/*
 * Copyright 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 android.service.autofill;

import static android.provider.Settings.Secure.AUTOFILL_USER_DATA_MAX_CATEGORY_COUNT;
import static android.provider.Settings.Secure.AUTOFILL_USER_DATA_MAX_FIELD_CLASSIFICATION_IDS_SIZE;
import static android.provider.Settings.Secure.AUTOFILL_USER_DATA_MAX_USER_DATA_SIZE;
import static android.provider.Settings.Secure.AUTOFILL_USER_DATA_MAX_VALUE_LENGTH;
import static android.provider.Settings.Secure.AUTOFILL_USER_DATA_MIN_VALUE_LENGTH;
import static android.view.autofill.Helper.sDebug;

import android.annotation.NonNull;
import android.annotation.Nullable;
import android.app.ActivityThread;
import android.content.ContentResolver;
import android.os.Bundle;
import android.os.Parcel;
import android.os.Parcelable;
import android.provider.Settings;
import android.service.autofill.FieldClassification.Match;
import android.text.TextUtils;
import android.util.ArraySet;
import android.util.Log;
import android.view.autofill.AutofillManager;
import android.view.autofill.Helper;

import com.android.internal.util.Preconditions;

import java.io.PrintWriter;
import java.util.ArrayList;

Defines the user data used for
field classification.
/**
 * Defines the user data used for
 * <a href="AutofillService.html#FieldClassification">field classification</a>.
 */
public final class UserData implements Parcelable {

    private static final String TAG = "UserData";

    private static final int DEFAULT_MAX_USER_DATA_SIZE = 50;
    private static final int DEFAULT_MAX_CATEGORY_COUNT = 10;
    private static final int DEFAULT_MAX_FIELD_CLASSIFICATION_IDS_SIZE = 10;
    private static final int DEFAULT_MIN_VALUE_LENGTH = 3;
    private static final int DEFAULT_MAX_VALUE_LENGTH = 100;

    private final String mId;
    private final String mAlgorithm;
    private final Bundle mAlgorithmArgs;
    private final String[] mCategoryIds;
    private final String[] mValues;

    private UserData(Builder builder) {
        mId = builder.mId;
        mAlgorithm = builder.mAlgorithm;
        mAlgorithmArgs = builder.mAlgorithmArgs;
        mCategoryIds = new String[builder.mCategoryIds.size()];
        builder.mCategoryIds.toArray(mCategoryIds);
        mValues = new String[builder.mValues.size()];
        builder.mValues.toArray(mValues);
    }

    
Gets the name of the algorithm that is used to calculate match scores. /**
     * Gets the name of the algorithm that is used to calculate
     * {@link Match#getScore() match scores}.
     */
    @Nullable
    public String getFieldClassificationAlgorithm() {
        return mAlgorithm;
    }

    
Gets the id.
/**
     * Gets the id.
     */
    public String getId() {
        return mId;
    }

    
@hide
/** @hide */
    public Bundle getAlgorithmArgs() {
        return mAlgorithmArgs;
    }

    
@hide
/** @hide */
    public String[] getCategoryIds() {
        return mCategoryIds;
    }

    
@hide
/** @hide */
    public String[] getValues() {
        return mValues;
    }

    
@hide
/** @hide */
    public void dump(String prefix, PrintWriter pw) {
        pw.print(prefix); pw.print("id: "); pw.print(mId);
        pw.print(prefix); pw.print("Algorithm: "); pw.print(mAlgorithm);
        pw.print(" Args: "); pw.println(mAlgorithmArgs);

        // Cannot disclose field ids or values because they could contain PII
        pw.print(prefix); pw.print("Field ids size: "); pw.println(mCategoryIds.length);
        for (int i = 0; i < mCategoryIds.length; i++) {
            pw.print(prefix); pw.print(prefix); pw.print(i); pw.print(": ");
            pw.println(Helper.getRedacted(mCategoryIds[i]));
        }
        pw.print(prefix); pw.print("Values size: "); pw.println(mValues.length);
        for (int i = 0; i < mValues.length; i++) {
            pw.print(prefix); pw.print(prefix); pw.print(i); pw.print(": ");
            pw.println(Helper.getRedacted(mValues[i]));
        }
    }

