/*
 * Copyright (C) 2017 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.settingslib.inputmethod;

import static com.android.settingslib.RestrictedLockUtils.EnforcedAdmin;

import android.annotation.UserIdInt;
import android.app.AlertDialog;
import android.content.ActivityNotFoundException;
import android.content.Context;
import android.content.Intent;
import android.content.res.Configuration;
import android.os.UserHandle;
import android.text.TextUtils;
import android.util.Log;
import android.view.ViewGroup;
import android.view.inputmethod.InputMethodInfo;
import android.view.inputmethod.InputMethodManager;
import android.view.inputmethod.InputMethodSubtype;
import android.widget.ImageView;
import android.widget.Switch;
import android.widget.Toast;

import androidx.preference.Preference;
import androidx.preference.Preference.OnPreferenceChangeListener;
import androidx.preference.Preference.OnPreferenceClickListener;
import androidx.preference.PreferenceViewHolder;

import com.android.internal.annotations.VisibleForTesting;
import com.android.settingslib.PrimarySwitchPreference;
import com.android.settingslib.R;
import com.android.settingslib.RestrictedLockUtilsInternal;

import java.text.Collator;
import java.util.List;

/**
 * Input method preference.
 *
 * This preference represents an IME. It is used for two purposes. 1) Using a switch to enable or
 * disable the IME 2) Invoking the setting activity of the IME.
 */
public class InputMethodPreference extends PrimarySwitchPreference
        implements OnPreferenceClickListener, OnPreferenceChangeListener {
    private static final String TAG = InputMethodPreference.class.getSimpleName();

    public interface OnSavePreferenceListener {
        /**
         * Called when this preference needs to be saved its state.
         *
         * Note that this preference is non-persistent and needs explicitly to be saved its state.
         * Because changing one IME state may change other IMEs' state, this is a place to update
         * other IMEs' state as well.
         *
         * @param pref This preference.
         */
        void onSaveInputMethodPreference(InputMethodPreference pref);
    }

    private final InputMethodInfo mImi;
    private final boolean mHasPriorityInSorting;
    private final OnSavePreferenceListener mOnSaveListener;
    private final InputMethodSettingValuesWrapper mInputMethodSettingValues;
    private final boolean mIsAllowedByOrganization;
    @UserIdInt
    private final int mUserId;

    private AlertDialog mDialog = null;

    /**
     * A preference entry of an input method.
     *
     * @param prefContext The Context this preference is associated with.
     * @param imi The {@link InputMethodInfo} of this preference.
     * @param isAllowedByOrganization false if the IME has been disabled by a device or profile
     *     owner.
     * @param onSaveListener The listener called when this preference has been changed and needs
     *     to save the state to shared preference.
     * @param userId The userId to specify the corresponding user for this preference.
     */
    public InputMethodPreference(final Context prefContext, final InputMethodInfo imi,
            final boolean isAllowedByOrganization, final OnSavePreferenceListener onSaveListener,
            final @UserIdInt int userId) {
        this(prefContext, imi, imi.loadLabel(prefContext.getPackageManager()),
                isAllowedByOrganization, onSaveListener, userId);
    }

    @VisibleForTesting
    InputMethodPreference(final Context prefContext, final InputMethodInfo imi,
            final CharSequence title, final boolean isAllowedByOrganization,
            final OnSavePreferenceListener onSaveListener, final @UserIdInt int userId) {
        super(prefContext);
        setPersistent(false);
        mImi = imi;
        mIsAllowedByOrganization = isAllowedByOrganization;
        mOnSaveListener = onSaveListener;
        setKey(imi.getId());
        setTitle(title);
        final String settingsActivity = imi.getSettingsActivity();
        if (TextUtils.isEmpty(settingsActivity)) {
            setIntent(null);
        } else {
            // Set an intent to invoke settings activity of an input method.
            final Intent intent = new Intent(Intent.ACTION_MAIN);
            intent.setClassName(imi.getPackageName(), settingsActivity);
            setIntent(intent);
        }
        // Handle the context by given userId because {@link InputMethodSettingValuesWrapper} is
        // per-user instance.
        final Context userAwareContext = userId == UserHandle.myUserId() ? prefContext :
                getContext().createContextAsUser(UserHandle.of(userId), 0);
        mInputMethodSettingValues = InputMethodSettingValuesWrapper.getInstance(userAwareContext);
        mUserId = userId;
        mHasPriorityInSorting = imi.isSystem()
                && InputMethodAndSubtypeUtil.isValidNonAuxAsciiCapableIme(imi);
        setOnPreferenceClickListener(this);
        setOnPreferenceChangeListener(this);
    }

