/*
 * 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.tv.settings.inputmethod;

import android.annotation.DrawableRes;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.app.Activity;
import android.app.admin.DevicePolicyManager;
import android.app.tvsettings.TvSettingsEnums;
import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.content.pm.ServiceInfo;
import android.content.res.Configuration;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.os.UserHandle;
import android.view.inputmethod.InputMethodInfo;
import android.view.inputmethod.InputMethodManager;

import androidx.annotation.Keep;
import androidx.preference.PreferenceCategory;
import androidx.preference.PreferenceScreen;

import com.android.settingslib.inputmethod.InputMethodAndSubtypeUtilCompat;
import com.android.settingslib.inputmethod.InputMethodPreference;
import com.android.settingslib.inputmethod.InputMethodSettingValuesWrapper;
import com.android.tv.settings.R;
import com.android.tv.settings.SettingsPreferenceFragment;
import com.android.tv.settings.util.SliceUtils;
import com.android.tv.twopanelsettings.slices.SliceShard;
import com.android.tv.twopanelsettings.slices.compat.Slice;

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

/**
 * Fragment for enabling/disabling virtual keyboard IMEs
 */
@Keep
public final class AvailableVirtualKeyboardFragment extends SettingsPreferenceFragment
        implements InputMethodPreference.OnSavePreferenceListener, SliceShard.Callbacks {
    private static final String VIRTUAL_KEYBOARD_LIST_KEY = "virtual_keyboard_list";

    private final ArrayList<TVInputMethodPreference> mInputMethodPreferenceList = new ArrayList<>();
    private InputMethodSettingValuesWrapper mInputMethodSettingValues;
    private InputMethodManager mImm;
    private DevicePolicyManager mDpm;
    private SliceShard mSliceShard;

    @Override
    public void onCreatePreferences(Bundle bundle, String s) {
        Activity activity = getActivity();
        mInputMethodSettingValues = InputMethodSettingValuesWrapper.getInstance(activity);
        mImm = activity.getSystemService(InputMethodManager.class);
        mDpm = activity.getSystemService(DevicePolicyManager.class);

        var sliceUri = SliceShard.Companion.getSliceUri(getResources(),
                R.string.virtual_keyboards_fragment_slice_uri, R.string.main_fragment_slice_uri,
                "available_virtual_keyboards");
        if (!SliceUtils.isSliceProviderValid(requireContext(), sliceUri)) {
            setPreferencesFromResource(R.xml.available_virtual_keyboards, null);
            return;
        }

        setPreferencesFromResource(R.xml.settings_loading, null);
        mSliceShard = new SliceShard(this, sliceUri, this,
                getString(R.string.available_virtual_keyboard_category),
                SliceShard.Companion.getPrefContext(requireContext()), true);
    }

    @Override
    public void onSlice(@androidx.annotation.Nullable Slice slice) {
        mSliceShard = null;
        if (slice == null) {
            setPreferencesFromResource(R.xml.available_virtual_keyboards, null);
        }
        configurePreferences();
    }

    private void configurePreferences() {
        mInputMethodSettingValues.refreshAllInputMethodAndSubtypes();
        updateInputMethodPreferenceViews();
    }

    @Override
    public void onResume() {
        super.onResume();
        // Refresh internal states in mInputMethodSettingValues to keep the latest
        // "InputMethodInfo"s and "InputMethodSubtype"s
        if (mSliceShard == null) {
            configurePreferences();
        }
    }

    @Override
    public void onSaveInputMethodPreference(final InputMethodPreference pref) {
        final boolean hasHardwareKeyboard = getResources().getConfiguration().keyboard
                == Configuration.KEYBOARD_QWERTY;
        InputMethodAndSubtypeUtilCompat.saveInputMethodSubtypeList(this,
                getContext().getContentResolver(), mImm.getInputMethodList(), hasHardwareKeyboard);
        // Update input method settings and preference list.
        mInputMethodSettingValues.refreshAllInputMethodAndSubtypes();
        for (final InputMethodPreference p : mInputMethodPreferenceList) {
            p.updatePreferenceViews();
        }
    }

