/*
 * Copyright (C) 2008 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.email.provider;

import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;

public abstract class EmailContent {
    // Newly created objects get this id
    public static final int NOT_SAVED = -1;
    // The base Uri that this piece of content came from
    public Uri baseUri;
    // Lazily initialized uri for this Content
    Uri uri = null;
    // The id of the Content
    public long _id = NOT_SAVED;
    
    // Write the Content into a ContentValues container
    public abstract ContentValues toContentValues();
    // Read the Content from a ContentCursor
    public abstract <T extends EmailContent> T restore (Cursor cursor);
    
    // The Uri is lazily initialized
    public Uri getUri() {
        if (uri == null)
            uri = ContentUris.withAppendedId(baseUri, _id);
        return uri;
    }
    
    public boolean isSaved() {
        return _id != NOT_SAVED;
    }
    
    @SuppressWarnings("unchecked")
    // The Content sub class must have a no-arg constructor
    static public <T extends EmailContent> T getContent(Cursor cursor, Class<T> klass) {
        try {
            T content = klass.newInstance();
            content._id = cursor.getLong(0);
            return (T)content.restore(cursor);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        }
        return null;
    }
    
    // Convenience method that saves or updates some Content
    public Uri saveOrUpdate(Context context) {
        if (!isSaved())
            return context.getContentResolver().insert(baseUri, toContentValues());
        else {
            if (update(context, toContentValues()) == 1)    
                return getUri();
            return null;
        }
    }
    
    public Uri save(Context context) {
        Uri res = context.getContentResolver().insert(baseUri, toContentValues());
        _id = Long.parseLong(res.getPathSegments().get(1));
        return res;
    }
    
    public int update(Context context, ContentValues contentValues) {
        return context.getContentResolver().update(getUri(), contentValues, null, null);
    }
}