    public InputMethodInfo getInputMethodInfo() {
        return mImi;
    }

    @Override
    public void onBindViewHolder(PreferenceViewHolder holder) {
        super.onBindViewHolder(holder);
        final Switch switchWidget = getSwitch();
        if (switchWidget != null) {
            // Avoid default behavior in {@link PrimarySwitchPreference#onBindViewHolder}.
            switchWidget.setOnClickListener(v -> {
                if (!switchWidget.isEnabled()) {
                    return;
                }
                final boolean newValue = !isChecked();
                // Keep switch to previous state because we have to show the dialog first.
                switchWidget.setChecked(isChecked());
                callChangeListener(newValue);
            });
        }
        final ImageView icon = holder.itemView.findViewById(android.R.id.icon);
        final int iconSize = getContext().getResources().getDimensionPixelSize(
                R.dimen.secondary_app_icon_size);
        if (icon != null && iconSize > 0) {
            ViewGroup.LayoutParams params = icon.getLayoutParams();
            params.height = iconSize;
            params.width = iconSize;
            icon.setLayoutParams(params);
        }
    }

    @Override
    public boolean onPreferenceChange(final Preference preference, final Object newValue) {
        // Always returns false to prevent default behavior.
        // See {@link TwoStatePreference#onClick()}.
        if (isChecked()) {
            // Disable this IME.
            setCheckedInternal(false);
            return false;
        }
        if (mImi.isSystem()) {
            // Enable a system IME. No need to show a security warning dialog,
            // but we might need to prompt if it's not Direct Boot aware.
            // TV doesn't doesn't need to worry about this, but other platforms should show
            // a warning.
            if (mImi.getServiceInfo().directBootAware || isTv()) {
                setCheckedInternal(true);
            } else if (!isTv()){
                showDirectBootWarnDialog();
            }
        } else {
            // Once security is confirmed, we might prompt if the IME isn't
            // Direct Boot aware.
            showSecurityWarnDialog();
        }
        return false;
    }

    @Override
    public boolean onPreferenceClick(final Preference preference) {
        // Always returns true to prevent invoking an intent without catching exceptions.
        // See {@link Preference#performClick(PreferenceScreen)}/
        final Context context = getContext();
        try {
            final Intent intent = getIntent();
            if (intent != null) {
                // Invoke a settings activity of an input method.
                context.startActivityAsUser(intent, UserHandle.of(mUserId));
            }
        } catch (final ActivityNotFoundException e) {
            Log.d(TAG, "IME's Settings Activity Not Found", e);
            final String message = context.getString(
                    R.string.failed_to_open_app_settings_toast,
                    mImi.loadLabel(context.getPackageManager()));
            Toast.makeText(context, message, Toast.LENGTH_LONG).show();
        }
        return true;
    }

    public void updatePreferenceViews() {
        final boolean isAlwaysChecked = mInputMethodSettingValues.isAlwaysCheckedIme(mImi);
        // When this preference has a switch and an input method should be always enabled,
        // this preference should be disabled to prevent accidentally disabling an input method.
        // This preference should also be disabled in case the admin does not allow this input
        // method.
        if (isAlwaysChecked) {
            setDisabledByAdmin(null);
            setSwitchEnabled(false);
        } else if (!mIsAllowedByOrganization) {
            EnforcedAdmin admin =
                    RestrictedLockUtilsInternal.checkIfInputMethodDisallowed(
                            getContext(), mImi.getPackageName(), mUserId);
            setDisabledByAdmin(admin);
        } else {
            setEnabled(true);
            setSwitchEnabled(true);
        }
        setChecked(mInputMethodSettingValues.isEnabledImi(mImi));
        if (!isDisabledByAdmin()) {
            setSummary(getSummaryString());
        }
    }