    
@hide
/** @hide */
    public static void dumpConstraints(String prefix, PrintWriter pw) {
        pw.print(prefix); pw.print("maxUserDataSize: "); pw.println(getMaxUserDataSize());
        pw.print(prefix); pw.print("maxFieldClassificationIdsSize: ");
        pw.println(getMaxFieldClassificationIdsSize());
        pw.print(prefix); pw.print("maxCategoryCount: "); pw.println(getMaxCategoryCount());
        pw.print(prefix); pw.print("minValueLength: "); pw.println(getMinValueLength());
        pw.print(prefix); pw.print("maxValueLength: "); pw.println(getMaxValueLength());
    }

    
A builder for UserData objects. /**
     * A builder for {@link UserData} objects.
     */
    public static final class Builder {
        private final String mId;
        private final ArrayList<String> mCategoryIds;
        private final ArrayList<String> mValues;
        private String mAlgorithm;
        private Bundle mAlgorithmArgs;
        private boolean mDestroyed;

        // Non-persistent array used to limit the number of unique ids.
        private final ArraySet<String> mUniqueCategoryIds;

        
Creates a new builder for the user data used for field
classification.
The user data must contain at least one pair of value -> categoryId, and more pairs can be added through the add(String, String) method. For example: 
new UserData.Builder("v1", "Bart Simpson", "name")
  .add("bart.simpson@example.com", "email")
  .add("el_barto@example.com", "email")
  .build();

Params:
id – id used to identify the whole UserData object. This id is also returned by AutofillManager.getUserDataId(), which can be used to check if the UserData is up-to-date without fetching the whole object (through AutofillManager.getUserData()).
value – value of the user data.
categoryId – string used to identify the category the value is associated with.
Throws:
IllegalArgumentException – if any of the following occurs:

  
id is empty
  
categoryId is empty
  
value is empty
  
the length of value is lower than UserData.getMinValueLength()
  
the length of value is higher than UserData.getMaxValueLength()
/**
         * Creates a new builder for the user data used for <a href="#FieldClassification">field
         * classification</a>.
         *
         * <p>The user data must contain at least one pair of {@code value} -> {@code categoryId},
         * and more pairs can be added through the {@link #add(String, String)} method. For example:
         *
         * <pre class="prettyprint">
         * new UserData.Builder("v1", "Bart Simpson", "name")
         *   .add("bart.simpson@example.com", "email")
         *   .add("el_barto@example.com", "email")
         *   .build();
         * </pre>
         *
         * @param id id used to identify the whole {@link UserData} object. This id is also returned
         * by {@link AutofillManager#getUserDataId()}, which can be used to check if the
         * {@link UserData} is up-to-date without fetching the whole object (through
         * {@link AutofillManager#getUserData()}).
         *
         * @param value value of the user data.
         * @param categoryId string used to identify the category the value is associated with.
         *
         * @throws IllegalArgumentException if any of the following occurs:
         * <ul>
         *   <li>{@code id} is empty</li>
         *   <li>{@code categoryId} is empty</li>
         *   <li>{@code value} is empty</li>
         *   <li>the length of {@code value} is lower than {@link UserData#getMinValueLength()}</li>
         *   <li>the length of {@code value} is higher than
         *       {@link UserData#getMaxValueLength()}</li>
         * </ul>
         */
        public Builder(@NonNull String id, @NonNull String value, @NonNull String categoryId) {
            mId = checkNotEmpty("id", id);
            checkNotEmpty("categoryId", categoryId);
            checkValidValue(value);
            final int maxUserDataSize = getMaxUserDataSize();
            mCategoryIds = new ArrayList<>(maxUserDataSize);
            mValues = new ArrayList<>(maxUserDataSize);
            mUniqueCategoryIds = new ArraySet<>(getMaxCategoryCount());

            addMapping(value, categoryId);
        }

        
Sets the algorithm used for field classification.
The currently available algorithms can be retrieve through AutofillManager.getAvailableFieldClassificationAlgorithms(). 
If not set, the default algorithm is used instead. 
Params:
name – name of the algorithm or null to used default.
args – optional arguments to the algorithm.
Returns:
this builder/**
         * Sets the algorithm used for <a href="#FieldClassification">field classification</a>.
         *
         * <p>The currently available algorithms can be retrieve through
         * {@link AutofillManager#getAvailableFieldClassificationAlgorithms()}.
         *
         * <p>If not set, the
         * {@link AutofillManager#getDefaultFieldClassificationAlgorithm() default algorithm} is
         * used instead.
         *
         * @param name name of the algorithm or {@code null} to used default.
         * @param args optional arguments to the algorithm.
         *
         * @return this builder
         */
        public Builder setFieldClassificationAlgorithm(@Nullable String name,
                @Nullable Bundle args) {
            throwIfDestroyed();
            mAlgorithm = name;
            mAlgorithmArgs = args;
            return this;
        }

