package com.example.ormlite.cursor;

import android.content.AsyncTaskLoader;
import android.content.Context;
import android.database.Cursor;

import com.j256.ormlite.dao.Dao;
import com.j256.ormlite.stmt.PreparedQuery;
import com.j256.ormlite.support.DatabaseConnection;
import com.j256.ormlite.android.AndroidCompiledStatement


import java.sql.SQLException;

import static com.j256.ormlite.stmt.StatementBuilder.StatementType.SELECT;

/**
 * Cursor loader supported by later Android APIs that allows asynchronous content loading.
 * Edited by andrei on 26/15/15
 * @author emmby
 */
public class OrmLiteCursorLoader<T> extends AsyncTaskLoader<Cursor> {

    protected Dao<T, ?> dao;
    protected PreparedQuery<T> query;
    protected Cursor cursor;

    public OrmLiteCursorLoader(Context context, Dao<T, ?> dao, PreparedQuery<T> query) {
        super(context);
        this.dao = dao;
        this.query = query;
//        dao.registerObserver(this);
    }

    @Override
    public Cursor loadInBackground() {
        Cursor cursor;
        try {
            DatabaseConnection connection = dao.getConnectionSource().getReadOnlyConnection();
            cursor = ((AndroidCompiledStatement) query.compile(connection, SELECT)).getCursor();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }

        // fill the cursor with results
        cursor.getCount();
        return cursor;
    }

    @Override
    public void deliverResult(Cursor newCursor) {
        if (isReset()) {
            // an async query came in while the loader is stopped
            if (newCursor != null) {
                newCursor.close();
            }
            return;
        }

        Cursor oldCursor = cursor;
        cursor = newCursor;

        if (isStarted()) {
            super.deliverResult(newCursor);
        }

        // close the old cursor if necessary
        if (oldCursor != null && oldCursor != newCursor && !oldCursor.isClosed()) {
            oldCursor.close();
        }
    }

    @Override
    protected void onStartLoading() {
        if (cursor == null) {
            forceLoad();
        } else {
            deliverResult(cursor);
            if (takeContentChanged()) {
                forceLoad();
            }
        }
    }

    @Override
    protected void onStopLoading() {
        cancelLoad();
    }



    @Override
    public void onCanceled(Cursor cursor) {
        if (cursor != null && !cursor.isClosed()) {
            cursor.close();
        }
    }

    @Override
    protected void onReset() {
        super.onReset();
        onStopLoading();
        if (cursor != null) {
            if (!cursor.isClosed()) {
                cursor.close();
            }
            cursor = null;
        }
    }

    /*
    You'll have to handle onChange() yourself since I removed the DaoObserver interface
    for it to be compatible with OrmLite 4.48
     */
    public void onChange() {
        onContentChanged();
    }

    public PreparedQuery<T> getQuery() {
        return query;
    }

    public void setQuery(PreparedQuery<T> mQuery) {
        this.query = mQuery;
    }
}