    private InputMethodManager getInputMethodManager() {
        return (InputMethodManager)getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
    }

    private String getSummaryString() {
        final InputMethodManager imm = getInputMethodManager();
        final List<InputMethodSubtype> subtypes = imm.getEnabledInputMethodSubtypeList(mImi, true);
        return InputMethodAndSubtypeUtil.getSubtypeLocaleNameListAsSentence(
                subtypes, getContext(), mImi);
    }

    private void setCheckedInternal(boolean checked) {
        super.setChecked(checked);
        mOnSaveListener.onSaveInputMethodPreference(InputMethodPreference.this);
        notifyChanged();
    }

    private void showSecurityWarnDialog() {
        if (mDialog != null && mDialog.isShowing()) {
            mDialog.dismiss();
        }
        final Context context = getContext();
        final AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setCancelable(true /* cancelable */);
        builder.setTitle(android.R.string.dialog_alert_title);
        final CharSequence label = mImi.getServiceInfo().applicationInfo.loadLabel(
                context.getPackageManager());
        builder.setMessage(context.getString(R.string.ime_security_warning, label));
        builder.setPositiveButton(android.R.string.ok, (dialog, which) -> {
            // The user confirmed to enable a 3rd party IME, but we might
            // need to prompt if it's not Direct Boot aware.
            // TV doesn't doesn't need to worry about this, but other platforms should show
            // a warning.
            if (mImi.getServiceInfo().directBootAware || isTv()) {
                setCheckedInternal(true);
            } else {
                showDirectBootWarnDialog();
            }
        });
        builder.setNegativeButton(android.R.string.cancel, (dialog, which) -> {
            // The user canceled to enable a 3rd party IME.
            setCheckedInternal(false);
        });
        builder.setOnCancelListener((dialog) -> {
            // The user canceled to enable a 3rd party IME.
            setCheckedInternal(false);
        });
        mDialog = builder.create();
        mDialog.show();
    }

    private boolean isTv() {
        return (getContext().getResources().getConfiguration().uiMode
                & Configuration.UI_MODE_TYPE_MASK) == Configuration.UI_MODE_TYPE_TELEVISION;
    }

    private void showDirectBootWarnDialog() {
        if (mDialog != null && mDialog.isShowing()) {
            mDialog.dismiss();
        }
        final Context context = getContext();
        final AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setCancelable(true /* cancelable */);
        builder.setMessage(context.getText(R.string.direct_boot_unaware_dialog_message));
        builder.setPositiveButton(android.R.string.ok, (dialog, which) -> setCheckedInternal(true));
        builder.setNegativeButton(android.R.string.cancel,
                (dialog, which) -> setCheckedInternal(false));
        mDialog = builder.create();
        mDialog.show();
    }

    public int compareTo(final InputMethodPreference rhs, final Collator collator) {
        if (this == rhs) {
            return 0;
        }
        if (mHasPriorityInSorting != rhs.mHasPriorityInSorting) {
            // Prefer always checked system IMEs
            return mHasPriorityInSorting ? -1 : 1;
        }
        final CharSequence title = getTitle();
        final CharSequence rhsTitle = rhs.getTitle();
        final boolean emptyTitle = TextUtils.isEmpty(title);
        final boolean rhsEmptyTitle = TextUtils.isEmpty(rhsTitle);
        if (!emptyTitle && !rhsEmptyTitle) {
            return collator.compare(title.toString(), rhsTitle.toString());
        }
        // For historical reasons, an empty text needs to be put at the first.
        return (emptyTitle ? -1 : 0) - (rhsEmptyTitle ? -1 : 0);
    }
}