package api;

import io.swagger.v3.jaxrs2.integration.resources.OpenApiResource;

import java.util.HashSet;
import java.util.Set;
import org.eclipse.jetty.rewrite.handler.RedirectPatternRule;
import org.eclipse.jetty.rewrite.handler.RewriteHandler;

import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.handler.InetAccessHandler;
import org.eclipse.jetty.servlet.DefaultServlet;
import org.eclipse.jetty.servlet.FilterHolder;
import org.eclipse.jetty.servlet.ServletContextHandler;
import org.eclipse.jetty.servlet.ServletHolder;
import org.eclipse.jetty.servlets.CrossOriginFilter;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.servlet.ServletContainer;

import settings.Settings;

public class ApiService {

	private final Server server;
	private final Set<Class<?>> resources;

	public ApiService() {
		// Resources to register
		this.resources = new HashSet<Class<?>>();
		this.resources.add(AddressesResource.class);
		this.resources.add(AdminResource.class);
		this.resources.add(AssetsResource.class);
		this.resources.add(BlocksResource.class);
		this.resources.add(NamesResource.class);
		this.resources.add(PaymentsResource.class);
		this.resources.add(TransactionsResource.class);
		this.resources.add(UtilsResource.class);

		this.resources.add(BlockExplorerResource.class); // block-explorer.html
		this.resources.add(OpenApiResource.class); // Swagger/OpenAPI
		this.resources.add(ApiDefinition.class); // API info
		this.resources.add(AnnotationPostProcessor.class); // For API resource annotations
		ResourceConfig config = new ResourceConfig(this.resources);

		// Create RPC server
		this.server = new Server(Settings.getInstance().getRpcPort());

		// IP address based access control
		InetAccessHandler accessHandler = new InetAccessHandler();
		for (String pattern : Settings.getInstance().getRpcAllowed()) {
			accessHandler.include(pattern);
		}
		this.server.setHandler(accessHandler);

		// URL rewriting
		RewriteHandler rewriteHandler = new RewriteHandler();
		accessHandler.setHandler(rewriteHandler);

		// Context
		ServletContextHandler context = new ServletContextHandler(ServletContextHandler.NO_SESSIONS);
		context.setContextPath("/");
		rewriteHandler.setHandler(context);

		FilterHolder filterHolder = new FilterHolder(CrossOriginFilter.class);
		filterHolder.setInitParameter("allowedOrigins", "*");
		filterHolder.setInitParameter("allowedMethods", "GET, POST");
		context.addFilter(filterHolder, "/*", null);

		// API servlet
		ServletContainer container = new ServletContainer(config);
		ServletHolder apiServlet = new ServletHolder(container);
		apiServlet.setInitOrder(1);
		context.addServlet(apiServlet, "/*");

		// Swagger-UI static content
		ClassLoader loader = this.getClass().getClassLoader();
		ServletHolder swaggerUIServlet = new ServletHolder("static-swagger-ui", DefaultServlet.class);
		swaggerUIServlet.setInitParameter("resourceBase", loader.getResource("resources/swagger-ui/").toString());
		swaggerUIServlet.setInitParameter("dirAllowed", "true");
		swaggerUIServlet.setInitParameter("pathInfoOnly", "true");
		context.addServlet(swaggerUIServlet, "/api-documentation/*");

		rewriteHandler.addRule(new RedirectPatternRule("/api-documentation", "/api-documentation/index.html")); // redirect to swagger ui start page
	}

	// XXX: replace singleton pattern by dependency injection?
	private static ApiService instance;

	public static ApiService getInstance() {
		if (instance == null) {
			instance = new ApiService();
		}

		return instance;
	}

	Iterable<Class<?>> getResources() {
		return resources;
	}

	public void start() {
		try {
			// Start server
			server.start();
		} catch (Exception e) {
			// Failed to start
			throw new RuntimeException("Failed to start API", e);
		}
	}

	public void stop() {
		try {
			// Stop server
			server.stop();
		} catch (Exception e) {
			// Failed to stop
		}
	}
}