/*
 * Copyright 2013 serso aka se.solovyev
 *
 * 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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * Contact details
 *
 * Email: se.solovyev@gmail.com
 * Site:  http://se.solovyev.org
 */

package org.solovyev.android.prefs;

import android.content.SharedPreferences;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

/**
 * Base class for {@link Preference} implementation. Contains preference key and default value
 *
 * @param <T> type of preference
 */
public abstract class AbstractPreference<T> implements Preference<T> {

    @Nonnull
    private final String key;

    private final T defaultValue;
    protected AbstractPreference(@Nonnull String key, @Nullable T defaultValue) {
        this.key = key;
        this.defaultValue = defaultValue;
    }

    @Nonnull
    public String getKey() {
        return key;
    }

    public T getDefaultValue() {
        return defaultValue;
    }

    @Override
    public final T getPreference(@Nonnull SharedPreferences preferences) {
        if (isSet(preferences)) {
            return getPersistedValue(preferences);
        } else {
            return this.defaultValue;
        }
    }

    @Override
    public T getPreferenceNoError(@Nonnull SharedPreferences preferences) {
        if (isSet(preferences)) {
            try {
                return getPersistedValue(preferences);
            } catch (RuntimeException e) {
                return this.defaultValue;
            }
        } else {
            return this.defaultValue;
        }
    }

    @Override
    public void putDefault(@Nonnull SharedPreferences.Editor editor) {
        putPreference(editor, this.defaultValue);
    }

    @Override
    public void putDefault(@Nonnull SharedPreferences preferences) {
        putPreference(preferences, this.defaultValue);
    }

    @Override
    public void putPreference(@Nonnull SharedPreferences.Editor editor, @Nullable T value) {
        if (value == null) {
            return;
        }
        putPersistedValue(editor, value);
    }

    @Override
    public void putPreference(@Nonnull SharedPreferences preferences, @Nullable T value) {
        if (value == null) {
            return;
        }
        final SharedPreferences.Editor editor = preferences.edit();
        putPersistedValue(editor, value);
        editor.apply();
    }

    @Override
    public boolean isSet(@Nonnull SharedPreferences preferences) {
        return preferences.contains(this.key);
    }

    @Override
    public final boolean tryPutDefault(@Nonnull SharedPreferences preferences) {
        final SharedPreferences.Editor editor = preferences.edit();
        final boolean changed = tryPutDefault(preferences, editor);
        editor.apply();
        return changed;
    }

    @Override
    public final boolean tryPutDefault(@Nonnull SharedPreferences preferences, @Nonnull SharedPreferences.Editor editor) {
        if (isSet(preferences)) {
            return false;
        }

        putDefault(editor);
        return true;
    }

    @Override
    public final boolean isSameKey(@Nonnull String key) {
        return this.key.equals(key);
    }

    /**
     * @param preferences preferences container
     * @return preference value from preferences with key defined by {@link #getKey()} method
     */
    @Nullable
    protected abstract T getPersistedValue(@Nonnull SharedPreferences preferences);

    /**
     * Method saved preference to preferences container editor
     *
     * @param editor editor in which value must be saved
     * @param value  value to be saved
     */
    protected abstract void putPersistedValue(@Nonnull SharedPreferences.Editor editor, @Nonnull T value);

}