    @Nullable
    private static Drawable loadDrawable(@NonNull final PackageManager packageManager,
            @NonNull final String packageName, @DrawableRes final int resId,
            @NonNull final ApplicationInfo applicationInfo) {
        if (resId == 0) {
            return null;
        }
        try {
            return packageManager.getDrawable(packageName, resId, applicationInfo);
        } catch (Exception e) {
            return null;
        }
    }

    @NonNull
    private static Drawable getInputMethodIcon(@NonNull final PackageManager packageManager,
            @NonNull final InputMethodInfo imi) {
        final ServiceInfo si = imi.getServiceInfo();
        final ApplicationInfo ai = si != null ? si.applicationInfo : null;
        final String packageName = imi.getPackageName();
        if (si == null || ai == null || packageName == null) {
            return new ColorDrawable(Color.TRANSPARENT);
        }
        // We do not use ServiceInfo#loadLogo() and ServiceInfo#loadIcon here since those methods
        // internally have some fallback rules, which we want to do manually.
        Drawable drawable = loadDrawable(packageManager, packageName, si.logo, ai);
        if (drawable != null) {
            return drawable;
        }
        drawable = loadDrawable(packageManager, packageName, si.icon, ai);
        if (drawable != null) {
            return drawable;
        }
        // We do not use ApplicationInfo#loadLogo() and ApplicationInfo#loadIcon here since those
        // methods internally have some fallback rules, which we want to do manually.
        drawable = loadDrawable(packageManager, packageName, ai.logo, ai);
        if (drawable != null) {
            return drawable;
        }
        drawable = loadDrawable(packageManager, packageName, ai.icon, ai);
        if (drawable != null) {
            return drawable;
        }
        return new ColorDrawable(Color.TRANSPARENT);
    }

    private void updateInputMethodPreferenceViews() {
        mInputMethodSettingValues.refreshAllInputMethodAndSubtypes();
        // Clear existing "TVInputMethodPreference"s
        mInputMethodPreferenceList.clear();
        List<String> permittedList = mDpm.getPermittedInputMethodsForCurrentUser();
        final Context context = getPreferenceManager().getContext();
        final PackageManager packageManager = getActivity().getPackageManager();
        final List<InputMethodInfo> imis = mInputMethodSettingValues.getInputMethodList();
        final int numImis = (imis == null ? 0 : imis.size());
        for (int i = 0; i < numImis; ++i) {
            final InputMethodInfo imi = imis.get(i);
            final boolean isAllowedByOrganization = permittedList == null
                    || permittedList.contains(imi.getPackageName());
            final TVInputMethodPreference pref = new TVInputMethodPreference(
                    context, imi, isAllowedByOrganization, this, UserHandle.myUserId());
            // TODO: Update the icon container in leanback_preference.xml to use LinearLayout.
            // This is a workaround to avoid the crash. b/146654624
            pref.setIconSize(0);
            pref.setIcon(getInputMethodIcon(packageManager, imi));
            mInputMethodPreferenceList.add(pref);
        }
        final Collator collator = Collator.getInstance();
        mInputMethodPreferenceList.sort((lhs, rhs) -> lhs.compareTo(rhs, collator));
        PreferenceCategory keyboardList = findPreference(VIRTUAL_KEYBOARD_LIST_KEY);
        keyboardList.removeAll();
        for (int i = 0; i < numImis; ++i) {
            final TVInputMethodPreference pref = mInputMethodPreferenceList.get(i);
            pref.setOrder(i);
            keyboardList.addPreference(pref);
            InputMethodAndSubtypeUtilCompat.removeUnnecessaryNonPersistentPreference(pref);
            pref.updatePreferenceViews();
        }
    }

    @Override
    protected int getPageId() {
        return TvSettingsEnums.SYSTEM_KEYBOARD_MANAGE_KEYBOARDS;
    }
}