package org.datasurvey.config;

import static java.net.URLDecoder.decode;

import java.io.File;
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Paths;
import java.util.*;
import javax.servlet.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.web.server.*;
import org.springframework.boot.web.servlet.ServletContextInitializer;
import org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.core.env.Profiles;
import org.springframework.util.CollectionUtils;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;
import tech.jhipster.config.JHipsterConstants;
import tech.jhipster.config.JHipsterProperties;

/**
 * Configuration of web application with Servlet 3.0 APIs.
 */
@Configuration
public class WebConfigurer implements ServletContextInitializer, WebServerFactoryCustomizer<WebServerFactory> {

    private final Logger log = LoggerFactory.getLogger(WebConfigurer.class);

    private final Environment env;

    private final JHipsterProperties jHipsterProperties;

    public WebConfigurer(Environment env, JHipsterProperties jHipsterProperties) {
        this.env = env;
        this.jHipsterProperties = jHipsterProperties;
    }

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        if (env.getActiveProfiles().length != 0) {
            log.info("Web application configuration, using profiles: {}", (Object[]) env.getActiveProfiles());
        }

        log.info("Web application fully configured");
    }

    /**
     * Customize the Servlet engine: Mime types, the document root, the cache.
     */
    @Override
    public void customize(WebServerFactory server) {
        // When running in an IDE or with ./mvnw spring-boot:run, set location of the static web assets.
        setLocationForStaticAssets(server);
    }

    private void setLocationForStaticAssets(WebServerFactory server) {
        if (server instanceof ConfigurableServletWebServerFactory) {
            ConfigurableServletWebServerFactory servletWebServer = (ConfigurableServletWebServerFactory) server;
            File root;
            String prefixPath = resolvePathPrefix();
            root = new File(prefixPath + "target/classes/static/");
            if (root.exists() && root.isDirectory()) {
                servletWebServer.setDocumentRoot(root);
            }
        }
    }

    /**
     * Resolve path prefix to static resources.
     */
    private String resolvePathPrefix() {
        String fullExecutablePath;
        try {
            fullExecutablePath = decode(this.getClass().getResource("").getPath(), StandardCharsets.UTF_8.name());
        } catch (UnsupportedEncodingException e) {
            /* try without decoding if this ever happens */
            fullExecutablePath = this.getClass().getResource("").getPath();
        }
        String rootPath = Paths.get(".").toUri().normalize().getPath();
        String extractedPath = fullExecutablePath.replace(rootPath, "");
        int extractionEndIndex = extractedPath.indexOf("target/");
        if (extractionEndIndex <= 0) {
            return "";
        }
        return extractedPath.substring(0, extractionEndIndex);
    }

    @Bean
    public CorsFilter corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration config = jHipsterProperties.getCors();
        if (!CollectionUtils.isEmpty(config.getAllowedOrigins()) || !CollectionUtils.isEmpty(config.getAllowedOriginPatterns())) {
            log.debug("Registering CORS filter");
            source.registerCorsConfiguration("/api/**", config);
            source.registerCorsConfiguration("/management/**", config);
            source.registerCorsConfiguration("/v2/api-docs", config);
            source.registerCorsConfiguration("/v3/api-docs", config);
            source.registerCorsConfiguration("/swagger-resources", config);
            source.registerCorsConfiguration("/swagger-ui/**", config);
        }
        return new CorsFilter(source);
    }
}