import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.annotation.TargetApi;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.graphics.Color;
import android.preference.PreferenceManager;
import android.support.annotation.NonNull;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.app.LoaderManager.LoaderCallbacks;
 
import android.content.CursorLoader;
import android.content.Loader;
import android.database.Cursor;
import android.net.Uri;
import android.os.AsyncTask;
 
import android.os.Build;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.text.TextUtils;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.inputmethod.EditorInfo;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
 
import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
 
import org.json.JSONException;
import org.json.JSONObject;
 
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
 
 
import static android.Manifest.permission.READ_CONTACTS;
 
/**
 * A login screen that offers login via name/password.
 * 通过账号/密码提供登录的登录屏幕。
 */
public class LoginActivity extends AppCompatActivity implements LoaderCallbacks<Cursor> {
 
    /**
     * Id to identity READ_CONTACTS permission request.
     * ID来标识READ_CONTACTS权限请求。
     */
    private static final int REQUEST_READ_CONTACTS = 0;
 
    /**
     * A dummy authentication store containing known user names and passwords.
     * 包含已知用户名和密码的虚假认证存储。
     * TODO: remove after connecting to a real authentication system.
     * 连接到真实身份验证系统后删除。
     */
    private static final String[] DUMMY_CREDENTIALS = new String[]{
            "foo@example.com:hello", "bar@example.com:world",
            //DUMMY_CREDENTTALS用于模拟已存在的账户，冒号前为账户，冒号后为密码
    };
    /**
     * Keep track of the login task to ensure we can cancel it if requested.
     * 跟踪登录任务以确保我们可以根据请求取消它。
     */
    private UserLoginTask mAuthTask = null;
 
    // UI references.
    private AutoCompleteTextView mUserNameView;
    private EditText mPasswordView;
    private View mProgressView;
    private View mLoginFormView;
 
    private SharedPreferences preferences;
    private SharedPreferences.Editor editor;
    //记住密码
    private CheckBox rememberPass;
    //自动登录
    private CheckBox autoLogin;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        if (Build.VERSION.SDK_INT >= 21) {
            View decorView = getWindow().getDecorView();
            decorView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                    | View.SYSTEM_UI_FLAG_LAYOUT_STABLE);
            getWindow().setStatusBarColor(Color.TRANSPARENT);
        }
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        preferences = PreferenceManager.getDefaultSharedPreferences(this);
        // Set up the login form. 设置登录表单
 
        rememberPass = (CheckBox) findViewById(R.id.remember_pass);
        autoLogin = (CheckBox) findViewById(R.id.auto_login);
        //账号输入
        mUserNameView = (AutoCompleteTextView) findViewById(R.id.UserName);
        populateAutoComplete();
        //密码输入
        mPasswordView = (EditText) findViewById(R.id.password);
        mPasswordView.setOnEditorActionListener(new TextView.OnEditorActionListener() {
            @Override
            public boolean onEditorAction(TextView textView, int id, KeyEvent keyEvent) {
                if (id == EditorInfo.IME_ACTION_DONE || id == EditorInfo.IME_NULL) {
                    attemptLogin();
                    return true;
                }
                return false;
            }
        });
 
        //记住密码
        boolean isRemember = preferences.getBoolean("remember_password",false);
        boolean isAutoLogin = preferences.getBoolean("auto_Login",false);
        if(isRemember ) {
            //将账户和密码都设置到文本框中
            String account = preferences.getString("UserName", "");
            String password = preferences.getString("password", "");
            mUserNameView.setText(account);
            mPasswordView.setText(password);
            rememberPass.setChecked(true);
            //自动登录
            if (isAutoLogin) {
                Intent intent = new Intent(LoginActivity.this, MainActivity.class);
                LoginActivity.this.startActivity(intent);
                Toast.makeText(getApplicationContext(), "自动登录", Toast.LENGTH_SHORT).show();
            }
        }
        //登录按钮
        Button mUserNameSignInButton = (Button) findViewById(R.id.UserName_sign_in_button);
        mUserNameSignInButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                attemptLogin();
            }
        });
        //注册按钮
        Button register = (Button) findViewById(R.id.register);
        register.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(LoginActivity.this,registerActivity.class);
                startActivity(intent);
            }
        });
 
        //方法最后两个mLoginFormView和mProgressView是用于获取显示的View，
        //在登陆的时候可以进行登陆窗口gone，ProgressBar visible的操作。
        mLoginFormView = findViewById(R.id.login_form);
        mProgressView = findViewById(R.id.login_progress);
    }
 
