;
    }

    // 通过授权令牌登录 Google Tasks
    private boolean loginGtask(String authToken) {
        int timeoutConnection = 10000;
        int timeoutSocket = 15000;
        HttpParams httpParameters = new BasicHttpParams();
        HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
        HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);
        mHttpClient = new DefaultHttpClient(httpParameters);
        BasicCookieStore localBasicCookieStore = new BasicCookieStore();
        mHttpClient.setCookieStore(localBasicCookieStore);
        HttpProtocolParams.setUseExpectContinue(mHttpClient.getParams(), false);

        // 登录 Google 任务
        try {
            String loginUrl = mGetUrl + "?auth=" + authToken;
            HttpGet httpGet = new HttpGet(loginUrl);
            HttpResponse response = mHttpClient.execute(httpGet);

            // 获取 Cookie
            List<Cookie> cookies = mHttpClient.getCookieStore().getCookies();
            boolean hasAuthCookie = false;
            for (Cookie cookie : cookies) {
                if (cookie.getName().contains("GTL")) {
                    hasAuthCookie = true;
                }
            }
            if (!hasAuthCookie) {
                Log.w(TAG, "未找到授权 Cookie");
            }

            // 获取客户端版本
            String resString = getResponseContent(response.getEntity());
            String jsBegin = "_setup(";
            String jsEnd = ");";

            int beginIndex = resString.indexOf(jsBegin);
            int endIndex = resString.indexOf(jsEnd);
            if (beginIndex != -1 && endIndex != -1) {
                String jsonString = resString.substring(beginIndex + jsBegin.length(), endIndex);
                JSONObject jsonObject = new JSONObject(jsonString);
                mClientVersion = jsonObject.optLong("clientVersion", -1);
            }
            return true;
        } catch (Exception e) {
            Log.e(TAG, "登录失败：" + e.getMessage());
            return false;
        }
    }

    // 获取 HTTP 响应内容
    private String getResponseContent(HttpEntity entity) throws IOException {
        InputStream inputStream = entity.getContent();
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        StringBuilder stringBuilder = new StringBuilder();
        String line;
        while ((line = bufferedReader.readLine()) != null) {
            stringBuilder.append(line).append("\n");
        }
        return stringBuilder.toString();
    }

    // 获取当前同步的 Google 帐号
    public Account getSyncAccount() {
        return mAccount;
    }

    // 获取已登录状态
    public boolean isLoggedin() {
        return mLoggedin;
    }
}