/**
 * This file is part of Graylog.
 *
 * Graylog is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Graylog is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Graylog.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.graylog2.shared.rest.resources.documentation;

import com.codahale.metrics.annotation.Timed;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.collect.ImmutableSet;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiParam;
import org.graylog2.plugin.BaseConfiguration;
import org.graylog2.plugin.rest.PluginRestResource;
import org.graylog2.rest.RestTools;
import org.graylog2.shared.plugins.PluginRestResourceClasses;
import org.graylog2.shared.rest.documentation.generator.Generator;
import org.graylog2.shared.rest.resources.RestResource;

import javax.inject.Inject;
import javax.inject.Named;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.HttpHeaders;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import static org.graylog2.shared.initializers.JerseyService.PLUGIN_PREFIX;

@Api(value = "Documentation", description = "Documentation of this API in JSON format.")
@Path("/api-docs")
public class DocumentationResource extends RestResource {

    private final Generator generator;
    private final BaseConfiguration configuration;

    @Inject
    public DocumentationResource(BaseConfiguration configuration,
                                 @Named("RestControllerPackages") String[] restControllerPackages,
                                 ObjectMapper objectMapper,
                                 PluginRestResourceClasses pluginRestResourceClasses) {

        this.configuration = configuration;

        final ImmutableSet.Builder<String> packageNames = ImmutableSet.<String>builder()
                .add(restControllerPackages);

        // All plugin resources get the plugin prefix + the plugin package.
        final Map<Class<?>, String> pluginRestControllerMapping = new HashMap<>();
        for (Map.Entry<String, Set<Class<? extends PluginRestResource>>> entry : pluginRestResourceClasses.getMap().entrySet()) {
            final String pluginPackage = entry.getKey();
            packageNames.add(pluginPackage);

            for (Class<? extends PluginRestResource> pluginRestResource : entry.getValue()) {
                pluginRestControllerMapping.put(pluginRestResource, pluginPackage);
            }
        }

        this.generator = new Generator(packageNames.build(), pluginRestControllerMapping, PLUGIN_PREFIX, objectMapper);
    }

    @GET
    @Timed
    @ApiOperation(value = "Get API documentation")
    @Produces(MediaType.APPLICATION_JSON)
    public Response overview() {
        return buildSuccessfulCORSResponse(generator.generateOverview());
    }

    @GET
    @Timed
    @ApiOperation(value = "Get detailed API documentation of a single resource")
    @Produces(MediaType.APPLICATION_JSON)
    @Path("/{route: .+}")
    public Response route(@ApiParam(name = "route", value = "Route to fetch. For example /system", required = true)
                          @PathParam("route") String route,
                          @Context HttpHeaders httpHeaders) {
        final String basePath = RestTools.buildEndpointUri(httpHeaders, configuration.getWebEndpointUri());
        return buildSuccessfulCORSResponse(generator.generateForRoute(route, basePath));
    }

    private Response buildSuccessfulCORSResponse(Map<String, Object> result) {
        return Response.ok(result)
                .header("Access-Control-Allow-Origin", "*") // Headers for Swagger UI.
                .header("Access-Control-Allow-Methods", "GET")
                .header("Access-Control-Allow-Headers", "Content-Type, api_key, Authorization")
                .build();
    }
}