    //先是通过mayRequestContacts判断是否继续执行，若通过判断则初始化Loaders，通过Loaders后台异步读取用户的账户信息。
    private void populateAutoComplete() {
        if (!mayRequestContacts()) {
            return;
        }
 
        getLoaderManager().initLoader(0, null, this);
    }
 
    //这个方法是用于请求用户以获取读取账户的权限，主要是为了适配6.0新的权限机制
    private boolean mayRequestContacts() {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
            return true;
        }
        if (checkSelfPermission(READ_CONTACTS) == PackageManager.PERMISSION_GRANTED) {
            return true;
        }
        if (shouldShowRequestPermissionRationale(READ_CONTACTS)) {
            Snackbar.make(mUserNameView, R.string.permission_rationale, Snackbar.LENGTH_INDEFINITE)
                    .setAction(android.R.string.ok, new View.OnClickListener() {
                        @Override
                        @TargetApi(Build.VERSION_CODES.M)
                        public void onClick(View v) {
                            requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS);
                        }
                    });
        } else {
            requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS);
        }
        return false;
    }
 
    /**
     * Callback received when a permissions request has been completed.
     * 当权限请求已完成时收到回调。
     */
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {
        if (requestCode == REQUEST_READ_CONTACTS) {
            if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                populateAutoComplete();
            }
        }
    }
 
 
    /**
     * Attempts to sign in or register the account specified by the login form.
     * 尝试登录或注册登录表单指定的帐户。
     * If there are form errors (invalid UserName, missing fields, etc.), the
     * 如果有表单错误（无效的电子邮件，缺少字段等）
     * errors are presented and no actual login attempt is made.
     * 出现错误并且没有进行实际的登录尝试。
     */
    private void attemptLogin() {
        if (mAuthTask != null) {
            return;
        }
 
        // Reset errors.重置错误。
        mUserNameView.setError(null);
        mPasswordView.setError(null);
 
 
        // Store values at the time of the login attempt.在登录尝试时存储值。
        String UserName = mUserNameView.getText().toString();
        String password = mPasswordView.getText().toString();
            editor = preferences.edit();
            if(autoLogin.isChecked()){
                editor.putBoolean("auto_Login",true);
            }
            if (rememberPass.isChecked()) {
                editor.putBoolean("remember_password", true);
                editor.putString("UserName", UserName);
                editor.putString("password", password);
            } else {
                editor.clear();
            }
            editor.apply();
 
        boolean cancel = false;
        View focusView = null;
 
        // Check for a valid password, if the user entered one.如果用户输入密码，请检查有效的密码。
        if (!TextUtils.isEmpty(password) && !isPasswordValid(password)) {
            mPasswordView.setError(getString(R.string.error_invalid_password));
            focusView = mPasswordView;
            cancel = true;
        }
 
        // Check
        if (TextUtils.isEmpty(UserName)) {
            mUserNameView.setError(getString(R.string.error_field_required));
            focusView = mUserNameView;
            cancel = true;
        } else if (!isUserNameValid(UserName)) {
            mUserNameView.setError(getString(R.string.error_invalid_UserName));
            focusView = mUserNameView;
            cancel = true;
        }
 
        if (cancel) {
            // There was an error; don't attempt login and focus the first
            //有一个错误;不要尝试登录并首先关注
            // form field with an error.
            //表单字段有错误。
            focusView.requestFocus();
        } else {
            // Show a progress spinner, and kick off a background task to
            //显示进度微调，并启动后台任务
            // perform the user login attempt.
            //执行用户登录尝试。
            showProgress(true);
            mAuthTask = new UserLoginTask(UserName, password);
            mAuthTask.execute((Void) null);
 
        }
    }
 
    private boolean isUserNameValid(String UserName) {
        //TODO: Replace this with your own logic 用你自己的逻辑代替这个
        return UserName.contains("@");
    }
 
    private boolean isPasswordValid(String password) {
        //TODO: Replace this with your own logic 用你自己的逻辑代替这个
        return password.length() > 4;
    }
 
    /**
     * Shows the progress UI and hides the login form.
     * 显示进度UI并隐藏登录表单。
     */
    @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
    private void showProgress(final boolean show) {
        // On Honeycomb MR2 we have the ViewPropertyAnimator APIs, which allow
        // for very easy animations. If available, use these APIs to fade-in
        // the progress spinner.
        
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2) {
            int shortAnimTime = getResources().getInteger(android.R.integer.config_shortAnimTime);
 
            mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
            mLoginFormView.animate().setDuration(shortAnimTime).alpha(
                    show ? 0 : 1).setListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
                }
            });
 
            mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
            mProgressView.animate().setDuration(shortAnimTime).alpha(
                    show ? 1 : 0).setListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
                }
            });
        } else {
            // The ViewPropertyAnimator APIs are not available, so simply show
            // and hide the relevant UI components.
            //ViewPropertyAnimator API不可用，因此只需显示和隐藏相关的UI组件。
            mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
            mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
        }
    }
 
    @Override
    public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
        return new CursorLoader(this,
                // Retrieve data rows for the device user's 'profile' contact.
                //检索设备用户的“个人资料”联系人的数据行。
                Uri.withAppendedPath(ContactsContract.Profile.CONTENT_URI,
                        ContactsContract.Contacts.Data.CONTENT_DIRECTORY), ProfileQuery.PROJECTION,
 
                ContactsContract.Contacts.Data.MIMETYPE +
                        " = ?", new String[]{ContactsContract.CommonDataKinds.UserName
                .CONTENT_ITEM_TYPE},
             
