/*
 * 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 io.prestosql.queryeditorui.resources;

import com.google.common.io.ByteStreams;
import com.google.inject.Inject;
import io.prestosql.queryeditorui.store.files.ExpiringFileStore;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.StreamingOutput;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;

@Path("/api/files")
public class FilesResource
{
    private final ExpiringFileStore fileStore;

    @Inject
    public FilesResource(ExpiringFileStore fileStore)
    {
        this.fileStore = fileStore;
    }

    @GET
    @Path("/{fileName}")
    @Produces(MediaType.APPLICATION_OCTET_STREAM)
    public Response getFile(@PathParam("fileName") String fileName)
    {
        final File file = fileStore.get(fileName);

        if (file == null) {
            return Response.status(Response.Status.NOT_FOUND).build();
        }
        else {
            return Response.ok(new StreamingOutput()
            {
                @Override
                public void write(OutputStream output)
                        throws IOException, WebApplicationException
                {
                    // TODO: Make this use chunked encoding?
                    try (FileInputStream inputStream = new FileInputStream(file)) {
                        ByteStreams.copy(inputStream, output);
                    }
                    finally {
                        output.close();
                    }
                }
            }).build();
        }
    }
}