        
Adds a new value for user data.
Params:
value – value of the user data.
categoryId – string used to identify the category the value is associated with.
Throws:
IllegalStateException – if:

  
build() already called
  
the value has already been added
  
the number of unique categoryId values added so far is more than UserData.getMaxCategoryCount()
  
the number of values added so far is is more than UserData.getMaxUserDataSize()
IllegalArgumentException – if any of the following occurs:

  
id is empty
  
categoryId is empty
  
value is empty
  
the length of value is lower than UserData.getMinValueLength()
  
the length of value is higher than UserData.getMaxValueLength()
/**
         * Adds a new value for user data.
         *
         * @param value value of the user data.
         * @param categoryId string used to identify the category the value is associated with.
         *
         * @throws IllegalStateException if:
         * <ul>
         *   <li>{@link #build()} already called</li>
         *   <li>the {@code value} has already been added</li>
         *   <li>the number of unique {@code categoryId} values added so far is more than
         *       {@link UserData#getMaxCategoryCount()}</li>
         *   <li>the number of {@code values} added so far is is more than
         *       {@link UserData#getMaxUserDataSize()}</li>
         * </ul>
         *
         * @throws IllegalArgumentException if any of the following occurs:
         * <ul>
         *   <li>{@code id} is empty</li>
         *   <li>{@code categoryId} is empty</li>
         *   <li>{@code value} is empty</li>
         *   <li>the length of {@code value} is lower than {@link UserData#getMinValueLength()}</li>
         *   <li>the length of {@code value} is higher than
         *       {@link UserData#getMaxValueLength()}</li>
         * </ul>
         */
        public Builder add(@NonNull String value, @NonNull String categoryId) {
            throwIfDestroyed();
            checkNotEmpty("categoryId", categoryId);
            checkValidValue(value);

            if (!mUniqueCategoryIds.contains(categoryId)) {
                // New category - check size
                Preconditions.checkState(mUniqueCategoryIds.size() < getMaxCategoryCount(),
                        "already added " + mUniqueCategoryIds.size() + " unique category ids");

            }

            Preconditions.checkState(!mValues.contains(value),
                    // Don't include value on message because it could contain PII
                    "already has entry with same value");
            Preconditions.checkState(mValues.size() < getMaxUserDataSize(),
                    "already added " + mValues.size() + " elements");
            addMapping(value, categoryId);

            return this;
        }

        private void addMapping(@NonNull String value, @NonNull String categoryId) {
            mCategoryIds.add(categoryId);
            mValues.add(value);
            mUniqueCategoryIds.add(categoryId);
        }

        private String checkNotEmpty(@NonNull String name, @Nullable String value) {
            Preconditions.checkNotNull(value);
            Preconditions.checkArgument(!TextUtils.isEmpty(value), "%s cannot be empty", name);
            return value;
        }

        private void checkValidValue(@Nullable String value) {
            Preconditions.checkNotNull(value);
            final int length = value.length();
            Preconditions.checkArgumentInRange(length, getMinValueLength(),
                    getMaxValueLength(), "value length (" + length + ")");
        }

        
Creates a new UserData instance. 
You should not interact with this builder once this method is called.
Throws:
IllegalStateException – if build() was already called.
Returns:
The built dataset./**
         * Creates a new {@link UserData} instance.
         *
         * <p>You should not interact with this builder once this method is called.
         *
         * @throws IllegalStateException if {@link #build()} was already called.
         *
         * @return The built dataset.
         */
        public UserData build() {
            throwIfDestroyed();
            mDestroyed = true;
            return new UserData(this);
        }

        private void throwIfDestroyed() {
            if (mDestroyed) {
                throw new IllegalStateException("Already called #build()");
            }
        }
    }