                ContactsContract.Contacts.Data.IS_PRIMARY + " DESC");
    }
 
    @Override
    public void onLoadFinished(Loader<Cursor> cursorLoader, Cursor cursor) {
        List<String> UserNames = new ArrayList<>();
        cursor.moveToFirst();
        while (!cursor.isAfterLast()) {
            UserNames.add(cursor.getString(ProfileQuery.ADDRESS));
            cursor.moveToNext();
        }
 
        addUserNamesToAutoComplete(UserNames);
    }
 
    @Override
    public void onLoaderReset(Loader<Cursor> cursorLoader) {
 
    }
 
    private void addUserNamesToAutoComplete(List<String> UserNameAddressCollection) {
        //Create adapter to tell the AutoCompleteTextView what to show in its dropdown list.
        //创建适配器以告诉AutoCompleteTextView在其下拉列表中显示什么。
        ArrayAdapter<String> adapter =
                new ArrayAdapter<>(LoginActivity.this,
                        android.R.layout.simple_dropdown_item_1line, UserNameAddressCollection);
 
        mUserNameView.setAdapter(adapter);
    }
 
 
    private interface ProfileQuery {
        String[] PROJECTION = {
                ContactsContract.CommonDataKinds.UserName.ADDRESS,
                ContactsContract.CommonDataKinds.UserName.IS_PRIMARY,
        };
 
        int ADDRESS = 0;
        int IS_PRIMARY = 1;
    }
 
    /**
     * Represents an asynchronous login/registration task used to authenticate
     * the user.
     * 表示用于验证用户的异步登录/注册任务。
     */
    public class UserLoginTask extends AsyncTask<Void, Void, Boolean> {
 
        private final String mUserName;
        private final String mPassword;
 
        UserLoginTask(String UserName, String password) {
            mUserName = UserName;
            mPassword = password;
        }
 
        @Override
        protected Boolean doInBackground(Void... params) {
            // TODO: attempt authentication against a network service.
            //尝试对网络服务进行身份验证。
 
            try {
                LoginRequest(mUserName,mPassword);
 
 
 
                // Simulate network access.模拟网络访问。
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                return false;
            }
 
            for (String credential : DUMMY_CREDENTIALS) {
                String[] pieces = credential.split(":");
                if (pieces[0].equals(mUserName)) {
                    // Account exists, return true if the password matches.
                    //帐户存在，如果密码匹配则返回true。
                    return pieces[1].equals(mPassword);
                }
            }
 
            // TODO: register the new account here.
            //在此注册新帐户。
            return true;
        }
 
        @Override
        protected void onPostExecute(final Boolean success) {
            mAuthTask = null;
            showProgress(false);
 
            if (success) {
                /*
                Intent intent = new Intent(LoginActivity.this,MainActivity.class);
                startActivity(intent);
                finish();
                */
            } else {
                mPasswordView.setError(getString(R.string.error_incorrect_password));
                mPasswordView.requestFocus();
            }
        }
 
        @Override
        protected void onCancelled() {
            mAuthTask = null;
            showProgress(false);
        }
    }
 
    public  void LoginRequest(final String account, final String password) {
        //请求地址
        String url = "http://8.130.38.15:8080/Whoere/LoginServlet?account="+account+"&password="+password;
        String tag = "Login";
 
        //取得请求队列
        RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
 
        //防止重复请求，所以先取消tag标识的请求队列
        requestQueue.cancelAll(tag);
 
        //创建StringRequest，定义字符串请求的请求方式为POST(省略第一个参数会默认为GET方式)
        final StringRequest request = new StringRequest(Request.Method.POST, url,
                new Response.Listener<String>() {
                    //@Override
                    public void onResponse(String response) {
                        try {
                            JSONObject jsonObject = (JSONObject) new JSONObject(response).get("params"); 
                            String result = jsonObject.getString("Result"); 
                            if (result.equals("success")) { 
                                //做自己的登录成功操作，如页面跳转
                                Intent intent = new Intent(LoginActivity.this,MainActivity.class);
                                startActivity(intent);
                                Toast.makeText(LoginActivity.this,"欢迎!",Toast.LENGTH_LONG).show();
                            } else {
                                if (result.equals("failed"))
                                Toast.makeText(LoginActivity.this,"账户或密码错误！",Toast.LENGTH_SHORT).show();
                            }
                        } catch (JSONException e) {
                            //做自己的请求异常操作，如Toast提示（“无网络连接”等）
                            Log.e("TAG", e.getMessage(), e);
                        }
                    }
                }, new Response.ErrorListener() {
            //@Override
            public void onErrorResponse(VolleyError error) {
                //做自己的响应错误操作，如Toast提示（“请稍后重试”等）
                Log.e("TAG", error.getMessage(), error);
            }
        }) {
            @Override
            protected Map<String, String> getParams()  {
                Map<String, String> params = new HashMap<>();
                params.put("Account", account);
                params.put("Password", password);
                return params;
            }
        };
 
        //设置Tag标签
        request.setTag(tag);
 
        //将请求添加到队列中
        requestQueue.add(request);
    }
}