    /////////////////////////////////////
    // Object "contract" methods. //
    /////////////////////////////////////
    @Override
    public String toString() {
        if (!sDebug) return super.toString();

        final StringBuilder builder = new StringBuilder("UserData: [id=").append(mId)
                .append(", algorithm=").append(mAlgorithm);
        // Cannot disclose category ids or values because they could contain PII
        builder.append(", categoryIds=");
        Helper.appendRedacted(builder, mCategoryIds);
        builder.append(", values=");
        Helper.appendRedacted(builder, mValues);
        return builder.append("]").toString();
    }

    /////////////////////////////////////
    // Parcelable "contract" methods. //
    /////////////////////////////////////

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel parcel, int flags) {
        parcel.writeString(mId);
        parcel.writeStringArray(mCategoryIds);
        parcel.writeStringArray(mValues);
        parcel.writeString(mAlgorithm);
        parcel.writeBundle(mAlgorithmArgs);
    }

    public static final Parcelable.Creator<UserData> CREATOR =
            new Parcelable.Creator<UserData>() {
        @Override
        public UserData createFromParcel(Parcel parcel) {
            // Always go through the builder to ensure the data ingested by
            // the system obeys the contract of the builder to avoid attacks
            // using specially crafted parcels.
            final String id = parcel.readString();
            final String[] categoryIds = parcel.readStringArray();
            final String[] values = parcel.readStringArray();
            final Builder builder = new Builder(id, values[0], categoryIds[0])
                    .setFieldClassificationAlgorithm(parcel.readString(), parcel.readBundle());
            for (int i = 1; i < categoryIds.length; i++) {
                builder.add(values[i], categoryIds[i]);
            }
            return builder.build();
        }

        @Override
        public UserData[] newArray(int size) {
            return new UserData[size];
        }
    };

    
Gets the maximum number of values that can be added to a UserData. /**
     * Gets the maximum number of values that can be added to a {@link UserData}.
     */
    public static int getMaxUserDataSize() {
        return getInt(AUTOFILL_USER_DATA_MAX_USER_DATA_SIZE, DEFAULT_MAX_USER_DATA_SIZE);
    }

    
Gets the maximum number of ids that can be passed to Builder.setFieldClassificationIds(AutofillId...). /**
     * Gets the maximum number of ids that can be passed to {@link
     * FillResponse.Builder#setFieldClassificationIds(android.view.autofill.AutofillId...)}.
     */
    public static int getMaxFieldClassificationIdsSize() {
        return getInt(AUTOFILL_USER_DATA_MAX_FIELD_CLASSIFICATION_IDS_SIZE,
            DEFAULT_MAX_FIELD_CLASSIFICATION_IDS_SIZE);
    }

    
Gets the maximum number of unique category ids that can be passed to the builder's constructor and Builder.add(String, String). /**
     * Gets the maximum number of unique category ids that can be passed to
     * the builder's constructor and {@link Builder#add(String, String)}.
     */
    public static int getMaxCategoryCount() {
        return getInt(AUTOFILL_USER_DATA_MAX_CATEGORY_COUNT, DEFAULT_MAX_CATEGORY_COUNT);
    }

    
Gets the minimum length of values passed to the builder's constructor or or Builder.add(String, String). /**
     * Gets the minimum length of values passed to the builder's constructor or
     * or {@link Builder#add(String, String)}.
     */
    public static int getMinValueLength() {
        return getInt(AUTOFILL_USER_DATA_MIN_VALUE_LENGTH, DEFAULT_MIN_VALUE_LENGTH);
    }

    
Gets the maximum length of values passed to the builder's constructor or or Builder.add(String, String). /**
     * Gets the maximum length of values passed to the builder's constructor or
     * or {@link Builder#add(String, String)}.
     */
    public static int getMaxValueLength() {
        return getInt(AUTOFILL_USER_DATA_MAX_VALUE_LENGTH, DEFAULT_MAX_VALUE_LENGTH);
    }

    private static int getInt(String settings, int defaultValue) {
        ContentResolver cr = null;
        final ActivityThread at = ActivityThread.currentActivityThread();
        if (at != null) {
            cr = at.getApplication().getContentResolver();
        }

        if (cr == null) {
            Log.w(TAG, "Could not read from " + settings + "; hardcoding " + defaultValue);
            return defaultValue;
        }
        return Settings.Secure.getInt(cr, settings, defaultValue);
    }
}